• 06/01/11: Shuttle Endeavour ends final mission with smooth landing
• 05/31/11: Endeavour astronauts close payload bay doors, prep shuttle for landing
• 05/31/11: Entry flight director briefing; updated forecast
• 05/30/11: Astronauts test re-entry systems, prep for Wednesday landing
• 05/30/11: STORRM test complete
• 05/30/11: Shuttle Endeavour undocks from space station
• 05/29/11: Shuttle Endeavour set for undocking from space station
• 05/29/11: Shuttle crew preps for farewell, hatch closure
• 05/28/11: Astronauts work on CO2 scrubber, transfers
• 05/28/11: Update: Astronauts work on station maintenance
• 05/27/11: Realtime coverage of STS-134 EVA No. 4
• 05/26/11: Endeavour astronauts set for final spacewalk
• 05/26/11: Astronauts inspect heat shield; Kelly talks to Tucson media
• 05/25/11: Update: ISLE protocol worked flawlessly; Feustel's eye irritation blamed on dish washing soap
• 05/25/11: Update: Spacewalk No. 3 ends
• 05/25/11: Update: Feustel complains of eye irritation
• 05/25/11: Update: Second set of U.S.-to-Russian segment power cables connected
• 05/25/11: Update: Antenna wiring complete
• 05/25/11: Update: Video converter mounted on Zarya
• 05/25/11: Update: STS-134 spacewalk No. 3 begins
• 05/24/11: Shuttle crew helps out with station maintenance; preps for third spacewalk
• 05/23/11: Soyuz TMA-20 lands in Kazakhstan
• 05/23/11: Soyuz TMA-20 undocks from space station
• 05/23/11: Shuttle crew takes time off amid Soyuz undocking preps
• 05/22/11: Space station change of command on eve of Soyuz departure
• 05/22/11: Update: Spacewalk No. 2 ends
• 05/22/11: Update: Astronauts complete drive gear lubrication, cover installation
• 05/22/11: Update: Astronauts in home stretch of marathon spacewalk
• 05/22/11: Update: Solar array drive gear lubrication work continues; spacewalkers running about an hour behind schedule
• 05/22/11: Update: Bolt problem prompts change in plans for solar array drive mechanism lubrication
• 05/22/11: Update: Ammonia coolant recharge complete; bolt problem assessed
• 05/22/11: Update: STS-134 spacewalk No. 2 begins
• 05/22/11: Astronauts suit up for second spacewalk
• 05/21/11: MMT determines damaged tile no threat to safe re-entry
• 05/21/11: Pope Benedict XVI calls shuttle-station crew
• 05/21/11: Gouged heat shield tile inspected
• 05/21/11: Astronauts begin work to inspect damaged tile
• 05/20/11: NASA orders 'focused inspection' of heat shield damage
• 05/20/11: NASA, Russians agree on out-of-this-world photo op
• 05/20/11: Update: Spacewalk No. 1 ends
• 05/20/11: Update: Spacesuit sensor failure forces astronauts to skip antenna wiring
• 05/20/11: Update: Ammonia line set up and ready for use Sunday
• 05/20/11: Update: Spacewalkers complete experiment swap out
• 05/20/11: Update: Spacewalk begins
• 05/20/11: Astronauts prep for spacewalk
• 05/19/11: Engineers continue shuttle heat shield assessment
• 05/19/11: Mission status briefing; Ting says AMS operating flawlessly
• 05/19/11: Kelly says wife doing well after surgery
• 05/19/11: AMS attached to station; Ting congratulates shuttle crew
• 05/18/11: NASA assesses tile damage on shuttle Endeavour
• 05/18/11: Shuttle Endeavour docks with space station
• 05/17/11: Mission Management Team briefing; preliminary assessment shows Katrina-damaged external tank performed well during ascent
• 05/17/11: Heat shield inspection complete; adding Atlantis' final rollover; mission status briefing
• 05/16/11: Adding post-launch news conference; correcting spacewalk dates, landing time
• 05/16/11: Shuttle Endeavour rockets away on final mission
• 05/16/11: Forecasters monitor low clouds; tile ding repaired
• 05/16/11: Astronauts board shuttle Endeavour
• 05/16/11: Shuttle Endeavour fueled for launch
• 05/15/11: Thruster rain covers blow off; no impact to countdown
• 05/15/11: Forecast unchanged; 70 percent 'go' for Monday launch
• 05/14/11: Shuttle Endeavour cleared for Monday launch
• 05/15/11: Forecast unchanged; 70 percent 'go' for Monday launch
• 05/14/11: Shuttle Endeavour cleared for Monday launch
• 05/13/11: Shuttle countdown begins; favorable weather expected
• 05/12/11: Endeavour astronauts return to Florida to prep for Monday launch
• 05/09/11: NASA managers agree to press ahead for May 16 launch of shuttle Endeavour
• 05/06/11: Launch delayed to at least May 16
• 05/06/11: NASA managers reassess Endeavour launch date amid ongoing repair work
• 05/04/11: Failure analysis indicates possible external short circuit
• 05/02/11: Shuttle launch slips to May 10, possibly later
• 05/01/11: Launch delayed to at least May 8
• 05/01/11: NASA rules out Monday launch try; avionics swap-out ordered
• 04/30/11: Thermostats fail to respond in initial low-temperature tests; more troubleshooting planned
• 04/30/11: Shuttle engineers troubleshoot electrical glitch
• 04/29/11: President tours space center, meets with shuttle crew; engineers assess repair options
• 04/29/11: President Obama lands at Cape Canaveral
• 04/29/11: Launch delayed at least 72 hours; quotes and details
• 04/29/11: LAUNCH SCRUB!
• 04/29/11: Progress supply ship docks with space station
• 04/29/11: Weathering storms, Endeavour fueled for launch
• 04/29/11: Shuttle fueling begins; weather 70 percent 'go' for launch
• 04/28/11: Storm front slows, shuttle launch now 70 percent 'go'
• 04/27/11: Shuttle countdown on track; Giffords flies to Florida for launch
• 04/26/11: STS-134 mission preview
• 04/26/11: Endeavour astronauts arrive; countown begins
• 04/19/11: Shuttle Endeavour cleared for April 29 launch
• 04/09/11: Government shutdown averted in last-minute deal
• 04/07/11: NASA braces for possible government shutdown
• 04/04/11: Shuttle launch delayed to April 29
• 03/24/11: Kelly remains hopeful injured wife can attend shuttle launch
• 03/23/11: Kelly abruptly opts out of pre-flight media interviews
• 03/14/11: Worker killed in launch pad mishap
• 03/11/11: Shuttle Endeavour hauled to launch pad
• 02/28/11: Shuttle Endeavour hauled to VAB for March 10 rollout to pad
• 02/04/11: Kelly to resume training for April shuttle flight
• 01/13/11: Backup commander named to replace Kelly in near-term training
• 01/08/11: Reb. Gabrielle Giffords shot
• 09/28/10: External tank for February shuttle flight arrives at KSC
• 08/26/10: $2 billion space station particle detector delivered to KSC
• 07/08/10: External tank for final planned shuttle mission heads to Florida
• 07/06/10: United Space Alliance announces shuttle layoffs
• 07/01/10: Shuttle target dates reset for Nov. 1 and Feb. 26
• 06/22/10: NASA begins two-week review of proposed shuttle launch date changes

CBS NEWS Coverage of Breaking Space News

03:10 AM EDT, 06/01/11: Shuttle Endeavour ends final mission with smooth landing

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Signaling the beginning of the end for NASA's storied shuttle program, the Endeavour plunged back to Earth Wednesday, closing out its 25th and final flight and passing the baton to its sistership Atlantis, which was hauled to the launching pad a few hours earlier for blastoff July 8 on the program's final voyage.

With commander Mark Kelly and pilot Gregory Johnson at the controls, Endeavour dropped out of a moonless sky and into the glare of powerful xenon floodlights after a fiery descent from orbit, settling to a ghostly touchdown on runway 15 at 2:34:51 a.m. EDT (GMT-4).

Barreling down the 300-foot-wide landing strip at more than 200 mph, Johnson deployed a large red-and-white braking parachute, Kelly brought the nose down and Endeavour coasted to a stop on the runway centerline.

"Houston, Endeavour. Wheels stopped," Kelly radioed in a traditional call to Houston.

"One-hundred-twenty-two-million miles flown during 25 challenging space flights, your landing ends a vibrant legacy for this amazing vehicle that will long be remembered," astronaut Barry "Butch" Wilmore replied from mission control. "Welcome home, Endeavour."

"Thank you, Houston," Kelly said. "You know, the space shuttle is an amazing vehicle, to fly through the atmosphere, hit it at Mach 25, steer through the atmosphere like an airplane, land on a runway, it is really, really an incredible ship.

"On behalf of my entire crew, I want to thank every person who's worked to get this mission going and every person who's worked on Endeavour. It's sad to see her land for the last time, but she really has a great legacy."

While engineers and technicians swarmed around the orbiter for post-flight "safing," Kelly, Johnson, European Space Agency flight engineer Roberto Vittori and spacewalkers Michael Fincke, Gregory Chamitoff and Andrew Feustel were expected to doff their pressure suits and join senior NASA managers on the runway for a traditional walk-around inspection before departing for crew quarters and reunions with friends and family.

Before leaving the orbiter, Johnson shut down the ship's three hydraulic power units and a moment later, their fiery exhaust plumes flickered out for the last time, a poignant reminder the shuttle's flying days were over.

During the course of Endeavour's 16-day mission, Kelly and his crewmates attached a $2 billion cosmic ray detector to the International Space Station, installed a pallet of spare components, staged four spacewalks to conduct needed maintenance and helped the station crew repair a U.S. oxygen generator and a carbon dioxide scrubber.

Mission duration was 15 days 17 hours 38 minutes and 23 seconds, a voyage spanning 248 complete orbits and 6.5 million miles since blastoff May 16. Over the course of its 25-mission career, Endeavour logged 122,853,853 million miles, 4,671 orbits and 299 days in space, carrying the first and last U.S. components to the International Space Station.

A few miles from the shuttle runway, a powerful Apollo-era crawler-transporter was slowly moving Atlantis into position atop pad 39A after a six-hour 3.4-mile trip from NASA's Vehicle Assembly Building.

A throng of space center workers, many of them facing layoffs after Atlantis' flight, turned out to witness the last shuttle "rollout," cheering as the shuttle emerged into the light of powerful floodlights around 8:45 p.m. Tuesday. Atlantis' crew -- commander Christopher Ferguson, pilot Douglas Hurley, Rex Walheim and Sandra Magnus -- mingled with the crowd and chatted with reporters about the looming end of the shuttle program.

"It's going to be a long time until you see a vehicle roll out to the pad that looks as beautiful as that," Walheim said, pointing toward Atlantis. "How can you beat that? An airplane on the side of a rocket. It's absolutely stunning. So I think we lose a little bit of grace, of beauty, and also a little bit of majesty (when the shuttle fleet is retired).

"You can't watch that vehicle roll by without thinking what an amazing achievement America has, that America can build something like that, put people inside and sling them off this Earth into space. It's absolutely amazing."

With Atlantis on its way to the pad, Kelly and his crewmates closed Endeavour's 60-foot-long payload bay doors at 10:45 p.m. Two hours and 45 minutes later, at 1:29:03 a.m., Kelly and Johnson carried out a two-minute 38-second firing of the shuttle's orbital maneuvering system rockets, slowing the ship by about 201 mph to drop it out of orbit for an hourlong glide back to Florida.

After a half-hour free fall, Endeavour plunged into the discernible atmosphere at an altitude of about 76 miles. A few minutes later, the orbiter entered the zone of peak heating, experiencing temperatures of more than 3,000 degrees Fahrenheit on its reinforced carbon carbon nose cap and wing leading edge panels.

Approaching Florida from the southwest, Endeavour streaked high above the Yucatan Peninsula, across the Gulf of Mexico and then over the west coast of Florida above Naples, descending steeply toward the Kennedy Space Center.

Taking over manual control at an altitude of about 50,000 feet, Kelly guided Endeavour through a sweeping 245-degree left overhead turn to line up on runway 15, settling to a tire-smoking touchdown a few moments later.

Over the next few months, Endeavour, like the shuttle Discovery before it, will be decommissioned and prepared for museum display.

Discovery, which completed its last flight in March, is going to the Smithsonian National Air and Space Museum's Steven F. Udvar-Hazy Center near Washington while Endeavour is bound for the Los Angeles Science Center. Atlantis will remain in Florida and go on display at the Kennedy Space Center's visitors complex.

Engineers plan to load Atlantis' external tank with super cold propellants June 15 to make sure suspect rib-like stringers can withstand the rigors of fueling and launch. The stringers were beefed up in the wake of cracks found in a tank used by Discovery earlier this year and engineers do not expect any problems. But the fueling test was ordered to make sure.

If all goes well, Ferguson and his three crewmates will blast off at 11:38 a.m. on July 8 and dock with the International Space Station two days later.

The primary goal of the flight is to deliver critical supplies as a hedge against problems that might delay commercial cargo ships being developed to fill in for the shuttle after the fleet is retired. Combined with deliveries by Russian and European cargo ships, Atlantis will carry enough supplies to support the station's six-person crew through 2012.

Atlantis originally was intended to serve as a launch-on-need emergency rescue vehicle in case Endeavour's crew ran into problems that might prevent a safe reentry. But NASA managers ultimately decided to use the agency's final set of boosters and its last external tank to launch one last space station resupply mission.

To get around the need for a stand-by rescue shuttle, NASA decided to limit Atlantis' crew to four. If Atlantis runs into a major problem, Ferguson, Hurley, Walheim and Magnus will be able to rotate home aboard Russian Soyuz spacecraft, a slow-motion "rescue" that would take a full year to complete.

But Ferguson and his crew believe the shuttle workforce will do everything possible to make sure the program ends on a high note.

"This is a tried and true group of professionals and it has been nothing but ultra impressive to see a lot of people who are clearly at a crossroads in their lives ... stay so focused and motivated on the final mission," Ferguson said.

"They clearly have a vested interest in making sure that this mission goes off as successful as we do. I've seen absolutely no indication of any ill feelings toward NASA, toward the country. I think they're just elated to have been a part of this program for 30 years."

CBS NEWS Coverage of Breaking Space News

-- Posted at 11:40 PM EDT, 05/31/11: Endeavour astronauts close payload bay doors, prep shuttle for landing
-- Updated at 12:02 AM EDT, 06/01/11: Updating deorbit ignition time, burn duration; fixing typos

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Commander Mark Kelly and his five crewmates rigged the shuttle Endeavour for re-entry and landing early Wednesday to close out the orbiter's 25th and final mission, the next-to-last flight for NASA's iconic orbiter. With forecasters predicting good weather, Kelly and pilot Gregory Johnson planned to fire Endeavour's braking rockets at 1:29 a.m. EDT (GMT-4), setting up a landing at 2:35 a.m.

As recovery crews gathered at the Kennedy Space Center's 3-mile-long shuttle runway to welcome Endeavour back to Earth, another team of engineers began hauling the shuttle Atlantis to launch pad 39A for work to ready the ship for blastoff July 8 on the shuttle program's final flight.

Atlantis' crew -- commander Christopher Ferguson, pilot Douglas Hurley, flight engineer Rex Walheim and Sandra Magnus -- marveled at the view as the spaceplane, mounted atop a powerful crawler-transporter, rolled past a throng of spaceport workers who gathered near the Vehicle Assembly Building to witness NASA's last shuttle "rollout."

"It's going to be a long time until you see a vehicle roll out to the pad that looks as beautiful as that," Walheim said, pointing at Atlantis. "How can you beat that? An airplane on the side of a rocket. It's absolutely stunning. So I think we lose a little bit of grace, of beauty, and also a little bit of majesty (when the shuttle fleet is retired). You can't watch that vehicle roll by without thinking what an amazing achievement America has, that America can build something like that, put people inside and sling them off this Earth into space. It's absolutely amazing."

With Atlantis on its way, Kelly and his crewmates -- pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- closed Endeavour's 60-foot-long payload bay doors at 10:45 p.m.

The astronauts had two landing opportunities Wednesday, the first at 2:35 a.m. and the second one orbit later at 4:11 a.m. If the weather or some other problem prevents re-entry, the crew plans to stay in orbit an extra 24 hours and try again Thursday. In that case, NASA also would activate its backup landing site at Edwards Air Force Base, Calif., and bring Endeavour down on one coast or the other.

But mission managers were hopeful it would not come to that and if all goes well, Kelly and Johnson will oversee a two-minute 38-second firing of the shuttle's orbital maneuvering system rockets starting at 1:29:03 a.m., slowing the ship by about 200 mph to drop it out of orbit for an hourlong glide back to Florida.

After a half-hour free fall, Endeavour will plunge into the discernible atmosphere at an altitude of about 76 miles. Approaching Florida from the southwest, Endeavour will streak high above the Yucatan Peninsula, across the Gulf of Mexico and then over the west coast of Florida above Naples, descending steeply toward the Kennedy Space Center.

Taking over manual control at an altitude of about 50,000 feet, Kelly plans to guide Endeavour through a sweeping 245-degree left overhead turn to line up on runway 15. Touchdown is expected at 2:35 a.m.

This status report will be updated after landing or as warranted. In the meantime, here is an updated timeline of events for both of Endeavour's Florida landing opportunities (in EDT; best viewed with fixed-width font):

Rev. 248 deorbit to KSC
Deorbit dT: 2:38
Deorbit dV: 201 mph

EDT...........EVENT

09:29 PM......Begin deorbit timeline
09:44 PM......Radiator stow
09:54 PM......Astronaut seat installation
10:00 PM......Computers set for deorbit prep
10:04 PM......Hydraulic system configuration
10:29 PM......Flash evaporator cooling system checks
10:35 PM......Final payload deactivation
10:49 PM......Payload bay doors closed
10:59 PM......Mission control 'go' for OPS-3 software load
11:09 PM......OPS-3 transition
11:34 PM......Entry switchlist verification
11:44 PM......Deorbit maneuver update
11:49 PM......Crew entry review
12:04 AM......Commander/pilot don entry suits
12:21 AM......Inertial measurement unit alignment
12:29 AM......Commander/pilot strap in; mission specialists don suits
12:46 AM......Shuttle steering check
12:49 AM......Hydraulic system prestart
12:56 AM......Toilet deactivation

01:09 AM......Mission control 'go' for deorbit burn
01:15 AM......Mission specialists seat ingress
01:24 AM......Single hydraulic power unit start
       
01:29:03 AM...Deorbit ignition
01:31:41 AM...Deorbit burn complete

02:03:33 AM...Entry interface
02:08:33 AM...1st roll command to left
02:16:58 AM...1st roll left to right
02:22:23 AM...C-band radar acquisition
02:28:48 AM...Velocity less than mach 2.5
02:31:01 AM...Velocity less than mach 1
02:31:56 AM...Left turn to runway 15
02:35:23 AM...Landing


Rev. 249 deorbit to KSC
Deorbit dT: 02:39
Deorbit dV: 199.8 mph

02:46 AM......Mission control 'go' for deorbit burn
02:52 AM......Mission specialists seat ingress
03:01 AM......Single APU start
       
03:06:53 AM...Deorbit ignition
03:09:32 AM...Deorbit burn complete

03:39:18 AM...Entry interface
03:44:15 AM...1st roll command to left
03:58:07 AM...C-band radar acquisition
03:58:31 AM...1st left to right roll reversal
04:04:33 AM...Velocity less than mach 2.5
04:06:46 AM...Velocity less than mach 1
04:07:14 AM...Left turn to runway 15
04:11:07 AM...Landing

CBS NEWS Coverage of Breaking Space News

-- Posted at 11:47 PM EDT, 05/30/11: Astronauts test Endeavour's re-entry systems, prep for landing Wednesday
-- Updated at 05:10 AM EDT, 05/31/11: Entry flight director briefing; updated forecast

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The Endeavour astronauts tested the shuttle's re-entry systems overnight Monday and began packing up for landing early Wednesday to close out the orbiter's 25th and final voyage.

"After Endeavour comes to a stop on the runway, hopefully in Florida, it'll head off to a museum," commander Mark Kelly told CBS News in an orbital interview. "It's certainly bittersweet. The space shuttle's been the workhorse of the U.S. space program for better than 30 years now, so it'll be sad to see it retired. But we are looking forward to new spacecraft and new destinations and we're all excited about the future."

If all goes well, Kelly and pilot Gregory Johnson will fire Endeavour's braking rockets at 1:29 a.m. EDT (GMT-4) Wednesday, setting up a landing on runway 15 at the Kennedy Space Center around 2:35 a.m. to wrap up a 6.5-million-mile voyage spanning 16 days and 248 orbits. A second landing opportunity is available one orbit later, at 4:11 a.m.

Forecasters with the Spaceflight Meteorology Group at the Johnson Space Center in Houston have been concerned about possibly high crosswinds for the past several days. But the latest forecast issued Monday evening called for "go" conditions for both Florida landing opportunities with crosswinds below NASA's 12-knot limit for nighttime landings.

"The weather is looking very promising," entry Flight Director Tony Ceccacci told reporters early Tuesday. "The past few days, the forecasts have been showing crosswinds above our fight rule limits for a nighttime landing. What has happened is, this high that we've had has set up and we were able to get a good trend last night and this evening. We're very confident that trend's going to stay the same for tomorrow.

"Right now, the forecasts are scattered (clouds) at 2,500, we have winds coming out of zero-eight-zero at six (knots) peaking at 10, giving us a crosswind of 10 knots, which is far below what we were predicting a couple of days ago. We're feeling pretty good about where we're going tomorrow."

The forecast for NASA's backup landing site at Edwards Air Force Base, Calif., calls for good conditions with high-but-acceptable headwinds. But Endeavour has enough on-board supplies to stay in orbit three days past Wednesday and Ceccacci said NASA will not call up Edwards for the first landing opportunity.

If Endeavour does not get back to Florida on Wednesday, however, NASA will activate Edwards and bring the crew down Thursday on one coast or the other.

"Wednesday morning, we're going to be calling up KSC only," Ceccacci said. "If we did have to wave off, the end-of-mission-plus-one day would be pick 'em day. Even though we have the end-of-mission-plus-three capability, we decided just due to the duration of the mission it would probably be smart to get the crew down at end of mission plus one."

Monday night, Kelly, Johnson and fight engineer Roberto Vittori fired up one of Endeavour's hydraulic power units in a routine pre-entry test of the ship's fight control systems. They also test fired the shuttle's maneuvering thrusters before taking time out to practice landing procedures using a laptop flight simulator.

Kelly, Johnson, Vittori and spacewalkers Michael Fincke, Gregory Chamitoff and Andrew Feustel planned to go to bed at 9:56 a.m. Tuesday and to get back up at 5:56 p.m. to begin landing preparations.

Endeavour's flight has generated widespread interest because of the looming end of the shuttle program and because of the story of Arizona Rep. Gabrielle Giffords, Kelly's wife, who was gravely injured in an assassination attempt in January. Recovering in Houston,Giffords flew to Florida to watch Endeavour's launching and underwent successful surgery last week to replace part of her skull.

Kelly told CBS News Monday that it had been difficult being away from his wife and that he looked forward to landing Wednesday.

"Having her there for launch made it particularly important to me, to have her and Claudia and Claire, our two daughters there, it was really a special moment," he said. "After what happened to her Jan. 8, the fact that she was able to recover to the point to walk on the airplane, walk off, make the trip to Florida twice, it was really special.

"Being away from here, to be honest, it's difficult. Fortunately, there's a phone on the space station, there's email, we can communicate and I'm looking forward to getting back there tomorrow."

Updated re-entry timelines for both Wednesday landing opportunities are posted on the Flight Data File page.

With Endeavour's return to Earth, NASA's focus will shift to preparing the shuttle Atlantis for launch July 8 on the program's 135th and final mission. A few hours before Endeavour begins its descent, engineers at the Kennedy Space Center plan to begin hauling Atlantis to launch pad 39A to ready the ship for its final blastoff.

Here is an updated timeline of major events leading up to Endeavour's re-entry (in EDT and mission elapsed time; includes revision M of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT......DD...HH...MM...SS...EVENT

05/30
06:56:00 PM...14...10...00...00...STS crew wakeup
09:06:00 PM...14...12...10...00...CBS News/network interviews
10:01:00 PM...14...13...05...00...Flight control system checkout
11:11:00 PM...14...14...15...00...Reaction control system hotfire
11:26:00 PM...14...14...30...00...PILOT landing simulations

05/31
12:26:00 AM...14...15...30...00...Endeavour tribute downlink
12:56:00 AM...14...16...00...00...Crew meal
02:16:00 AM...14...17...20...00...Deorbit review
02:46:00 AM...14...17...50...00...Cabin stow begins
05:00:00 AM...14...20...04...00...Mission status briefing on NASA TV
05:46:00 AM...14...20...50...00...Ergometer stow
06:16:00 AM...14...21...20...00...Wing leading edge sensor deactivation
06:26:00 AM...14...21...30...00...L-1 comm check
06:30:00 AM...14...21...50...00...B-roll/astronaut Cady Coleman
06:36:00 AM...14...21...40...00...Laptop computer stow (part 1)
06:46:00 AM...14...21...50...00...Ku-band antenna stow
07:00:00 AM...14...22...04...00...Live interviews with Cady Coleman
09:56:00 AM...15...01...00...00...Crew sleep begins
11:00:00 AM...15...02...04...00...Daily video highlights reel on NASA TV
05:56:00 PM...15...09...00...00...Crew wakeup (begin flight day 17)
08:26:00 PM...15...11...30...00...Group B computer powerup
08:41:00 PM...15...11...45...00...Inertial measurement unit alignment
09:06:00 PM...15...12...10...00...Laptop computer stow (part 2)
09:26:00 PM...15...12...30...00...Deorbit timeline begins
10:49:00 PM...15...13...49...00...Payload bay door closing

06/01
01:29:43 AM...15...16...33...15...Deorbit ignition (rev. 248)
02:35:23 AM...15...17...38...55...Landing on runway 15, Kennedy Space Center

03:06:53 AM...15...18...10...25...Deorbit ignition (rev. 249)
04:11:07 AM...15...19...14...39...Landing on runway 15, Kennedy Space Center

CBS NEWS Coverage of Breaking Space News

11:50 PM EDT, 05/30/11: Astronauts test re-entry systems, prep for Wednesday landing

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The Endeavour astronauts tested the shuttle's re-entry systems overnight Monday and began packing up for landing early Wednesday to close out the orbiter's 25th and final voyage.

"After Endeavour comes to a stop on the runway, hopefully in Florida, it'll head off to a museum," commander Mark Kelly told CBS News in an orbital interview. "It's certainly bittersweet. The space shuttle's been the workhorse of the U.S. space program for better than 30 years now, so it'll be sad to see it retired. But we are looking forward to new spacecraft and new destinations and we're all excited about the future."

If all goes well, Kelly and pilot Gregory Johnson will fire Endeavour's braking rockets at 1:29 a.m. EDT (GMT-4) Wednesday, setting up a landing on runway 15 at the Kennedy Space Center around 2:35 a.m. to wrap up a 6.5-million-mile voyage spanning 16 days and 248 orbits. A second landing opportunity is available one orbit later, at 4:11 a.m.

Forecasters with the Spaceflight Meteorology Group at the Johnson Space Center in Houston have been concerned about possibly high crosswinds for the past several days. But the latest forecast issued Monday evening called for "go" conditions for both Florida landing opportunities, with scattered clouds at 2,000 feet and winds out of 70 degrees at 8 knots with gusts to 12. For runway 15, the crosswinds are expected to be just below NASA's 12-knot limit for night landings.

The forecast for NASA's backup landing site at Edwards Air Force Base, Calif., calls for good conditions with high-but-acceptable headwinds. But Endeavour has enough on-board supplies to stay in orbit three days past Wednesday and entry Flight Director Tony Ceccacci is not expected to call up Edwards for the first landing opportunity.

If Endeavour does not get back to Florida on Wednesday, however, NASA likely will activate Edwards and bring the crew down Thursday on one coast or the other.

"In general, we have what we call end-of-mission-plus-three capability, which is three full days of capability to extend beyond our planned end of mission day if we should need it," LeRoy Cain, chairman of NASA's Mission Management Team, said Monday afternoon. "Now, the plan that we talked about today is one whereby in all likelihood we'll be able to land (Wednesday), at least from a weather standpoint.

"If we're not able to, then we would in all likelihood call up Edwards and try to land at end of mission plus one. It's been a long mission ... and so it's unlikely we would use anything beyond EOM plus one."

Ceccacci plans to brief reporters on his landing strategy at 5 a.m. Tuesday. In the meantime, updated re-entry timelines are posted on the Flight Data File page.

Monday night, Kelly, Johnson and fight engineer Roberto Vittori fired up one of Endeavour's hydraulic power units in a routine pre-entry test of the ship's fight control systems. They also test fired the shuttle's maneuvering thrusters before taking time out to practice landing procedures using a laptop flight simulator.

Kelly, Johnson, Vittori and spacewalkers Michael Fincke, Gregory Chamitoff and Andrew Feustel planned to go to bed at 9:56 a.m. Tuesday and to get back up at 5:56 p.m. to begin landing preparations.

Endeavour's flight has generated widespread interest because of the looming end of the shuttle program and because of the story of Arizona Rep. Gabrielle Giffords, Kelly's wife, who was gravely injured in an assassination attempt in January. Recovering in Houston,Giffords flew to Florida to watch Endeavour's launching and underwent successful surgery last week to replace part of her skull.

Kelly told CBS News Monday that it had been difficult being away from his wife and that he looked forward to landing Wednesday.

"Having her there for launch made it particularly important to me, to have her and Claudia and Claire, our two daughters there, it was really a special moment," he said. "After what happened to her Jan. 8, the fact that she was able to recover to the point to walk on the airplane, walk off, make the trip to Florida twice, it was really special.

"Being away from here, to be honest, it's difficult. Fortunately, there's a phone on the space station, there's email, we can communicate and I'm looking forward to getting back there tomorrow."

With Endeavour's return to Earth, NASA's focus will shift to preparing the shuttle Atlantis for launch July 8 on the program's 135th and final mission. A few hours before Endeavour begins its descent, engineers at the Kennedy Space Center plan to begin hauling Atlantis to launch pad 39A to ready the ship for its final blastoff.

Here is an updated timeline for the final two days of Endeavour's mission (in EDT and mission elapsed time; includes revision M of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT......DD...HH...MM...SS...EVENT

05/30
06:56:00 PM...14...10...00...00...STS crew wakeup
09:06:00 PM...14...12...10...00...CBS News/network interviews
10:01:00 PM...14...13...05...00...Flight control system checkout
11:11:00 PM...14...14...15...00...Reaction control system hotfire
11:26:00 PM...14...14...30...00...PILOT landing simulations

05/31
12:26:00 AM...14...15...30...00...Endeavour tribute downlink
12:56:00 AM...14...16...00...00...Crew meal
02:16:00 AM...14...17...20...00...Deorbit review
02:46:00 AM...14...17...50...00...Cabin stow begins
05:00:00 AM...14...20...04...00...Mission status briefing on NASA TV
05:46:00 AM...14...20...50...00...Ergometer stow
06:16:00 AM...14...21...20...00...Wing leading edge sensor deactivation
06:26:00 AM...14...21...30...00...L-1 comm check
06:30:00 AM...14...21...50...00...B-roll/astronaut Cady Coleman
06:36:00 AM...14...21...40...00...Laptop computer stow (part 1)
06:46:00 AM...14...21...50...00...Ku-band antenna stow
07:00:00 AM...14...22...04...00...Live interviews with Cady Coleman
09:56:00 AM...15...01...00...00...Crew sleep begins
11:00:00 AM...15...02...04...00...Daily video highlights reel on NASA TV
05:56:00 PM...15...09...00...00...Crew wakeup (begin flight day 17)
08:26:00 PM...15...11...30...00...Group B computer powerup
08:41:00 PM...15...11...45...00...Inertial measurement unit alignment
09:06:00 PM...15...12...10...00...Laptop computer stow (part 2)
09:26:00 PM...15...12...30...00...Deorbit timeline begins
10:49:00 PM...15...13...49...00...Payload bay door closing

06/01
01:29:43 AM...15...16...33...15...Deorbit ignition (rev. 248)
02:35:23 AM...15...17...38...55...Landing on runway 15, Kennedy Space Center

03:06:53 AM...15...18...10...25...Deorbit ignition (rev. 249)
04:11:07 AM...15...19...14...39...Landing on runway 15, Kennedy Space Center

CBS NEWS Coverage of Breaking Space News

-- Posted 08:34 PM EDT, 05/29/11: Endeavour astronauts prep for undocking
-- Updated at 12:15 AM EDT, 05/30/11: Shuttle Endeavour undocks from space station
-- Updated at 01:00 AM EDT, 05/30/11: Adding photos
-- Updated at 05:30 AM EDT, 05/30/11: STORRM test complete
-- Updated at 07:30 AM EDT, 05/30/11: Mission status briefing

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The shuttle Endeavour undocked from the International Space Station for the 12th and final time late Sunday, backing away for a fly-around photo survey before moving back to within 1,000 feet or so to test navigation sensors and software intended for use in NASA's next generation manned spacecraft.

Sailing 220 miles above Bolivia, the shuttle's docking system disengaged its counterpart on the space station's forward port at 11:55 p.m. EDT (GMT-4) and the orbiter pulled away directly in front of the lab complex.

"Houston and station, we have physical separation," an astronaut radioed as the two spacecraft separated.

A few moments later, space station flight engineer Ronald Garan rang the ship's bell in the forward Harmony module and, following naval tradition, announced "Endeavour, departing. Fair winds and following seas, guys."

"Thanks, Ron. We appreciate all the help," shuttle commander Mark Kelly replied.

"It was a pleasure serving with you boys," Garan said.

Following standard practice, pilot Gregory Johnson was at the controls for undocking, guiding the shuttle to a point about 400 feet directly in front of the outpost before kicking off a slow 360-degree photo-survey fly around, looping up above, behind, below and back out in front of the laboratory at a distance of about 600 feet. A small rocket firing then put Endeavour on a trajectory carrying it back above and behind the station.

Kelly took over at that point to carry out a partial re-rendezvous to test navigation sensors and software developed for NASA's next-generation spacecraft, the Multi-Purpose Crew Vehicle.

"It's the first time we'll be doing a re-rendezvous with space station, and it's a different kind of rendezvous," Kelly said in a pre-launch NASA interview. "The plan is after we undock, we'll go out to about 400 feet, we'll do a fly-around like we normally do, and then when we come up back in front of the space station again, we're then going to do this series of burns where we're going to fall behind.

"Then we're going to come back in doing a profile that's actually quite similar to what Apollo used for a rendezvous. Instead of coming up on the R-bar, which is right underneath the space station, or the V-bar, which is the direction it's going, we're going to come up on a 45-degree angle from behind. The sensor (is a) more advanced laser system, cameras, that can give some very accurate range and range-rate data. ... So we're going to test that as we come up to the space station."

Designed for the Bush administration's Constellation moon program, the four-seat MPCV capsule, originally known as Orion, is being developed by NASA for future flights to a variety of deep space targets, including the moon, near-Earth asteroids and, eventually, Mars.

Known by an acronym that's a stretch by even NASA standards -- the Sensor Test for Orion Relative Navigation Risk Mitigation -- the STORRM sensor package is mounted in the shuttle's cargo bay. It includes a high-definition camera and a laser that flashes on and off 30 times a second to "illuminate" targets mounted on the space station.

By analyzing reflected laser light, STORRM software can compute the distance between the two spacecraft and their relative velocity.

The STORRM equipment was operated by astronaut Andrew Feustel during Endeavour's approach to the station May 18 and engineers said it worked well. Since then, the recorder used to store data from the high definition docking camera failed and the system did not boot up for the post-undocking rendezvous test.

Even so, Heather Hinkel, the STORRM principal investigator, said the laser system worked as expected during the re-rendezvous Monday.

"We were able to get (laser) data throughout the entire undock, re-rendzvous and final separation trajectory," she said. "The software performed flawlessly. We had no anomalies."

Including data collected during docking, the STORRM system collected nearly 600 gigabytes of data that will be analyzed in the coming weeks to assess the system's performance.

Shuttle Flight Director Gary Horlacher said Endeavour flew a near-perfect trajectory for the test, dropping back about 29,000 feet before beginning its re-approach to the station.

"We did the fly-around, got our standard photos of the entire outside of the space station," he said. "Once the fly-around was complete, the crew started the STORRM trajectory. All those burns went perfectly, the trajectory was right on the money and everything just went really, really well."

Coming back toward the space station, "we targeted 1,000 feet below and 300 feet behind," Horlacher said. "We got to about 950 feet from the space station and the trajectory stalled out, the crew did not have to do any braking pulses whatsoever and we just fell away. So again, the trajectory was right on the money."

Horlacher said before launch that STORRM represented "an outstanding way to take advantage of the spaceflight capabilities we have today with the shuttle and the space station to demonstrate new technologies that will be used for future spacecraft."

"This capability is being designed for Orion, but is absolutely applicable for any spacecraft doing dockings, in lunar orbit, in Mars orbit, anywhere," he said. "To me, it's a very significant progression of advancing technologies for future applications."

A final separation burn was carried out at 4:38 a.m. and Endeavour departed the area.

"Over the past year and a half, it's been a pleasure to work with the software and hardware developers for STORRM," Feustel radioed. "Everybody did a great job getting the components ready for flight and we look forward to continued development of this hardware and software and hope that it contributes to the development of future vehicles."

"Drew we appreciate your words," astronaut Megan McArthur replied from mission control. "We've got a room full of happy people down here. Thanks very much."

With the STORRM test complete, Kelly, Gregory, Feustel and their crewmates -- Michael Fincke, Gregory Chamitoff and European Space Agency astronaut Roberto Vittori -- planned to call it a day and go to bed at 10:56 a.m. They will test the shuttle's re-entry systems overnight Monday and to pack up early Tuesday. If all goes well, Kelly will guide Endeavour to a landing back at the Kennedy Space Center around 2:35 a.m. Wednesday.

A few miles away, engineers will be wrapping up rollout of the shuttle Atlantis to pad 39A for work to ready the ship for launch July 8 on NASA's 135th and final shuttle mission. Rollout is scheduled to begin at 8 p.m. Tuesday, a few hours before Endeavour's re-entry begins.

CBS NEWS Coverage of Breaking Space News

-- Posted 08:34 PM, 05/29/11: Endeavour astronauts prep for undocking
-- Updated at 12:15 AM, 05/30/11: Shuttle Endeavour undocks from space station

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The shuttle Endeavour undocked from the International Space Station for the 12th and final time late Sunday, backing away for a fly-around photo survey before moving back to within 1,000 feet or so to test navigation sensors and software intended for use in NASA's next generation manned spacecraft.

Sailing 220 miles above Bolivia, the shuttle's docking system disengaged its counterpart on the space station's forward port at 11:55 p.m. EDT (GMT-4) and the orbiter pulled away directly in front of the lab complex.

"Houston and station, we have physical separation," an astronaut radioed as the two spacecraft separated.

A few moments later, space station flight engineer Ronald Garan rang the ship's bell in the forward Harmony module and, following naval tradition, announced "Endeavour, departing. Fair winds and following seas, guys."

"Thanks, Ron. We appreciate all the help," shuttle commander Mark Kelly replied.

"It was a pleasure serving with you boys," Garan said.

Following standard practice, Endeavour pilot Gregory Johnson was at the controls for undocking, guiding the shuttle to a point about 400 feet directly in front of the outpost before kicking off a slow 360-degree photo-survey fly around, looping up above, behind, below and back out in front of the laboratory at a distance of about 600 feet. A small rocket firing was planned to put Endeavour on a trajectory carrying it back above and behind the station.

Kelly was expected to take over at that point to carry out a partial re-rendezvous to test navigation sensors and software developed for NASA's next-generation spacecraft, the Multi-Purpose Crew Vehicle.

"It's the first time we'll be doing a re-rendezvous with space station, and it's a different kind of rendezvous," Kelly said in a NASA interview. "The plan is after we undock, we'll go out to about 400 feet, we'll do a fly-around like we normally do, and then when we come up back in front of the space station again, we're then going to do this series of burns where we're going to fall behind.

"Then we're going to come back in doing a profile that's actually quite similar to what Apollo used for a rendezvous. Instead of coming up on the R-bar, which is right underneath the space station, or the V-bar, which is the direction it's going, we're going to come up on a 45-degree angle from behind. The sensor (is a) more advanced laser system, cameras, that can give some very accurate range and range-rate data. ... So we're going to test that as we come up to the space station."

Originally designed for the Bush administration's Constellation moon program, the four-seat MPCV capsule, known as Orion, is being developed by NASA for future flights to a variety of deep space targets, including the moon, near-Earth asteroids and, eventually, Mars.

Known by an acronym that's a stretch by even NASA standards -- the Sensor Test for Orion Relative Navigation Risk Mitigation -- the STORRM sensor package is mounted in the shuttle's cargo bay. It includes a high-definition camera and a laser that will flash on and off 30 times a second to "illuminate" targets mounted on the space station.

By analyzing reflected laser light, STORRM software can compute the distance between the two spacecraft and their relative velocity.

The STORRM equipment was astronaut Andrew Feustel during Endeavour's approach to the station May 18 and engineers said it worked well. Since then, the recorder used to store data from the high definition docking camera failed and the camera is not expected to be available for the post-undocking rendezvous test.

"It looks likely we won't be able to record any docking camera data for the undock and re-rendezvous," said Heather Hinkel, the principal investigator. "So that's a big disappointment to the STORRM team. We're really fortunate we got great data on rendezvous, we met about two thirds of our objectives already."

As for the post-undocking test, "whatever we get will be sufficient," she said. "The re-rendezvous was designed to meet the (laser scan) objectives. So we have our primary objective coming up at that long range on that re-rendezvous trajectory. ... We were fortunate that we got as much as we did (during Endeavour's approach to the station). We feel we'll have been able to assess enough to feel that camera will be a good camera to use for Orion."

Shuttle Flight Director Gary Horlacher said the STORRM laser system "will be taking data all the way out until the sensors drop lock outside 20,000 feet. Then we'll go ahead and do an orbit lowering burn, which is going to bring us down below the space station and get us set up for the trajectory to mimic the Orion approach to the space station."

That trajectory is "designed to have us stall out about 1,000 feet below and 300 feet behind the space station," Horlacher said. "And then orbital mechanics will pull us down and away. STORRM sensors will continue to take data until the sensors drop lock. And when we get outside that range, we'll go ahead and call the docked mission complete and then we'll get our nominal water dumps accomplished and get the ship prepared to come back home."

Horlacher said STORRM represents "an outstanding way to take advantage of the spaceflight capabilities we have today with the shuttle and the space station to demonstrate new technologies that will be used for future spacecraft."

"This capability is being designed for Orion, but is absolutely applicable for any spacecraft doing dockings, in lunar orbit, in Mars orbit, anywhere," he said. "To me, it's a very significant progression of advancing technologies for future applications."

A final separation burn is planned for 4:38 a.m. With the STORRM test complete, Kelly, Gregory, Feustel and their crewmates -- Michael Fincke, Gregory Chamitoff and European Space Agency astronaut Roberto Vittori -- will wrap up a busy day and go to bed at 10:56 a.m. They plan to test the shuttle's re-entry systems overnight Monday and to pack up early Tuesday. If all goes well, Kelly will guide Endeavour to a landing back at the Kennedy Space Center around 2:35 a.m. Wednesday.

A few miles away, engineers will be wrapping up rollout of the shuttle Atlantis to pad 39A for work to ready the ship for launch July 8 on NASA's 135th and final shuttle mission. Rollout is scheduled to begin at 8 p.m. Tuesday, a few hours before Endeavour's re-entry begins.

Here is an updated timeline of the crew's planned activities for flight days 14 and 15 (in EDT and mission elapsed time; includes revision L of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT...DD...HH...MM...SS...EVENT

05/29
11:55 PM...13...14...59...00...UNDOCKING
11:56 PM...13...15...00...40...ISS holds attitude

05/30
12:00 AM...13...15...04...00...50 ft: reselect -X jets
12:02 AM...13...15...06...00...75 ft: low-z jets
12:13 AM...13...15...17...09...Sunrise
12:22 AM...13...15...26...00...Start flyaround at 400 ft
12:31 AM...13...15...35...30...Range = 600 feet
12:33 AM...13...15...37...00...ISS maneuvers to TEA attitude
12:33 AM...13...15...37...30...Shuttle directly above ISS
12:40 AM...13...15...44...48...Noon
12:45 AM...13...15...49...00...Shuttle directly behind ISS
12:56 AM...13...16...00...30...Shuttle directly below ISS
01:08 AM...13...16...12...00...Shuttle directly in front of ISS
01:08 AM...13...16...12...00...Separation burn No. 1
01:08 AM...13...16...12...26...Sunset
01:16 AM...13...16...20...00...STORRM* timeline begins
01:36 AM...13...16...40...00...Separation burn No. 2
01:44 AM...13...16...48...43...Sunrise
02:12 AM...13...17...16...17...Noon
02:24 AM...13...17...28...30...Range greater than 19,000 feet
02:36 AM...13...17...40...39...NH2 STORRM rocket firing
02:39 AM...13...17...43...51...Sunset
02:50 AM...13...17...54...40...Iss maneuvers to DTO attitude
02:58 AM...13...18...02...40...MC5 STORRM rocket firing
03:15 AM...13...18...19...58...Sunrise
03:23 AM...13...18...27...40...NSR STORRM rocket firing
03:28 AM...13...18...32...40...Range less than 20,000 feet (closest approach)
03:37 AM...13...18...41...40...MC6 STORRM rocket firing
03:57 AM...13...19...01...40...TPI STORRM rocket firing
04:11 AM...13...19...15...14...Sunset
04:38 AM...13...19...42...40...Separation burn No. 3
04:47 AM...13...19...51...20...Sunrise
04:56 AM...13...20...00...00...Crew meals begin
05:05 AM...13...20...09...40...Range greater than 20,000 feet
05:56 AM...13...21...00...00...EVA unpack and stow
06:30 AM...13...21...34...00...Mission status briefing on NASA TV
07:16 AM...13...22...20...00...Maui DTO
07:26 AM...13...22...30...00...Post EVA entry preps
07:56 AM...13...23...00...00...Undocking video playback
08:01 AM...13...23...05...00...Group B computer powerdown
08:11 AM...13...23...15...00...ISS daily planning conference
10:56 AM...14...02...00...00...STS crew sleep begins
01:00 PM...14...04...04...00...Mission Management Team briefing on NASA TV
06:56 PM...14...10...00...00...STS crew wakeup
09:06 PM...14...12...10...00...CBS News/network crew interviews
10:01 PM...14...13...05...00...Flight control system checkout
11:11 PM...14...14...15...00...Reaction control system hotfire

* Sensor Test for Orion Relative Navigation Risk Mitigation

CBS NEWS Coverage of Breaking Space News

08:35 PM EDT, 05/29/11: Shuttle Endeavour set for undocking from space station

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The shuttle Endeavour's crew prepared for undocking from the International Space Station late Sunday to close out the orbiter's 12th and final visit to the sprawling lab complex.

Appropriately enough with the shuttle program down to its final two missions, the astronauts plan to test new navigation sensors and software after undocking to help engineers perfect a new system intended for use in NASA's Multi-Purpose Crew Vehicle, a four-seat capsule being developed for deep space exploration.

Commander Mark Kelly and his five crewmates -- pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- went to bed shortly before 11:30 a.m. EDT (GMT-4) Sunday after bidding the station's three-man crew farewell. The astronauts were awakened at 7:26 p.m. with a recording of "Slowness" by the Tucson band Calexico, beamed up for Kelly and his wife, Arizona Rep. Gabrielle Giffords.

"It's about two people on a trip reaching across the distance and it references places like Signal Hill and Gate's Pass and Tucson," Kelly said. "I know she really, really wants to get back there and is really looking forward to that. So it's an appropriate song because that's coming soon. Thanks."

With Johnson at the controls, Endeavour is scheduled to pull away from the space station's forward port at 11:55 p.m.

Following standard practice, Johnson will guide the shuttle to a point about 400 feet directly in front of the outpost before kicking off a slow 360-degree photo-survey fly around, looping up above, behind, below and back out in front of the laboratory at a distance of about 600 feet. A small rocket firing then will put Endeavour on a trajectory carrying it back above and behind the station.

Kelly then plans to take over for a partial re-rendezvous to test navigation sensors and software developed for NASA's next-generation spacecraft, the Multi-Purpose Crew Vehicle.

"It's the first time we'll be doing a re-rendezvous with space station, and it's a different kind of rendezvous," Kelly said in a NASA interview. "The plan is after we undock, we'll go out to about 400 feet, we'll do a fly-around like we normally do, and then when we come up back in front of the space station again, we're then going to do this series of burns where we're going to fall behind.

"Then we're going to come back in doing a profile that's actually quite similar to what Apollo used for a rendezvous. Instead of coming up on the R-bar, which is right underneath the space station, or the V-bar, which is the direction it's going, we're going to come up on a 45-degree angle from behind. The sensor (is a) more advanced laser system, cameras, that can give some very accurate range and range-rate data. ... So we're going to test that as we come up to the space station."

Originally designed for the Bush administration's Constellation moon program, the four-seat MPCV capsule, known as Orion, is being developed by NASA for future flights to a variety of deep space targets, including the moon, near-Earth asteroids and, eventually, Mars.

Known by an acronym that's a stretch by even NASA standards -- the Sensor Test for Orion Relative Navigation Risk Mitigation -- the STORRM sensor package is mounted in the shuttle's cargo bay. It includes a high-definition camera and a laser that will flash on and off 30 times a second to "illuminate" targets mounted on the space station.

By analyzing reflected laser light, STORRM software can compute the distance between the two spacecraft and their relative velocity.

The STORRM equipment was used during Endeavour's approach to the station May 18 and engineers said it worked well. Since then, the recorder used to store data from the high definition docking camera failed and the camera is not expected to be available for the post-undocking rendezvous test.

"It looks likely we won't be able to record any docking camera data for the undock and re-rendezvous," said Heather Hinkel, the principal investigator. "So that's a big disappointment to the STORRM team. We're really fortunate we got great data on rendezvous, we met about two thirds of our objectives already."

As for the post-undocking test, "whatever we get will be sufficient," she said. "The re-rendezvous was designed to meet the (laser scan) objectives. So we have our primary objective coming up at that long range on that re-rendezvous trajectory. ... We were fortunate that we got as much as we did (during Endeavour's approach to the station). We feel we'll have been able to assess enough to feel that camera will be a good camera to use for Orion."

Shuttle Flight Director Gary Horlacher said the STORRM laser system "will be taking data all the way out until the sensors drop lock outside 20,000 feet. Then we'll go ahead and do an orbit lowering burn, which is going to bring us down below the space station and get us set up for the trajectory to mimic the Orion approach to the space station."

That trajectory is "designed to have us stall out about 1,000 feet below and 300 feet behind the space station," Horlacher said. "And then orbital mechanics will pull us down and away. STORRM sensors will continue to take data until the sensors drop lock. And when we get outside that range, we'll go ahead and call the docked mission complete and then we'll get our nominal water dumps accomplished and get the ship prepared to come back home."

Horlacher said STORRM represents "an outstanding way to take advantage of the spaceflight capabilities we have today with the shuttle and the space station to demonstrate new technologies that will be used for future spacecraft."

"This capability is being designed for Orion, but is absolutely applicable for any spacecraft doing dockings, in lunar orbit, in Mars orbit, anywhere," he said. "To me, it's a very significant progression of advancing technologies for future applications."

A final separation burn is planned for 4:38 a.m. With the STORRM test complete, the Endeavour astronauts will wrap up a busy day and go to bed at 10:56 a.m. They plan to test the shuttle's re-entry systems overnight Monday and to pack up early Tuesday. If all goes well, Kelly will guide Endeavour to a landing back at the Kennedy Space Center around 2:35 a.m. Wednesday.

A few miles away, engineers will be wrapping up rollout of the shuttle Atlantis to pad 39A for work to ready the ship for launch July 8 on NASA's 135th and final shuttle mission. Rollout is scheduled to begin at 8 p.m. Tuesday, a few hours before Endeavour's re-entry begins.

Here is an updated timeline of the crew's planned activities for flight days 14 and 15 (in EDT and mission elapsed time; includes revision K of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT...DD...HH...MM...SS...EVENT

05/29
07:26 PM...13...10...30...00...STS/ISS crew wakeup
08:56 PM...13...12...00...00...ISS daily planning conference
10:11 PM...13...13...15...00...Group B computer powerup
10:46 PM...13...13...50...00...ISS maneuver to undocking attitude
11:11 PM...13...14...15...00...Undocking timeline begins
11:37 PM...13...14...41...02...Sunset
11:55 PM...13...14...59...00...UNDOCKING
11:56 PM...13...15...00...40...ISS holds attitude

05/30
12:00 AM...13...15...04...00...50 ft: reselect -X jets
12:02 AM...13...15...06...00...75 ft: low-z jets
12:13 AM...13...15...17...09...Sunrise
12:22 AM...13...15...26...00...Start flyaround at 400 ft
12:31 AM...13...15...35...30...Range = 600 feet
12:33 AM...13...15...37...00...ISS maneuvers to TEA attitude
12:33 AM...13...15...37...30...Shuttle directly above ISS
12:40 AM...13...15...44...48...Noon
12:45 AM...13...15...49...00...Shuttle directly behind ISS
12:56 AM...13...16...00...30...Shuttle directly below ISS
01:08 AM...13...16...12...00...Shuttle directly in front of ISS
01:08 AM...13...16...12...00...Separation burn No. 1
01:08 AM...13...16...12...26...Sunset
01:16 AM...13...16...20...00...STORRM* timeline begins
01:36 AM...13...16...40...00...Separation burn No. 2
01:44 AM...13...16...48...43...Sunrise
02:12 AM...13...17...16...17...Noon
02:24 AM...13...17...28...30...Range greater than 19,000 feet
02:36 AM...13...17...40...39...NH2 STORRM rocket firing
02:39 AM...13...17...43...51...Sunset
02:50 AM...13...17...54...40...Iss maneuvers to DTO attitude
02:58 AM...13...18...02...40...MC5 STORRM rocket firing
03:15 AM...13...18...19...58...Sunrise
03:23 AM...13...18...27...40...NSR STORRM rocket firing
03:28 AM...13...18...32...40...Range less than 20,000 feet (closest approach)
03:37 AM...13...18...41...40...MC6 STORRM rocket firing
03:57 AM...13...19...01...40...TPI STORRM rocket firing
04:11 AM...13...19...15...14...Sunset
04:38 AM...13...19...42...40...Separation burn No. 3
04:47 AM...13...19...51...20...Sunrise
04:56 AM...13...20...00...00...Crew meals begin
05:05 AM...13...20...09...40...Range greater than 20,000 feet
05:56 AM...13...21...00...00...EVA unpack and stow
06:30 AM...13...21...34...00...Mission status briefing on NASA TV
07:16 AM...13...22...20...00...Maui DTO
07:26 AM...13...22...30...00...Post EVA entry preps
07:56 AM...13...23...00...00...Undocking video playback
08:01 AM...13...23...05...00...Group B computer powerdown
08:11 AM...13...23...15...00...ISS daily planning conference
10:56 AM...14...02...00...00...STS crew sleep begins
01:00 PM...14...04...04...00...Mission Management Team briefing on NASA TV
06:56 PM...14...10...00...00...STS crew wakeup
09:06 PM...14...12...10...00...CBS News/network crew interviews
10:01 PM...14...13...05...00...Flight control system checkout
11:11 PM...14...14...15...00...Reaction control system hotfire

* Sensor Test for Orion Relative Navigation Risk Mitigation

CBS NEWS Coverage of Breaking Space News

-- Posted 03:16 AM EDT, 05/29/11: Shuttle crew preps for farewell, hatch closure
-- Updated at 08:00 AM EDT, 05/29/11: Mission status briefing; shuttle crew returns to Endeavour; hatches closed

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The Endeavour astronauts wrapped up last-minute experiment transfers early Sunday, bid farewell to the crew of the International Space Station and moved back aboard the shuttle to prepare the ship for undocking Sunday night.

Commander Mark Kelly thanked the three-man station crew for its hospitality, saying "we had a very successful mission."

"We got the Alpha Magnetic Spectrometer installed, which is really a remarkable thing for physics and for science," he said. "That sensor's already collecting massive amounts of data and we're looking forward to hearing what those discoveries are."

Kelly, pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori also delivered a pallet of spare parts, staged four spacewalks and helped service one of the station's oxygen generators and a carbon dioxide removal assembly.

"It was a really good 10 days or so that we were docked here," Kelly said. "We're looking forward to getting home, we're going to leave these guys to some peace and quiet and not disturb their space station anymore."

Thanks to a two-week launch delay, Endeavour arrived May 18 as three members of the station's 27th crew were winding up their mission. Outgoing commander Dimitry Kondratyev, Paolo Nespoli and Catherine Coleman departed and returned to Earth aboard a Russian Soyuz spacecraft on May 23, leaving Andrey Borisenko, Alexander Samokutyaev and Ronald Garan behind as the core members of the Expedition 28 crew. Three additional crew members -- Sergei Volkov, Michael Fossum and Satoshi Furukawa -- are expected to arrive June 9.

"It was really great seeing you guys," Garan told Kelly and his shuttle crewmates. "We were just in awe of the finely oiled machine that was STS-134. Great EVAs, great robotics, great transfer, AMS getting installed. Special thanks to Taz (Chamitoff) and Spanky (Fincke) for all your work on the oxygen generation system, on the carbon dioxide removal assembly. We're all looking forward to seeing the mysteries solved from the AMS.

"So on behalf of Expedition 27, Expedition 28, the entire ISS team, we want to thank you and the entire STS-134 mission team for leaving the space station ready for its continued utilization for at least the next decade. You've really left us in good shape and it was really a big success."

Added Borisenko, the Expedition 28 commander: "Thank you very much and soft landing."

After a final round of hugs and handshakes, the shuttle crew floated back aboard Endeavour. Chamitoff and Fincke, both veterans of long-duration stays aboard the station, pretended to stay behind and Feustel playfully pulled them back. The main hatch between the two spacecraft was closed at 7:23 a.m. EDT (GMT-4).

Kelly and his crewmates were scheduled to go to bed at 11:26 a.m. and to get back up at 7:26 p.m. to prepare for undocking four-and-a-half hours later, 11:55 p.m. Johnson plans to guide Endeavour through a 360-degree loop around the station before turning over control to Kelly, who will oversee a partial re-rendezvous, approaching to within about 1,000 feet of the lab complex to test new docking sensor technology being developed for NASA's deep space exploration capsule, the Multi-Purpose Crew Vehicle.

The astronauts plan to test Endeavour's re-entry systems overnight Monday and to pack up early Tuesday for landing back at the Kennedy Space Center around 2:35 a.m. Wednesday.

Here is an updated timeline of the crew's planned activities for flight days 14 and 15 (in EDT and mission elapsed time; includes revision K of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT...DD...HH...MM...SS...EVENT

05/29
08:46 AM...12...23...50...00...ISS daily planning conference
10:56 AM...13...02...00...00...ISS crew sleep begins
11:26 AM...13...02...30...00...STS crew sleep begins
01:00 PM...13...04...04...00...Daily video highlights reel on NASA TV
07:26 PM...13...10...30...00...STS/ISS crew wakeup
08:56 PM...13...12...00...00...ISS daily planning conference
10:11 PM...13...13...15...00...Group B computer powerup
10:46 PM...13...13...50...00...ISS maneuver to undocking attitude
11:11 PM...13...14...15...00...Undocking timeline begins
11:37 PM...13...14...41...02...Sunset

11:55 PM...13...14...59...00...UNDOCKING

11:56 PM...13...15...00...00...Initial separation
11:56 PM...13...15...00...40...ISS holds attitude

05/30
12:00 AM...13...15...04...00...50 ft: reselect -X jets
12:02 AM...13...15...06...00...75 ft: low-z jets
12:13 AM...13...15...17...09...Sunrise
12:22 AM...13...15...26...00...Start flyaround at 400 ft
12:31 AM...13...15...35...30...Range = 600 feet
12:33 AM...13...15...37...00...ISS maneuvers to TEA attitude
12:33 AM...13...15...37...30...Shuttle directly above ISS
12:40 AM...13...15...44...48...Noon
12:45 AM...13...15...49...00...Shuttle directly behind ISS
12:56 AM...13...16...00...30...Shuttle directly below ISS
01:08 AM...13...16...12...00...Shuttle directly in front of ISS
01:08 AM...13...16...12...00...Separation burn No. 1
01:08 AM...13...16...12...26...Sunset
01:16 AM...13...16...20...00...STORRM* timeline begins
01:36 AM...13...16...40...00...Separation burn No. 2
01:44 AM...13...16...48...43...Sunrise
02:12 AM...13...17...16...17...Noon
02:24 AM...13...17...28...30...Range greater than 19,000 feet
02:36 AM...13...17...40...39...NH2 STORRM rocket firing
02:39 AM...13...17...43...51...Sunset
02:50 AM...13...17...54...40...Iss maneuvers to DTO attitude
02:58 AM...13...18...02...40...MC5 STORRM rocket firing
03:15 AM...13...18...19...58...Sunrise
03:23 AM...13...18...27...40...NSR STORRM rocket firing
03:28 AM...13...18...32...40...Range less than 20,000 feet (closest approach)
03:37 AM...13...18...41...40...MC6 STORRM rocket firing
03:57 AM...13...19...01...40...TPI STORRM rocket firing
04:11 AM...13...19...15...14...Sunset
04:38 AM...13...19...42...40...Separation burn No. 3
04:47 AM...13...19...51...20...Sunrise
04:56 AM...13...20...00...00...Crew meals begin
05:05 AM...13...20...09...40...Range greater than 20,000 feet
05:56 AM...13...21...00...00...EVA unpack and stow
06:30 AM...13...21...34...00...Mission status briefing on NASA TV
07:16 AM...13...22...20...00...Maui DTO
07:26 AM...13...22...30...00...Post EVA entry preps
07:56 AM...13...23...00...00...Undocking video playback
08:01 AM...13...23...05...00...Group B computer powerdown
08:11 AM...13...23...15...00...ISS daily planning conference
10:56 AM...14...02...00...00...STS crew sleep begins
01:00 PM...14...04...04...00...Mission Management Team briefing on NASA TV
06:56 PM...14...10...00...00...STS crew wakeup
09:06 PM...14...12...10...00...CBS News/network crew interviews
10:01 PM...14...13...05...00...Flight control system checkout
11:11 PM...14...14...15...00...Reaction control system hotfire

* Sensor Test for Orion Relative Navigation Risk Mitigation

CBS NEWS Coverage of Breaking Space News

-- Posted at 03:01 AM EDT, 05/28/11: Astronauts work on CO2 scrubber, transfers
-- Updated at 11:00 AM EDT, 05/28/11: Mission status briefing

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The shuttle Endeavour's crew helped out with repairs to one of the International Space Station's carbon dioxide scrubbers Saturday, packed up spacesuits and other EVA gear for return to Earth and transferred equipment and supplies to and from the lab complex as NASA's next-to-last shuttle mission moved into the home stretch.

At mission control in Houston, flight controllers marvled at spectacular photos of Endeavour and the International Space Station that were captured during a spacewalk Friday by astronauts Michael Fincke and Gregory Chamitoff:

http://spaceflight.nasa.gov/gallery/images/shuttle/sts-134/html/iss028e005634.html

http://spaceflight.nasa.gov/gallery/images/shuttle/sts-134/html/iss028e005638.html

Fincke and Chamitoff, both veterans of previous long-duration stays aboard the space station, spent the day Saturday replacing a CO2-absorbing cartridge, or bed, in one of the station's two U.S. carbon dioxide removal assemblies. The unit was pulled out of its rack in the Tranquility module earlier in the mission.

"One of the critical items we wanted to get repaired is the carbon dioxide removal assembly, or CDRA," said Flight Director Derek Hassmann. "It's a piece of hardware that wasn't necessarily engineered or designed to be repaired on orbit, but over the last several years we've had a number of different issues with the unit and we've come a long way in terms of our ability to repair CDRA on orbit."

Using the roomy Japanese Kibo laboratory, Fincke and Chamitoff worked through a complicated procedure to remove the CO2-absorbing cartridge and install a replacement.

"Everything went back where it was supposed to," Fincke reported toward the end of the crew's day. "We're very optimistic this is going to work out very nicely after we install it tomorrow."

"You guys have done a great job, we sure appreciate all the hard work you've done all day today," radioed Lucia McCullough from mission control.

"Like we said at the beginning of the day, we feel very honored ... to be treated like station crew members and getting the job done," Fincke said. "The can-do crew is back."

Fincke, veteran of two earlier long-duration stays aboard the space station, set a new U.S. record for space endurance Friday evening, chalking up his 377th day in orbit during three missions.

Fincke now stands at 20th on the list of most experienced space fliers behind 19 Russian cosmonauts led by Sergei Krikalev, who has logged 803 days in space during six missions. Assuming Endeavour lands Wednesday as planned, Fincke will pass cosmonaut Pavel Vinogradov and move into a tie with cosmonaut Valery Korzun for the 18th spot with 382 days off planet.

Along with work to repair the CDRA, the astronauts also prepared two spacesuits for transfer back to Endeavour and set up another for incoming station flight engineer Michael Fossum, scheduled to arrive aboard a Soyuz spacecraft next month.

"In addition to the CDRA work and transfer, we also did a lot of work in the joint airlock," Hassmann said. "One of the things we have to do on every shuttle mission is get the shuttle crew's spacesuits ready for return on the orbiter. For this particular mission, Drew Feustel and Mike Fincke are the designated astronauts who would perform (an emergency) spacewalk is one was required after undock. So one of the things we have to do toward the end of each of these missions is to prepare their spacesuits for return on the shuttle."

The astronauts were scheduled to go to bed just before noon EDT (GMT-4). Wakeup is planned for 7:56 p.m. The combined crews will work overnight to wrap up equipment and experiment transfers to the shuttle before holding a traditional farewell ceremony and closing hatches between the station and the shuttle shortly after 7 a.m.

If all goes well, Endeavour will undock just before midnight Sunday, setting up a landing back at the Kennedy Space Center around 2:35 a.m. Wednesday to close out the shuttle's 25th and final flight.

CBS NEWS Coverage of Breaking Space News

03:20 AM EDT, 05/28/11 Update: Astronauts work on station maintenance

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The shuttle Endeavour's crew helped out with repairs to one of the International Space Station's carbon dioxide scrubbers Saturday, packed up spacesuits and other EVA gear and transferred equipment and supplies to and from the lab complex as NASA's next-to-last shuttle mission moved into the home stretch.

Endeavour spacewalker Michael Fincke, veteran of two earlier long-duration stays aboard the space station, set a new U.S. record for space endurance Friday evening, chalking up his 377th day in orbit during three missions.

Fincke now stands at 20th on the list of most experienced space fliers behind 19 Russian cosmonauts led by Sergei Krikalev, who has logged 803 days aloft during six missions. Assuming Endeavour lands Wednesday morning as planned, Fincke will pass cosmonaut Pavel Vinogradov and move into a tie with cosmonaut Valery Korzun for the 18th spot with 382 days off planet.

Fincke and crewmate Gregory Chamitoff spent the morning working on a carbon dioxide removal assembly, or CDRA, that was pulled out of the Tranquility module earlier. The complex devices use desiccant beds to condition incoming air before it is passed through absorbent beds to remove CO2. A replacement for one of the beds in the Tranquility CDRA was carried aloft aboard Endeavour.

Shuttle pilot Gregory Johnson plans to discuss the mission with reporters starting at 8:46 a.m. EDT (GMT-4), followed by a mission status briefing at 9:30 a.m. The astronauts are scheduled to go to bed a few minutes before noon.

Here is an updated timeline of the crew's planned activities (in EDT and mission elapsed time; includes revision K of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT...DD...HH...MM...SS...EVENT

05/27
07:56 PM...11...11...00...00...STS/ISS crew wakeup
10:16 PM...11...13...20...00...PAO event
11:06 PM...11...14...10...00...Post EVA spacesuit reconfig
10:56 PM...11...14...00...00...Carbon dioxide removal assembly (CDRA) bed replacement

05/28
02:56 AM...11...18...00...00...Crew meals begin (start flight day 13)
04:01 AM...11...19...05...00...Frame install
04:21 AM...11...19...25...00...Middeck transfers
08:46 AM...11...23...50...00...Johnson interviews on NASA TV
09:11 AM...12...00...15...00...ISS daily planning conference
09:30 AM...12...00...34...00...Mission status briefing on NASA TV
11:26 AM...12...02...30...00...ISS crew sleep begins
11:56 AM...12...03...00...00...STS crew sleep begins
01:00 PM...12...04...04...00...Daily video highlights reel on NASA TV
04:45 PM...12...07...49...00...Flight director update on NASA TV
06:45 PM...12...09...49...00...Flight director update replay on NASA TV
07:56 PM...12...11...00...00...STS crew wakeup

CBS NEWS Coverage of Breaking Space News

08:10 AM EDT, 05/27/11: Realtime coverage of STS-134 EVA No. 4

By WILLIAM HARWOOD
CBS News/Kennedy Space Center

08:10 AM EDT, 05/27/11 Update: STS-134 EVA No. 4 ends

Astronauts Michael Fincke and Gregory Chamitoff attached the shuttle Endeavour's heat shield inspection boom to the International Space Station Friday, completing the U.S. segment of the orbital lab complex after 12 years of construction and more than 1,000 hours of spacewalk assembly time.

Pausing to snap a final few pictures before returning to the Quest airlock, Chamitoff marked the milestone with a brief tribute to Endeavour, the shuttle and station programs and the thousands of engineers and technicians around the world who contributed to the high-flying project.

"At this time, now that we're almost done here, I wanted to say a few words," he said. "This is the last flight of the space shuttle Endeavour and it's also the last spacewalk of shuttle crew members in station assembly. It's kind of fitting that Endeavour is here because Endeavour was the first shuttle∫ to begin construction of the station and so it's fitting that she's here for the last mission to finish assembly.

"During this EVA, we tallied altogether collectively over a thousand hours of spacewalks as part of station assembly. Mike and I have the honor here to share this last spacewalk and of course, with all the folks working on the ground, the thousands of people who helped build this, working in the shuttle and the station programs. We're floating here on the shoulders of giants. This space station is a pinnacle of human achievement and international cooperation -- 12 years of building and 15 countries. And now it's the brightest star in the sky and hopefully the doorstep to our future. So congratulations everybody on assembly complete."

The Russians plan to add at least one more module to the station, a laboratory called Nauka that will take the place of the Pirs docking compartment in 2011 or 2012. Thirteen Russian spacewalks are planned to decommission and undock Pirs and to attach the new multi-purpose lab module.

Chamitoff and FIncke began repressurizing the station's Quest airlock compartment at 7:39 a.m. EDT (GMT-4) to officially conclude a seven-hour-hour 24-minute spacewalk, the 159th EVA devoted to station assembly and maintenance since construction began in 1998, the eighth so far this year and the fourth and final excursion planned by Endeavour's crew. Total space station EVA time now stands at 1,002 hours and 37 minutes, or 41.8 days.

It was the ninth spacewalk for Fincke, who now ranks as the sixth most experience spacewalker in the world with 48 hours and 37 minutes of EVA time, and the second for Chamitoff, whose total stands at 13 hours and 43 minutes. The total for Endeavour's mission through four EVAs is 28 hours and 44 minutes.

The primary goal of the final shuttle spacewalk was to attach Endeavour's no-longer-needed heat shield inspection boom to the space station and to attach a grapple fixture that will permit the lab's robot arm to use it as a 50-foot-long extension for future maintenance and repairs. The astronauts also released clamps on a spare robot arm fitting.

"I wanted to say congratulations to the shuttle program for all the wonderful successes we've had over the past 30-something years," Fincke said in the airlock. "It's a privilege that Endeavour's hosting the last spacewalk by a space shuttle crew. So congratulations to the EVA development teams. We've come a long way. From me and Greg and the rest of the crew, congratulations."

The shuttle Atlantis is scheduled for launch July 8 on the 135th and final shuttle mission to deliver critical supplies to the outpost. One spacewalk is planned, to retrieve a failed coolant system pump and to install an experiment, but it will be carried out by space station crew members.

12:40 AM EDT, 05/27/11 Update: STS-134 EVA No. 4 begins

Floating in the International Space Station's Quest airlock, astronauts Michael Fincke and Gregory Chamitoff switched their spacesuits to battery power at 12:15 a.m. EDT (GMT-4) to officially kick off a planned six-and-a-half-hour spacewalk, the fourth and final excursion planned for the shuttle Endeavour's mission.

The first major objective of today's EVA is to mount the shuttle's no-longer-needed heat shield inspection boom on the space station's solar power truss, giving the lab's robot arm a 50-foot-long extension for use during future maintenance and repair work.

This is the 159th spacewalk devoted to station assembly and maintenance since construction began in 1998, the eighth so far this year, the fourth and final EVA planned by the Endeavour astronauts, the ninth for Fincke and the second for Chamitoff.

CBS NEWS Coverage of Breaking Space News

08:36 PM EDT, 05/26/11 Endeavour astronauts set for final spacewalk

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Astronauts Michael Fincke and Gregory Chamitoff geared up Thursday for a planned six-and-a-half-hour spacewalk early Friday, the fourth and final excursion planned by the Endeavour astronauts and the last space station EVA to be carried out by a visiting shuttle crew.

The spacewalk, the 159th devoted to station assembly and maintenance since construction began in 1998, is scheduled to get underway around 12:46 a.m. EDT (GMT-4) when Fincke and Chamitoff switch their spacesuits to battery power.

In a pair of space milestones, Fincke and Chamitoff expect to push total space station EVA assembly time past the 1,000-hour mark -- the total stood at 995 hours and 13 minutes through 158 previous spacewalks -- and later today, Fincke will become the most experienced U.S. astronaut with more than 377 days in space during Endeavour's mission and two earlier long-duration space station expeditions.

Fincke will eclipse the previous U.S. record, held by chief astronaut Peggy Whitson, around 7 p.m. Friday, replacing her at 20th on the list of most experienced space fliers behind 19 Russians led by Sergei Krikalev, who has logged 803 days in space across six missions. Assuming Endeavour lands June 1 as planned, Fincke will pass cosmonaut Pavel Vinogradov and move into a tie with cosmonaut Valery Korzun for the 18th spot with 382 days off planet.

For identification, Fincke, call sign EV-1, will be wearing an unmarked spacesuit for today's EVA while Chamitoff, EV-3, will be wearing a suit with broken red stripes around the legs.

The primary goal of the spacewalk is to mount Endeavour's no-longer-needed 50-foot-long heat shield inspection boom on the front of the space station's power truss so it will be available after the shuttle fleet is retired to give lab crews additional reach when using the station's robot arm for maintenance or repairs.

To clear the way for the transfer, Endeavour's crew used the boom early Thursday to carry out a final inspection of the shuttle's heat shield to make sure the ship's nose cap and wing leading edge panels have not suffered any damage since a similar inspection the day after launch.

After exiting the space station's Quest airlock, Fincke and Chamitoff will set up foot restraints on the power truss and Endeavour pilot Gregory "Box" Johnson, operating the station's robot arm, will hand the boom to the two spacewalkers. After manually mounting the boom on attachment fixtures, Fincke will disconnect electrical cables leading to a no-longer-needed laser scanner and heat shield inspection camera.

Then they will remove the grapple fixture on the other end of the boom that was used by the shuttle's robot arm and replace it with a fixture designed for the station arm.

"That boom will be left behind on the space station with the idea that at some point if the space station has to do some work, it would give the robotic arm more reach if it could use this boom as well," Chamitoff said in a NASA interview. "We have left it up there before, we have the mechanisms in place to leave it up there.

"We'll be attaching that boom to the truss, locking it in place. Normally the shuttle arm grabs that boom at the end, and the station arm has a grapple fixture in the middle. But if we're going to use it on the station at some future point, you want to be able to grab it from the end. The grapple fixture at the end is not the right kind and we have to change it,so it'll be kind of fun for Mike.

"Because we're kind of tearing this thing apart in a way, we're taking off that end, replacing it with a station grapple fixture, and we have to cut some wires and pull this thing off completely and while we're doing that I'll be on the station robotic arm and Box will be flying me around. That'll be an exciting task to do."

After a few other minor maintenance tasks, Fincke and Chamitoff will call it a day. A mission status briefing is planned for 9 a.m.

Here is an updated timeline of the crew's planned activities for flight day 12 (in EDT and mission elapsed time; includes revision I of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT...DD...HH...MM...SS...EVENT

05/26
07:56 PM...10...11...00...00...Crew wakeup (begin flight day 12)
08:56 PM...10...12...00...00...EVA-3: Hygiene break
09:21 PM...10...12...25...00...EVA-3: Crew lock depress to 10.2 psi
09:41 PM...10...12...45...00...EVA-3: Campout EVA prep
09:46 PM...10...12...50...00...ISS daily planning conference
11:11 PM...10...14...15...00...EVA-3: Spacesuit purge
11:26 PM...10...14...30...00...EVA-3: Spacesuit pre-breathe

05/27
12:16 AM...10...15...20...00...EVA-3: Crew lock depressurization
12:41 AM...10...15...45...00...Station arm (SSRMS) grapples inspection boom (OBSS)
12:46 AM...10...15...50...00...EVA-4: Spacesuits to battery power
12:51 AM...10...15...55...00...EVA-4: Egress and setup
12:51 AM...10...15...55...00...Shuttle arm (SRMS) ungrapples OBSS
01:16 AM...10...16...20...00...SSRMS moves OBSS to stow
01:21 AM...10...16...25...00...EVA-4: OBSS stow on station truss
02:16 AM...10...17...20...00...EVA-4: P6 power and data grapple fixture retrieve
03:41 AM...10...18...45...00...EVA-4/EV-2: OBSS EFGF/PDFG swap
03:41 AM...10...18...45...00...EVA-4/EV-1: OBSS EFGF/PDFG swap
05:01 AM...10...20...05...00...EVA-4/EV-1: Stow ETGF in TSA
05:21 AM...10...20...25...00...EVA-4/EV-2: OTP inspection
05:36 AM...10...20...40...00...EVA-4: ELC-3 Dexrre arm release
06:46 AM...10...21...50...00...EVA-4: Cleanup and ingress
07:16 AM...10...22...20...00...EVA-4: Airlock repressurization
07:31 AM...10...22...35...00...Spacesuit servicing
07:31 AM...10...22...35...00...SRMS powerdown
09:00 AM...11...00...04...00...Mission status briefing on NASA TV
09:11 AM...11...00...15...00...ISS daily planning conference
11:26 AM...11...02...30...00...ISS crew sleep begins
11:56 AM...11...03...00...00...STS crew sleep begins
01:00 PM...11...04...04...00...Daily video highlights reel on NASA TV
04:00 PM...11...07...04...00...MMT briefing on NASA TV
04:45 PM...11...07...49...00...Flight director update on NASA TV
06:45 PM...11...09...49...00...Flight director update replayon NASA TV
07:56 PM...11...11...00...00...Crew wakeup

CBS NEWS Coverage of Breaking Space News

06:58 AM EDT, 05/26/11 Astronauts inspect heat shield; Kelly talks to Tucson media

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The Endeavour astronauts carried out a final inspection of the shuttle's heat shield early Thursday, fielded questions from reporters and geared up for a fourth and final spacewalk Friday, an excursion that will push EVA assembly time past the 1,000-hour mark.

Endeavour commander Mark Kelly told reporters in Tucson that his wife, Arizona Rep. Gabrielle Giffords, is recovering from surgery to replace part of her skull and "she sounds really good, very upbeat."

Giffords was shot in the head Jan. 8 during an assassination attempt that left six dead and more than a dozen wounded. A federal judge ruled Wednesday that Jared Loughner, the accused gunman, is not mentally competent to stand trial, ordering treatment and additional assessments at a federal psychiatric facility.

Asked about his perspective on the tragedy from the vantage point of space, Kelly said "it is an incredibly striking and beautiful planet and it's hard to understand how these things happen, I mean how violent a place it can also be. The pope touched on that a little bit when he spoke to us about a week ago."

Kelly said he was looking forward to a two-way video conference with his wife, a chance to share the view from 220 miles up.

"I plan to do it from the (multi-window) cupola, give her a chance to look outside, look at the space shuttle docked at the space station," Kelly told an interviewer. "That's an incredible view, to see Endeavour sitting there with the planet just below its tail. I'm looking forward to talking to her. I've been speaking to her every night before I go to bed , but it'll be nice to do it via video, to be able to see how she's doing and for her to join us on board the space station for a little bit."

Talking with his wife on the space station's internet protocol telephone, "I can see how she's progressing and she's doing really, really well. She's looking forward to me getting back and I'm looking forward to getting back to Houston and seeing her."

In a departure from normal practice, the shuttle crew carried out a final heat shield inspection overnight, using the shuttle's robot arm and an instrumented boom to look for any signs of damage to the ship's nose cap and wing leading edge panels that might have occurred since launch May 16.

After a joint crew news conference, the astronauts planned to review the procedures and plans for Friday's spacewalk, the final EVA by a visiting shuttle crew.

After the crew's third spacewalk Wednesday, space station EVA construction time stood at 995 hours and 13 minutes. Michael Fincke and Gregory Chamitoff plan to spend six-and-a-half hours outside the lab complex Friday, pushing cumulative spacewalk time to more than 1,000 hours since assembly began in 1998.

"A thousand hours, that's pretty impressive," Fincke said. "We've really come a long way with spacewalking, we've learned a lot from our Russian partners and they've learned a lot for us."

Fincke and Chamitoff plan to spend the night in the space station's Quest airlock at a reduced pressure of 10.2 pounds per square inch to help purge nitrogen from their bloodstreams and prevent the bends when working in NASA's low-pressure spacesuits. The crew successfully tested a new protocol for Wednesday's spacewalk that does not require the overnight campout, but because of an earlier problem with a carbon dioxide sensor in Chamitoff's suit, mission planners opted to use the older procedure for the mission's final EVA.

Engineers spent a bit of time Wednesday assessing what, if anything, to do about an apparent piece of debris, or perhaps a loose wire, that is causing an issue with a robot arm attachment fitting that was secured to the side of the Russian Zarya module during the crew's third spacewalk.

The power and data grapple fixture, or PDGF, will enable the station's robot arm to attach itself to the Russian segment of the station for repair work and inspections of areas that might otherwise be difficult to see.

"The only minor delta that may come up is on EVA 3, when we installed the power and data grapple fixture on the (Zarya module), we noted there's a piece of some sort of debris or maybe grounding wire that's caught in that," space station Flight Director DIna Contella said Wednesday afternoon. "And so right now, the engineering and ops teams are off assessing whether we want to do anything with that on EVA-4, maybe go take a better look, do we remove the FOD (foreign object debris), is it the kind of thing where we need to bring it in to repair it. So they're off talking about that right now, so we'll see what comes out of those meetings."

Here is an updated timeline of the crew's planned activities for flight day 11 (in EDT and mission elapsed time; includes revision I of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT...DD...HH...MM...SS...EVENT

05/25
07:56 PM...09...11...00...00...STS/ISS crew wakeup
09:26 PM...09...12...30...00...ISS daily planning conference
10:56 PM...09...14...00...00...Starboard wing survey
02:01 PM...09...14...06...00...Mark KellyTucson media interviews

05/26
01:41 AM...09...16...45...00...Nose cap survey
02:41 AM...09...17...45...00...Spacesuit swap
02:41 AM...09...17...45...00...Port wing survey
03:41 AM...09...18...45...00...EVA-4: Equipment lock preps
04:26 AM...09...19...30...00...Crew meals begin
05:41 AM...09...20...45...00...Crew news conference
06:21 AM...09...21...25...00...EVA-4: Tools configured
07:06 AM...09...22...10...00...Laser scan downlink
07:51 AM...09...22...55...00...EVA-4: Procedures review
09:11 AM...10...00...15...00...ISS daily planning conference
09:30 AM...10...00...34...00...Mission status briefing on NASA TV
10:21 AM...10...01...25...00...EVA-4: Mask/pre-breathe
10:30 AM...10...01...34...00...Replay of crew news conference on NASA TV
11:11 AM...10...02...15...00...EVA-4: Airlock depress to 10.2 psi
11:26 AM...10...02...30...00...ISS crew sleep begins
11:56 AM...10...03...00...00...STS crew sleep begins
01:00 PM...10...04...04...00...Daily video highlights reel on NASA TV
05:45 PM...10...08...49...00...Flight director update on NASA TV
06:45 PM...10...09...49...00...Flight director update replay on NASA TV
07:56 PM...10...11...00...00...STS crew wakeup

CBS NEWS Coverage of Breaking Space News

By WILLIAM HARWOOD
CBS News

12:05 PM EDT, 05/25/11 Update: ISLE protocol worked flawlessly; Feustel's eye irritation blamed on dish washing soap

A new pre-spacewalk protocol designed to streamline efforts to prevent the bends when astronauts work in NASA's low-pressure spacesuits worked flawlessly in its first operational use, NASA managers said after a successful six-and-a-half-hour spacewalk Wednesday.

In the old "campout" protocol, spacewalkers had to spend the night in the space station's airlock at a reduced pressure of 10.2 psi to help purge nitrogen from their bloodstreams. They also had to wear oxygen masks the night before for lengthy periods.

The new in-suit light exercise protocol, or ISLE, skips the overnight campout in favor of light exercise the day of the spacewalk while breathing pure oxygen. The technique was tested extensively on the ground, but today's spacewalk by Michel Fincke and Andrew Feustel was its first test in orbit.

"The flight surgeon reported there were no medical issues whatsoever, no symptoms, no issues, no difference whatsoever," said Flight Director Derek Hassmann. "So he gave the crew a clean bill of health and the crew had nothing but positive feedback about the protocol."

NASA managers said before launch that if the ISLE protocol worked well, they would consider using it for the fourth and final spacewalk of Endeavour's mission, an excursion Friday by Fincke and Gregory Chamitoff. But because the ISLE technique uses a bit more of a suit's carbon-dioxide scrubbing lithium hydroxide -- and because Chamitoff had problems with a CO2 sensor during a spacewalk Friday -- the old campout protocol will be used Friday.

As for today's spacewalk, the only problem of any significance was a case of eye irritation that caused Feustel a fair amount of discomfort. Allison Bollinger, the lead spacewalk officer at the Johnson Space Center, said the most likely cause was a helmet visor anti-fogging compound -- dish washing soap -- that flaked off inside his helmet.

"After speaking to him after the EVA, we believe this was the anti-fog," she said. "Prior to going out EVA each time, the crew members apply an anti-fog solution to the inside of their helmet in order to prevent fogging. We've seen this happen a couple of times in the past where if you're not careful about buffing the anti-fog just the right amount that it can flake off every once in a while and get in a crew member's eye. This anti-fog is actually just off-the-shelf dish washing soap. So if you've ever had soap in your eye, you know how that feels."

Feustel eventually cleared it up by rubbing his eye against a foam block in the helmet that can be used to help an astronaut clear his or her ears during airlock depressurization.

"He made an interesting comment that I'd never thought of before, that tears in space don't run down your face, the actually kind of conglomerate around your eyeball," Bollinger said. "He was able to rub his eye against that valsalva device to get the tears free and then he said he was able to press (on)."

CBS NEWS Coverage of Breaking Space News

By WILLIAM HARWOOD
CBS News

08:45 AM EDT, 05/25/11 Update: Spacewalk No. 3 ends

Astronauts Michael Fincke and Andrew Feustel returned to the Quest airlock, closed the hatch and began repressurizing at 8:37 a.m. EDT (GMT-4), officially ending a six-hour and 54-minute spacewalk. The astronauts accomplished all of their primary objectives and other than a brief hiatus when Feustel reported uncomfortable eye irritation, there were no problems of any significance.

This was the 158th spacewalk devoted to station assembly and maintenance since construction began in 1998, the seventh so far this year and the third for the Endeavour astronauts. Total station EVA time now stands at 995 hours and 13 minutes while the total for Endeavour's mission is 21 hours and 20 minutes. Feustel, completing his sixth spacewalk, has now logged 42 hours and 18 minutes of EVA time, moving him up to 14th on the list of most experience spacewalkers. Fincke, completing his eighth excursion, has now logged 41 hours and 13 minutes, moving up to a tie for 18th.

-----------------------------------------------------------

07:35 AM EDT, 05/25/11 Update: Feustel complains of eye irritation

On Earth, it's a trivial matter to rub an irritated eye. But wearing a space helmet, it's another matter.

"Just an FYI, my right eye is stinging like crazy right now," spacewalk Andrew Feustel reported near the end of a planned six-and-a-half-hour spacewalk. "It's watering a lot. Must have gotten something (in it)."

"Houston copies," astronaut Steve Swanson radioed from mission control.

"Boy, that's not fun," Feustel said. "Wow."

"Sorry, buddy," sympathized fellow spacewalker Michael Fincke.

"Oh boy, that's (garble)," Feustel said. "Wonder if that's what mace feels like?"

"You're still on the bottom of the airlock right?" spacewalk coordinator Gregory Chamitoff radioed, making sure Feustel was close to safety if needed.

"Yeah. Wow," said Feustel, wondering if an anti-fogging agent might have been to blame.

"I don't think you should go anywhere unless that gets better," Chamitoff said.

"Yeah, I agree," Feustel said.

A few minutes later, Feustel said "OK, I just rubbed my eye against the valsalva, that helped a bit." He was referring to a foam fixture in the helmet that can be used to block the nostrils to relieve pressure in the ears. "OK, feeling better."

"Getting better?" Chamitoff asked.

"Yeah."

"You sure?"

"Yeah, the rubbing helped a lot," Feustel said. "I've got my eyes open now."

He and Fincke then pressed on with the final tasks on their spacewalk timeline.

CBS NEWS Coverage of Breaking Space News

By WILLIAM HARWOOD
CBS News

07:00 AM EDT, 05/25/11 Update: Second set of U.S.-to-Russian segment power cables connected

Astronauts Andrew Feustel and Michael Fincke have hooked up a second set of electrical jumpers to provide additional redundancy for routing power from U.S. solar arrays to the Russian segment of the International Space Station.

"Nothing's stopped working on the space station, right?" Feustel joked after making one of several connections.

Working in an electrical junction known as the "rat's nest" where numerous power and data cables are connected, Fincke hooked up one end of the multi-cable jumper while Feustel connected the other end at the interface between the U.S. and Russian segments.

At one point, Fincke lost track of his safety tether and had to get help from Feustel to get untangled.

"I apologize to the team," Fincke said. "It was dark and I was upside down."

"Was it scary?" Feustel joked.

"No, but it wasn't frustrating because we got the job done," FIncke said.

"You guys did a great job," said spacewalk coordinator Gregory Chamitoff. "That was a difficult task."

"Wait until you see the pictures," Fincke said. "They don't call it a bird's nest or some other kind of nest, it's definitely a rat's nest."

Helmet cam pictures are posted on the CBS News updates page:

http://www.cbsnews.com/network/news/space/home/spacenews/files/5d4239e94f79b15e4e23decbbc736aac-262.html

CBS NEWS Coverage of Breaking Space News

By WILLIAM HARWOOD
CBS News

05:30 AM EDT, 05/25/11 Update: Antenna wiring complete

The Endeavour spacewalkers have finished hooking up antennas that were installed during a spacewalk Friday and are moving back to the Russian Zarya module to connect a second set of jumpers to help route U.S. solar array power to the Russian segment of the International Space Station.

The antennas enable "a wireless system to be working outside the station," spacewalk coordinator Gregory Chamitoff said in a NASA interview. "There are experiments and payloads outside the space station. They need to communicate to the data system and they're installing a couple of antennas and all the wiring for that to enable those pieces of equipment or experiments to communicate to internal systems through those antennas."

Chamitoff and Andrew Feustel attached the antennas during the crew's first spacewalk, but they were unable to finish wiring them into the Destiny laboratory's electrical system. Feustel and Michael FIncke finished the job today. As of this writing, Feustel and Fincke are running about a half hour ahead of schedule.

-----------------------------------------------------------

04:10 AM EDT, 05/25/11 Update: Jumpers for power channels 1 and 4 installed

The first of two sets of jumper cables needed to improve power distribution from NASA's solar arrays to the Russian segment of the International Space Station have been installed. The astronauts are now moving on to hooking up to antennas that were installed during the crew's first spacewalk. So far, today's spacewalk is proceeding smoothly with no problems of any significance.

CBS NEWS Coverage of Breaking Space News

By WILLIAM HARWOOD
CBS News

03:45 AM EDT, 05/25/11 Update: Video converter mounted on Zarya

Spacewalkers Andrew Feustel and Michael FIncke have mounted a video signal converter on the Russian Zarya module for use with a new robot arm attachment fitting installed earlier this morning.

The next major item on the agenda is to install cabling between the Zarya module and the U.S. Unity compartment to add redundancy to the system that routes power from the station's four NASA-supplied solar arrays to the Russian segment of the lab complex. Two sets of cables are required, one tied into power distribution channels 1 and 4 and the other connected to channels 2 and 3.

After the first set of cables is installed, the astronauts will hook up wiring for antennas installed during the crew's first spacewalk before pressing ahead with installation of jumpers for power channels 2 and 3.

-----------------------------------------------------------

03:15 AM EDT, 05/25/11 Update: Robot arm attachment fitting mounted on Russian module

Running about a half hour ahead of schedule, astronauts Andrew Feustel and Michael Fincke have mounted a robot arm power and data grapple fixture, or PDGF, to the Russian Zarya module. The PDFG eventually will allow the station's Canadian-built robot arm to attach itself to the Russian segment of the space station to assist spacewalkers or provide visibility into previously inaccessible areas.

Feustel and Fincke now are working to install a video signal converter to properly format television signals from the robot arm for relay to the U.S. segment through Russian hardware.

CBS NEWS Coverage of Breaking Space News

By WILLIAM HARWOOD
CBS News

02:00 AM EDT, 05/25/11 Update: STS-134 spacewalk No. 3 begins

Astronauts Andrew Feustel and Michael Fincke, floating in the International Space Station's Quest airlock, switched their spacesuits to battery power at 1:43 a.m. EDT (GMT-4) to officially begin a planned six-and-a-half-hour spacewalk, the third of four planned by the shuttle Endeavour's crew.

"It's great to be back outside," Fincke marveled a few minutes later. "The most beautiful planet in the universe."

"Nice view, isn't it?" Feustel agreed.

For identification, Feustel, call sign EV-1, is wearing a suit with red stripes around the legs while Fincke, EV-2, is wearing an unmarked suit.

The primary goals of the spacewalk are to mount a power and data grapple fixture on the left side of the Russian Zarya module that can be used later as a base for the station's Canadian-built robot arm. The astronauts also plan to install wiring between the U.S. and Russian segments of the station to improve redundancy in the system that feeds power from the lab's NASA-supplied solar arrays.

Feustel and Fincke plan to install a video signal conditioner for the power and data grapple fixture; to finish connecting wiring needed by new antennas installed during the crew's first spacewalk; and to carry out photo documentation of experiments mounted on the station's power truss.

Here is an updated timeline of major events based on the actual start time (in EDT and event elapsed time):

EDT........HH...MM...EVENT

01:43 AM...00...00...EVA-3: Spacesuits to battery power
01:48 AM...00...05...EVA-3: Airlock egress and setup
02:23 AM...00...40...EVA-3: Power and data grapple fixture ((PDGF) setup
02:48 AM...01...05...EVA-3: Retrieve PDGF and attachment fitting
03:13 AM...01...30...EVA-3: PDGF install
03:28 AM...01...45...EVA-3: Video signal conditioner install
03:58 AM...02...15...EVA-3: Unity/Zarya channel 1/4 cable install
04:43 AM...03...00...EVA-3: Antenna cable install
05:43 AM...04...00...EVA-3: Unity/Zarya channel 2/3 cable install
06:43 AM...05...00...EVA-3: EV-1: PDGF and Zarya thruster photos
06:43 AM...05...00...EVA-3: EV-2: Zarya cleanup
06:58 AM...05...15...EVA-3: EV-1: STP-H3 experiment infrared imagery
06:58 AM...05...15...EVA-3: EV-2: High pressure gas tank grapple fixture insulation install
07:43 AM...06...00...EVA-3: Cleanup and airlock ingress
08:13 AM...06...30...EVA-3: Airlock repressurization

In a departure from past practice, the astronauts followed a new pre-spacewalk protocol to purge nitrogen from their bloodstreams to prevent the bends when working in NASA's 5-psi spacesuits.

Unlike the "campout" protocol used for scores of previous spacewalks, the "in-suit light exercise" pre-breathe protocol, or ISLE for short, does not require the astronauts to spend the night before sealed in the station's airlock at a reduced pressure of 10.2 psi. Instead, the astronauts perform light exercise while breathing pure oxygen the morning of the spacewalk.

"We think this is an improvement over the campout protocol," said space station Flight Director Derek Hassmann. "And of course, the main thing we're after here is crew safety. All of these crew protocols are designed to prevent the bends. Leading up to this, we put the ISLE protocol through all the standard medical reviews and tests that both the campout and exercise pre-breathe protocols have been subjected to, and everybody's comfortable it's completely safe. We think it offers some significant advantages."

This is the 158th spacewalk devoted to station assembly and maintenance since construction began in 1998, the seventh so far this year, the eighth for Fincke and the sixth for Feustel. Going into today's excursion, total station EVA time stood at 988 hours and 19 minutes, including 14 hours and 26 minutes for the Endeavour crew's first two spacewalks.

CBS NEWS Coverage of Breaking Space News

03:00 PM EDT, 05/24/11 Update: Shuttle crew helps out with station maintenance; preps for third spacewalk

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The Endeavour astronauts helped out with space station maintenance Tuesday, beginning work to service a carbon dioxide scrubber and to install a filter in a U.S. oxygen generator amid preparations for an overnight spacewalk, the third of four planned by the shuttle's crew.

The U.S. segment of the station is equipped with two carbon dioxide removal assemblies, or CDRAs, one in the Destiny lab module and the other in Tranquility, that use a desiccant bed to condition incoming air before it is passed through an absorbent bed to remove CO2.

A replacement for one of the beds in the Tranquility CDRA was carried aloft aboard Endeavour and shuttle commander Mark Kelly, joined by space station flight engineer Ronald Garan, started the repair work Tuesday.

Michael Fincke and Gregory Chamitoff, both veterans of long-duration stays aboard the station, started maintenance work on a U.S. oxygen generator that has had problems with contamination in the water that is broken down to produce oxygen. The astronauts are installing a new filter assembly and associated plumbing that may resolve the issue. After leak checks, the OGA will be activated later in the week for test runs and analysis.

In a bit of unplanned maintenance, Fincke also replaced a remote power control module, or RPCM, that "tripped" overnight, knocking out power to high definition video systems and disabling gear used to transmit science data to the ground. Older-style RPCMs have a known problem with built-in firmware and NASA is in the process of replacing them with upgraded versions. In this case, Fincke installed a replacement and downstream systems were brought back on line without incident.

The astronauts went to bed just before noon EDT (GMT-4). They will begin flight day 10 at 7:56 p.m. and quickly move into preparations for an overnight spacewalk by Fincke and Andrew Feustel. The excursion is scheduled to begin around 1:46 a.m. Wednesday

The primary goals of the spacewalk are to mount a power and data grapple fixture on the left side of the Russian Zarya module that can be used later as a base for the station's Canadian-built robot arm. They also plan to install wiring between the U.S. and Russian segments of the station to improve redundancy in the system that feeds power from the lab's NASA-supplied solar arrays to the Russian segment of the station.

"The Canadarm space station arm has a capability of walking around the space station from end to end to do different tasks," Feustel said in a NASA interview. "The Russian segment doesn't really have any of those bases for the arm to walk on to. This is an opportunity for us to actually attach one of these base mechanisms onto (Zarya) to allow the arm to walk onto that position and do some tasks in areas that it wouldn't have been able to reach previous to this."

The spacewalkers also plan to install a video signal conditioner for the power and data grapple fixture; to finish connecting wiring needed by new antennas installed during the crew's first spacewalk; and to carry out photo documentation of experiments mounted on the station's power truss.

One item on the crew's original EVA-3 timeline was deleted to make room for the antenna wiring. Installation of a data cable needed before the Zarya robot arm base station can be used was deferred to a future spacewalk.

For the first two spacewalks, and scores that preceded them, spacewalkers used a so-called "campout" protocol to purge nitrogen from their bloodstreams to prevent the bends while working in NASA's low-pressure spacesuits.

The campout protocol required spacewalkers to wear oxygen masks for one hour the night before an EVA and then to spend the night in the station's airlock at a reduced pressure of 10.2 psi. The day of the spacewalk, the astronauts would put the masks back on, repressurize the airlock, eat breakfast and attend to hygiene, depress the airlock back to 10.2 psi, take the masks off and don their spacesuits. Then another 50 minutes breathing pure oxygen was required before the spacewalk could begin.

For EVA No. 3, Fincke and Feustel will test a new protocol known as the "in-suit light exercise" pre-breathe protocol, or ISLE for short.

Extensive testing on the ground indicates spacewalkers can remove nitrogen by simply performing light exercise the morning of the excursion -- the equivalent of walking a 70-minute mile -- while breathing pure oxygen. By avoiding the overnight campout, astronauts will not be isolated before a spacewalk and a fire alarm or other problem would not force them to open the airlock and delay a long-planned spacewalk.

"It doesn't require the overnight campout that was used for most of the previous EVAs on the last several flights," said space station Flight Director Derek Hassmann. "In terms of complexity, in terms of the quality of life for the crew, this ISLE protocol is a pretty significant upgrade because we don't have that point the night before where the two EVA crew has to go in the airlock, and we shut the hatch, and they're forced to spend the night in the airlock.

"With this in-suit light exercise, or ISLE, protocol, the night before an EVA looks exactly like any other night during the mission. They wake up, they don't have to stay on the portable breathing apparatus, they don't have to stay on the oxygen masks. So up until the point where they actually begin the EVA prep the morning of, it looks just like any other day.

"We think this is an improvement over the campout protocol," he said. "And of course, the main thing we're after here is crew safety. All of these crew protocols are designed to prevent the bends. Leading up to this, we put the ISLE protocol through all the standard medical reviews and tests that both the campout and exercise pre-breathe protocols have been subjected to, and everybody's comfortable it's completely safe. We think it offers some significant advantages."

For the first test run of the new protocol, Fincke and Chamitoff will spend 20 minutes on pure oxygen at rest, followed by 50 minutes of light exercise and then 30 more minutes at rest.

Lead spacewalk officer Allison Bolinger said that along with improving the quality of life for spacewalkers, the ISLE protocol will save oxygen.

"Post shuttle retirement, this will be a big deal for station," she said. "The crew members will also spend less time on the oxygen masks, which for some crew members can be uncomfortable. They're not isolated in the airlock overnight, which is also a benefit.

"The one drawback to this protocol, though, it does take longer in the morning to get out the door than it does with the campout protocol. So (airlock) egress we estimate to be about 30 minutes later than if we had done the campout protocol."

Here is an updated timeline of the crew's planned activities for flight day 10 (in EDT and mission elapsed time; includes revision G of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT...DD...HH...MM...SS...EVENT

05/24
01:00 PM...08...04...04...00...Daily video highlights reel on NASA TV
05:45 PM...08...08...49...00...Flight director update on NASA TV
05:45 PM...08...09...49...00...Flight director update replay on NASA TV
07:56 PM...08...11...00...00...STS/ISS crew wakeup (begin flight day 10)
09:11 PM...08...12...15...00...EVA-3: ISLE EVA prep (new in-suit light exercise protocol)
09:26 PM...08...12...30...00...ISS daily planning conference
11:21 PM...08...14...25...00...EVA-3: Spacesuit purge
11:36 PM...08...14...40...00...EVA-3: ISLE spacesuit pre-breathe

05/25
01:16 AM...08...16...20...00...EVA-3: Crew lock depressurization
01:46 AM...08...16...50...00...EVA-3: Spacesuits to battery power (official start time)
01:51 AM...08...16...55...00...EVA-3: Egress and setup
02:31 AM...08...17...35...00...EVA-3: PDGF setup
03:01 AM...08...18...05...00...EVA-3: Retrieve PDGF and attachment fitting
03:21 AM...08...18...25...00...EVA-3: Install PDGF on Zarya
03:36 AM...08...18...40...00...EVA-3: Install video signal conditioner
04:06 AM...08...19...10...00...EVA-3: FGB Y jumper install (channel 1/4)
04:51 AM...08...19...55...00...EVA-3: EWC antenna cable install (from EVA-1)
05:51 AM...08...20...55...00...EVA-3: Zarya Y jumper (channel 2/3)
06:56 AM...08...22...00...00...EVA-3: EV-1: PDGF/Zarya thruster photos
06:56 AM...08...22...00...00...EVA-3: EV-2: Zarya cleanup
07:11 AM...08...22...15...00...EVA-3: EV-1: STP-H3 IR experiment imagery
07:11 AM...08...22...15...00...EVA-3: EV-2: High pressure gas tank grapple fixture insulation install
07:51 AM...08...22...55...00...EVA-3: Cleanup and ingress
08:21 AM...08...23...25...00...EVA-3: Airlock repressurization
08:31 AM...08...23...35...00...Spacesuit servicing
09:11 AM...09...00...15...00...ISS daily planning conference
10:00 AM...09...01...04...00...Mission status briefing on NASA TV
11:26 AM...09...02...30...00...ISS crew sleep begins
11:56 AM...09...03...00...00...STS crew sleep begins

CBS NEWS Coverage of Breaking Space News

-- Posted at 11:57 AM EDT, 05/23/11: Soyuz TMA-20 prepped for shuttle photo op, re-entry and landing
-- Updated at 03:25 PM EDT, 05/23/11: Soyuz hatch closed for undocking
-- Updated at 06:05 PM EDT, 05/23/11: Soyuz TMA-20 undocks from space station
-- Updated at 09:45 PM EDT, 05/23/11: Deorbit rocket firing
-- Updated at 10:55 PM EDT, 05/23/11: Soyuz TMA-20 lands in Kazakhstan

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Outgoing space station commander Dmitry Kondratyev, Italian astronaut Paolo Nespoli and Catherine "Cady" Coleman undocked and returned to Earth Monday, pausing briefly to snap long-sought pictures of the station with a space shuttle attached before dropping out of orbit and landing in Kazakhstan to close out a 159-day voyage.

Sailing 220 miles above eastern China, the Soyuz TMA-20 spacecraft undocked from the Russian Rassvet mini-research module at 5:35 p.m. EDT (GMT-4), backing straight away from the space station.

In a dramatic break with normal practice, Kondratyev halted the Soyuz's departure at a distance of about 600 feet directly behind the lab complex to give Nespoli a chance to capture what likely will become one of the signature images of the shuttle-station era.

Black-and-white television views from the Soyuz showed the two spacecraft against the limb of the planet as they flew in concert at five miles per second. Similar photos of the shuttle Atlantis undocking from the Russian Mir space station were shot 16 years ago by the crew of a Soyuz spacecraft but until Monday, there were no such views of the shuttle and the International Space Station.

But Nespoli's high-resolution photographs and high definition video will not be seen until Tuesday or Wednesday, after compact camera cards are copied on the ground and flown to Moscow and Houston.

With the photo survey complete, Kondratyev and his crewmates rigged the Soyuz for re-entry, firing the ship's braking rockets at 9:36 p.m. to begin the descent to Earth. The three modules making up the Soyuz TMA-20 vehicle separated at 10:01 p.m. and the descent module with the returning station fliers slammed into the atmosphere at an altitude of about 62 miles at 10:03 p.m.

The fiery re-entry appeared to go smoothly and a large parachute inflated as planned as the spacecraft fell toward the landing zone near Dzhezkazgan, Kazakhstan.

The final moments of the return to Earth were captured in live video and at 10:27 p.m. (8:27 a.m. local time), the capsule touched down, closing out a mission spanning 159 days, seven hours and 17 minutes since launch Dec. 15.

"This was a textbook entry for Dmitry Kondratyev, Paolo Nespoli and Cady Coleman," said NASA mission control commentator Rob Navias. "All of the functions of the Soyuz TMA-20 were by the book, no issues reported."

The descent module landed upright and Russian recovery forces rushed to the scene to assist the returning station crew, along with U.S. and Russian flight surgeons. All three space fliers were in good spirits, smiling and chatting with support personnel and sharing a satellite phone to call family members back home.

"Hey, how are you guys?" Coleman could be heard saying to her family.

After initial medical checks, Kondratyev, Nespoli and Coleman were expected to fly by helicopter to Karaganda, Kazakhstan. Coleman and Nespoli then planned to board a NASA jet for a flight back to Houston while Kondratyev heads for Star City near Moscow.

Nespoli photographed the space station through a porthole in the Soyuz TMA-20 habitation module starting about 15 minutes after undocking. Five minutes after that, at 5:55 p.m., Expedition 28 commander Andrey Borisenko monitored space station rocket firings to kick off a 15-minute, 129-degree turn, presenting a side-on view to the Soyuz with the shuttle in profile on the left and the Russian segment of the lab on the right.

In all, Nespoli had about 25 minutes to complete his work before Kondratyev fired the Soyuz TMA-20's thrusters to depart the area, keeping the ship on track for re-entry and landing.

The normal practice for a Soyuz undocking calls for all three crew members, wearing Russian pressure suits, to be strapped into their seats in the spacecraft's central descent module. The forward habitation module and the aft propulsion section are jettisoned just before re-entry to burn up in the atmosphere. As such, the hatch between the descent module and habitation module is closed and leak tested before undocking.

For the photo shoot, the hatch was closed for undocking as usual, but re-opened a few minutes later so Nespoli can use the porthole in the forward compartment. A few minutes after a separation "burn," was was expected to remove digital photo cards from his cameras and make his way back into the cramped descent module, taking the seat to Kondratyev's left. The hatch then was to be sealed for leak tests to verify the integrity of the central command module.

"This is the first time we've ever done something like this where we have a Soyuz undocking during a shuttle mission," said space station Flight Director Derek Hassmann. "There are a number of challenges associated with doing that. There were engineering challenges in terms of the analysis we needed to do to make sure it was safe for the Soyuz to undock relative to loading on the solar arrays and other constraints."

Another complicating factor was an offset sleep schedule that had the Endeavour astronauts, plus Expedition 28 flight engineer Ronald Garan, following one sleep cycle while the departing Expedition 27 crew, along with Borisenko and flight engineer Alexander Samokutyaev, going to bed several hours later.

"On a station docked mission, this is the first time we've had offset sleep schedules and it's been a little bit of a challenge to manage the communication loops to the crew," Hassmann said. "But we're getting better at that as the days go by, so I'm really happy the way this has worked out."

Barring a mission extension, Endeavour is scheduled to undock May 29 for a landing back at the Kennedy Space Center on June 1. Borisenko, Samokutyaev and Garan will have the space station to themselves until June 9 when three fresh crew members -- Soyuz TMA-02M commander Sergei Volkov, Michael Fossum and Satoshi Furukawa -- are scheduled to arrive following launch June 7 from the Baikonur Cosmodrome in Kazakhstan.

CBS NEWS Coverage of Breaking Space News

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Strapped into a Russian Soyuz spacecraft, outgoing Expedition 27 commander Dmitry Kondratyev, Italian astronaut Paolo Nespoli and Catherine "Cady" Coleman undocked from the International Space Station Monday, pausing briefly to snap long-awaited pictures of the station with a space shuttle attached before setting up for landing in Kazakhstan to close out a five-and-a-half-month stay in orbit.

Sailing 220 miles above eastern China, the Soyuz TMA-20 spacecraft undocked from the Russian Rassvet mini-research module at 5:35 p.m. EDT (GMT-4), backing straight away from the space station.

In a dramatic break with normal practice, Kondratyev halted the Soyuz's departure at a distance of about 600 feet directly behind the lab complex to give Nespoli a chance to capture what likely will become one of the signature images of the shuttle-station era.

With the shuttle program slated for retirement after one more flight in July, Monday's photo op came at almost the last possible minute, a family portrait of sorts showing the world's largest manned spacecraft in the same frame.

Black-and-white television views from the Soyuz showed the two spacecraft against the limb of the planet as they flew in concert at five miles per second. Similar photos of the shuttle Atlantis undocking from the Russian Mir space station were shot 16 years ago by the crew of a Soyuz spacecraft but until Monday, there were no such views of the shuttle and the International Space Station.

But Nespoli's high-resolution photographs and high definition video will not be seen until Tuesday or Wednesday, after compact camera cards are copied on the ground and flown to Moscow and Houston.

With the photo survey complete, Kondratyev and his crewmates planned to rig the Soyuz for re-entry, setting up for a four-minute 25 second deorbit rocket firing starting at 9:36:14 p.m. The three modules making up the Soyuz TMA-20 vehicle will separate at 10:01 p.m. and the descent module with the returning station fliers will slam into the atmosphere at an altitude of about 62 miles at 10:03 p.m.

The-entry trajectory was designed to set up a landing near Dzhezkazgan, Kazakhstan, at 10:26 p.m., 159 days, seven hours and 17 minutes after launch Dec. 15.

Russian recovery forces were standing by to assist the returning station crew, along with U.S. and Russian flight surgeons. Additional recovery crews were stationed farther back along the trajectory in case of any problems that might result in a steeper-than-normal "ballistic" re-entry.

After initial medical checks, Kondratyev, Nespoli and Coleman were expected to fly by helicopter to Karaganda, Kazakhstan. Coleman and Nespoli then planned to board a NASA jet for a flight back to Houston while Kondratyev heads for Star City near Moscow.

Nespoli photographed the space station through a porthole in the Soyuz TMA-20 habitation module starting about 15 minutes after undocking. Five minutes after that, at 5:55 p.m., Expedition 28 commander Andrey Borisenko monitored space station rocket firings to kick off a 15-minute, 129-degree turn, presenting a side-on view to the Soyuz with the shuttle in profile on the left and the Russian segment of the lab on the right.

In all, Nespoli had about 25 minutes to complete his work before Kondratyev fired the Soyuz TMA-20's thrusters to depart the area, keeping the ship on track for re-entry and landing.

The normal practice for a Soyuz undocking calls for all three crew members, wearing Russian pressure suits, to be strapped into their seats in the spacecraft's central descent module. The forward habitation module and the aft propulsion section are jettisoned just before re-entry to burn up in the atmosphere. As such, the hatch between the descent module and habitation module is closed and leak tested before undocking.

For the photo shoot, the hatch was closed for undocking as usual, but re-opened a few minutes later so Nespoli can use the porthole in the forward compartment. A few minutes after a separation "burn," was was expected to remove digital photo cards from his cameras and make his way back into the cramped descent module, taking the seat to Kondratyev's left. The hatch then was to be sealed for leak tests to verify the integrity of the central command module.

"This is the first time we've ever done something like this where we have a Soyuz undocking during a shuttle mission," said space station Flight Director Derek Hassmann. "There are a number of challenges associated with doing that. There were engineering challenges in terms of the analysis we needed to do to make sure it was safe for the Soyuz to undock relative to loading on the solar arrays and other constraints."

Another complicating factor was an offset sleep schedule that had the Endeavour astronauts, plus Expedition 28 flight engineer Ronald Garan, following one sleep cycle while the departing Expedition 27 crew, along with Borisenko and flight engineer Alexander Samokutyaev, going to bed several hours later.

"On a station docked mission, this is the first time we've had offset sleep schedules and it's been a little bit of a challenge to manage the communication loops to the crew," Hassmann said. "But we're getting better at that as the days go by, so I'm really happy the way this has worked out."

Barring a mission extension, Endeavour is scheduled to undock May 29 for a landing back at the Kennedy Space Center on June 1. Borisenko, Samokutyaev and Garan will have the space station to themselves until June 9 when three fresh crew members -- Soyuz TMA-02M commander Sergei Volkov, Michael Fossum and Satoshi Furukawa -- are scheduled to arrive following launch June 7 from the Baikonur Cosmodrome in Kazakhstan.

Here is a timeline of the crew's planned activities (in EDT and mission elapsed time; includes revision G of the NASA television schedule; includes Soyuz TMA-20 undocking/landing timeline with ISS-27 mission elapsed time; best viewed with fixed-width font):

DATE/EDT..DDD...HH...MM...SS...EVENT

05/23
05:35 PM..159...02...25...35...Soyuz TMA-20 undocking
05:36 PM..159...02...27...15...ISS to LVLH attitude
05:38 PM..159...02...28...35...Soyuz manual separation burn No. 1
05:41 PM..159...02...31...35...Arrival at stationkeeping (590-650 feet)
05:41 PM..159...02...31...35...Soyuz habitation module ingress
05:43 PM..159...02...33...55...ISS return to undocking attitude
05:44 PM..159...02...35...08...Daily orbit 13 Russian ground station LOS
05:50 PM..159...02...40...35...Begin ISS photography
05:52 PM..159...02...43...03...Orbital noon
05:55 PM..159...02...45...35...ISS maneuver to photography attitude
06:06 PM..159...02...56...35...ISS in photo attitude
06:15 PM..159...03...05...35...Soyuz manual separation burn No. 2
06:20 PM..159...03...10...35...Habitation module egress; start leak checks
06:20 PM..159...03...10...55...Orbital sunset -- photography complete
06:21 PM..159...03...11...35...ISS maneuver to duty attitude
06:56 PM..159...03...46...36...Orbital sunrise
07:00 PM..159...03...50...35...Russian to US attitude control handover
07:00 PM..159...03...50...35...Hatch and suit leak checks complete
07:02 PM..159...03...52...43...Daily orbit 14 Russian ground station AOS
07:19 PM..159...04...10...08...Daily orbit 14 Russian ground station LOS
07:36 PM..159...04...26...35...Sunrise at landing Site
08:26 PM...07...11...30...00...STS crew/Garan wakeup (begins shuttle flight day 9)
08:30 PM..159...05...20...48...Daily orbit 15 Russian ground station AOS
08:53 PM..159...05...44...33...Daily orbit 15 Russian ground station LOS
09:15 PM...07...12...19...00...Soyuz TMA-20 landing coverage begins on NASA TV
09:36 PM..159...06...26...49...Soyuz deorbit burn start (257.7 mph)
09:40 PM..159...06...31...14...Deorbit burn complete
10:03 PM..159...06...54...11...Atmospheric entry (62 miles altitude)
10:11 PM..159...07...02...24...Command to open parachute (6.6 miles altitude)
10:26 PM..159...07...17...24...Soyuz TMA-20 landing

CBS NEWS Coverage of Breaking Space News

03:45 AM EDT, 05/23/11: Shuttle crew takes time off amid Soyuz undocking preps

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The Endeavour astronauts took the day off Monday amid preparations for the afternoon departure of three space station crew members aboard a Russian Soyuz ferry craft to close out a 159-day stay in space.

Shortly after wakeup late Sunday, shuttle commander Mark Kelly and astronaut Michael Fincke fielded questions from Mesa Verde Elementary School classmates of 9-year-old Christina Green, killed during an attempt to assassinate Kelly's wife, Gabrielle Giffords, in January.

Asked what inspired him to become an astronaut, Kelly told the students "over the last four months, I've come to admire your classmate, Christina Green, very much, I've learned a lot about her."

"When I was Christina's age is when Apollo astronauts were walking on the moon ... and I remember watching that on TV and thinking if I worked really hard in school and really, really focused and concentrated, maybe someday I would have the opportunity to fly in space. And I did work hard, and it did work out. But I would say it was those early Apollo astronauts, like Neil Armstrong and Gene Cernan and John Young, who inspired me."

He concluded the question-and-answer session by promising to sign and return a school yearbook he carried into space aboard Endeavour.

"Since my wife, Congresswoman Giffords, is from Tucson, Arizona, I spend a lot of time there," he said. "I'm a big fan of Tucson and the Arizona Wildcats. I didn't have a Mesa Elementary School shirt but what I do have is ... your yearbook, the Mesa Verde Mountain Lions 2010-2011 with me here in space, and I'll get a picture of this with the Earth in the background and hopefully I can bring it back and hand it over to your school."

He opened the yearbook to a page honoring Christina Green and said "it's a very nice yearbook, Mike and I just signed it and I'll get my other crew members and the space station crew members to sign it and we'll send it back to you.

"Again, it was really great to be with you at Mesa Verde today and I hope to see you soon," Kelly concluded. "So long."

The shuttle astronauts are scheduled to go to bed at 12:26 p.m. EDT (GMT-4) and unless they get up early, they will miss the departure of Expedition 27 commander Dmitry Kondratyev, Italian astronaut Paolo Nespoli and NASA astronaut Catherine "Cady" Coleman aboard the Soyuz TMA-20 spacecraft.

Hatch closure is planned for 2:21 p.m. followed by undocking at 5:35 p.m. Landing in Kazakhstan is expected at 10:26 p.m.

In a departure from normal practice, Kondratyev plans to pause at a distance of about 600 feet while Nespoli, working in the Soyuz's forward habitation module, takes video and still pictures of the lab complex with the shuttle Endeavour attached. A few minutes later, the station will maneuver to present a side-on view showing the shuttle in profile.

The pictures will be the first showing the shuttle-station complex from a distance, a last chance to capture a family portrait before the shuttle program comes to an end in July. But the Soyuz has no way to downlink the imagery and it will not be seen until a day or two after landing.

An undocking preview will be posted later today. In the meantime, here is an updated timeline of the crew's planned activities (in EDT and mission elapsed time; includes revision G of the NASA television schedule; includes Soyuz TMA-20 undocking/landing timeline with ISS-27 MET; best viewed with fixed-width font):

DATE/EDT..DDD...HH...MM...SS...EVENT

05/22
08:56 PM...06...12...00...00...STS crew/Garan wakeup
10:46 PM...06...13...50...00...PAO education event
11:26 PM...06...14...30...00...Crew off duty

05/23
03:41 AM...06...18...45...00...Crew meals begin
04:41 AM...06...19...45...00...Crew off duty
05:00 AM...06...20...04...00...U.S. PAO education event replay
06:00 AM...06...21...04...00...ISS crew wakeup
07:00 AM...06...22...04...00...U.S. PAO education event replay
08:00 AM...06...23...04...00...U.S. PAO education event replay
09:26 AM...07...00...30...00...Soyuz TMA-20 departure preps
09:31 AM...07...00...35...00...Italian president VIP call (on NASA TV)
09:11 AM...07...00...15...00...ISS daily planning conference
09:31 AM...07...00...35...00...PAO event
10:00 AM...07...01...04...00...Mission status briefing on NASA TV
11:56 AM...07...03...00...00...Garan sleep begins
12:26 PM...07...03...30...00...STS crew sleep begins
02:00 PM...07...05...04...00...Soyuz TMA-20 farewell/hatch closure
04:00 PM...07...07...04...00...Daily video highlights reel on NASA TV
04:40 PM..159...01...30...35...US to Russian attitude control system handover
04:52 PM..159...01...42...35...ISS maneuver to undocking attitude
05:24 PM..159...02...15...11...Sunrise
05:29 PM..159...02...20...07...Daily orbit 13 Russian ground station AOS
05:31 PM..159...02...21...35...ISS to free drift
05:32 PM..159...02...22...35...Nominal separation command
05:35 PM..159...02...25...35...Physical separation/hooks open
05:36 PM..159...02...27...15...ISS to LVLH snap-and-hold
05:38 PM..159...02...28...35...Soyuz manual separation burn #1
05:41 PM..159...02...31...35...Arrival at stationkeeping (590-650 feet)
05:41 PM..159...02...31...35...Habitation module ingress
05:43 PM..159...02...33...55...ISS return to undocking attitude
05:44 PM..159...02...35...08...Daily orbit 13 Russian ground station LOS
05:50 PM..159...02...40...35...Begin ISS photography
05:52 PM..159...02...43...03...Noon
05:55 PM..159...02...45...35...ISS maneuver to photography attitude
06:06 PM..159...02...56...35...ISS in photo attitude
06:15 PM..159...03...05...35...Soyuz manual separation burn #2
06:20 PM..159...03...10...35...Habitation module egress; start leak checks
06:20 PM..159...03...10...55...Sunset -- photography complete
06:21 PM..159...03...11...35...ISS maneuver to duty attitude
06:56 PM..159...03...46...36...Sunrise
07:00 PM..159...03...50...35...Russian to US attitude control handover
07:00 PM..159...03...50...35...Hatch and suit leak checks complete
07:02 PM..159...03...52...43...Daily orbit 14 Russian ground station AOS
07:19 PM..159...04...10...08...Daily orbit 14 Russian ground station LOS
07:36 PM..159...04...26...35...Sunrise at landing Site
08:26 PM...07...11...30...00...STS crew/Garan wakeup (begins FD-9)
08:30 PM..159...05...20...48...Daily orbit 15 Russian ground station AOS
08:53 PM..159...05...44...33...Daily orbit 15 Russian ground station LOS
09:15 PM...07...12...19...00...Soyuz TMA-20 landing coverage begins on NASA TV
09:36 PM..159...06...26...49...Soyuz deorbit burn start (257.7 mph)
09:40 PM..159...06...31...14...Deorbit burn complete
10:03 PM..159...06...54...11...Atmospheric entry (62 miles altitude)
10:11 PM..159...07...02...24...Command to open parachute (6.6 miles altitude)
10:26 PM..159...07...17...24...Landing
11:01 PM...07...14...05...00...Equipment lock preps
11:31 PM...07...14...35...00...ISS crew sleep begins
11:46 PM...07...14...50...00...EVA-3: Tools configured
11:46 PM...07...14...50...00...OBSS undock

CBS NEWS Coverage of Breaking Space News

-- Posted at 11:55 AM EDT, 05/22/11: Space station change of command on eve of Soyuz departure
-- CORRECTED at 04:30 PM EDT, 05/22/11: Fixing Andrey Borisenko's first name in second graf

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--A little more than an hour after a spacewalk by two shuttle astronauts, the crew of the International Space Station held a change-of-command ceremony to mark the departure Monday of Expedition 27 commander Dmitry Kondratyev, Italian astronaut Paolo Nespoli and NASA astronaut Catherine "Cady" Coleman.

Floating in the Japanese Kibo laboratory module, Kondratyev handed over command to cosmonaut Andrey Borisenko, who will head up the Expedition 28 crew when Kondratyev, Nespoli and Coleman undock in their Soyuz TMA-20 spacecraft Monday evening and head back to Earth to close out a 159-day stay in space.

"Houston, thank you all for great help and support and looking forward to working with you again," Kondratyev radioed after the brief ceremony. "Thanks a lot."

Departing at 5:35 p.m. EDT (GMT-4) Monday, an hour-and-a-half earlier than usual, Kondratyev plans to back away from the lab complex and then briefly halt while the space station executes a slow turn to set up a one-of-a-kind photo opportunity. Nespoli, working in the Soyuz forward habitation module, plans to capture the only photos and video ever shot showing the space station from a distance with a shuttle attached.

Borisenko and his two station crewmates -- NASA astronaut Ronald Garan and cosmonaut Alexander Samokutyaev -- will form the core of the station's 28th long-duration crew. Three fresh crew members -- Soyuz TMA-02M commander Sergei Volkov, Michael Fossum and Satoshi Furukawa -- are scheduled for launch from the Baikonur Cosmodrome in Kazakhstan on June 7, arriving at the space station two days later.

CBS NEWS Coverage of Breaking Space News

10:20 AM EDT, 05/22/11 Update: Spacewalk No. 2 ends

By WILLIAM HARWOOD
CBS News

Astronauts Michael Fincke and Andrew Feustel began repressurizing the space station's Quest airlock at 10:12 a.m. EDT, officially ending a marathon eight-hour seven-minute spacewalk. The astronauts accomplish both of their primary objectives, recharging a solar array coolant system with ammonia and lubricating a solar array drive mechanism.

But trouble with bolts holding thermal covers in place on the solar alpha rotary joint mechanism put the crew behind schedule and in the end, only three of the four covers were re-installed. One was brought back to the airlock for a more detailed examination inside the station.

"Guys, congratulations, that was an awesome EVA," spacewalk coordinator Gregory Chamitoff radioed. "That was a lot of hard work and a lot of training leading up to this and you guys did really, really great. I'm proud to be part of your team."

"Thanks, Greg. Couldn't have done it without you, buddy," Fincke replied.

This was the 157th spacewalk devoted to station assembly and maintenance since construction began in 1998, the sixth so far this year and the second for the Endeavour astronauts. Total station EVA time now stands at 988 hours and 19 minutes while the total for Endeavour's mission is 14 hours and 26 minutes. Feustel, completing his fifth spacewalk, has now logged 35 hours and 24 minutes of EVA time, moving him up to 30th on the list of most experience spacewalkers. Fincke, completing his seventh excursion, has now logged 34 hours and 19 minutes, moving up to 32nd.

CBS NEWS Coverage of Breaking Space News

09:20 AM EDT, 05/22/11 Update: Astronauts complete drive gear lubrication, cover installation

By WILLIAM HARWOOD
CBS News

Astronauts Andrew Feustel and Michael Fincke have completed lubrication of a massive solar array drive gear and re-installation of three thermal covers, the final task planned for today's spacealk. A fourth cover will be brought back inside the International Space Station for an examination after problems with retention washers that allowed at least one bolt to float away earlier.

Flight controllers have decided decontamination procedures will not be required for Feustel. While he was in the vicinity of an ammonia vent line during earlier work to recharge a solar array coolant system, controllers have concluded there is little likelihood that any trapped ammonia ice on his spacesuit could have survived the extended spacewalk. As a result, there is no need for a 30-minute "bake-out" procedure. But controllers are still discussing whether any testing is required to make sure.

As of 9:20 a.m. EDT, spacewalk duration stood at seven hours and 15 minutes. The astronauts are in the process of collecting tools and equipment before making their way back to the Quest airlock module.

CBS NEWS Coverage of Breaking Space News

08:30 AM EDT, 05/22/11 Update: Astronauts in home stretch of marathon spacewalk

By WILLIAM HARWOOD
CBS News

Running almost an hour and a half behind schedule, astronauts Andrew Feustel and Michael Fincke have completed work to lubricate the snares in a Canadian robot arm attachment and to mount coolant system radiator stowage beams to the International Space Station's power truss. The spacewalkers are making their way back to the left-side solar array drive mechanism to complete work to lubricate a bearing race to reduce long-term wear and tear.

It is not yet clear whether the astronauts will have time to re-install thermal covers over the solar alpha rotary joint that were removed earlier to provide access to the drive gear. Problems with loose bolts in the covers put the crew behind schedule earlier. That lost time, plus another half hour that may be needed to make sure Feustel's spacesuit wasn't contaminated by ammonia coolant during earlier work to recharge the reservoir in a solar array, could add an hour or more to the EVA's duration.

Flight controllers are still assessing whether decontamination procedures will be required for Feustel because of his proximity to an ammonia vent line. If decontamination is required, the spacewalkers likely will not reinstall the four SARJ thermal covers and the work will be deferred to a future excursion.

CBS NEWS Coverage of Breaking Space News

07:00 AM EDT, 05/22/11 Update: Solar array drive gear lubrication work continues; spacewalkers running about an hour behind schedule

By WILLIAM HARWOOD
CBS News

Work to lubricate one side of a massive solar array drive gear is complete. To bring the other side of the gear into view under four removed thermal covers, flight controllers will send commands to drive the left-side solar alpha rotary joint through 200 degrees, a procedure that will take about 45 minutes to complete.

Once the drive is stopped, astronauts Andrew Feustel and Michael Fincke will apply more Braycote grease to the bearing race of the drive gear in a bid to reduce friction and increase the mechanism's operational lifetime.

While the SARJ gear is driving to its new position, Feustel will install a lens cover on a camera used by the Canadian Special Purpose Dexterous Manipulator, or Dextre, a robot arm attachment fitting that in some cases can take the place of a spacewalking astronaut. With the lens cover in place, Feustel plans to lubricate the snares used by Dextre to hold components in place.

Fincke, meanwhile, will install two grapple bar stowage beams that will provide a temporary mounting point for coolant system radiator panels if replacement operations are ever required.

The spacewalkers are running about an hour behind schedule, in large part because of problems with bolts holding the SARJ thermal covers in place. Only four covers were removed and only three will be re-installed at the end of the spacewalk. Flight controllers now estimate the spacewalk, originally planned for six-and-a-half hours, likely will run past the seven-hour 15-minute mark.

CBS NEWS Coverage of Breaking Space News

05:30 AM EDT, 05/22/11 Update: Bolt problem prompts change in plans for solar array drive mechanism lubrication

By WILLIAM HARWOOD
CBS News

Trouble with bolts holding thermal covers in place on one of the space station's solar array drive mechanisms has forced flight controllers to modify plans for lubricating the underlying drive gear. When astronaut Michael Fincke removed the first two thermal covers, several supposedly captive bolts popped loose and floated free. Fincke managed to snag at least two bolts with his gloved hand, one from each panel, but two others apparently floated away.

Flight controllers, unsure about what was causing the bolts to release from lock washers in the thermal covers, told Fincke and astronaut Andrew Feustel not to remove as many covers as originally planned and to lubricate the solar alpha rotary joint as best they can with reduced access.

"We're going to minimize the number of covers we're going to take off," astronaut Steve Swanson radioed the crew from mission control. "We're going to continue with cover 16, since we're partway done with that, we're going to do cover 13 and cover nine. And those are the only covers we're going to take off at this time, we'll do the best job we can at lubing it, etc., but that's how far we're going with the covers."

He told the Fincke not to drive the bolts all the way out with his power tool and instead to loosen them and attempt to make the final few rotations by hand to avoid putting too much stress on the materials.

"I'd like to be even more methodical than usual on these," Fincke told Feustel. "We'll get the job done, but be very careful."

"The obvious concern is foreign object debris, in other words, any of the bolts or washers coming free," said mission control commentator Kyle Herring. "The obvious desire also is to get the port solar alpha rotary joint lubricated because it will be quite some time before that opportunity presents itself again. So that's what the teams have been discussing in the background."

Working to finish removing cover No. 16, Fincke reported yet another bolt popping off. Again, he managed to catch it with his gloved hand.

"I got the bolt," Fincke reported.

"That's your, like, fourth great catch, Mike," astronaut Gregory Chamitoff said from the shuttle Endeavour's flight deck.

"We're watching very closely and Spanky's doing a great job of being gentle," Swanson said. "And again, he gets the golden glove award for another catch. That's fantastic. We really don't have a good answer now why that's happening. We're going to have to talk about it."

Pressing ahead, Fincke removed panel 13 and nine without incident, reporting that each cover's bolts remained in place.

While that work was going on, Feustel used a nitrogen vent tool to purge an ammonia line used earlier to re-fill the coolant reservoir in the station's left-side outboard solar array. He reported a spray of ammonia ice crystals exiting the vent tool toward the rear of the station, staying well clear to prevent any hitting his spacesuit.

"I saw one piece that looked like it was headed my way, it was headed low, so I can't confirm it actually made contact," he reported. "It went out of my view sort of down past my waist and my legs. That was the only piece that I felt would be worth looking for. The other items were small, probably less than a centimeter in size, flakes, that were headed my way. The one piece that was coming was probably one-and-half centimeters in diameter, maybe a little larger."

Feustel then joined Fincke at the solar alpha rotary joint to begin lubricating the drive gear with Bracote grease.

CBS NEWS Coverage of Breaking Space News

04:25 AM EDT, 05/22/11 Update: Ammonia coolant recharge complete; bolt problem assessed

By WILLIAM HARWOOD
CBS News

Astronauts Andrew Feustel and Micheal Finke connected a final few ammonia jumpers, completing a path from a storage tank to the International Space Station's outboard left-side solar array. Then, after a successful leak test, Feustel made final connections and threw two valves to begin flowing about five pounds of ammonia to the port six solar array to replace coolant that's been lost due to a slow leak.

The astronauts were on the lookout for leaks, but no obvious problems were reported and the ammonia recharge procedure was completed without incident. Feustel then worked to attach a nitrogen vent tool to the ammonia line to purge any coolant still trapped inside before breaking down the cross-segment jumpers used to get the coolant to the far left end of the station's power truss.

Working in parallel, Fincke gathered tools and began work to remove thermal covers on the left-side solar alpha rotary joint, or SARJ, a massive drive mechanism used to rotate the outboard solar arrays to track the sun. In a critical bit of preventive maintenance, the astronauts plan to use grease guns to lubricate the drive gear to reduce friction and long-term wear and tear.

At least one bolt used to hold a cover in place popped out and floated away as the cover was removed. Flight controllers asked Fincke to hold off removing any additional covers while engineers assessed the issue and what, if anything, to do about a locking washer that appeared to be floating free inside the bolt's housing.

"I was really careful with these bolts and it didn't help me out," Fincke commented. A few minutes later he added, "I can confirm I was super extra careful and I was very surpsied to see it shoot."

Flight controllers joked about having Fincke wave his hands about to gently coax the washer free. But a more serious attempt likely will be made because of the threat a loose washer could pose to the geared solar array drive mechanism.

The covers in question have been removed and replaced before, and engineers suspect some of the lock washers may have been bent slightly, reducing their ability to hold the bolts in place. Flight controllers are re-evaluating how many covers to take off and whether the SARJ drive gear can be lubricated with fewer panels removed.

"Spanky, sorry you're having such a hard time with those bolts, buddy," Feustel radioed, using Fincke's nickname.

"Yeah, man, I was being really careful, too," Fincke replied.

"Yeah, I heard you. Bummer."

"That's all right," Fincke said. "We have a great team. We'll figure it out."

"We'll get photos, we'll lube what we can and we'll put back together what we can," Feustel said.

"Exactly."

CBS NEWS Coverage of Breaking Space News

02:20 AM EDT, 05/22/11 Update: STS-134 spacewalk No. 2 begins

By WILLIAM HARWOOD
CBS News

Floating in the International Space Station's Quest airlock module, Andrew Feustel and Michael Fincke switched their spacesuits to battery power at 2:05 a.m. EDT (GMT-4) to officially begin a planned six-and-a-half-hour spacewalk, the second of four planned by the Endeavour astronauts.

For identification, Feustel, call sign EV-1, is wearing a suit with solid red stripes around the legs while Fincke, EV-2,is wearing a suit with no markings.

The primary goals of the excursion are to add about five pounds of ammonia to the coolant system of the International Space Station's left-side outboard solar array and to lubricate a massive solar array drive mechanism to reduce long-term wear and tear.

This is the 157th spacewalk devoted to station assembly and maintenance since construction began in 1998, the sixth so far this year, the fifth for Feustel and the seventh for Fincke.

==================================

CBS NEWS Coverage of Breaking Space News

12:40 AM EDT, 05/22/11: Astronauts suit up for second spacewalk By WILLIAM HARWOOD CBS News

KENNEDY SPACE CENTER, FL--Astronauts Andrew Feustel and Michael Fincke suited up for a planned six-and-a-half-hour spacewalk Sunday to top off the ammonia coolant in one of the International Space Station's solar arrays and to lubricate a massive solar array drive mechanism to reduce long term wear and tear.

The excursion was scheduled to begin around 2:16 a.m. EDT (GMT-4) when the astronauts switch their spacesuits to battery power. For identification Feustel, call sign EV-1, is wearing a suit with red stripes while Fincke, EV-2, is wearing a suit with no markings.

This will be the 157th spacewalk devoted to space station assembly and maintenance since construction began in 1998, the sixth so far this year and the second of four planned by the Endeavour astronauts. It is the fifth spacewalk overall for Feustel, veteran of the most recent Hubble Space Telescope servicing mission, and the seventh for Fincke, who conducted six EVAs during earlier long-duration stays aboard the station.

The primary objective of Sunday's EVA is to route about five pounds of ammonia through a long multi-section hose stretching from a tank near the center of the station's power truss to the left-side outboard set of solar arrays, known as P6. About 55 pounds of ammonia circulate through radiators on each set of arrays to cool internal electrical components and P6 has a small leak somewhere in its coolant system.

During a spacewalk Friday, Feustel and astronaut Gregory Chamitoff hooked up hose segments and jumpers across truss segments to complete the line needed to reach P6. One set of jumpers was then disconnected to allow the left-side solar alpha rotary joint, or SARJ, to rotate normally so the P4 and P6 radiators could track the sun as required. The port SARJ will be stopped and the jumpers reconnected for the ammonia top off.

It will take about 10 minutes to recharge the P6 coolant system. After that, Fuestel will vent the line with nitrogen to remove any residual ammonia. Two ventings are required, one lasting 17 minutes and one about four minutes.

NASA has a history of problems with ammonia quick-disconnect fittings, and there are more than a half-dozen connections required for the P6 radiator fill. If either spacewalker gets ammonia on his suit, NASA will implement a "bake out" protocol to make sure any ammonia ice crystals sublimate away before the astronauts re-enter the space station.

"This isn't your household cleaner ammonia," Fincke said, "this is high-grade industrial ammonia so we have to be super careful not to get it on us or to spill it because it's quite dangerous if we brought it back inside. But we're going to recharge the ammonia lines. ... There's a series of jumpers that we have to go across, including the rotating solar alpha rotary joint, so we have some jumpers, a series of hoses that will fully charge our ammonia system.

"While Drew's doing that, I get to do a lubrication job, add some grease, some Braycote, to our solar alpha rotary joint," Fincke said. "We found the original design had some extra friction that we weren't expecting and it started to grind our joint (on the right side of the station). So since then, every couple years, (we've) started to add some grease on it and it rotates great. However, we won't have that ability so much in the future, so while Drew's working with the ammonia system I'll be lubricating the outside of the (left-side) solar alpha rotary joint so it can last another five to ten years, no problem."

When the SARJ work is complete and the astronauts have verified that all tools, tethers and jumpers are inboard of the port SARJ, commands will be sent to rotate the solar arrays through 200 degrees. The 45-minute procedure will spread the grease already applied and bring the other side of the gear and race into position for lubrication.

While the array is slowly rotating, Feustel will install a lens cover on a camera used by the Canadian Special Purpose Dexterous Manipulator, or Dextre, a robot arm attachment fitting that in some cases can take the place of a spacewalking astronaut. With the lens cover in place, Feustel plans to lubricate the snares used by Dextre to hold components in place.

Fincke, meanwhile, will install two grapple bar stowage beams that will provide a temporary mounting point for radiator panels if replacement operations are ever required.

Finally, Fincke and Feustel will apply a final bead of grease to the SARJ race ring before re-installing six covers and heading back to the airlock.

Because of the possibility of ammonia contamination, "we've got the procedures in place such that we will decontaminate the EVA crew once they get inside the airlock," said Flight Director Derek Hassmann. "We've got (sensors) that will monitor the amount of ammonia in the atmosphere. So we feel comfortable going forward with the EVA with the understanding that if we do get contaminated with ammonia, which is possible, we understand how to clean the crew up and keep them safe once they come inside."

Here is an updated timeline of the crew's planned activities for flight day seven (in EDT and mission elapsed time; includes revision F of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT...DD...HH...MM...SS...EVENT

05/21

09:26 PM...05...12...30...00...STS crew/Garan wakeup
10:01 PM...05...13...05...00...EVA-2: Airlock repress/hygiene break
10:51 PM...05...13...55...00...EVA-2: Airlock depress to 10.2 psi
11:11 PM...05...14...15...00...EVA-2: EVA prep

05/22

12:41 AM...05...15...45...00...EVA-2: Spacesuit purge
12:56 AM...05...16...00...00...EVA-2: Spacesuit prebreathe
01:46 AM...05...16...50...00...EVA-2: Crew lock depressurization
02:16 AM...05...17...20...00...EVA-2: Spacesuits to battery power
02:21 AM...05...17...25...00...EVA-2: Egress and setup
02:51 AM...05...17...55...00...EVA-2: P3-P4 re-route
03:06 AM...05...18...10...00...EVA-2/EV-1: Fill P5-P6 EAS jumper
03:06 AM...05...18...10...00...EVA-2/EV-2: ATA to fill
03:31 AM...05...18...35...00...EVA-2/EV-2: Port SARJ remove covers
04:06 AM...05...19...10...00...EVA-2/EV-1: Port SARJ remove covers
04:26 AM...05...19...30...00...EVA-2/EV-2: Port SARJ 1st lube
04:36 AM...05...19...40...00...EVA-2/EV-1: EAS setup/vent
05:01 AM...05...20...05...00...ISS crew wakeup
05:06 AM...05...20...10...00...EVA-2/EV-1: NH3 vent tool cleanup
05:11 AM...05...20...15...00...EVA-2/EV-2: P3-P4 NH3 jumper stow
05:32 AM...05...20...36...00...EVA-2/EV-1: NH3 jumper stow
05:46 AM...05...20...50...00...EVA-2/EV-2: S1 radiator grapple bar stow
05:46 AM...05...20...50...00...EVA-2/EV-1: ATA vent
06:26 AM...05...21...30...00...EVA-2/EV-1: SPDM LEE lube
06:56 AM...05...22...00...00...EVA-2/EV-2: Port SARJ 2nd lube
07:01 AM...05...22...05...00...EVA-2/EV-1: Port SARJ 2nd lube
07:31 AM...05...22...35...00...EVA-2: Port SARJ cover install
08:21 AM...05...23...25...00...EVA-2: Cleanup and ingress
08:46 AM...05...23...50...00...EVA-2: Airlock repressurization
09:01 AM...06...00...05...00...Spacesuit servicing
10:30 AM...06...01...34...00...Mission status briefing on NASA TV
11:31 AM...06...02...35...00...ISS change of command ceremony
12:26 PM...06...03...30...00...Garan sleep begins
12:56 PM...06...04...00...00...STS crew sleep begins
05:46 PM...06...08...50...00...ISS daily planning conference
06:45 PM...06...09...49...00...Flight director update
07:45 PM...06...10...49...00...Flight director replay
08:31 PM...06...11...35...00...ISS crew sleep begins
08:56 PM...06...12...00...00...STS crew/Garan wakeup
10:45 PM...06...13...49...00...Educational event with Tucson school

================================

CBS NEWS Coverage of Breaking Space News

-- Posted at 12:58 AM EDT, 05/21/11: Astronauts begin work to inspect damaged tile
-- Updated at 05:05 AM EDT, 05/21/11: Gouged heat shield tile inspected
-- Updated at 02:20 PM EDT, 05/21/11: MMT briefing delayed to 5 p.m. EDT
-- Updated at 04:20 PM EDT, 05/21/11: MMT briefing moved up to 4:30 p.m. EDT
-- Updated at 05:40 PM EDT, 05/21/11: MMT determines damaged tile no threat to safe re-entry

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The shuttle Endeavour's crew used an instrumented boom on the ship's robot arm Saturday to carry out a close-up, focused inspection of a damaged heat shield tile on the belly of the orbiter. By late afternoon, analysts concluded the damage posed no threat to the orbiter and NASA's Mission Management Team cleared the ship for re-entry as is.

"So all good results all the way around," said MMT Chairman LeRoy Cain. "Ultimately, their recommendation to the MMT was that we clear this area. In accepting that recommendation, we're essentially clearing the vehicle for re-entry at this point. There were no dissenting opinions, no alternate opinions, the entire team was pretty much on board with the assessments that were done."

NASA managers were optimistic that would be the case, based on an analysis of long-range telephoto views shot during Endeavour's final approach to the station Wednesday, but the focused inspection was ordered Friday to make absolutely sure.

The inspection work began after midnight when the space station's robot arm was used to pull Endeavour's heat shield inspection boom, or OBSS, out of the ship's cargo bay for hand off to the shuttle's 50-foot-long arm. Pilot Gregory Johnson, overseeing a series of computerized maneuvers, then positioned the arm under the shuttle's right side for close-up photos and laser scans.

The imagery and laser scans showed the damage site measured 2.43 inches by 2.95 inches with a maximum depth of .89 inches. Cain said the analysis showed the aluminum structure below the damage site would experience maximum temperatures of around 219 degrees Fahrenheit during re-entry, well below the 350-degree safety limit.

"With this data, to include the laser data that the team was able to acquire from the focused inspection, the analyses teams went back and essentially what they did is verify how much tile is still in the cavity," Cain said. "Because, of course, it's more important what remains than it is what's gone, per se. What we're interested in is protecting the structure underneath the tile and the associated systems."

And based on that analysis, "it was clearly OK," he said.

To make doubly sure they were on solid ground, analysts created a three-dimensional representation of the damage that had the uniform shape required for computer modeling. As such, the computer model assumed more damage than was seen in the actual gouge, "and in running that analysis, they determined we still cleared with plenty of margin."

The astronauts went to bed no knowing the Damage Assessment Team results, but Cain said they knew engineers were optimistic. With the damage site cleared for entry as is, the astronauts will have one less worry as they prepare for a second spacewalk Sunday to add ammonia coolant to a space station solar array.

Here is a timeline of the crew's remaining schedule for flight day six (in EDT and mission elapsed time; includes revision E of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT...DD...HH...MM...SS...EVENT

05/21
12:56 PM...05...04...00...00...Garan sleep begins
01:26 PM...05...04...30...00...Shuttle crew sleep begins
02:00 PM...05...05...04...00...Replay of PAO event with Pope Benedict XVI
03:16 PM...05...06...20...00...ISS evening planning conference
04:30 PM...05...07...34...00...Mission Management Team briefing on NTV
05:31 PM...05...08...35...00...ISS crew sleep begins
06:45 PM...05...09...49...00...Flight director update on NTV
08:45 PM...05...11...49...00...Flight director update replay on NTV
09:26 PM...05...12...30...00...Shuttle crew wakeup

CBS NEWS Coverage of Breaking Space News

08:15 AM EDT, 05/21/11: Pope Benedict XVI calls shuttle-station crew

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Pope Benedict XVI called the combined crews of the shuttle Endeavour and the International Space Station Saturday, wishing commander Mark Kelly's gravely wounded wife, Gabrielle Giffords, a steady recovery and asking station flight engineer Paolo Nespoli how he endured news of his mother's death in the isolation of space.

Speaking from a desk at the Vatican, the pope focused on the role of science and technology in solving problems on Earth and inspiring young people.

"From the space station, you have a very different view of the Earth, you fly over different continents and nations several times a day," he said, reading prepared remarks. "I think it must be obvious to you how we all live together on one Earth and how absurd it is that we fight and kill each (other).

"I know that Mark Kelly's wife was a victim of a serious attack and I hope her health continues to improve. When you're contemplating the Earth from up there, do you ever wonder about the way nations and people live together down here, about how science can contribute to the cause of peace?"

"Thank you for the kind words, your holiness, and thank you for mentioning my wife, Gabby," Kelly replied. "It's a very good question. We fly over most of the world and you don't see borders, but at the same time we realize that people fight with each other and there's a lot of violence in this world and it's really an unfortunate thing."

Kelly said people frequently fight over resources, pointing out that "the science and technology that we put into the space station to develop a solar power capability gives us pretty much an unlimited amount of energy. And if those technologies could be adapted more on Earth, we could possibly reduce some of that violence."

Pope Benedict asked the astronauts about their impression of the environment from the vantage point of space, wondering if "you see signs of phenomena to which we need to be more attentive?"

"It really is an extraordinary vantage point we have up here," station flight engineer Ronald Garan said. "On the one hand, we can see how indescribably beautiful the planet we have been given is. But on the other hand, we can really clearly see how fragile it is. The atmosphere when viewed from space is paper thin. And to think that this paper thin layer is all that separates every living thing from the vacuum of space is really a sobering thought."

The pope spoke in Italian to station flight engineer Paolo Nespoli, who's mother died in Italy May 2.

"Dear Paolo. I know that a few days ago your mom left you and in a few days you will come back home and you will not find her waiting for you," the pope said in translated remarks. "We're all close to you. Me too, I have prayed for her. How have you been living through this time of pain on the International Space Station? Do you feel isolated and alone? Or do you feel united amongst ourselves in a community that follows you with attention and affection?"

"Holy father, I felt your prayers and everyone's prayers arriving up here," Nespoli replied. "My colleagues on board the station were very close to me at this important time for me, a very intense moment, as well as my brothers and sisters, my uncles, my aunts, my relatives were close to my mom in her last moments. I'm very grateful for this. I felt very far, but also very close. And the thought of feeling all of you near me at this time has been a great relief. I also want to thank the Italian and American space agencies that had given me the opportunity so that I was able to speak with her in her last moments."

CBS NEWS Coverage of Breaking Space News

-- Posted at 12:58 AM EDT, 05/21/11: Astronauts begin work to inspect damaged tile
-- Updated at 05:05 AM EDT, 05/21/11: Gouged heat shield tile inspected

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The shuttle Endeavour's crew used the ship's robot arm Saturday to carry out a close-up, focused inspection of a damaged heat shield tile on the belly of the orbiter to help engineers determine whether the ship can safely re-enter Earth's atmosphere as is or whether more analysis or repairs might be needed.

Zoomed-in camera views showed the damage site in sharp detail, but it was not obvious to the untrained eye whether the depth of the gouge posed any sort of a threat. It appeared similar in appearance to tile damage seen in a 2007 flight that was cleared for entry as is, and NASA managers said Friday they did not believe the current "area of interest" posed a threat to a safe re-entry.

But the inspection was ordered to make sure, and engineers at the Johnson Space Center in Houston were standing by to convert the data into a three-dimensional map to fully assess the dimensions of the gouge and any potential safety issues it might pose. LeRoy Cain, chairman of NASA's Mission Management Team plans to brief reporters at 4 p.m. EDT (GMT-4) on the progress of the analysis.

The inspection work began after midnight when the space station's robot arm was used to pull Endeavour's heat shield inspection boom, or OBSS, out of the ship's cargo bay for hand off to the shuttle's 50-foot-long arm. Pilot Gregory Johnson, overseeing a series of computerized maneuvers, then positioned the arm under the shuttle's right side for close-up photos and laser scans.

Based on photos shot during Endeavour's approach to the space station Wednesday, the damage site appears to measure 3.22 inches by 2.49 inches. With today's inspection, engineers will be able to add the depth of the gouge to the analysis. That data, in combination with the thickness of the tile, the heat load experienced at that location and other factors will help engineers determine whether Endeavour can safely re-enter as is.

The inspection ended around 4:30 a.m.

At 7:11 a.m., the astronauts plan to take a call from Pope Benedict XVI at the Vatican. The shuttle-station crew includes two Italians -- station flight engineer Paolo Nespoli and Endeavour flight engineer Roberto Vittori -- and the VIP call will be the first from a pope to an orbiting spacecraft.

The rest of the crew's day will be devoted to making preparations for a spacewalk Sunday by astronauts Andrew Feustel and Michael Fincke to recharge a solar array ammonia coolant reservoir.

The shuttle crew is scheduled to go to bed at 1:26 p.m. with a wakeup call expected at 9:26 p.m. A mission status briefing is planned for 11:30 a.m. followed by a Mission Management Team update at 4 p.m. to review the focused inspection.

Here is a timeline of the crew's planned activities for flight day six (in EDT and mission elapsed time; includes revision E of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT...DD...HH...MM...SS...EVENT

05/20
09:26 PM...04...12...30...00...STS crew wakeup

05/21
12:31 AM...04...15...35...00...Station arm (SSRMS) grapples inspection boom (OBSS)
12:56 AM...04...16...00...00...OBSS unberth
01:11 AM...04...16...15...00...Quick-disconnect mod
01:21 AM...04...16...25...00...OBSS handoff to shuttle arm (SRMS)
01:36 AM...04...16...40...00...SSRMS ungrapple
02:01 AM...04...17...05...00...ISS crew wakeup
02:11 AM...04...17...15...00...SRMS maneuver review
02:41 AM...04...17...45...00...Focused inspection begins
03:01 AM...04...18...05...00...ISS daily planning conference
03:41 AM...04...18...45...00...REBA checkout
03:56 AM...04...19...00...00...EVA-2: Equipment lock preps
04:26 AM...04...19...30...00...Crew meals begin
04:41 AM...04...19...45...00...Focused inspection ends
05:41 AM...04...20...45...00...Laser scan (LDRI) downlink
07:11 AM...04...22...15...00...PAO event (Pope Benedict XVI calls shuttle crew)
07:31 AM...04...22...35...00...EVA-2: Tools configured
08:36 AM...04...23...40...00...LDRI downlink
09:21 AM...05...00...25...00...EVA-2: Procedures review
10:00 AM...05...01...04...00...Replay of PAO event with Pope Benedict XVI
11:30 AM...05...02...34...00...Mission status briefing on NTV
11:51 AM...05...02...55...00...EVA-2: Mask pre-breathe
12:36 PM...05...03...40...00...EVA-2: Airlock depress to 10.2 psi
12:56 PM...05...04...00...00...Garan sleep begins
01:26 PM...05...04...30...00...STS crew sleep begins
02:00 PM...05...05...04...00...Replay of PAO event with Pope Benedict XVI
03:16 PM...05...06...20...00...ISS evening planning conference
04:00 PM...05...07...04...00...Mission Management Team briefing on NTV
05:31 PM...05...08...35...00...ISS crew sleep begins
06:45 PM...05...09...49...00...Flight director update on NTV
08:45 PM...05...11...49...00...Flight director update replay on NTV
09:26 PM...05...12...30...00...STS crew/Garan wakeup

CBS NEWS Coverage of Breaking Space News

01:00 AM EDT, 05/21/11: Astronauts begin work to inspect damaged tile

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The shuttle Endeavour's crew began work early Saturday to carry out a close-up, focused inspection of a damaged heat shield tile on the belly of the orbiter to help engineers determine whether the ship can safely re-enter Earth's atmosphere as is or whether more analysis or repairs might be needed. NASA managers do not believe the "area of interest" poses a safety threat, but the inspection was ordered to make sure.

Because of clearance issues, the space station's robot arm was used to pull Endeavour's heat shield inspection boom, or OBSS, out of the ship's cargo bay for hand off to the shuttle's 50-foot-long arm. Pilot Gregory Johnson, overseeing a series of computerized maneuvers, plans to position the arm under the shuttle's right side for close-up photos and laser scans to precisely measure the dimensions and depth of the gouge.

The data will be downlinked to the Johnson Space Center in Houston where NASA's Damage Assessment Team will be standing by to carry out a detailed evaluation. The damaged tile, located between the right main landing gear door and a liquid oxygen feed line port, is the only area of concern with the shuttle's heat shield that has not yet been cleared for entry.

At 7:11 a.m. EDT (GMT-4), the astronauts plan to take a call from Pope Benedict XVI at the Vatican. The shuttle-station crew includes two Italians -- station flight engineer Paolo Nespoli and Endeavour flight engineer Roberto Vittori -- and the VIP call will be the first from a pope to an orbiting spacecraft.

The rest of the crew's day will be devoted to making preparations for a spacewalk Sunday by astronauts Andrew Feustel and Michael Fincke to recharge a solar array ammonia coolant reservoir.

The shuttle crew is scheduled to go to bed at 1:26 p.m. with a wakeup call expected at 9:26 p.m. A mission status briefing is planned for 11:30 a.m. followed by a Mission Management Team update at 4 p.m. to review the focused inspection.

Here is an updated timeline of the crew's planned activities for flight day six (in EDT and mission elapsed time; includes revision E of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT...DD...HH...MM...SS...EVENT

05/20
09:26 PM...04...12...30...00...STS crew wakeup

05/21
12:31 AM...04...15...35...00...Station arm (SSRMS) grapples inspection boom (OBSS)
12:56 AM...04...16...00...00...OBSS unberth
01:11 AM...04...16...15...00...Quick-disconnect mod
01:21 AM...04...16...25...00...OBSS handoff to shuttle arm (SRMS)
01:36 AM...04...16...40...00...SSRMS ungrapple
02:01 AM...04...17...05...00...ISS crew wakeup
02:11 AM...04...17...15...00...SRMS maneuver review
02:41 AM...04...17...45...00...Focused inspection begins
03:01 AM...04...18...05...00...ISS daily planning conference
03:41 AM...04...18...45...00...REBA checkout
03:56 AM...04...19...00...00...EVA-2: Equipment lock preps
04:26 AM...04...19...30...00...Crew meals begin
04:41 AM...04...19...45...00...Focused inspection ends
05:41 AM...04...20...45...00...Laser scan (LDRI) downlink
07:11 AM...04...22...15...00...PAO event (Pope Benedict XVI calls shuttle crew)
07:31 AM...04...22...35...00...EVA-2: Tools configured
08:36 AM...04...23...40...00...LDRI downlink
09:21 AM...05...00...25...00...EVA-2: Procedures review
10:00 AM...05...01...04...00...Replay of PAO event with Pope Benedict XVI
11:30 AM...05...02...34...00...Mission status briefing on NTV
11:51 AM...05...02...55...00...EVA-2: Mask pre-breathe
12:36 PM...05...03...40...00...EVA-2: Airlock depress to 10.2 psi
12:56 PM...05...04...00...00...Garan sleep begins
01:26 PM...05...04...30...00...STS crew sleep begins
02:00 PM...05...05...04...00...Replay of PAO event with Pope Benedict XVI
03:16 PM...05...06...20...00...ISS evening planning conference
04:00 PM...05...07...04...00...Mission Management Team briefing on NTV
05:31 PM...05...08...35...00...ISS crew sleep begins
06:45 PM...05...09...49...00...Flight director update on NTV
08:45 PM...05...11...49...00...Flight director update replay on NTV
09:26 PM...05...12...30...00...STS crew/Garan wakeup

CBS NEWS Coverage of Breaking Space News

04:55 PM EDT, 05/20/11: NASA orders 'focused inspection' of heat shield damage

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The Endeavour astronauts will use an instrumented boom on the end of the shuttle's robot arm early Saturday to make a close-up, "focused" inspection of a gouge in a heat shield tile on the belly of the orbiter that was spotted during final approach to the space station, NASA managers said Friday.

LeRoy Cain, chairman of NASA's Mission Management Team, said shuttle pilot Gregory Johnson would oversee computer-assisted maneuvers to put the arm under the shuttle's right side to take high-resolution photos and laser scans of the damage site.

The data will be downlinked to NASA's Damage Assessment Team, or DAT, to determine if Endeavour can safely re-enter Earth's atmosphere as is or whether more analysis or repairs might be needed. Engineers suspect the former, but the inspection was ordered to make sure.

The Endeavour astronauts went to bed shortly before 1:30 p.m. EDT (GMT-4) and are scheduled to wake up to begin flight day six at 9:26 p.m. At 12:35 a.m. Saturday, the space station's robot arm will pull the inspection boom out of Endeavour's cargo bay and hand it off to the shuttle's arm. The actual damage inspection will begin around 2:41 a.m.

"There's nothing alarming here and we're really not concerned," Cain told reporters Friday. "We're doing what we understand and know we need to go do in these scenarios. This is one that we feel pretty confident we're going to be able to clear it once we get some higher fidelity data."

But since engineers don't know that for sure, "we take it in this order," Cain said. "We go get the better data, do the higher fidelity, more accurate, less conservative analysis, get the answer and from that answer determine if there's anything beyond that that we need to do. But our sense is that this is not one that ultimately we're going to be concerned about."

During Endeavour's final approach to the space station Wednesday, the crew of the station photographed the heat shield tiles on the shuttle's belly during a now-routine back-flip maneuver directly below the lab complex. Image analysts spotted seven "areas of interest" that required additional analysis. All of those were cleared for re-entry as is with one exception: a relatively deep gouge in a tile between Endeavour's right-side main landing gear door and a smaller door that covers a liquid-oxygen feed line port.

"Ultimately, we determined that we're going to go do a focused inspection to get some more data on this particular site," Cain said.

CBS NEWS Coverage of Breaking Space News

03:10 PM EDT, 05/20/11: NASA, Russians agree on out-of-this-world photo op

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--An Italian astronaut aboard a departing Russian Soyuz ferry craft Monday will snap out-of-this-world pictures and video showing the International Space Station with the shuttle Endeavour attached before heading for a landing in Kazakhstan, NASA officials said Friday.

With the shuttle program slated for retirement after one more flight in July, the one-of-a-kind photo opportunity comes at almost the last possible minute. The pictures snapped Monday will capture the first and only time a shuttle and the station have appeared in the same field of view from a remote vantage point, a family portrait expected to grace history books for years to come.

"This is going to be a great opportunity for the spaceflight community," said Kenneth Todd, space station integration manager at the Johnson Space Center in Houston.

The opportunity to take the pictures arose when an electrical glitch forced NASA to delay Endeavour's launching fro April 29 to May 16, ensuring the shuttle would still be docked when the Soyuz TMA-20 spacecraft departed. Expedition 27 commander Dimitry Kondratyev, Italian astronaut and flight engineer Paolo Nespoli and NASA astronaut Catherine "Cady" Coleman are scheduled to land in Kazakhstan Monday evening U.S. time to close out a 159-day stay in space.

NASA first suggested a Soyuz fly-around earlier this year, but it would have required a Soyuz undocking and re-docking and the Russians, citing technical considerations, did not go along. NASA managers were hoping for an opportunity during the final shuttle flight in July when the Endeavour launch delay presented a less complicated scenario.

To accommodate the photo survey, Kondratyev will undock at 5:35 p.m. EDT (GMT-4) Monday, about an hour and a half earlier than originally planned. Flying manually, Kondratyev will back the Soyuz straight away from the lab complex and begin station keeping at a distance of about 600 feet. Nespoli, seated to the commander's left in the spacecraft's central descent module, will move into the forward, normally closed habitation module to photograph the shuttle-station "stack" through a window with a direct line of sight.

While Nespoli is preparing his cameras and a laser range finder for use, the space station will carry out a 130-degree rotation to provide an unobstructed side view of the shuttle-station complex, with Endeavour on the left end of the stack just above the limb of the Earth. The station's orientation at undocking and its subsequent 2-degree-per-second maneuver were carefully planned to keep the sun out of Kondratyev's eyes while ensuring good lighting for the imagery.

Once the brief photo window closes, Nespoli will float back into the cramped descent module and seal the hatchway to the habitation section. That hatch is normally closed and locked before undocking and the Soyuz crew will have to carry out leak checks, along with suit checks, to ensure a safe descent after the photo opportunity ends. Landing is targeted for 10:26 p.m. Monday.

Unlike the space shuttle, which is equipped with a KU-band antenna for near-continuous communications through a NASA satellite network, the Soyuz crew will have no way to transmit the images from space. NASA managers will be standing by in Kazakhstan to copy the digital photos and video so the long-sought imagery can make its way to both Moscow and Houston.

Details remain to be worked out, however, and it's not yet clear when the imagery will be released to the media.

In the meantime, here is a timeline of major re-entry events (in EDT and mission elapsed time; best viewed with fixed-width font):

EDT/EST.......DDD...HH...MM...SS...EVENT

12/15/10 (EST)
02:09:25 PM...000...00...00...00...Soyuz TMA-20 Launch

5/23/11 (EDT)
04:40:00 PM...159...01...30...35...US to Russian attitue control system handover
04:52:00 PM...159...01...42...35...ISS maneuver to undocking attitude
05:24:36 PM...159...02...15...11...Sunrise
05:29:32 PM...159...02...20...07...Daily orbit 13 Russian ground station AOS
05:31:00 PM...159...02...21...35...ISS to free drift
05:32:00 PM...159...02...22...35...Nominal separation command
05:35:00 PM...159...02...25...35...Physical separation/hooks open
05:36:40 PM...159...02...27...15...ISS to LVLH snap-and-hold
05:38:00 PM...159...02...28...35...Soyuz manual separation burn #1
05:41:00 PM...159...02...31...35...Arrival at stationkeeping (590-650 feet)
05:41:00 PM...159...02...31...35...Habitation module ingress
05:43:20 PM...159...02...33...55...ISS return to undocking attitude
05:44:33 PM...159...02...35...08...Daily orbit 13 Russian ground station LOS
05:50:00 PM...159...02...40...35...Begin ISS photography
05:52:28 PM...159...02...43...03...Noon
05:55:00 PM...159...02...45...35...ISS maneuver to photography attitude
06:06:00 PM...159...02...56...35...ISS in photo attitude
06:15:00 PM...159...03...05...35...Soyuz manual separation burn #2
06:20:00 PM...159...03...10...35...Habitation module egress; start leak checks
06:20:20 PM...159...03...10...55...Sunset -- photography complete
06:21:00 PM...159...03...11...35...ISS maneuver to duty attitude
06:56:01 PM...159...03...46...36...Sunrise
07:00:00 PM...159...03...50...35...Russian to US attitude control handover
07:00:00 PM...159...03...50...35...Hatch and suit leak checks complete
07:02:08 PM...159...03...52...43...Daily orbit 14 RGS AOS
07:19:33 PM...159...04...10...08...Daily orbit 14 RGS LOS
07:36:00 PM...159...04...26...35...Sunrise at landing Site
08:30:13 PM...159...05...20...48...Daily orbit 15 RGS AOS
08:53:58 PM...159...05...44...33...Daily orbit 15 RGS LOS
09:36:14 PM...159...06...26...49...Soyuz deorbit burn start (257.7 mph)
09:40:39 PM...159...06...31...14...Deorbit burn complete
10:03:36 PM...159...06...54...11...Atmospheric entry (62 miles altitude)
10:11:49 PM...159...07...02...24...Command to open parachute (6.6 miles altitude)
10:26:49 PM...159...07...17...24...Landing

CBS NEWS Coverage of Breaking Space News

09:35 AM EDT, 05/20/11 Update: Spacewalk No. 1 ends

By WILLIAM HARWOOD
CBS News

Astronauts Andrew Feustel and Gregory "Taz" Chamitoff returned to the Quest airlock and began repressurizing the cramped chamber at 9:29 a.m. EDT (GMT-4), officially ending a six-hour 19-minute spacewalk, the first of four planned for the shuttle Endeavour's mission.

The excursion ended a few minutes early because of a carbon dioxide sensor failure in Chamitoff's spacesuit. While the astronaut's CO2 scrubber continued working normally, NASA flight rules prompted controllers to use more conservative estimates for how long he could remain outside, As a result, work to finish wiring in a pair of antennas was ruled out and the astronauts were told to pack up their tools and head back to the airlock.

Three more spacewalks are planned and the antenna wiring presumably will be added to one of the other excursions.

"I'd like to congratulate you both on an outstanding EVA, it was a pleasure working with you," radioed Michael Fincke, the spacewalk coordinator. "You guys did great, we got a lot done. And Taz, congratulations on your first EVA. I know it was a dream come true and it was definitely awesome. Good work."

This was the 156th spacewalk devoted to station assembly and maintenance since construction began in 1998, the fifth so far this year, the fourth for Feustel and the first for Chamitoff. Station assembly spacewalk time now stands at 980 hours and 12 minutes, or 40.8 days.

CBS NEWS Coverage of Breaking Space News

08:40 AM EDT, 05/20/11 Update: Spacesuit sensor failure forces astronauts to skip antenna wiring

By WILLIAM HARWOOD
CBS News

Spacewalkers Andrew Feustel and Gregory Chamitoff were told to skip a final bit of work Friday because of a carbon dioxide sensor failure in Chamitoff's spacesuit. The sensor problem forced flight controllers to adopt more conservative guidelines that did not leave the astronauts enough time to finish hooking up new wireless antennas, a job that involved a fair amount of re-wiring.

The antenna work was the final major objective of the spacewalk, which had proceeded smoothly to that point. Feustel and Chamitoff successfully replaced a materials science space exposure experiment package, installed a light on a crew equipment cart, replaced a cover on a solar array rotary joint and connected jumpers and hoses for use during a spacewalk Sunday to recharge ammonia coolant on one of the space station's solar arrays.

The new antennas, attached to a pair of spacewalk handrails, were mounted on the station and the astronauts were getting ready to remove micrometeoroid shielding to gain access to a wiring panel when Chamitoff's CO2 sensor failed.

"I'm getting a CO2 'bad sensor' message," Chamitoff radioed at 7:41 a.m.

"Say again, Taz?" spacewalk coordinator Michael Fincke asked.

"CO2 sensor bad message."

"Copy, CO2 bad sensor message. We'll meet you in the checklist," Fincke replied. "It pretty much says you are to periodically monitor your physical condition because your CO2 sensor has failed. If you notice symptoms you'll let us know and your helmet purge valve will go to open and we'll terminate the EVA. But in the meantime, if you have no symptoms we're going to continue. How copy?

"Understood. And I'll be monitoring my own symptoms."

"OK, and I know with all your station experience you know your CO2 symptoms well and we won't worry about it," Fincke said. "But we might bother you every 15 or 20 minutes to see how you're doing."

At the time of the failure, controllers calculated Chamitoff's suit would be good for more than seven seven hours. But after the sensor failure, adopting more conservative calculations, they concluded he needed to be back in the airlock within about 90 minutes. That did not leave enough time to complete the antenna re-wiring.

CBS NEWS Coverage of Breaking Space News

06:55 AM EDT, 05/20/11 Update: Ammonia line set up and ready for use Sunday

By WILLIAM HARWOOD
CBS News

Astronauts Andrew Feustel and Gregory Chamitoff connected a series of jumpers and hoses to set up a long ammonia line stretching the length of the International Space Station's left-side power truss.

During a spacewalk Sunday by Feustel and astronaut Michael Fincke, coolant will be routed to the outboard left-side solar array to recharge its ammonia supply.

The astronauts now are working on their final planned task, installation of two antennas built into handrails, to improve wireless communications for experiments and other systems outside the lab complex.

CBS NEWS Coverage of Breaking Space News

05:15 AM EDT, 05/20/11 Update: Spacewalkers complete experiment swap out

By WILLIAM HARWOOD
CBS News

Astronauts Gregory Chamitoff and Andrew Feustel have accomplished the first objective of today's spacewalk, moving a space exposure experiment package from the space station to the shuttle Endeavour for return to Earth and installing a fresh experiment package in its place.

Chamitoff now plans to install a light on a crew equipment cart on the forward side of the station's solar power truss while Feustel re-installs a protective cover on one of the station's solar array rotary joints that was removed during earlier servicing.

With those tasks complete, the astronauts will begin work to hook up ammonia coolant jumpers on the left side of the power truss. The goal is to set up a long ammonia line from a storage tank near the center of the truss to the outboard left-side solar array, which has a small leak in its coolant supply.

During a spacewalk Sunday, Feustel and Michael Fincke plan to replace lost coolant in the array. But first, segments of the ammonia supply line must be connected and vented.

CBS NEWS Coverage of Breaking Space News

03:15 AM EDT, 05/20/11 Update: Spacewalk begins

By WILLIAM HARWOOD
CBS News

Floating in the International Space Station's Quest airlock module, Andrew Feustel and Gregory Chamitoff switched their spacesuits to battery power at 3:10 a.m. EDT (GMT-4) to officially begin a planned six-and-a-half-hour spacewalk, the first of four planned by the Endeavour astronauts.

For identification, Feustel, call sign EV-1, is wearing a suit with solid red stripes around the legs while Chamitoff, EV-3, is wearing a suit with broken stripes.

The primary goals of the excursion are to replace a materials science space exposure experiment, to install an antenna for improved external communications and to set up an ammonia line that will be used during a second spacewalk Sunday to add coolant to a solar array reservoir that has a slow leak.

This is the 156th spacewalk devoted to station assembly and maintenance since construction began in 1998, the fifth so far this year, the fourth for Feustel and the first for Chamitoff.

CBS NEWS Coverage of Breaking Space News

12:50 AM EDT, 05/20/11: Astronauts prep for spacewalk

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Astronauts Andrew Feustel and Gregory Chamitoff are gearing up for a six-and-a-half-hour spacewalk to set up ammonia transfer lines between a storage tank and the International Space Station's outboard left-side solar arrays to clear the way for work during a second spacewalk Sunday to top off a leaking coolant reservoir.

The astronauts spent the night in the station's Quest airlock at a reduced pressure of 10.2 pounds per square inch to help remove nitrogen from their bloodstreams and prevent the bends when working in NASA's low-pressure spacesuits. They plan to switch their suits to battery power around 3:16 a.m. EDT (GMT-4) to officially kick off the first of four spacewalks planned for the shuttle Endeavour's mission.

For identification, Feustel, call sign EV-1, will be wearing a suit with solid red stripes around the legs while Chamitoff, in the EV-2 role, will be wearing a suit with broken stripes.

This will be the 156th spacewalk devoted to station assembly and maintenance since construction began in 1998, the fifth so far this year, the fourth for Feustel and the first for Chamitoff. Going into Friday's excursion, total space station EVA time stood at 973 hours and 53 minutes, or about 40.6 days.

The primary goals of the mission's first spacewalk are to retrieve a materials science space exposure experiment mounted on External Logistics Carrier No. 2; to install a replacement; and to hook up ammonia line jumpers to set up a pipeline from an ammonia coolant tank near the center of the station's power truss to the outboard left-side solar array.

The Materials International Space Station Experiments -- MISSE -- are the size of suitcases.

"It's a space exposure experiment," Chamitoff said in a NASA interview. "Basically they're like large suitcases with lots of samples inside, and those samples can be everything from materials to paints to coatings to electronic equipment to biological samples, and they can come from different organizations.

"The idea is to expose these things to the harsh environment of space for a long period and see what happens -- if the seeds will still germinate, if a paint material will protect what's below it, see if a circuit can still work and to help us design better systems for the future.

"There are two experiments out there that are a part of MISSE 7," Chamitoff said. "We're going to retrieve those, close (them) up, take them back, put them in the shuttle cargo bay, and then we take new ones out of the cargo bay, MISSE 8, and we install them up on the truss. They'll be out there for six months to a year before they come in."

The spacewalkers then will turn their attention to preparations for topping off the ammonia coolant supply in the port six, or P6, solar array segment.

Each of the station's four sets of solar arrays are equipped with radiators that use circulating ammonia to carry away heat generated by batteries and electronics subsystems. Engineers have been monitoring a small leak in the P6 coolant system and during the crew's second spacewalk, the astronauts will top off the coolant in the P6 radiator panels. But first, Feustel and Chamitoff must hook up the jumpers to complete what amounts to a long hose running from an ammonia storage tank on the P1 truss segment all the way out to P6.

"We have to sort of connect a lot of ammonia hoses between a lot of segments including one that jumps across the rotating solar alpha rotary joint, which normally can't have a hose running across (it). It has to spin freely," Chamitoff said.

"We're going to go out and we're going to connect all these hoses and then vent them basically so that they're filled with N2, the nitrogen. We're going to vent them so that they're ready to be used for the ammonia fill on the next EVA."

After the line is vented, the segment crossing the solar alpha rotary joint -- the P3/P4 jumper -- will be disconnected so the outboard arrays can rotate as required to track the sun. Those jumpers will be reconnected during the second spacewalk when the ammonia fill will take place.

After the jumper work, Chamitoff and Feustel will install a new wireless antenna that can be used by external experiments and other payloads.

"There are experiments and payloads outside the space station (that) need to communicate to the data system and they're installing a couple of antennas and all the wiring for that to enable those pieces of equipment or experiments to communicate to internal systems," Chamitoff said.

"It's a lot of wiring. It's a little messy with long wires and it takes a while. The thing that's maybe a little interesting about that is just that in order for us to do that, they have to disable some things internally. We may lose communication. We may have to wave through the window and say everything's OK, and then go down and finish the work and come back and say everything's OK. We'll see how that goes but it should be interesting."

Here is an updated timeline of the crew's planned activities for flight day five (in EDT and mission elapsed time; includes revision D of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT...DD...HH...MM...SS...EVENT

05/19
10:26 PM...03...13...30...00...STS crew/Garan wakeup (flight day 5)
11:01 PM...03...14...05...00...EVA-1: Airlock repress/hygiene break
11:51 PM...03...14...55...00...EVA-1: Airlock depress to 10.2 psi

05/20
12:11 AM...03...15...15...00...EVA-1: Campout EVA prep
01:41 AM...03...16...45...00...EVA-1: Spacesuit purge
01:56 AM...03...17...00...00...EVA-1: Spacesuit prebreathe
02:01 AM...03...17...05...00...ISS crew wakeup
02:46 AM...03...17...50...00...EVA-1: Crew lock depressurization
03:16 AM...03...18...20...00...EVA-1: Spacesuits to battery power
03:21 AM...03...18...25...00...EVA-1: Egress and setup
03:31 AM...03...18...35...00...ISS daily planning conference
03:41 AM...03...18...45...00...EVA-1: MISSE 7 retrieve
04:41 AM...03...19...45...00...EVA-1/EV-2: P3 CETA light install
04:41 AM...03...19...45...00...EVA-1/EV-1: MISSE 8 install
05:06 AM...03...20...10...00...EVA-1/EV-2: Starboard SARJ cover 7 install
05:21 AM...03...20...25...00...EVA-1/EV-1: P3-P4 NH3 jumper install
05:31 AM...03...20...35...00...EVA-1/EV-2: P3-P4 NH3 jumper install
05:56 AM...03...21...00...00...EVA-1/EV-1: P5-P6 NH3 jumper install
05:56 AM...03...21...00...00...EVA-1/EV-2: P4 NH3 jumper stow
06:11 AM...03...21...15...00...EVA-1/EV-1: P6 EAS jumper install
06:31 AM...03...21...35...00...EVA-1: Lab EWC antenna
07:31 AM...03...22...35...00...EVA-1/EV-2: P3-P4 mate
07:51 AM...03...22...55...00...EVA-1: P16A/J16A mate
08:36 AM...03...23...40...00...EVA-1/EV-1: P1-P2 mate
08:36 AM...03...23...40...00...EVA-1/EV-2: Cleanup
08:51 AM...03...23...55...00...EVA-1/EV-1: QD tool bag reconfig
09:16 AM...04...00...20...00...EVA-1: Cleanup and airlock ingress
09:46 AM...04...00...50...00...EVA-1: Airlock repressurization
10:01 AM...04...01...05...00...Post-EVA servicing
11:30 AM...04...02...34...00...Mission status briefing No. 1 on NTV
12:56 PM...04...04...00...00...Garan sleep begins
01:00 PM...04...04...04...00...Mission status briefing No. 2 on NTV
01:26 PM...04...04...30...00...STS crew sleep begins
03:00 PM...04...06...04...00...Daily highlights reel on NTV (repeated hourly)
03:16 PM...04...06...20...00...ISS daily planning conference
04:00 PM...04...07...04...00...Mission Management Team briefing on NTV
05:31 PM...04...08...35...00...ISS crew sleep begins
07:45 PM...04...10...49...00...Flight director update on NTV
08:45 PM...04...11...49...00...Flight director update replay on NTV
09:26 PM...04...12...30...00...STS crew/Garan wakeup (flight day 6)

CBS NEWS Coverage of Breaking Space News

07:15 PM, 05/19/11: Engineers continue shuttle heat shield assessment

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Engineers have eliminated one of three damage sites on the shuttle Endeavour's heat shield tiles as an area of concern and a second may be dismissed and deemed safe for re-entry as is by Friday, a senior manager said Thursday. But one damage site on the shuttle's belly may require an additional, "focused," inspection Saturday to make sure repairs are not needed.

LeRoy Cain, chairman of NASA's Mission Management Team, made it clear during a status briefing Thursday that he was not overly concerned by the damage to Endeavour's heat shield tiles, saying the primary area of interest was very similar to a tile gouge seen during a 2007 mission by Endeavour. In that case, a focused inspection was carried out and engineers determined, correctly as it turned out, that the shuttle could safely re-enter without the need for any repairs.

Addressing the "worry factor" for Endeavour's current mission, Cain said "when I was here yesterday, I talked about the fact that I am not concerned about the damage that we're seeing here, it's certainly not alarming. And the team is not concerned about it. My confidence is largely derived from the fact that we have a very good process for dispositioning these things, we know exactly how to go assess them, we've gotten better and better at it and we know that our models are doing nothing but improving as time goes on and we get more experience.

"In the event that we do come up to a point in our assessment where we feel like we need to get some more data, we know how to go do that, i.e., focused inspection, which we're talking about doing now. ... And then when it comes right down to it, if focused inspection and the analysis of the data from focused inspection determine we didn't have the kind of margins here that we wanted to have, then we do have some options to go do some repair."

In the wake of the 2003 Columbia disaster, NASA developed tile repair tools that range from STA-54, a thick material applied with a grease gun-like applicator that could be used by spacewalking astronauts to fill in a tile gouge, to a heat-resistant overlay that could be bolted in place over a larger damage site.

"But that's really about as far as I want to take this discussion because I feel pretty confident if, in fact, we're not able to clear it by the morning, when we get the focused inspection data we'll be able to clear this problem and not have to do anything. But having said that, we're going to go do whatever is necessary and we're going to follow the data all the way along."

During Endeavour's approach to the International Space Station Wednesday, commander Mark Kelly guided the ship through a computer-assisted back-flip maneuver to expose the shuttle's belly to the lab complex. Station astronauts Catherine Coleman, Paolo Nespoli and Expedition 27 commander Dmitry Kondratyev, photographed the shuttle's heat shield with powerful telephoto lenses to help engineers look for any signs of damage.

The photographs showed seven damage sites under the right wing running in a rough line from the right-side main landing gear door to an aft elevon, or wing flap. As of Wednesday, four of the seven sites had been ruled safe for entry as is and by Thursday, one of the remaining sites was eliminated, leaving just two areas of concern.

One of those, a gouge running across the hingeline of Eneavour's right-side inboard elevon, may be eliminated by Friday, Cain said. The other site, located between the right main landing gear door and an external tank liquid oxygen feel line port, may be more difficult to assess without a focused inspection to help determine the depth of the gouge.

The damage site measures 3.22 inches by 2.49 inches and is believed to be about seven tenths of an inch deep. The 2007 impact cited earlier by Cain resulted in a gouge measuring 3.48 inches by 2.31 inches with a depth of 1.12 inches. In that case, engineers eventually cleared Endeavour for re-entry as is and the shuttle completed a safe landing.

"In summary, we have some more work to do on a couple of these sites," Cain said. "Petty high confidence we're going to clear one of them, some possibility we're going to clear the other one. We have procedures built and timelines built and ready to go to the crew tomorrow morning whatever the scenario might be, for one or both of the sites. Or neither of them."

In a focused inspection, a camera on the end of the space station's robot arm would be used to carefully inspect a damage site of interest. If such an inspection is ordered for Endeavour, the astronauts would use a three-hour block of off-duty time early Saturday, starting around 2:26 a.m. EDT (GMT-4).

CBS NEWS Coverage of Breaking Space News

-- Posted at 01:50 AM EDT, 05/19/11: Endeavour astronauts set to install $2 billion cosmic ray detector
-- Updated at 04:10 AM EDT, 05/19/11: AMS pulled from shuttle cargo bay; installation proceeding
-- Updated at 06:50 AM EDT, 05/19/11: AMS attached to station; Ting congratulates shuttle crew
-- CORRECTED at 07:25 AM EDT, 05/19/11: Deleting incorrect electron volt/light bulb conversion
-- Updated at 01:45 PM EDT, 05/19/11: Mission status briefing; Ting says AMS operating flawlessly

Editor's note... Portions of this status report were written for the CBS News STS-134 mission preview.

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The Endeavour astronauts installed a $2 billion cosmic ray detector on the International Space Station Thursday, a powerful magnet surrounded by a complex array of sensors that will study high-energy particles from the depths of space and time to look for clues about the formation and evolution of the universe.

"Thank you very much for the great ride and safe delivery of AMS to the station," radioed Sam Ting, the Nobel laureate who has managed the Alpha Magnetic Spectrometer project for more than 15 years. "Your support and fantastic work have taken us one step closer to realizing the science potential of AMS. With your help, for the next 20 years, AMS on the station will provide us a better understanding of the origin of the universe."

"Thank you, Sam," Endeavour commander Mark Kelly replied from the International Space Station. "I was just looking out the window of the orbiter and AMS looks absolutely fantastic on the truss. I know you guys are really excited and you're probably getting data and looking at it already."

Within two or three hours of installation and activation, the AMS was sending down a torrent of data, recording the passage of thousands of cosmic ray particles.

"The detector has 300,000 channels in the electronics, 650 microprocessors and the detectors are aligned to (an accuracy of) one tenth of a human hair," Ting told reporters at a mission status briefing. "We immediately checked all the detectors, everything functioned properly. Not a single one was broken, not a single electronic channel was malfunctioning. Right away, we began to see an enormous amount of data coming down."

Ting showed off two sample graphs marking the passage of an electron with an energy of 20 billion electron volts and a carbon nucleus with an energy of 42 billion electron volts.

"This shows the detector functioned properly without any noticeable deformation whatsoever," he said. "We're very pleased. It took us 17 years to build this thing and (for the) duration of the space station we will be there, hopefully 10 to 20 years, and we hope ... we will be able to make an important contribution to our understanding of the origin of the universe."

Astronauts Andrew Feustel and Roberto Vittori, working on the shuttle's aft flight deck, started the installation operation just before 3 a.m. EDT (GMT-4), using Endeavour's 50-foot-long arm to slowly pull the 7.5-ton Alpha Magnetic Spectrometer from its perch at the back of the orbiter's payload bay.

After moving it to a point over the right side of the shuttle, pilot Gregory Johnson and Gregory "Taz" Chamitoff, operating the station's robot arm from a computer console inside the lab's multi-window cupola module, took over to move AMS into position for attachment on the upper right side of the station's power truss. A motorized claw mechanism in the truss then locked the detector in place on three guide pins just after 5:45 a.m.

A few minutes later,an umbilical assembly for power and data was mated by remote control. No other crew interaction was required and data collection began almost immediately.

"And Houston, from the cupola, I've got some great news," Chamitoff radioed just before 6 a.m. "The UMA mate is complete, AMS is now successfully installed. So huge congratulations to everyone on the AMS team. I'm sure Professor Ting and his group have been holding their breath. You guys can all start breathing again now."

Said Johnson: "It's a great milestone for the hundreds of scientists from 16 countries around he world who have been working on the AMS for more than a decade. It's been our honor to play a small role in this huge undertaking."

"That is just awesome guys," said astronaut Megan McArthur in mission control. "That is great news for scientists, engineers and inquisitive people around the world. Thank you for your skillful work in a very important task. We're just thrilled."

AMS is roughly cube shaped, measuring 15 feet wide, 11 feet tall and 10 feet deep, tipping the scales at 15,251 pounds. Using a powerful magnet to bend the trajectories of high-energy cosmic rays -- charged particles from supernovas, neutron stars, black holes and other cosmic enigmas -- scientists will look for evidence of antimatter and as-yet-undetected dark matter, believed to make up a quarter of the the universe.

AMS may even find evidence of strange particles made up of quarks in different arrangements than those found on Earth. Or something completely unexpected.

The AMS "really probes the foundations of modern physics," Ting said before launch. "But to my collaborators and I, the most exciting objective of AMS is to probe the unknown, to search for phenomena which exist in nature but yet we have not the tools or the imagination to find."

Built at CERN, the European Organization for Nuclear Research, and managed by the U.S. Department of Energy, the $2 billion AMS is an international collaboration between 16 nations, 60 institutes and some 600 physicists. Ting, a soft-spoken Chinese-American physicist who shared the 1976 Nobel Prize in physics, is a tireless advocate.

"The largest accelerator on Earth is 16 miles in circumference, the large Hadron Collider, LHC," he said. "In LHC there are four big experiments. Thousands and thousands of physicists work there trying to understand the beginning of the universe, what is the origin of mass, why different particles have different masses.

"The cost of ISS is about 10 times more than the LHC. The LHC has four experiments. On the space station, to study particle physics, the origin of the universe, (we only have) AMS. And that's why we're very grateful to the United States House of Representatives and the Senate, which passed the resolution to support NASA to have an additional flight to put us in space."

The Large Hadron Collider is capable of generating energies as high as 7 trillion electron volts. To put that in perspective, 1 trillion electron volts is roughly equivalent to the energy of a single flying mosquito. But in particle physics, that energy is concentrated in a single sub-atomic particle and particles from deep space can have energies as high as 100 million trillion electron volts.

"This means that no matter how accelerators are here on Earth, you cannot compete with the cosmos," Ting said.

One of the many mysteries AMS was designed to explore is what happened to the anti-matter that must have been created in the big bang. Scientists believe equal amounts of matter and anti-matter were produced, but a slight imbalance -- or some other factor -- resulted in a universe dominated by normal matter. Or at least a nearby universe made up of normal matter.

"If the universe comes from a big bang, before the big bang it is vacuum," Ting told reporters recently. "Nothing exists in vacuum. So in the beginning, you have (negatively charged) electron, you must have a (positively charged) positron so the charge is balanced. So you have matter, you must have antimatter, otherwise we would not have come from the vacuum.

"So now the universe is 14 billion years old, you have all of us, made out of matter. The question is, where is the universe made out of antimatter? With this experiment, the reason we designed it to such a large size with so many layers of repetitive position detectors is to search for the existence of antimatter to the age of the observable universe, anti-helium, anti-carbon.

"We can distinguish this particle from billions of ordinary particles," he said. "If you think about it, this is not a trivial job. In the city of Houston during the rainy season, you have about 10 billion raindrops per second. If you want to find one that's a different color, it's somewhat difficult. This illustrates the precision this detector is going to achieve."

Dark matter, the mysterious, as-yet-undetected material believed to provide the glue -- gravity -- needed to hold galaxies and clusters of galaxies together, is believed to make up a quarter of the universe compared to the 4 percent made up of the normal matter familiar to human senses. The rest is believed to be in the form of dark energy, a repulsive force that appears to be speeding up the expansion of the universe.

While AMS cannot directly detect dark matter, it can detect the particles that would be produced in dark matter collisions.

AMS also will be on the lookout for so-called "strangelets," sub-atomic particles made up of quarks in different combinations than particles found on Earth. There are six types of quarks -- known as up, down, top, bottom, charm and strange -- but protons and neutrons making up normal matter seen on Earth are made up of just two -- different combinations of up quarks and down quarks.

"The smallest particle are called quarks," Ting said. "We know six quarks exist. But it's very, very strange. All the material on Earth is made up of just two, up and down. We know in the accelerator, six types exist, but on Earth you only see the first two. So the simple question you want to ask is, where's the material made out of three types of quarks? Up, down and strange? It's a very simple question, but a very, very important question."

Whatever AMS discovers, scientists will have plenty of data to work with. Some 25,000 particle detections per second are expected when the instrument is up and running.

"We're gathering data at seven gigabits per second," said Trent Martin, the AMS project manager at the Johnson Space Center in Houston. "We can't send that huge amount of data down through the space station data system, it's just too much.

"So the onboard computers actually go through a process of condensing that data down to just the data that we're truly interested in, compressing it as much as possible. We send down data on average at about six megabits per second, constantly for the entire time that AMS is on. The computers can store up data and we can burst it down at a much higher rate."

Asked to speculate on what AMS might discover, Ting declined, saying "Most physicists who predict the future normally end up regretting it."

"My responsibility and the responsibility of my senior collaborators is to make sure the instrument is correct," he said. "Because the detector is so sensitive, everything we measure is something new. We want to make sure it's done correctly."

After AMS is in place on the station's starboard-three (S3) truss segment, the astronauts will spend the rest of the day preparing for a spacewalk Friday by Chamitoff and Andrew Feustel, the first of four excursions planned for Endeavour's mission. Both astronauts plan to spend the night in the station's Quest airlock module at a reduced pressure of 10.2 pounds per square inch to help purge nitrogen from their bloodstreams and prevent the bends when working in NASA's low-pressure spacesuits.

The primary goals of the first spacewalk are to retrieve a materials science space exposure experiment; to install a replacement; and to hook up ammonia line jumpers to set up a pipeline from an ammonia coolant tank near the center of the power truss to the outboard left-side solar array. During a second spacewalk, ammonia will be pumped into the array reservoir to replace coolant that has been lost due to a slow leak.

CBS NEWS Coverage of Breaking Space News

10:45 AM EDT, 05/19/11: Kelly says wife doing well after surgery

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Checking on his injured wife from space, shuttle commander Mark Kelly said Thursday Arizona Rep. Gabrielle Giffords came through surgery Wednesday, to replace a piece of her skull, in good condition and that she's recovering comfortably in Houston.

"I had a chance at the end of the day to call her mom, her chief of staff and my brother periodically as the surgery was going on and she's doing really well," Kelly told an interviewer with PBS NewsHour early Thursday. "Everything went as planned, her neurosurgeons are very happy, she's recuperating. She's actually getting back to therapy today. So it went really, really well."

Giffords was shot in the head at point blank range during an assassination attempt in January and her recovery and rehabilitation, along with Kelly's decision to fly aboard Endeavour as planned, has generated intense media interest.

Giffords flew to Florida for Kelly's original April 29 launch attempt and returned for Endeavour's blastoff Monday on a 16-day space station assembly mission.

"Obviously, this has been a long road since Jan. 8 for us," Kelly said. "Her having surgery yesterday was not planned all along, but she was ready and the doctors wanted to do it then and it didn't make sense to wait a couple of weeks until I got back. So I've been thinking a little bit about that, but it's pretty common surgery and it went really well."

He said Giffords was "really excited to be at the launch, really enjoyed it a lot. She was there with not only my kids, but all the children and spouses of the rest of the crew and they really had a great time despite the fact that we went through some clouds there in about 20 seconds" and disappeared from view.

While her recovery from a devastating wound has been remarkable, Kelly said he did not know when Giffords might be released from the Institute for Rehabilitation and Research Memorial Hermann -- TIRR -- in Houston.

"Rehab is a long process from a traumatic brain injury and it's not even measured in weeks, it's normally months," he told The Associated Press. "At some point, she'll become an out patient there at TIRR. We don't know exactly when that is going to be, but I'm looking forward to that. She's got some recovery here from the procedure she had yesterday then she's going to be back in full-time rehab."

Kelly and his crewmates are scheduled to land back at the Kennedy Space Center on June 1.

CBS NEWS Coverage of Breaking Space News

Editor's note... Portions of this status report were written for the CBS News STS-134 mission preview.

-- Posted at 01:50 AM EDT, 05/19/11: Endeavour astronauts set to install $2 billion cosmic ray detector
-- Updated at 04:10 AM EDT, 05/19/11: AMS pulled from shuttle cargo bay; installation proceeding
-- Updated at 06:50 AM EDT, 05/19/11: AMS attached to station; Ting congratulates shuttle crew
-- CORRECTED at 07:25 AM EDT, 05/19/11: Deleting incorrect electron volt/light bulb conversion

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The Endeavour astronauts installed a $2 billion cosmic ray detector on the International Space Station Thursday, a powerful magnet surrounded by a complex array of sensors that will study high-energy particles from the depths of space and time to look for clues about the formation and evolution of the universe.

"Thank you very much for the great ride and safe delivery of AMS to the station," radioed Sam Ting, the Nobel laureate who has managed the Alpha Magnetic Spectrometer project for more than 15 years. "Your support and fantastic work have taken us one step closer to realizing the science potential of AMS. With your help, for the next 20 years, AMS on the station will provide us a better understanding of the origin of the universe."

"Thank you, Sam," Endeavour commander Mark Kelly replied from the International Space Station. "I was just looking out the window of the orbiter and AMS looks absolutely fantastic on the truss. I know you guys are really excited and you're probably getting data and looking at it already."

Ting thanked the astronauts again, saying "it has been a very difficult experiment and I think in the next 20 to 30 years, nobody will be able to do such a thing again. I hope together with you we will try to make a contribution to a better understanding of our universe."

Astronauts Andrew Feustel and Roberto Vittori, working on the shuttle's aft flight deck, started the installation operation just before 3 a.m. EDT (GMT-4), using Endeavour's 50-foot-long arm to slowly pull the 7.5-ton Alpha Magnetic Spectrometer from its perch at the back of the orbiter's payload bay.

After moving it to a point over the right side of the shuttle, pilot Gregory Johnson and Gregory "Taz" Chamitoff, operating the station's robot arm from a computer console inside the lab's multi-window cupola module, took over to move AMS into position for attachment on the upper right side of the station's power truss. A motorized claw mechanism in the truss then locked the detector in place on three guide pins just after 5:45 a.m.

A few minutes later,an umbilical assembly for power and data was mated by remote control. No other crew interaction is required and data collection will begin almost immediately.

"And Houston, from the cupola, I've got some great news," Chamitoff radioed just before 6 a.m. "The UMA mate is complete, AMS is now successfully installed. So huge congratulations to everyone on the AMS team. I'm sure Professor Ting and his group have been holding their breath. You guys can all start breathing again now."

Said Johnson: "It's a great milestone for the hundreds of scientists from 16 countries around he world who have been working on the AMS for more than a decade. It's been our honor to play a small role in this huge undertaking."

"That is just awesome guys," said astronaut Megan McArthur in mission control. "That is great news for scientists, engineers and inquisitive people around the world. Thank you for your skillful work in a very important task. We're just thrilled."

AMS is roughly cube shaped, measuring 15 feet wide, 11 feet tall and 10 feet deep, tipping the scales at 15,251 pounds. Using a powerful magnet to bend the trajectories of high-energy cosmic rays -- charged particles from supernovas, neutron stars, black holes and other cosmic enigmas -- scientists will look for evidence of antimatter and as-yet-undetected dark matter, believed to make up a quarter of the the universe.

AMS may even find evidence of strange particles made up of quarks in different arrangements than those found on Earth. Or something completely unexpected.

The AMS "really probes the foundations of modern physics," Ting said before launch. "But to my collaborators and I, the most exciting objective of AMS is to probe the unknown, to search for phenomena which exist in nature but yet we have not the tools or the imagination to find."

Built at CERN, the European Organization for Nuclear Research, and managed by the U.S. Department of Energy, the $2 billion AMS is an international collaboration between 16 nations, 60 institutes and some 600 physicists. Ting, a soft-spoken Chinese-American physicist who shared the 1976 Nobel Prize in physics, is a tireless advocate.

"The largest accelerator on Earth is 16 miles in circumference, the large Hadron Collider, LHC," he said. "In LHC there are four big experiments. Thousands and thousands of physicists work there trying to understand the beginning of the universe, what is the origin of mass, why different particles have different masses.

"The cost of ISS is about 10 times more than the LHC. The LHC has four experiments. On the space station, to study particle physics, the origin of the universe, (we only have) AMS. And that's why we're very grateful to the United States House of Representatives and the Senate, which passed the resolution to support NASA to have an additional flight to put us in space."

The Large Hadron Collider is capable of generating energies as high as 7 trillion electron volts. To put that in perspective, 1 trillion electron volts is roughly equivalent to the energy of a single flying mosquito. But in particle physics, that energy is concentrated in a single sub-atomic particle and particles from deep space can have energies as high as 100 million trillion electron volts.

"This means that no matter how accelerators are here on Earth, you cannot compete with the cosmos," Ting said.

One of the many mysteries AMS was designed to explore is what happened to the anti-matter that must have been created in the big bang. Scientists believe equal amounts of matter and anti-matter were produced, but a slight imbalance -- or some other factor -- resulted in a universe dominated by normal matter. Or at least a nearby universe made up of normal matter.

"If the universe comes from a big bang, before the big bang it is vacuum," Ting told reporters recently. "Nothing exists in vacuum. So in the beginning, you have (negatively charged) electron, you must have a (positively charged) positron so the charge is balanced. So you have matter, you must have antimatter, otherwise we would not have come from the vacuum.

"So now the universe is 14 billion years old, you have all of us, made out of matter. The question is, where is the universe made out of antimatter? With this experiment, the reason we designed it to such a large size with so many layers of repetitive position detectors is to search for the existence of antimatter to the age of the observable universe, anti-helium, anti-carbon.

"We can distinguish this particle from billions of ordinary particles," he said. "If you think about it, this is not a trivial job. In the city of Houston during the rainy season, you have about 10 billion raindrops per second. If you want to find one that's a different color, it's somewhat difficult. This illustrates the precision this detector is going to achieve."

Dark matter, the mysterious, as-yet-undetected material believed to provide the glue -- gravity -- needed to hold galaxies and clusters of galaxies together, is believed to make up a quarter of the universe compared to the 4 percent made up of the normal matter familiar to human senses. The rest is believed to be in the form of dark energy, a repulsive force that appears to be speeding up the expansion of the universe.

While AMS cannot directly detect dark matter, it can detect the particles that would be produced in dark matter collisions.

AMS also will be on the lookout for so-called "strangelets," sub-atomic particles made up of quarks in different combinations than particles found on Earth. There are six types of quarks -- known as up, down, top, bottom, charm and strange -- but protons and neutrons making up normal matter seen on Earth are made up of just two -- different combinations of up quarks and down quarks.

"The smallest particle are called quarks," Ting said. "We know six quarks exist. But it's very, very strange. All the material on Earth is made up of just two, up and down. We know in the accelerator, six types exist, but on Earth you only see the first two. So the simple question you want to ask is, where's the material made out of three types of quarks? Up, down and strange? It's a very simple question, but a very, very important question."

Whatever AMS discovers, scientists will have plenty of data to work with. Some 25,000 particle detections per second are expected when the instrument is up and running.

"We're gathering data at seven gigabits per second," said Trent Martin, the AMS project manager at the Johnson Space Center in Houston. "We can't send that huge amount of data down through the space station data system, it's just too much.

"So the onboard computers actually go through a process of condensing that data down to just the data that we're truly interested in, compressing it as much as possible. We send down data on average at about six megabits per second, constantly for the entire time that AMS is on. The computers can store up data and we can burst it down at a much higher rate."

Asked to speculate on what AMS might discover, Ting declined, saying "Most physicists who predict the future normally end up regretting it."

"My responsibility and the responsibility of my senior collaborators is to make sure the instrument is correct," he said. "Because the detector is so sensitive, everything we measure is something new. We want to make sure it's done correctly."

After AMS is in place on the station's starboard-three (S3) truss segment, the astronauts will spend the rest of the day preparing for a spacewalk Friday by Chamitoff and Andrew Feustel, the first of four excursions planned for Endeavour's mission. Both astronauts plan to spend the night in the station's Quest airlock module at a reduced pressure of 10.2 pounds per square inch to help purge nitrogen from their bloodstreams and prevent the bends when working in NASA's low-pressure spacesuits.

The primary goals of the first spacewalk are to retrieve a materials science space exposure experiment; to install a replacement; and to hook up ammonia line jumpers to set up a pipeline from an ammonia coolant tank near the center of the power truss to the outboard left-side solar array. During a second spacewalk, ammonia will be pumped into the array reservoir to replace coolant that has been lost due to a slow leak.

The shuttle astronauts will go to bed at 2:26 p.m.

Here is an updated timeline of the crew's planned activities for flight day four (in EDT and mission elapsed time; includes revision C of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT...DD...HH...MM...SS...EVENT

05/18
10:56 PM...02...14...00...00...STS crew wakeup

05/19
01:56 AM...02...17...00...00...Shuttle arm (SRMS) grapples AMS
02:01 AM...02...17...05...00...ISS crew wakeup
02:21 AM...02...17...25...00...SRMS unberths AMS
03:01 AM...02...18...05...00...Station arm (SSRMS) grapples AMS
03:26 AM...02...18...30...00...SRMS ungrapples AMS
03:31 AM...02...18...35...00...ISS daily planning conference
03:41 AM...02...18...45...00...SSRMS moves AMS to attach point
04:31 AM...02...19...35...00...AMS PGSC deactivation
04:41 AM...02...19...45...00...SSRMS installs AMS (stage one)
04:56 AM...02...20...00...00...SSRMS installs AMS (stage two)
05:16 AM...02...20...20...00...EVA-1: Equipment lock preps
05:26 AM...02...20...30...00...AMS umbilical mate
05:41 AM...02...20...45...00...SSRMS releases AMS
06:11 AM...02...21...15...00...PAO event
06:31 AM...02...21...35...00...Crew meals begin
08:01 AM...02...23...05...00...Quick-disconnect familiarization
08:31 AM...02...23...35...00...EVA-1: Tools configured
10:01 AM...03...01...05...00...PAO event
10:21 AM...03...01...25...00...EVA-1: Procedures review
12:30 PM...03...03...34...00...Mission status briefing on NTV
12:51 PM...03...03...55...00...EVA-1: Mask prebreathe/tool config
01:36 PM...03...04...40...00...EVA-1: Airlock depress to 10.2 psi
01:56 PM...03...05...00...00...Garan sleep begins
02:01 PM...03...05...05...00...Soyuz departure preps
02:26 PM...03...05...30...00...STS crew sleep begins
03:01 PM...03...06...05...00...ISS daily planning conference
04:00 PM...03...07...04...00...Mission Management Team briefing on NTV
05:00 PM...03...08...04...00...Daily highlights reel on NTV (repeated hourly)
05:31 PM...03...08...35...00...ISS crew sleep begins
07:45 PM...03...10...49...00...Flight director update on NTV
09:45 PM...03...12...49...00...Flight director update replay on NTV
10:26 PM...03...13...30...00...STS crew/Garan wakeup

CBS NEWS Coverage of Breaking Space News

05:10 PM EDT, 05/18/11: NASA assesses tile damage on shuttle Endeavour

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Close-up photos of heat shield tiles on the shuttle Endeavour's belly taken during final approach to the International Space Station Wednesday revealed several gouges and dings from apparent debris impacts during launch. LeRoy Cain, chairman of NASA's Mission Management Team, said three "areas of interest" may require an additional focused inspection Saturday to collect more data.

"This is not cause for alarm, it's not cause for any concern," he said. "We know how to deal with these things in terms of how to assess them. We know that if we get to the point where we need some more data for our assessment, we have a plan for going and doing that."

Cain showed reporters a chart listing seven damage sites on the belly of the shuttle, all of them on the right side of the spacecraft starting at the right main landing gear door and running in a rough line back to the right-side inboard elevon, or wing flap.

Three of those seven damage sites were shown in yellow, indicating engineers have not yet been able to fully characterize the potential threat and what, if anything, might need to be done.

"These are three areas that are an example of some areas where the team wants to do some more work, some more assessment," Cain said. "At this point, what we have said is we don't have any reason for concern or alarm.

"As you know, we have a focused inspection placeholder in the timeline. ... We've asked the ops team to go to the next level of preparation in terms of ensuring we don't do anything to preclude being able to do that focussed inspection if, in fact, the team comes back and says our analytical techniques were not able to clear one or more of these sites."

The damage was spotted after commander Mark Kelly guided Endeavour through a back-flip maneuver to expose the underside of the shuttle to cameras on board the International Space Station before docking. The belly of the shuttle experiences extreme heating during re-entry, second only to the ship's reinforced carbon carbon nose cap and wing leading edge panels.

In a procedure that has become routine in the wake of the 2003 Columbia disaster -- a mishap triggered by damage to a wing leading edge panel -- astronauts Paolo Nespoli and Catherine "Cady" Coleman, working in the Russian Zvezda command module, snapped hundreds of images of Endeavour's belly tiles using 400-mm and 800-mm telephoto lenses as Kelly guided the ship through a 360-degree rotation. As usual, the digital photos were downlinked to the Johnson Space Center for analysis.

Nothing obvious could be seen in standard-resolution television views of the rendezvous pitch maneuver that were beamed down from the station in near realtime, but the zoomed-in photos shot by the station astronauts clearly revealed multiple damage sites, including the three highighted by Cain.

One, on the right landing gear door, measures 5.9 inches long and 1.23 inches wide. Another ding downstream of the door measures 3.28 inches by 2.43 inches. The third area of interest crosses the hinge line of the right-side inboard elevon, measuring 6.52 inches by 2.32 inches.

The question for engineers is how deep the gouges might be, how thick the tiles in question area and what sort of temperatures tiles in those areas experience during re-entry.

The shuttle crew's flight plan includes a block of off-duty time Saturday at the beginning of their "day," starting at 12:26 a.m. EDT (GMT-4), that was set aside for such an inspection if needed.

Focused inspections have been carried out during four post-Columbia shuttle missions. One of those was STS-118, an August 2007 flight by Endeavour that was commanded by Kelly's twin brother Scott.

In that case, engineers concluded a softball-size chunk of foam insulation broke away from a bracket supporting the 17-inch-wide liquid oxygen feel line attached to the outside of the shuttle's external tank during launch. An instant later, the foam slammed into a support strut that helps hold the back end of the shuttle to the tank. The debris broke into several pieces and one ricocheted off the strut and directly into the belly of the shuttle, gouging a pit measuring 3.48 by 2.31 inches across.

Engineers eventually concluded no repairs were needed and the astronauts completed a safe re-entry.

Tile repair tools were developed in the wake of the Columbia disaster to give shuttle crews a way to fill in potentially dangerous gouges and other types of damage and the astronauts are trained to use them. But NASA managers would not order a repair unless absolutely necessary out of concern additional damage might result that could make matters worse.

Cain said he did not want to speculate on what, if anything, might be required for Endeavour.

"I am not concerned, myself and the team, we're certainly not alarmed by what we're seeing here," he said. "We undertand the work we need to go do and we're very much in the midst of doing that work."

Endeavour made the climb to space using external tank No. 122, a Columbia-era tank that was damaged when high winds from Hurricane Katrina caused part of the roof of its manufacturing cell to collapse at Lockheed Martin's Michoud Assembly Facility in New Orleans.

"ET-122 was in one of our production cells down at Michoud when Hurricane Katrina hit and several small chunks of concrete were dislodged from the room and fell on the tank, damaging the foam," shuttle Program Manager John Shannon said before launch. "We kind of put that tank to the side while we were doing normal processing.

"I asked the team several years ago to go back and look at ET-122 and see if it was a viable flight tank. All the foam in that area was dissected. The LOX tank, they did eddy current (testing), they did all kinds of non-destructive analysis on it. It was a very good tank, so they replaced that foam, they went to the intertank area, there was one stringer that had been nicked, they took that stringer off, put a new one on, re-foamed that area."

The foam insulation on the tank is nearly 10 years old. To make sure it was still up to the rigors of launch, "they did pull tests all over the tank, they did assessments to make sure it's a good tank and safe to fly," Shannon said. "Then they did all of the return-to-flight modifications that we had done on tanks after Columbia."

"We have a lot of confidence in ET-122," he said before launch. "It doesn't look real pretty because we did some foam patches, it looks a little more like the hail-damaged tank that we flew, which I think was ET-120. But from all out testing and experience, we have high confidence in that tank."

As with all post-Columbia flights, Endeavour's ascent was monitored by batteries of launch pad cameras, radar and long-range trackers, on the lookout for any signs of foam insulation falling from the external tank that could damage the shuttle's fragile heat shield.

Debris poses the biggest threat during the first two minutes and 15 seconds of flight when the dense lower atmosphere can cause lightweight insulation to come to a near standstill in a fraction of a second. The accelerating space shuttle can then slam into it at a high relative velocity.

A phenomenon known as "cryo pumping" can cause foam to pop off later in ascent when liquefied air trapped under the foam near the top of the liquid hydrogen tank warms and expands as the fuel level drops during the climb to space. But testing and flight experience show cryopumping typically happens well after the aerodynamically sensitive period.

Given the history of Endeavour's "hurricane tank," mission managers expected to see more foam insulation falling away during the climb to space than usual because not all of the post-Columbia tank improvements were carried out for the repaired tank.

But NASA managers said after launch only a handful of debris events were noted in the ascent imagery. Three of those occurred well outside the aerodynamically sensitive transport time while two others occurred toward the end of the window of vulnerability. All appeared to be relatively minor.

CBS NEWS Coverage of Breaking Space News

-- Posted at 02:00 AM EDT, 05/18/11: Shuttle Endeavour closes in on space station
-- Updated at 03:55 AM EDT, 05/18/11: Terminal initiation burn complete
-- Updated at 05:35 AM EDT, 05/18/11: Shuttle performs back-flip maneuver
-- Updated at 06:35 AM EDT, 05/18/11: Shuttle Endeavour docks with space station
-- Updated at 08:30 AM EDT, 05/18/11: Hatches opened; shuttle crew welcomed aboard space station
-- Updated at 09:50 AM EDT, 05/18/11: Mission status briefing

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--With commander Mark Kelly at the controls, the shuttle Endeavour caught up with the International Space Station early Wednesday, looping under and then ahead of the lab complex before gliding back to a "silky smooth" docking at the station's forward port at 6:14 a.m. EDT (GMT-4).

"Houston and station, capture's confirmed," pilot Gregory Johnson radioed as the two spacecraft sailed through orbital darkness 220 miles above the south Pacific Ocean.

Inside the space station, European Space Agency astronaut Paolo Nespoli rang the ship's bell in a traditional naval welcome, announcing "Endeavour, arriving."

As usual with shuttle-station linkups, it took most of an orbit to lock the two spacecraft together and complete leak checks before hatches were opened around 7:38 a.m.

Kelly, Johnson, Andrew Feustel, Michael Fincke, Gregory Chamitoff, and European Space Agency astronaut Roberto Vittori floated into the station's Harmony module at 8:10 a.m., welcomed aboard by Expedition 27 commander Dmitry Kondratyev and his five crewmates, Andrey Borisenko, Alexander Samokutyaev, Ronald Garan, Catherine Coleman and Nespoli.

"It's good to be back," said Kelly, who last visited the station in June 2008.

Live television from inside the Harmony module showed the two crews hugging and shaking hands amid smiles and laughter. A few minutes later, they split up for a required safety briefing to familiarize the shuttle fliers with emergency procedures aboard the station.

"The entire rendezvous, approach, RPM (rendezvous pitch maneuver) and final docking was really silky smooth today, we had no anomalies to work, no problems whatsoever, everything went really, really well," said shuttle Flight Director Gary Horlacher.

Kelly's wife, Arizona Rep. Gabrielle Giffords, who was shot in the head in an assassination attempt last January, was expected to undergo surgery Wednesday in Houston to replace a section of her skull that was removed earlier. Giffords flew to Florida last weekend to watch Endeavour's launch Monday and her recovery has been the focus of intense media interest.

Horlacher said he did not know any details about Giffords' medical treatment, but he said it had not affected Kelly's performance in orbit.

"If you didn't know any of that was going on, you wouldn't have any idea that those kind of things are going on in his personal life," Horlacher said. "He's doing great. As far as that actual medical activity, I don't have any details on that. I know the surgeons are keeping him informed appropriately."

The combined crews faced a long day of work transferring spacesuits and other equipment from Endeavour to the station and using both vehicles' robot arms to move a massive pallet of spare components from the shuttle's cargo bay to an attachment point on the left side of the station's power truss. The shuttle's other primary payload, the $2 billion Alpha Magnetic Spectrometer cosmic ray detector, will be attached to the right side of the truss on Thursday.

The terminal phase of today's rendezvous began with a 10-second rocket firing at 3:37 a.m. to begin closing the final 9.8 mies between the shuttle and the space station. Catching up from behind, Kelly paused the approach 600 feet directly below the space station and carried out a computer-assisted 360-degree back-flip maneuver to expose heat shield tiles on the belly of the orbiter to the lab crew.

Nespoli and Coleman, working in the Russian Zvezda command module, photographed the shuttle with powerful telephoto lenses to help engineers complete an on-going assessment of the shuttle's heat shield.

Television cameras aboard the station captured the initial moments of the rendezvous pitch maneuver, or RPM, but the satellite link dropped out due to the lab's orientation and the rest of the maneuver went unseen on live television. Video was downlinked later showing spectacular views of the full rotation.

With the rendezvous pitch maneuver complete, Kelly guided Endeavour up to a point about 300 feet directly in front of the space station with the orbiter's nose pointed toward deep space and its payload bay toward the station. Working from Endeavour's aft flight deck, he deftly guided the orbiter to a picture-perfect docking at the space station's forward port to cap a two-day rendezvous that began Monday with liftoff from the Kennedy Space Center.

Throughout the final stages of today's approach, Feustel monitored navigation sensors and software designed for NASA's post-shuttle Orion exploration capsule to help engineers calibrate the system and characterize its performance. After undocking May 29, the new system, known by the acronym STORRM, will be put to the test during a re-rendezvous exercise to verify its performance in real-world conditions.

"They had a really good day," Horlacher said. "They had all their systems up, collected data all the way in to the final docking. ... The STORRM folks will be pulling data down for the next few days from their avionics box and be all set up for the undock several days down the road."

In the midst of a busy first few days of docked activity, three of the station's crew members -- Coleman, Nespoli and Kondratyev -- will be gearing up to undock and return to Earth Monday aboard the Soyuz TMA-20 ferry craft. Because the departing crew members need to adjust their sleep cycle to synch up with the landing day timeline -- and because of a two-week launch delay for the Endeavour astronauts -- the two crews are working in staggered shifts.

Garan, assisting the shuttle crew during the early portion of the docked flight, will go to bed at 2:26 p.m., followed a half hour later by Kelly and his crewmates. The station crew plans to go to bed at 5:31 p.m. After the Soyuz TMA-20 departure, the remaining station crew members will adjust their sleep cycles to synch up with the shuttle crew.

Here is a timeline for the remainder of the crew's planned activities for flight day three (in EDT and mission elapsed time; includes revision C of the NASA television schedule; best viewed with fixed-width font):

DATE/EDT...DD...HH...MM...SS...EVENT

09:16 AM...02...00...20...00...Shuttle arm (SRMS) unberths ELC-3 cargo pallet
09:56 AM...02...01...00...00...SRMS hands ELC-3 to station arm (SSRMS)
10:21 AM...02...01...25...00...SRMS ungrapples ELC-3
10:31 AM...02...01...35...00...SSRMS maneuvers to install ELC-3
11:41 AM...02...02...45...00...ELC-3 install (stage one)
11:51 AM...02...02...55...00...Video playback ops
11:56 AM...02...03...00...00...ELC-3 install (stage two)
12:16 PM...02...03...20...00...SSRMS ungrapples ELC-3
12:21 PM...02...03...25...00...ELC-3 power cable mate
02:56 PM...02...06...00...00...STS crew sleep begins
03:41 PM...02...06...45...00...ISS evening planning conference
04:00 PM...02...07...04...00...Mission Management Team briefing on NASA TV
05:00 PM...02...08...04...00...Daily highlights reel on NASA TV (repeated hourly)
05:31 PM...02...08...35...00...ISS crew sleep begins
09:45 PM...02...12...49...00...ISS flight director update
10:40 PM...02...13...44...00...ISS flight director update replay
10:56 PM...02...14...00...00...Endeavour crew/Garan wakeup

CBS NEWS Coverage of Breaking Space News

-- Posted at 01:15 AM EDT, 05/17/11: Astronauts prep for heat shield inspection, spacesuit checkout
-- Updated at 10:25 AM EDT, 05/17/11: Heat shield inspection complete; adding Atlantis' final rollover; mission status briefing
-- Updated at 05:45 PM EDT, 05/17/11: Mission Management Team briefing; preliminary assessment shows Katrina-damaged external tank performed well during ascent

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The Endeavour astronauts, working a deep overnight shift thanks to a two-week launch delay, carried out a detailed inspection of the shuttle's reinforced carbon carbon nose cap and wing leading edge panels Tuesday, a standard post-Columbia check to look for any signs of damage that might have occurred during launch Monday.

The astronauts also checked out the spacesuits that will be used for four planned spacewalks at the International Space Station and carried out two rendezvous rocket firings to fine tune the shuttle's approach to the lab complex. Docking is targeted for 6:16 a.m. EDT (GMT-4) Wednesday (a docking timeline has been posted on the STS-134 Flight Data File page).

LeRoy Cain, chairman of NASA's Mission Management Team at the Johnson Space Center in Houston, said ongoing inspections and analysis of launch day imagery, radar tracking and sensor data are not yet complete, but "the preliminary assessments that we have is that everything looks really, really good so far, and we're not tracking any issues as far as that's concerned."

External tank No. 122 was damaged during Hurricane Katrina when the roof of its manufacturing cell at Lockheed Martin's Michoud Assembly Facility near New Orleans collapsed due to high winds. The tank underwent extensive repairs, but engineers were not able to implement the full suite of post-Columbia upgrades. Before launch, managers said they expected to see more foam insulation losses than usual during Endeavour's launch, but only four such "events," all relatively minor, were noted in ascent imagery.

"The performance of this tank really was outstanding," Cain said. "We didn't have but only a few debris events, and the events we had, we believe preliminarily, were less than the allowable in terms of size and mass. So we were well inside the risk we were willing to accept in terms of debris from this tank."

The analysis is not yet complete, but so far, there are no obvious signs of trouble with Endeavour's heat shield.

"We'll turn our attention toward the rendezvous and docking starting tonight ... with a docking around (6:15 a.m.) tomorrow," Cain said. "So we're very much looking forward to getting back to space station. This is an extremely important mission for us."

The primary goals of NASA's next-to-last shuttle mission are delivery of spare parts and supplies to the International Space Station, along with a $2 billion particle physics detector known as the Alpha Magnetic Spectrometer, or AMS. If all goes well, a pallet of spare components will be attached to the space station's power truss a few hours after docking Wednesday and AMS will be attached on Thursday.

"They're very excited, they're ready to get AMS safely on board the space station and get it activated," Cain said. "So that's an extremely important milestone for us, not just the agency or not even just for our nation, frankly. A lot of folks around the world are watching intently, and we look very much forward to that activity."

With Endeavour's mission proceeding smoothly, engineers at the Kennedy Space Center hauled the shuttle Atlantis, mounted atop a custom transporter, out of its processing hangar for the short trip to the nearby Vehicle Assembly Building where it will be attached to NASA's final external tank and the agency's last set of solid-fuel boosters.

If all goes well, Atlantis will be hauled to launch pad 39A starting around 8 p.m. on May 31, a trip that should be nearing completion as Endeavour glides back to Earth around 2:32 a.m. on June 1 to wrap up its 25th and final mission.

NASA managers have not yet set an official target date for Atlantis' launch on the shuttle program's 135th and final flight pending an assessment of the launch pad after Endeavour's blastoff Monday. But Atlantis should be ready to go between July 11 and 14.

The move to the VAB began at 8:03 a.m. and ended around 1:50 p.m. Normally, orbiters are hauled directly into the assembly building but in this case, managers decided to park Atlantis between its processing facility hangar and the VAB for several hours to give Kennedy Space Center employees a chance to take pictures marking the shuttle program's last "rollover."

"It looked great under a clear blue sky with the sun shining off the white blankets," Stephen Clark, a reporter with Spaceflight Now, said in an instant message. "Big crowds came out to see the shuttle leave the hangar for the last time. It's parked outside to let some of the employees stop by for a parting snapshot and see a flight-ready shuttle up close for the last time."

Atlantis' crew -- commander Christopher Ferguson, pilot Douglas Hurley, Rex Walheim and Sandra Magnus -- mingled with onlookers, posing for pictures and thanking workers for getting the shuttle ready for flight one last time.

For the heat shield inspection aboard Endeavour, pilot Gregory Johnson, Michael Fincke and Roberto Vittori used Endeavour's robot arm to pick up a 50-foot-long extension called the orbiter boom sensor system, or OBSS, that is equipped with a laser scanner and high-resolution camera. Following a carefully choreographed sequence, the astronauts scanned the shuttle's nose cap and RCC wing leading edge panels, which experience the most extreme heating during re-entry.

Shuttle Flight Director Gary Horlacher said he did not spot anything unusual in the realtime video downlinked by the crew.

"Of course, a lot of the issues that can occur in the RCC are not visible to the eye, so the engineers really have to take a good, hard look at the data once it's on the ground," he said. "But everything looked really good today."

Engineers at the Johnson Space Center in Houston will fold the observations into an on-going assessment of launch-day photography, radar scans and data from wing leading edge sensors to assess the overall health of Columbia's thermal protection system.

A telephoto inspection of the heat shield tiles on the shuttle's belly will be carried out by the space station's crew during final approach Wednesday, starting around 4:01 a.m., when commander Mark Kelly guides the shuttle through a back-flip known as a rendezvous pitch maneuver, or RPM, that will expose the shuttle's underside to the lab crew.

"The data we're collecting today is actually being processed as we speak," Horlacher said. "It will continue to be processed while the crew sleeps, and hopefully we'll get most of that behind them by the time the RPM data becomes available tomorrow. Once all that's in, if everything goes well, we expect to hear initial feedback probably right after the crew goes to sleep tomorrow after the docking."

After the heat shield inspection Tuesday, the astronauts mounted the OBSS back on the right side of the shuttle's cargo bay before locking the robot arm onto External Logistics Carrier No. 3, a massive pallet of spare parts and components that will be mounted on the space station's power truss shortly after docking.

"A couple of other activities we'll accomplish on flight day two, a couple of the spacewalkers will check out their spacesuits, make sure everything is looking good there and be ready to transfer those over to the space station," Horlacher said before launch. "And then the rest of the crew activities for the day will be checking out some of the rendezvous systems for the (station docking) on flight day three. That'll include centerline camera installation, orbiter docking system ring extension, rendezvous tools check out."

The crew began an eight-hour sleep period a few minutes before 3 p.m. Wakeup to begin flight day three is expected at 10:56 p.m.

Kelly, Johnson, Fincke, Vittori, Gregory Chamitoff and Andrew Feustel blasted off Monday at 8:56 a.m., two weeks late because of work to repair an electrical glitch. The delay moved the launch time from mid afternoon to the morning hours, resulting in an overnight work schedule for the crew.

The astronauts began their second day in space at 11:56 p.m. Monday, enjoying a recording of U2's "Beautiful Day" beamed up from mission control. The tune was requested by Kelly's wife, Gabrielle Giffords, and his two daughters.

"It's good to be waking up in space again," Kelly said. "I want to thank Gabby, Claudia and Claire for that great wakeup song. It's always good to hear U2, a beautiful day in space."

Before going to bed Monday afternoon, the astronauts downlinked video from the crew cabin, showing a bit of the work needed to set up the shuttle for orbital operations. Everyone took a moment to say hello to family, friends and flight controllers.

"Hey, guys, here we are, Roberto and I, we're on the middeck, we're setting up our water purification system," Chamitoff said to the camera. "We've been in space now for what, four hours, five hours, something like that. It's amazing, we're all feeling great. This is awesome! I can't wait to get back to the space station."

Said Vittori, veteran of two flights to the space station aboard Russian Soyuz spacecraft: "My first ride on the shuttle was an amazing launch. I was a little afraid, but I quickly adapted and it's very interesting to work with the shuttle systems. It's easier here in microgravity than it was during the training flow. Most of the equipment here just makes sense, it's very intuitive. Happy to be here."

"It was a great ride up, an awesome flight up," Chamitoff said, grinning.

CBS NEWS Coverage of Breaking Space News

-- Posted at 01:15 AM EDT, 05/17/11: Astronauts prep for heat shield inspection, spacesuit checkout
-- Updated at 10:25 AM EDT, 05/17/11: Heat shield inspection complete; adding Atlantis' final rollover; mission status briefing

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The Endeavour astronauts, working a deep overnight shift thanks to a two-week launch delay, carried out a detailed inspection of the shuttle's reinforced carbon carbon nose cap and wing leading edge panels Tuesday, a standard post-Columbia check to look for any signs of damage that might have occurred during launch Monday.

The astronauts also checked out the spacesuits that will be used for four planned spacewalks at the International Space Station and carried out the first of two rendezvous rocket firings to fine tune the shuttle's approach to the lab complex. Docking is targeted for 6:16 a.m. EDT (GMT-4) Wednesday. A preliminary docking timeline has been posted on the STS-134 Flight Data File page:

http://www.cbsnews.com/network/news/space/home/flightdata/main.html#134_DOCKING

"Endeavour's performing absolutely flawlessly, we're tracking no significant issues whatsoever with the vehicle and the crew is doing outstanding as well," said shuttle Flight Director Gary Horlacher.

At the Kennedy Space Center, meanwhile, engineers hauled the shuttle Atlantis, mounted atop a custom transporter, out of its processing hangar for the short trip to the nearby Vehicle Assembly Building where it will be attached to NASA's last external tank and the agency's last set of solid-fuel boosters.

If all goes well, Atlantis will be hauled to launch pad 39A starting around 8 p.m. on May 31, a trip that should be nearing completion as Endeavour glides back to Earth around 2:32 a.m. on June 1 to wrap up its 25th and final mission.

NASA managers have not yet set an official target date for Atlantis' launch on the shuttle program's 135th and final flight pending an assessment of the launch pad after Endeavour's blastoff Monday. But Atlantis should be ready to go between July 11 and 14.

The move to the VAB began at 8:03 a.m. Normally, orbiters are hauled directly into the assembly building but in this case, managers decided to park Atlantis between its processing facility hangar and the VAB for several hours to give Kennedy Space Center employees a chance to take pictures marking the shuttle program's last "rollover."

"It looked great under a clear blue sky with the sun shining off the white blankets," Stephen Clark, a reporter with Spaceflight Now, said in an instant message. "Big crowds came out to see the shuttle leave the hangar for the last time. It's parked outside to let some of the employees stop by for a parting snapshot and see a flight-ready shuttle up close for the last time."

Atlantis' crew -- commander Christopher Ferguson, pilot Douglas Hurley, Rex Walheim and Sandra Magnus -- mingled with onlookers, posing for pictures and thanking workers for getting the shuttle ready for flight one last time.

For the heat shield inspection aboard Endeavour, pilot Gregory Johnson, Michael Fincke and Roberto Vittori used Endeavour's robot arm to pick up a 50-foot-long extension called the orbiter boom sensor system, or OBSS, that is equipped with a laser scanner and high-resolution camera. Following a carefully choreographed sequence, the astronauts scanned the shuttle's nose cap and RCC wing leading edge panels, which experience the most extreme heating during re-entry.

Horlacher said he did not spot anything unusual in the realtime video downlinked by the crew.

"Of course, a lot of the issues that can occur in the RCC are not visible to the eye, so the engineers really have to take a good, hard look at the data once it's on the ground," he said. "But everything looked really good today."

Engineers at the Johnson Space Center in Houston will fold the observations into an on-going assessment of launch-day photography, radar scans and data from wing leading edge sensors to assess the overall health of Columbia's thermal protection system.

A telephoto inspection of the heat shield tiles on the shuttle's belly will be carried out by the space station's crew during final approach Wednesday, starting around 4:01 a.m., when commander Mark Kelly guides the shuttle through a back-flip known as a rendezvous pitch maneuver, or RPM, that will expose the shuttle's underside to the lab crew.

"The data we're collecting today is actually being processed as we speak," Horlacher said. "It will continue to be processed while the crew sleeps, and hopefully we'll get most of that behind them by the time the RPM data becomes available tomorrow. Once all that's in, if everything goes well, we expect to hear initial feedback probably right after the crew goes to sleep tomorrow after the docking."

After the heat shield inspection Tuesday, the astronauts mounted the OBSS back on the right side of the shuttle's cargo bay before locking the robot arm onto External Logistics Carrier No. 3, a massive pallet of spare parts and components that will be mounted on the space station's power truss shortly after docking.

"A couple of other activities we'll accomplish on flight day two, a couple of the spacewalkers will check out their spacesuits, make sure everything is looking good there and be ready to transfer those over to the space station," Horlacher said before launch. "And then the rest of the crew activities for the day will be checking out some of the rendezvous systems for the (station docking) on flight day three. That'll include centerline camera installation, orbiter docking system ring extension, rendezvous tools check out."

The crew was scheduled to go to bed at 2:56 p.m. Wakeup to begin flight day three is expected at 10:56 p.m.

Kelly, Johnson, Fincke, Vittori, Gregory Chamitoff and Andrew Feustel blasted off Monday at 8:56 a.m., two weeks late because of work to repair an electrical glitch. The delay moved the launch time from mid afternoon to the morning hours, resulting in an overnight work schedule for the crew.

The astronauts began their second day in space at 11:56 p.m. Monday, enjoying a recording of U2's "Beautiful Day" beamed up from mission control. The tune was requested by Kelly's wife, Gabrielle Giffords, and his two daughters.

"It's good to be waking up in space again," Kelly said. "I want to thank Gabby, Claudia and Claire for that great wakeup song. It's always good to hear U2, a beautiful day in space."

Before going to bed Monday afternoon, the astronauts downlinked video from the crew cabin, showing a bit of the work needed to set up the shuttle for orbital operations. Everyone took a moment to say hello to family, friends and flight controllers.

"Hey, guys, here we are, Roberto and I, we're on the middeck, we're setting up our water purification system," Chamitoff said to the camera. "We've been in space now for what, four hours, five hours, something like that. It's amazing, we're all feeling great. This is awesome! I can't wait to get back to the space station."

Said Vittori, veteran of two flights to the space station aboard Russian Soyuz spacecraft: "My first ride on the shuttle was an amazing launch. I was a little afraid, but I quickly adapted and it's very interesting to work with the shuttle systems. It's easier here in microgravity than it was during the training flow. Most of the equipment here just makes sense, it's very intuitive. Happy to be here."

"It was a great ride up, an awesome flight up," Chamitoff said, grinning.

CBS NEWS Coverage of Breaking Space News

-- Posted at 09:43 AM EDT, 05/16/11: Shuttle Endeavour rockets away on final mission
-- Updated at 11:25 AM EDT, 05/16/11: Adding post-launch news conference; correcting spacewalk dates, landing time

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Running two weeks late because of an electrical glitch, the repaired shuttle Endeavour finally blasted off and rocketed into orbit for the last time Monday, putting on a spectacular, if brief, show for several hundred thousand spectators expected for NASA's next-to-last shuttle launch.

Carrying a $2 billion particle physics experiment, critical supplies and spare parts bound for the International Space Station, Endeavour's three main engines flashed to life at and throttled up to full power while computers monitored their performance 50 times per second.

Six-and-a-half seconds later, at 8:56:28 a.m. EDT (GMT-4), Endeavour's twin solid-fuel boosters ignited with a rush of 5,000-degree exhaust, instantly pushing the spacecraft away from pad 39A.

Accelerating through 100 mph -- straight up -- in just eight seconds, Endeavour climbed away and quickly disappeared from view as it knifed through low-level clouds, wheeling about to line up on a northeasterly trajectory paralleling the East Coast.

Shuttle commander Mark Kelly's wife, Arizon Rep. Gabrielle Giffords, watched Endeavour's ground-shaking takeoff from the roof of the Launch Control Center 3.4 miles from pad 39A, with her mother, Mark Kelly's twin brother Scott and other family members. Giffords was shot in the head during a January assassination attempt and her recovery has generated intense media interest.

She flew to Florida for Endeavour's initial launch attempt April 29 when the ship was grounded by an electrical problem with the shuttle's hydraulic system. She flew back Sunday for Kelly's second launch try, but privacy screens shielded her from view. A spokeswoman said she was relieved Endeavour got off, saying "good stuff" after the shuttle climbed away.

"I think relief was her biggest feeling," said Pia Carusone, Gifford's chief of staff. "She was very proud. ... It was an exciting moment for her to watch."

The early stages Endeavour's climb to space appeared normal as the shuttle rocketed away atop a churning cloud of exhaust from its solid-fuel boosters. Two minutes and five seconds later, the boosters, their propellant depleted, were jettisoned, falling to the Atlantic Ocean 30 miles below where recovery ships were standing by.

Endeavour continued toward orbit on the power of its three hydrogen-fueled main engines, looking like a brilliant, fast-moving star in the daytime sky as it arced toward the northeast horizon.

A camera mounted on the side of the ship's external tank showed spectacular views of the clouds dropping away below and later, the limb of the Earth behind the accelerating spaceship. No major debris could be seen falling away from the tank during the first two minutes and 15 seconds of flight when the dense lower atmosphere can cause high-velocity impacts with the shuttle's fragile heat shield.

But Bill Gerstenmaier, chief of space operations at NASA headquarters, said engineers spotted two small pieces of foam insulation falling away between two minutes and six seconds into flight and two minutes and 14 seconds. He said neither piece appeared to strike the orbiter, but engineers will carry out a detailed photo assessment as usual.

Endeavour's external tank -- ET-122 -- was damaged when a roof collapsed at the Lockheed Martin Michoud Assembly Facility manufacturing plant in New Orleans. The tank was repaired, but NASA managers said before launch they expected to see more foam than usual break away during launch.

But overall, the tank appeared to perform well and eight-and-a-half minutes after liftoff, Endeavour separated and slipped into its planned preliminary orbit. Scott Kelly gave Giffords and Mark Kelly's two daughters red roses after the shuttle's main engines shut down.

"There were hugs all around, absolutely, it was very celebratory," Carusone said.

Kelly, pilot Gregory Johnson, European Space Agency flight engineer Roberto Vittori and Fincke, veteran of two previous long-duration stays aboard the International Space Station, made the climb to orbit strapped into seats on Endeavour's upper flight deck.

Strapped in on the shuttle's lower deck were Andrew Feustel and Gregory Chamitoff, another station veteran.

If all goes well, Kelly will guide Endeavour to a docking at the space station's forward port around 6:15 a.m. Wednesday. A pallet of spare components will be robotically bolted to left side of the station's power truss a few hours later. The next day, the 7.5-ton Alpha Magnetic Spectrometer, the mission's showcase payload, will be attached to the right side of the power truss.

Using a massive magnet to bend the trajectories of high-energy cosmic rays -- charged particles from supernovas, neutron stars, black holes and other cosmic enigmas -- scientists will look for evidence of antimatter and as-yet-undetected dark matter, believed to make up a quarter of the mass of the universe.

AMS may even find evidence of strange particles made up of quarks in different arrangements than those found on Earth. Or something completely unexpected.

The AMS "really probes the foundations of modern physics," said Sam Ting, a Nobel Laureate who manages the multinational experiment. "But to my collaborators and I, the most exciting objective of AMS is to probe the unknown, to search for phenomena which exist in nature but yet we have not the tools or the imagination to find."

AMS will operate autonomously after it is connected to station power, beaming down a continuous stream of data for at least 10 years and possibly longer if the lab is funded past 2020.

Fincke, Feustel and Chamitoff, working in alternating two-man teams, plan to carry out four spacewalks May 20, 22, 25 and 27 to retrieve one materials science exposure experiment and to install another; to refill the ammonia coolant reservoir in the station's far left-side solar array; to re-lubricate a solar array rotary joint; to install a robot arm attachment fitting on the Russian Zarya module; and to perform needed maintenance.

Endeavour is scheduled to land back at the Kennedy Space Center around 2:32 a.m. on Wednesday, June 1.

"It is an extremely complex mission," said shuttle Program Manager John Shannon. "It's a long period of time docked to the station, four EVAs, a tremendous amount of activity internal to the ISS, we're going to put a world-class experiment on the ISS and get it all hooked up.

"I think the missions we are executing now in complexity are the most difficult missions that not just NASA, but any nation has ever flown in space. And I would include Apollo in that discussion. I think the missions we do right now are more complicated than what we were doing even during the moon landings."

NASA attempted to launch Endeavour April 29, but the countdown was called off when a "string" of fuel line heaters used by one of the shuttle's three hydraulic power units failed to activate.

Engineers were unable to immediately determine what might have caused a short in a power switching box in the shuttle's aft engine compartment. Playing it safe, the box, called an aft load control assembly, was replaced, along with thermostats and associated wiring.

While that work was going on, engineers reviewing data from thermostat tests last June noticed a brief, previously undetected current spike. A close inspection of the thermostat in question revealed damaged insulation and an exposed conductor.

Engineers believe the exposed conductor likely triggered the short that prevented the heaters from powering up April 29. The repaired heater system worked normally during the countdown Monday and there were no obvious problems during the climb to space.

"OK, Mark, it looks like a great day to launch Endeavour for the final time," Launch Director Mike Leinbach radioed Kelly a few minutes before takeoff. "So on behalf of the thousands of proud Americans who have been part of her journey, good luck, God speed and we'll see you back here June 1."

"Thank you sir," Kelly replied. "On this final flight of space shuttle Endeavour, we want to thank the tens of thousands of dedicated employees that have put there hands on this incredible ship and dedicated their lives to the space shuttle program.

"This mission represents the power of teamwork, commitment and exploration, it is in the DNA of our great country to reach for the stars and explore. We must not stop. To all of the millions watching today, including our spouses, children, family and friends, we thank you for your support."

CBS NEWS Coverage of Breaking Space News

09:20 AM EDT, 05/16 Update: Shuttle Endeavour rockets away on final mission

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Running two weeks late because of an electrical glitch, the repaired shuttle Endeavour finally blasted off and rocketed into orbit for the last time Monday, putting on a spectacular, if brief, show for several hundred thousand spectators expected for NASA's next-to-last shuttle launch.

Carrying a $2 billion particle physics experiment, critical supplies and spare parts bound for the International Space Station, Endeavour's three main engines flashed to life at and throttled up to full power while computers monitored their performance 50 times per second.

Six-and-a-half seconds later, at 8:56:28 a.m. EDT (GMT-4), Endeavour's twin solid-fuel boosters ignited with a rush of 5,000-degree exhaust, instantly pushing the spacecraft away from pad 39A.

Accelerating through 100 mph -- straight up -- in just eight seconds, Endeavour climbed away and quickly disappeared from view as it knifed through low-level clouds, wheeling about to line up on a northeasterly trajectory paralleling the East Coast.

Shuttle commander Mark Kelly's wife, Arizon Rep. Gabrielle Giffords, watched Endeavour's ground-shaking takeoff from the roof of the Launch Control Center 3.4 miles from pad 39A, with her mother, Mark Kelly's twin brother Scott and other family members. Giffords was shot in the head during a January assassination attempt and her recovery has generated intense media interest.

She flew to Florida for Endeavour's initial launch attempt April 29 when the ship was grounded by an electrical problem with the shuttle's hydraulic system. She flew back Sunday for Kelly's second launch try, but privacy screens shielded her from view and her reaction to the launching was not immediately known.

The early stages Endeavour's climb to space appeared normal as the shuttle rocketed away atop a churning cloud of exhaust from its solid-fuel boosters. Two minutes and five seconds later, the boosters, their propellant depleted, were jettisoned, falling to the Atlantic Ocean 30 miles below where recovery ships were standing by.

Endeavour continued toward orbit on the power of its three hydrogen-fueled main engines, looking like a brilliant, fast-moving star in the daytime sky as it arced toward the northeast horizon.

A camera mounted on the side of the ship's external tank showed spectacular views of the clouds dropping away below and later, the limb of the Earth behind the accelerating spaceship. No major debris could be seen falling away from the tank during the first two minutes and 15 seconds of flight when the dense lower atmosphere can cause high-velocity impacts with the shuttle's fragile heat shield.

Endeavour's external tank -- ET-122 -- was damaged when a roof collapsed at the Lockheed Martin Michoud Assembly Facility manufacturing plant in New Orleans. The tank was repaired, but NASA managers said before launch they expected to see more foam than usual break away during launch.

But overall, the tank appeared to perform well and eight-and-a-half minutes after liftoff, Endeavour separated and slipped into its planned preliminary orbit.

At the controls on Endeavour's upper flight deck were Kelly, pilot Gregory Johnson, European Space Agency flight engineer Roberto Vittori and Fincke, veteran of two previous long-duration stays aboard the International Space Station.

Strapped in on the shuttle's lower deck were Andrew Feustel and Gregory Chamitoff, another station veteran.

If all goes well, Kelly will guide Endeavour to a docking at the space station's forward port around 6:15 a.m. Wednesday. A pallet of spare components will be robotically bolted to left side of the station's power truss a few hours later. The next day, the 7.5-ton Alpha Magnetic Spectrometer, the mission's showcase payload, will be attached to the right side of the power truss.

Using a massive magnet to bend the trajectories of high-energy cosmic rays -- charged particles from supernovas, neutron stars, black holes and other cosmic enigmas -- scientists will look for evidence of antimatter and as-yet-undetected dark matter, believed to make up a quarter of the mass of the universe.

AMS may even find evidence of strange particles made up of quarks in different arrangements than those found on Earth. Or something completely unexpected.

The AMS "really probes the foundations of modern physics," said Sam Ting, a Nobel Laureate who manages the multinational experiment. "But to my collaborators and I, the most exciting objective of AMS is to probe the unknown, to search for phenomena which exist in nature but yet we have not the tools or the imagination to find."

AMS will operate autonomously after it is connected to station power, beaming down a continuous stream of data for at least 10 years and possibly longer if the lab is funded past 2020.

Fincke, Feustel and Chamitoff, working in alternating two-man teams, plan to carry out four spacewalks May 3, 5, 7 and 9 to retrieve one materials science exposure experiment and to install another; to refill the ammonia coolant reservoir in the station's far left-side solar array; to re-lubricate a solar array rotary joint; to install a robot arm attachment fitting on the Russian Zarya module; and to perform needed maintenance.

Endeavour is scheduled to land back at the Kennedy Space Center on Friday, May 13. But if the shuttle is in good shape after docking, NASA managers plan to extend the flight one or two days to give the crew more time to help their station colleagues with needed maintenance.

"It is an extremely complex mission," said shuttle Program Manager John Shannon. "It's a long period of time docked to the station, four EVAs, a tremendous amount of activity internal to the ISS, we're going to put a world-class experiment on the ISS and get it all hooked up.

"I think the missions we are executing now in complexity are the most difficult missions that not just NASA, but any nation has ever flown in space. And I would include Apollo in that discussion. I think the missions we do right now are more complicated than what we were doing even during the moon landings."

NASA attempted to launch Endeavour April 29, but the countdown was called off when a "string" of fuel line heaters used by one of the shuttle's three hydraulic power units failed to activate.

Engineers were unable to immediately determine what might have caused a short in a power switching box in the shuttle's aft engine compartment. Playing it safe, the box, called an aft load control assembly, was replaced, along with thermostats and associated wiring.

While that work was going on, engineers reviewing data from thermostat tests last June noticed a brief, previously undetected current spike. A close inspection of the thermostat in question revealed damaged insulation and an exposed conductor.

Engineers believe the exposed conductor likely triggered the short that prevented the heaters from powering up April 29. The repaired heater system worked normally during the countdown Monday and there were no obvious problems during the climb to space.

"OK, Mark, it looks like a great day to launch Endeavour for the final time," Launch Director Mike Leinbach radioed Kelly a few minutes before takeoff. "So on behalf of the thousands of proud Americans who have been part of her journey, good luck, God speed and we'll see you back here June 1."

"Thank you sir," Kelly replied. "On this final flight of space shuttle Endeavour, we want to thank the tens of thousands of dedicated employees that have put there hands on this incredible ship and dedicated their lives to the space shuttle program.

"This mission represents the power of teamwork, commitment and exploration, it is in the DNA of our great country to reach for the stars and explore. We must not stop. To all of the millions watching today, including our spouses, children, family and friends, we thank you for your support."

CBS NEWS Coverage of Breaking Space News

7:15 AM EDT, 05/16 Update: Forecasters monitor low clouds; tile ding repaired

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The Endeavour astronauts have strapped in, the shuttle's hatch has been closed and sealed and the countdown is ticking smoothly toward launch at 8:56:28 a.m. EDT GMT-4). The only technical issue so far this morning has been a minor ding to a heat shield tile near the shuttle's side hatch that required a patch by launch pad technicians.

Forecasters, meanwhile, are monitoring a deck of low clouds that could cause problems as launch time approaches.

NASA flight rules forbid a launch if crosswinds at the shuttle's emergency runway exceed 15 knots and if broken clouds below 6,000 feet encroach on the space center. Those rules can be waived if an astronaut flying a shuttle training jet deems the weather acceptable for an emergency return-to-launch-site landing, but only if conditions are only marginally worse than the launch commit criteria as written.

The tile damage appeared minor and technicians at the pad used a tile repair kit to fill in the ding. There are no other technical issues of any significance.

CBS NEWS Coverage of Breaking Space News

6 AM EDT, 05/16 Update: Astronauts board shuttle Endeavour

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Commander Mark Kelly and his crewmates began strapping in aboard the shuttle Endeavour Monday to await liftoff on the 134th shuttle mission. There are no technical problems of any significance and forecasters are hopeful about the weather, although low clouds and brisk crosswinds remain a concern.

Kelly, pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori departed crew quarters around 5:10 a.m. EDT (GMT-4), smiling and waving to Kennedy Space Center workers and reporters before entering NASA's "astrovan" for the trip to the pad.

"Dear God, please bless our crew," Fincke said in a morning Twitter update. "Help us in our mission and to return safely home. Please help me not to mess anything up."

Endeavour was grounded April 29 by a short circuit that knocked out one set of fuel line heaters used by auxiliary power unit No. 1, one of three that provide the hydraulic power needed to move the ship's engine nozzles and aerosurfaces. The short eventually was traced to damaged insulation and an exposed conductor on a thermostat.

The thermostat was replaced, along with an avionics control box and wiring between the box and the heaters. The system was activated during fueling Monday, when cryogenic propellants flowing through main engine plumbing caused temperatures in the aft engine compartment to drop, and telemetry showed the heaters were operating normally.

CBS NEWS Coverage of Breaking Space News

03:00 AM EDT, 05/16 Update: Shuttle Endeavour fueled for launch

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Working by remote control, engineers loaded the shuttle Endeavour's external tank with a half-million gallons of supercold liquid oxygen and hydrogen rocket fuel early Monday, setting the stage for launch on NASA's next-to-last shuttle mission.

The three-hour fueling procedure began on time at 11:36 p.m . EDT (GMT-4) Sunday when the propellants began moving through transfer lines to the shuttle, flowing through the ship's main propulsion system to condition the main engines to cryogenic temperatures and then into the external tank's hydrogen and oxygen sections. The procedure was completed by 2:36 a.m. Monday when the tank was topped off and fueling transitioned to "stable replenish" mode.

Endeavour's crew -- commander Mark Kelly, pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- plans to don their bright orange pressure suits and head for the pad to strap in around 5:41 a.m. The hatch to Endeavour's crew compartment will be closed a few minutes before 7 a.m.

Liftoff is targeted for 8:56:28 a.m., the opening of a five-minute launch window that roughly coincides with the moment Earth's rotation carries pad 39A into the plane of the International Space Station's orbit.

There are no technical problems of any significance at the launch pad and forecasters are continuing to predict a 70 percent chance of acceptable weather. The only concerns are possibly high crosswinds and a slight chance of low clouds.

Here is a list of major remaining countdown events (in EDT; best viewed with fixed-width font):

HH...MM...SS...EDT...........EVENT

06...20...00...02:36 AM......Begin 2-hour 30-minute built-in hold (T-minus 3 hours)
06...20...00...02:36 AM......Closeout crew to white room
06...20...00...02:36 AM......External tank in stable replenish mode
06...17...00...02:39 AM......Ascent flight control team on console
06...05...00...02:51 AM......Astronaut support personnel comm checks
05...35...00...03:21 AM......Pre-ingress switch reconfig
05...26...00...03:30 AM......NASA TV launch coverage begins
04...25...00...04:31 AM......Final crew weather briefing
04...15...00...04:41 AM......Crew suit up begins
03...50...00...05:06 AM......Resume countdown (T-minus 3 hours)

03...45...00...05:11 AM......Crew departs O&C building
03...15...00...05:41 AM......Crew ingress
02...25...00...06:31 AM......Astronaut comm checks
02...00...00...06:56 AM......Hatch closure
01...30...00...07:26 AM......White room closeout

01...10...00...07:46 AM......Begin 10-minute built-in hold (T-minus 20m)
01...00...00...07:56 AM......NASA test director countdown briefing
01...00...00...07:56 AM......Resume countdown (T-minus 20m)

00...59...00...07:57 AM......Backup flight computer to OPS 1
00...55...00...08:01 AM......KSC area clear to launch

00...49...00...08:07 AM......Begin final built-in hold (T-minus 9m)
00...24...00...08:32 AM......NTD launch status verification
00...09...00...08:47:28 AM...Resume countdown (T-minus 9m)

00...07...30...08:48:58 AM...Orbiter access arm retraction
00...05...00...08:56:28 AM...Launch window opens (placeholder; not needed for STS-134)
00...05...00...08:51:28 AM...Hydraulic power system (APU) start
00...04...55...08:51:33 AM...Terminate LO2 replenish
00...04...00...08:52:28 AM...Purge sequence 4 hydraulic test
00...04...00...08:52:28 AM...IMUs to inertial
00...03...55...08:52:33 AM...Aerosurface profile
00...03...30...08:52:58 AM...Main engine steering test
00...02...55...08:53:33 AM...LO2 tank pressurization
00...02...35...08:53:53 AM...Fuel cells to internal reactants
00...02...30...08:53:58 AM...Clear caution-and-warning memory
00...02...00...08:54:28 AM...Crew closes visors
00...01...57...08:54:31 AM...LH2 tank pressurization
00...00...50...08:55:38 AM...SRB joint heater deactivation
00...00...31...08:55:57 AM...Shuttle GPCs take control of countdown
00...00...21...08:56:07 AM...SRB steering test
00...00...07...08:56:21 AM...Main engine start (T-6.6 seconds)
00...00...00...08:56:28 AM...SRB ignition (LAUNCH)

CBS NEWS Coverage of Breaking Space News

-- Posted at 09:28 AM EDT, 05/15/11: Forecast unchanged with 70 percent chance of good weather Monday
-- Updated at 10:20 AM EDT, 05/15/11: Updating launch time (2 second change)
-- Updated at 01:00 PM EDT, 05/15/11: Rotating service structure pulled away from shuttle
-- Updated at 04:35 PM EDT, 05/15/11: Thruster rain covers blow off; no impact to countdown

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Engineers prepared the shuttle Endeavour for fueling Sunday, setting the stage for blastoff Monday on a long-awaited space station assembly mission. Commander Mark Kelly's wife, Arizona Rep. Gabrielle Giffords, flew to the space center from Houston to await liftoff at 8:56:28 a.m. EDT (GMT-4) Monday.

Forecasters are predicting a 70 percent chance of good weather. Storms rolled across the state overnight, but conditions improved as the morning wore on and engineers were cleared to retract a protective gantry from the shuttle a few minutes before noon to clear the way for fueling.

NASA television cameras focused on the nose of the orbiter showed protective rain covers over three rocket thruster nozzles pulled free in brisk winds, exposing the jets to the elements. Designed to pull away during launch, the Tyvek covers are intended to keep rain out of the nozzles before takeoff that could freeze and cause problems in orbit. But forecasters say rain is not expected before Monday's launch and the countdown proceeded toward fueling as planned.

The three-hour fueling procedure was scheduled to begin at 11:36 p.m. Kelly and his crewmates -- pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- plan to start strapping in at 5:41 a.m. Monday to await liftoff on Endeavour's 25th and final flight.

Other than the missing Tyvek covers, there are no technical problems of any significance at pad 39A and forecasters are optimistic about the weather.

"The mid- and upper-atmosphere will dry out today, and there is only a slight chance for late afternoon thunderstorms associated with the west coast sea breeze," according to the forecast provided by the 45th Weather Squadron at Patrick Air Force Base. "Winds will decrease into the evening hours, and weather is favorable for tanking tonight. By launch time, the weather forecast is generally favorable, but the forecast wind speed and direction causes some concern for a Shuttle Landing Facility (SLF) crosswind violation. There is also just a slight concern for a low-cloud ceiling."

A major problem during the early minutes of flight could force the crew to attempt an emergency return to the SLF and NASA flight rules require generally clear skies and crosswinds at or below 15 knots. The forecast for Monday calls for scattered clouds at 3,500 feet with winds out of 250 degrees at 10 knots with gusts to 15. Almost all of that is a crosswind on SLF runway 15/33.

The forecast for Tuesday calls for a 60 percent chance of a delay due to crosswinds, low clouds and rain, but the outlook improves to 80 percent "go" on Wednesday.

CBS NEWS Coverage of Breaking Space News

09:30 AM EDT, 05/15/11: Forecast unchanged; 70 percent 'go' for Monday launch

The updated forecast for Monday's planned launch of the shuttle Endeavour was unchanged Sunday with a 70 percent chance of acceptable weather. Thunderstorms passed south of the Kennedy Space Center early Sunday, but the weather was expected to be favorable for the noon rollback of a protective gantry around the shuttle.

Engineers plan to begin fueling Endeavour at 11:36 p.m. EDT (GMT-4), setting up a launch attempt at 8:56:26 a.m. Monday.

"The mid- and upper-atmosphere will dry out today, and there is only a slight chance for late afternoon thunderstorms associated with the west coast sea breeze," according to the forecast provided by the 45th Weather Squadron at Patrick Air Force Base. "Winds will decrease into the evening hours, and weather is favorable for tanking tonight. By launch time, the weather forecast is generally favorable, but the forecast wind speed and direction causes some concern for a Shuttle Landing Facility (SLF) crosswind violation. There is also just a slight concern for a low-cloud ceiling."

A major problem during the early minutes of flight could force the crew to attempt an emergency return to the SLF and NASA flight rules require generally clear skies and crosswinds at or below 15 knots. The forecast for Monday calls for scattered clouds at 3,500 feet with winds out of 250 degrees at 10 knots with gusts to 15. Almost all of that is a crosswind on SLF runway 15/33.

The forecast for Tuesday calls for a 60 percent chance of a delay due to crosswinds, low clouds and rain, but the outlook improves to 80 percent "go" on Wednesday.

CBS NEWS Coverage of Breaking Space News

06:15 PM EDT, 05/14/11: Shuttle Endeavour cleared for Monday launch

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL-WIth the shuttle Endeavour's countdown proceeding smoothly toward launch Monday, NASA managers carried out a final processing review Saturday and said they were confident the electrical glitch that grounded the ship April 29 has been safely resolved. There are no other technical problems of any significance and forecasters are continuing to predict a 70 percent chance of good weather at launch time Monday.

"We had a really good meeting today, unanimous consent from the Mission Management Team to press on with the launch countdown," said Mike Moses, MMT chairman and director of shuttle integration at the Kennedy Space Center. "Everything's in really great shape, really no issues at all.

"We took our time to walk through the issue that caused the launch scrub last time, the APU-1 heater problem, to make sure we truly understood our resolution and our fix, that everybody had a chance to see that. ... And everybody was fine with that."

Early Saturday, engineers pumped liquid oxygen and hydrogen aboard to power Endeavour's three electricity-producing fuel cells. If all goes well, a protective gantry will be pulled away from the shuttle around noon Sunday, exposing the ship to view and setting the stage for fueling.

Working by remote control, engineers plan to begin pumping a half-million gallons of liquid oxygen and hydrogen rocket fuel into Endeavour's external tank starting at 11:36 p.m. EDT (GMT-4) Sunday. The procedure should be complete by 2:36 a.m. Monday.

After a final weather briefing, commander Mark Kelly and his crewmates -- pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- plan to head for the launch pad to begin strapping in around 5:41 a.m.

Liftoff is targeted for 8:56:26 a.m., the opening of a five-minute launch window marking roughly the moment when Earth's rotation carries the pad into the plane of the space station's orbit. Launch Director Mike Leinbach said law enforcement authorities are predicting up to a half-million spectators for Endeavour's final launching.

"You'll recall for the first launch attempt on that Friday afternoon, the estimate was between 500,000 and 750,000," he said. "So they're not quite expecting that big surge, but it'll still be a heck of a traffic jam after launch."

Weather permitting, of course.

Shuttle weather officer Kathy Winters said stormy weather was expected to pass through the area overnight Saturday, clearing out through the day Sunday. The forecast calls for a 70 percent chance of acceptable weather at launch time Monday, with the only concerns being possibly high crosswinds and low ceilings at the shuttle's emergency runway. A major problem during the first few minutes of flight could force Kelly and Johnson to attempt an emergency return-to-launch-site abort and NASA flight rules require generally clear skies and light crosswinds.

Stormy weather is expected to move through the area again on Tuesday, lowering the odds of a launch to just 40 percent, but conditions are expected to improve to 80 percent "go" on Wednesday.

The primary goals of the 134th shuttle mission are to deliver the $2 billion Alpha Magnetic Spectrometer particle physics detector to the International Space Station, along with a pallet of critical spare parts and components being stockpiled to protect against failures after the shuttle fleet is retired. Four spacewalks are planned to perform needed maintenance and upgrades.

Assuming an on-time launch, Kelly will guide Endeavour to a docking a the station's forward port around 6:15 a.m. Wednesday. The spare parts pallet, known as External Logistics Carrier No. 3, will be attached to the left side of the station's power truss a few hours after docking while AMS will be attached to the right side of the truss the next day.

Endeavour is scheduled to undock from the lab complex around 11:53 p.m. May 29, setting up a landing back at the Kennedy Space Center around 2:32 a.m. on June 1. That same morning, engineers will be hauling the shuttle Atlantis to the launch pad for the shuttle program's 135th and final flight. Launch is currently targeted for the second week in July.

NASA attempted to get Endeavour off the ground April 29, but a presumed short circuit knocked out power to a set of hydraulic system fuel line heaters and the countdown was called off. Engineers believe damaged insulation on a thermostat connector triggered an undetected short circuit during testing last June that blew fuse elements in a power switching circuit used by the heaters in question.

The circuit was not powered up again until the day of launch, when engineers noticed the B-string heaters were not responding as required. The countdown was called off and NASA launched an extensive engineering evaluation.

Playing it safe, the aft load control assembly power distribution box that included the blown fuse elements was replaced, along with thermostats and associated wiring. Extensive tests show the circuitry is working normally and engineers do not anticipate any additional problems with the system.

Engineers discovered the damaged thermostat insulation after reviewing data from last June that showed a previously undetected current spike during a test involving that same thermostat. While they have not been able to conclusively prove the insulation problem caused the short, no other problems have been found that could explain what happened.

"The only piece that's missing is the molten metal you'd see as an arc jumped from the bare wire to whatever ground point it had," Moses said. "But we were actually at the time heating this thermostat up with a heat gun that has a metal tip on it. If we inadvertently managed to touch that metal tip to the wire, it would have melted directly through the insulator, come into direct contact with the wire and shorted without an arc jumping the gap.

"So we postulate that's what happened. You could be a lawyer (and) say that we haven't exactly proven that was exactly it, but in our minds we are good to go and we have no problems expected with this APU heater any more in this count."

CBS NEWS Coverage of Breaking Space News

12:30 PM EDT, 05/13/11: Shuttle countdown begins; favorable weather expected

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Engineers restarted the shuttle Endeavour's countdown Friday, setting the stage for a delayed launch Monday on a flight to deliver supplies, spare parts and a $2 billion particle physics detector to the International Space Station. There are no technical problems of any significance at pad 39A and forecasters are predicting a 70 percent chance of good weather.

"We're counting and working on some of our avionics checkouts right at the beginning of the count as we normally do," said NASA Test Director Jeff Spaulding. "I am really proud of our teams working so hard over the last couple of weeks. They have done an outstanding job to get us ready for this launch on the historic and final flight of space shuttle Endeavour."

Working in Firing Room No. 4 at the Launch Control Center 3.4 miles from pad 39A, engineers started Endeavour's countdown at 7 a.m. EDT (GMT-4) Friday. Liquid hydrogen and oxygen will be pumped aboard to power the shuttle's eectricity-producing fuel cell system Saturday. A protective gantry is scheduled to be pulled away from the shuttle at noon Sunday, exposing the ship to view and setting the stage for fueling.

If all goes well, the three-hour fueling procedure will begin at 11:36 p.m. Sunday and Endeavour's crew -- commander Mark Kelly, pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- will begin strapping in around 5:41 a.m. Monday to await liftoff.

Shuttle missions to the International Space Station typically enjoy 10-minute launch windows centered around the moment Earth's rotation carries the launch pad into the plane of the station's orbit. To maximize performance, NASA usually targets the middle of the 10-minute window.

But because of recent changes to the station's orbit, rendezvous requirements and other factors, the opening of the window and the preferred "in-plane" launch time are roughly the same for Endeavour's second launch try. Liftoff is targeted for 8:56:26 a.m. EDT Monday and the window will close five minutes later.

Shuttle weather officer Kathy Winters said forecasters are predicting a 70 percent chance of acceptable weather Monday with the primary concerns being slightly high crosswinds at the shuttle's emergency runway. The odds drop to 60 percent "go" on Tuesday and improve to 80 percent favorable on Wednesday.

Winters said the timing of a trough expected to move through the area Sunday could bring afternoon storms and cause problems for engineers trying to move the gantry away from the space shuttle. But she said the system was expected to clear out in time for fueling and launch.

NASA attempted to launch Endeavour on its 25th and final flight April 29, but the countdown was called off when engineers were unable to activate a "string" of hydraulic system fuel line heaters used by auxiliary power unit No. 1. Extensive troubleshooting and analysis showed the problem likely involved a power switching circuit in an avionics box known as an aft load control assembly, one of three in the shuttle's engine compartment.

ALCA No. 2 was removed and engineers quickly discovered blown fuse elements in a so-called "hybrid driver" responsible for routing power to the heater string in question. But engineers were unable to find a problem in the box or the associated wiring that might explain the presumed short circuit that blew the fuse elements.

In a bid to cover as many failure modes possible, ALCA No. 2 was replaced and new wiring was installed between the box and the suspect B-string heaters. In addition, thermostats used to activate the heaters were replaced.

While that work was going on, engineers reviewing heater test data discovered a previously unnoticed 18-amp spike during a thermostat test last June. An inspection of the thermostat in question found an insulation breach and an exposed conductor that might be the cause of the short that blew the hybrid driver circuit in the original ALCA.

But a microscopic inspection of the thermostat found no obvious physical evidence of a short. The thermostat is considered the most likely cause of the heater failure that grounded Endeavour, but the data are not conclusive and the problem is still considered an "unexplained anomaly."

CBS NEWS Coverage of Breaking Space News

12:25 PM EDT, 05/12/11: Endeavour astronauts return to Florida to prep for Monday launch

By WILLIAM HARWOOD
CBS News

After extensive troubleshooting and repairs to fix an electrical problem with the shuttle Endeavour's hydraulic power system, commander Mark Kelly and his five crewmates flew back to Florida Thursday to prepare for a delayed launch Monday on a long-awaited space station assembly mission, the orbiter's 25th and final flight.

The countdown is scheduled to begin Friday morning, setting up a launch attempt at 8:56:26 a.m. EDT (GMT-4) Monday. Forecasters are predicting a 70 percent chance of good weather.

Hoping for the best, Kelly, pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori landed at the Kennedy Space Center's shuttle runway aboard a NASA training jet shortly after 9 a.m. after a flight from Houston.

"It's great to be back," Kelly told reporters. "Four days from now, we should all be strapped in and ready to go. Hopefully the weather will be good. (Launch Director) Mike Leinbach just told us the vehicle is in great condition. We really appreciate all the hard work by the team that's worked over the last couple of weeks to get shuttle Endeavour ready."

Kelly said the crew's families, presumably including his wife, Arizona Rep. Gabrielle Giffords, "will be down later in the week."

"All of our kids are in school and they missed a lot of school last (time) and we couldn't let that happen again," he said. "So they'll be down over the weekend, even though I'm sure they'd rather be here in Florida now."

Giffords, who is recovering from a gunshot wound to the head in a January assassination attempt, flew to Florida for the crew's first launch attempt and is expected to return for the second.

"I'd just like to say on behalf of all of us, we all know Mark's been through a lot the past few months," Chamitoff said Thursday. "He's done an incredible job keeping track of all the details of this mission. I flew with him on (mission) STS-124, he's truly an amazing commander and all of us feel really, really lucky to have him guide us through this complex mission."

Endeavour was grounded April 29 when hydraulic system fuel line heaters failed to activate as required when the shuttle was being fueled for launch. Extensive troubleshooting revealed blown fuse elements on a power switching circuit card inside an engine compartment avionics box packed with electrical distribution gear. Engineers have been unable to find the short that caused the fuse to blow, but the box was replaced, along with thermostats and the power line between the box and the heaters.

The system worked normally in a battery of tests and engineers are confident the heaters will operate as required when Endeavour is loaded with supercold propellants Monday, subjecting the hydraulic system fuel lines to low temperatures.

Engineers plan to start Endeavour's countdown at 7 a.m. Friday. Liquid oxygen and hydrogen will be pumped aboard Saturday to power the ship's three electricity producing fuel cells and a protective gantry will be pulled away from the ship Sunday at noon, exposing the orbiter to view and clearing the way for fuel loading.

The three-hour fueling procedure is scheduled to get underway around 11:36 p.m. Sunday. If all goes well, Kelly and his crewmates will begin strapping in at 5:41 a.m. Monday to await liftoff on the 134th shuttle mission.

The primary goals of the flight are to deliver a $2 billion particle physics detector to the International Space Station, along with supplies and a pallet of critical spare parts and components. Four spacewalks are planned to carry out needed external maintenance and the shuttle crew will help their station colleagues service a U.S. carbon dioxide removal system, along with transferring supplies and experiment hardware.

The launch delay has complicated the mission flight plan because of the scheduled departure of a Soyuz ferry craft May 23 carrying three space station crew members back to Earth. The station crew must adjust their sleep cycles to synch up with the re-entry schedule, which is dictated by the station's orbit and the location of the Soyuz landing zone in Kazakhstan.

But the Endeavour crew will be on a different sleep cycle through undocking day because of their time of launch and landing in Florida. After the Soyuz departs, the station crew members will adjust their schedules to synch back up with the shuttle astronauts.

CBS NEWS Coverage of Breaking Space News

05:20 PM EDT, 05/09/11: NASA managers agree to press ahead for May 16 launch of shuttle Endeavour

By WILLIAM HARWOOD
CBS News

NASA managers met Monday and cleared the shuttle Endeavour for a second launch try May 16 after weekend work to re-wire and re-test hydraulic power system fuel line heaters blamed for derailing an April 29 launch attempt.

"Right now, we're in good shape," said Launch Director Mike Leinbach. "Endeavour's looking good, the team is upbeat. I went to the meeting this morning and they're ready to go. Hopefully, this time the heaters will work and we'll be able to launch on time next Monday morning."

While engineers have not yet found the root cause of a short circuit that effectively blew a fuse in a power supply circuit, the replacement of critical hardware, installation of by-pass wiring and extensive testing have given agency managers confidence the problem has been resolved.

"We've replaced everything except the heaters, and we've wrung those out with at least five separate checks and full functionals afterwards and now have extremely high confidence that the problem is no longer on the ship or in any of the electronics," said Mike Moses, director of shuttle integration at the Kennedy Space Center.

"We don't still exactly have root cause, but we basically have really good, comprehensive proof that we have managed to remove that failure."

Assuming final tests and checkout go smoothly, engineers will restart Endeavour's countdown at 7 a.m. EDT (GMT-4) Friday, setting up a launch at 8:56:26 a.m. Monday, roughly the moment Earth's rotation carries launch pad 39A into the plane of the International Space Station's orbit.

Endeavour's crew -- commander Mark Kelly, pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- plans to fly back to Florida Thursday morning to prepare for launch. Kelly's wife, Arizona Rep. Gabrielle Giffords, recovering from a January assassination attempt, is expected to attend the launching, but her schedule is not yet known.

Thanks to the launch slip, Endeavour's 25th and final flight will be carried out in the deep overnight hours U.S. time, with docking at the International Space Station expected at 6:15 a.m. on May 18. Four spacewalks are planned, on May 20, 22, 25 and 28, before undocking around 11:52 p.m. on May 29 and landing back at the Kennedy Space Center around 2:32 a.m. on June 1.

The two-week delay has forced NASA to consider a corresponding slip for NASA's final planned shuttle mission, pushing launch of the Atlantis from June 28 to around July 15. Moses said a firm target date will not be set until after Endeavour gets off the ground and engineers get a better idea of how much launch pad damage they might have to repair and how much work remains to ready Atlantis for flight.

The Endeavour astronauts will face a more challenging timeline than usual because of the departure of three space station crew members -- Expedition 27 commander Dmitry Kondratyev, Paolo Nespoli and NASA flight engineer Catherine Coleman -- on May 23 aboard the Soyuz TMA-20 spacecraft.

The departing astronauts must sleep shift to accommodate the Soyuz landing time, putting them out of synch with the shuttle crew's sleep schedule. As it is, Kelly and his crewmates will be asleep when the Soyuz undocks.

NASA flight planners are revising the shuttle timeline to make sure the departing station crew members are not disturbed as they adjust their sleep cycle to accommodate re-entry and landing and to make sure needed station maintenance gets done before Endeavour's departure.

Mission managers decided earlier to extend Endeavour's mission by two days to simplify flight planning. But orchestrating the required work with multiple sleep schedules remains a significant challenge.

"This one's pretty close to the edge," Moses said. "A sleep shift another hour or two worse than this would probably tell us we can't do it. So this is about the furthest we'd want to stretch for a dual docked operation."

Endeavour was grounded April 29 when one of two "strings" of fuel line heaters used by one of the shuttle's three hydraulic power units failed to power up normally. While the system can safely operate with a single string, a subsequent failure could result in a fuel line rupture, knocking auxiliary power unit No. 1 out of action and possibly contaminating the aft engine compartment with toxic hydrazine.

NASA managers stopped the countdown and ordered an investigation to find out what went wrong. There were three possible explanations: trouble with a fuse panel in the shuttle's cockpit that routes power to the APU system; a problem with the aft load control assembly, an electrical distribution box upstream of the heaters; or trouble with downstream heaters, thermostats and wiring.

Subsequent testing showed the cockpit fuse panel was working normally and that commands were reaching ALCA No. 2 as required. Additional tests indicated the thermostats in question were healthy but not getting power from the distribution box. As a result, ALCA No. 2 was removed from avionics bay No. 5 in Endeavour's aft engine compartment for a detailed failure analysis.

Engineers quickly found vaporized fuse elements in a so-called "hybrid driver" circuit responsible for routing power to APU 1's B-string fuel line heaters. But it's not yet known whether the blown circuitry was the result of a problem inside the power box or the result of a short in external wiring.

At launch pad 39A, meanwhile, a replacement ALCA was installed, but fuel line heater power was not immediately reconnected to make sure whatever caused the initial problem did not damage the replacement box.

Engineers met late last week and discussed three options: replacing the wiring between ALCA No. 2 and the heater thermostats; replacing all the wiring, thermostats and heaters downstream of ALCA No. 2; and pressing ahead "as is" with the replacement ALCA and the original wiring.

They opted to replace the wiring between ALCA No. 2 and the heaters. That work was carried out over the weekend. The new line, which Moses estimated was about 20 feet long, was plugged into ALCA-2, the system was activated and tests showed the heaters were receiving power as required. Work was underway Monday to remove access platforms from the shuttle's engine compartment and to re-install an access door to prepare the ship for flight.

"We ran a whole bunch of tests," Moses said. "We did continuity checks ... and made sure that wire was intact and didn't go to ground anywhere. We measured the resistance of this line, it measured within family of what the resistance of the heater measured the last time it was checked about two years ago. We saw no changes in the resistance of these heaters, we saw no open circuits with the continuity checks.

"We did what we call a high-pot, or high potential, check of all the orbiter wiring and the heaters where you basically put high voltage, but low current, into the system and you'll see that voltage jump across any gaps if there is an insulation breakdown, it would show up as that high pot test grounded itself out. And we saw no problems in either the orbiter wiring or in the heaters.

"Then we did functional checks, which culminated last night in our full up retest of this APU system where we basically operated the heaters on both an external power supply and then the new (ALCA-2) power supply," Moses said. "And we saw full functionality out of all five of these heaters as they were supposed to work."

Engineers will be monitoring the system closely next Monday when the shuttle is loaded with supercold propellants. As the temperature in the aft engine compartment drops, the fuel line thermostats should respond, powering the heaters on as needed.

If the heaters again fail to activate, Moses said mission managers will consider pressing ahead with launch anyway given the redundancy in the system and the knowledge that major elements have been replaced.

But that remains to be seen. NASA's launch commit criteria require both heater strings to be operational for a countdown to proceed and it's not yet clear if a waiver would be a viable option.

In any case, mission managers are confident it won't come to that. Engineers are continuing to test the suspect ALCA that was removed from Endeavour "but it's going to take a long time until we can say we definitely found a problem inside that box," Moses said.

"And so we wanted to make sure our flight rationale didn't need us to have that root cause and by replacing the box and replacing the wiring, we think we have that."

In a bit of late-breaking news, Moses said engineers reviewing test data collected last June have found evidence of a previously unknown 10-amp spike during a heater thermostat test carried out in the shuttle's processing hangar. Whether that spike was the result of a short that could explain the problem seen April 29 is not yet known.

The thermostat in question was replaced as part of the on-going troubleshooting and "if this turns out to be the root cause, we've removed it from the ship," Moses said.

CBS NEWS Coverage of Breaking Space News

-- Posted at 11:58 AM EDT, 05/06/11: NASA managers reassess Eneavour launch date
-- Updated at 03:25 PM EDT, 05/06/11: Launch delayed to at least May 16

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Launch of the shuttle Endeavour, grounded April 29 by an electrical glitch in the ship's hydraulic system, will be delayed until at least May 16 pending additional troubleshooting and repairs, NASA managers said Friday.

Engineers have not yet pinned down the cause of the short circuit that vaporized fusing in a heater control power switch, but a replacement power switching box has been installed and NASA managers have approved a plan to replace wiring between the box and the heaters in question to clear the way for a second launch attempt.

During work to install the new wiring, engineers noticed a crimped cable in a wiring bundle, officials said Friday, and additional tests were planned to find out if that might be the cause of the initial short. NASA managers plan to brief reporters on the status of repairs and overall launch processing Monday.

Going into Endeavour's launch campaign, mission managers had been holding open an option to extend the flight by two days to give the shuttle crew time to help out with needed station maintenance. The idea was to add the extra days to the mission after Endeavour docked with the station.

But on Friday, NASA made that official, extending the flight to 16 days to eliminate multiple timelines and ease flight planning.

For a launch at 8:56 a.m. EDT (GMT-4) on May 16, Endeavour's countdown would begin around 7 a.m. on Friday, May 13. The shuttle would dock with the International Space Station around 6 a.m. on May 18, undock around 11 p.m. on May 29 and land back at the Kennedy Space Center around 2:30 a.m. on June 1.

Complicating mission planning, three of the space station's six crew members -- Dmitry Kondratyev, Paolo Nespoli and Catherine Coleman -- are scheduled to return to Earth May 23 aboard a Russian Soyuz spacecraft. Preparing for undocking will require sleep shifting that will put the station and shuttle crews on different schedules.

The primary goals of Endeavour's flight are to deliver a pallet of spare parts and to install a $2 billion particle physics experiment on the station's power truss. The Endeavour astronauts also plan to stage four spacewalks to perform critical maintenance, but the launch delay is expected to result in a major flight plan revision and the EVA schedule is not yet clear.

Endeavour was grounded during the final hours of a launch countdown April 29 when one of two "strings" of fuel line heaters used by one of the shuttle's three hydraulic power units failed to power up normally. While the system can safely operate with a single string, a subsequent failure could result in a fuel line rupture, knocking auxiliary power unit No. 1 out of action and possibly contaminating the aft engine compartment with toxic hydrazine.

At the time of the failure, engineers believed there were three possible explanations: trouble with a fuse panel in the shuttle's cockpit that routes power to the APU system; a problem with the aft load control assembly, an electrical distribution box upstream of the heaters; or trouble with downstream heaters or thermostats.

Subsequent testing showed the cockpit fuse panel was working normally and that commands were reaching ALCA No. 2 as required. Additional tests indicated the thermostats in question were healthy but not getting power from the distribution box. As a result, ALCA No. 2 was removed from avionics bay No. 5 in Endeavour's aft engine compartment for a detailed failure analysis.

Engineers quickly found vaporized fuse elements in a so-called "hybrid driver" circuit responsible for routing power to APU 1's B-string fuel line heaters. But it was not immediately clear whether the blown circuitry was the result of a problem inside the power box or the result of a short in external wiring.

At launch pad 39A, meanwhile, a replacement ALCA was installed, but fuel line heater power was not immediately reconnected to make sure whatever caused the initial problem did not damage the replacement box.

Engineers met Thursday and discussed three options: replacing the wiring between ALCA No. 2 and the heater thermostats; replacing all the wiring, thermostats and heaters downstream of ALCA No. 2; and pressing ahead "as is" with the replacement ALCA and the original wiring.

They opted to replace the wiring between ALCA No. 2 and the heaters. The original power line will remain in place but will not be plugged in to protect against the possibility of a short. Whether the crimped wire found Friday was a factor in the short remains to be seen.

CBS NEWS Coverage of Breaking Space News

12:10 PM EDT, 05/06/11: NASA managers reassess Endeavour launch date amid ongoing repair work

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Engineers have not yet pinned down the cause of a short circuit that vaporized fusing in a heater control power switch April 29, delaying launch of the shuttle Endeavour on its 25th and final flight. But a replacement power switching box has been installed and NASA managers have approved a plan to replace wiring between the box and the heaters in question to clear the way for a second launch attempt.

Senior shuttle managers planned to meet Friday afternoon to set a new launch target date. The current "no-earlier-than" target is May 10, but sources said the launching is expected to slip another week or so, to around May 16, because of time needed to complete repairs, retesting and to carry out a fresh three-day countdown.

For a launch at 8:56 a.m. EDT (GMT-4) on May 16, Endeavour's countdown would begin around 7 a.m. on Friday, May 13. The shuttle would dock with the International Space Station around 6 a.m. on May 18, undock on May 27 and land back at the Kennedy Space Center around 3:20 a.m. on May 30.

NASA managers are holding open an option to extend the mission by two days to give the shuttle crew time to help out with needed station maintenance. Complicating mission planning, three of the space station's six crew members -- Dmitry Kondratyev, Paolo Nespoli and Catherine Coleman -- are scheduled to return to Earth May 23 aboard a Russian Soyuz spacecraft, leaving the lab understaffed until three replacements arrive June 9.

The primary goals of Endeavour's flight are to deliver a pallet of spare parts and to install a $2 billion particle physics experiment on the station's power truss. The Endeavour astronauts also plan to stage four spacewalks to perform critical maintenance, but the launch delay and Soyuz departure are expected to result in a major flight plan revision and the EVA schedule is not yet clear.

Endeavour was grounded during the final hours of a launch countdown April 29 when one of two "strings" of fuel line heaters used by one of the shuttle's three hydraulic power units failed to power up normally. While the system can safely operate with a single string, a subsequent failure could result in a fuel line rupture, knocking auxiliary power unit No. 1 out of action and possibly contaminating the aft engine compartment with toxic hydrazine.

At the time of the failure, engineers believed there were three possible explanations: trouble with a fuse panel in the shuttle's cockpit that routes power to the APU system; a problem with the aft load control assembly, an electrical distribution box upstream of the heaters; or trouble with downstream heaters or thermostats.

Subsequent testing showed the cockpit fuse panel was working normally and that commands were reaching ALCA No. 2 as required. Additional tests indicated the thermostats in question were healthy but not getting power from the distribution box. As a result, ALCA No. 2 was removed from avionics bay No. 5 in Endeavour's aft engine compartment for a detailed failure analysis.

Engineers quickly found vaporized fuse elements in a so-called "hybrid driver" circuit responsible for routing power to APU 1's B-string fuel line heaters. But it was not immediately clear whether the blown circuitry was the result of a problem inside the power box or the result of a short in external wiring.

At launch pad 39A, meanwhile, a replacement ALCA was installed, but fuel line heater power was not immediately reconnected to make sure whatever caused the initial problem did not damage the replacement box.

Engineers met Thursday and discussed three options: replacing the wiring between ALCA No. 2 and the heater thermostats; replacing all the wiring, thermostats and heaters downstream of ALCA No. 2; and pressing ahead "as is" with the replacement ALCA and the original wiring.

They opted to replace the wiring between ALCA No. 2 and the heaters. The original power line will remain in place but will not be plugged in to protect against the possibility of a short. With a replacement ALCA and new downstream wiring, engineers are hopeful the heaters will work normally.

CBS NEWS Coverage of Breaking Space News

01:20 PM EDT, 05/04/11: Failure analysis indicates possible external short circuit

By WILLIAM HARWOOD
CBS News

Engineers inspecting a suspect electrical distribution box removed from the shuttle Endeavour after a launch scrub last week have found blown internal fusing that could be the result of an external, yet-to-be-identified short circuit somewhere in the ship's complex electrical system, officials said Wednesday. But they cautioned that troubleshooting is not yet complete and a problem with the box itself has not yet been ruled out.

Hoping for the best, engineers installed a replacement aft load control assembly switching box in Endeavour's engine compartment, but initial testing has been modified to make sure the new box is not inadvertently damaged by whatever caused the presumed short Friday.

Endeavour was grounded when telemetry indicated one of two redundant "strings" of fuel line heaters used by one of the ship's three hydraulic power units had not activated as required. Testing showed no obvious problems upstream of an aft load control assembly switching unit that routes power to the system and no obvious problems with the downstream heaters or thermostats.

On Saturday, engineers decided to replace ALCA No. 2 on the assumption that something had failed inside the box, preventing power from reaching the heaters. The box was removed from avionics bay No. 5 in Endeavour's engine compartment Monday, clearing the way for installation of a replacement.

The ALCA is one of three in the aft compartment that routes power to nine critical subsystems, including the hydraulic system, from three major circuits, or buses.

On the assumption a fault would be found in the suspect power box, NASA managers said Monday Endeavour's launch would be on hold until at least May 10 to give engineers time to install the replacement ALCA, retest downstream systems and to ready the shuttle for another three-day countdown.

If additional testing confirms an external short -- and if engineers are not able to quickly find and fix whatever might have caused it -- launch likely will face an additional delay. Endeavour's current launch window extends through May 29. The next available window opens June 19 based on temperature constraints related to the space station's orbit.

Only two fights remain on NASA's shuttle manifest, Endeavour's mission and a final flight by the shuttle Atlantis that is currently scheduled for launch June 28. Endeavour's launch delay likely will trigger a slip for Atlantis, but managers have not yet made any official changes.

CBS NEWS Coverage of Breaking Space News

05:50 PM EDT, 05/02/11: Shuttle launch slips to May 10, possibly later

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Work to replace and retest an electrical distribution box in the shuttle Endeavour's engine compartment will push the crew's next launch attempt to at least May 10, agency managers said Monday. An official launch date is expected Friday, after repairs are complete.

In the wake of a launch scrub last Friday, NASA managers said Sunday the next attempt to launch Endeavour on its 25th and final mission would be delayed to Mother's Day at least and possibly longer.

A more realistic assessment Monday, based on a detailed review of the work needed to replace the suspect aft load control assembly, showed it would not be possible to complete repairs in time to start a fresh countdown Thursday for a launch on Sunday.

Instead, mission managers agreed to target May 10 as a "no-earlier-than" date pending successful repairs. If that scenario holds up, a fresh countdown would start around 9:30 a.m. EDT (GMT-4) Saturday for a launch attempt at 11:21 a.m. next Tuesday, May 10. But engineers believe it will be difficult to meet that target and that May 11 is a more realistic option.

Endeavour was grounded Friday when telemetry showed hydraulic power system fuel line heaters were not working properly. Subsequent tests isolated the problem to aft load control assembly No. 2 in the shuttle's engine compartment.

The ALCA is one of three electrical switching units in the aft compartment that routes power to a variety of critical systems. Replacing ALCA No. 2 is relatively straight forward, but verifying that all the downstream systems are properly connected and operating is expected to take two full days.

The replacement unit should be in place Tuesday, clearing the way for testing to begin. Engineers also will evaluate the faulty unit to verify the presumed fault.

A launch on May 10 at 11:21 a.m. would set up a docking at the International Space Station around 8:20 a.m. on May 12. The shuttle's primary payload, a $2 billion particle physics experiment, would be attached to the lab's power truss the next day.

Four spacewalks would carried out on May 14, 16, 18 and 20 with undocking on tap around 1:15 a.m. on May 22 and landing back at the Kennedy Space Center around 5:50 a.m. on May 24.

Going into Endeavour's final launch campaign, NASA managers planned to add two days to Endeavour's mission to give the crew more time to help out with needed station maintenance.

But with Friday's launch delay, the prospects for a mission extension are not clear cut because of the scheduled undocking of a Russian Soyuz ferry craft on May 23. Three of the station's six crew members will be returning to Earth that day and they must adjust their sleep shifts to accommodate the re-entry and landing time.

For a launch on May 8, two extension days were still available for Endeavour's crew, assuming an Air Force Atlas rocket gets off on time Friday.

For a launch on May 9, one extension day is available but for a launch on May 10, station crew sleep shifting and other factors would preclude any additional days for the shuttle crew, officials said. For a launch on May 11, both extension days should be available.

CBS NEWS Coverage of Breaking Space News

-- Posted at 09:45 AM, 05/01/11: Avionics swap-out ordered; shuttle launch on hold
-- Updated at 10:15 AM, 05/01/11: Shuttle crew flies back to Houston; adding quote
-- Updated at 04:30 PM, 05/01/11: Launch delayed to at least May 8; news conference; quotes and details

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Engineers have traced an electrical problem blamed for grounding the shuttle Endeavour Friday to an avionics box in the ship's engine compartment, officials said Sunday. Replacing the box will delay launch until at least May 8 -- Mother's Day -- and possibly later.

"I'm here to disappoint everybody by saying I'm not going to tell you what the new launch date is because I have no idea," MIke Moses, chairman of NASA's Mission Management Team, told reporters after engineers decided on a course of action. "We have a lot to evaluate, both the work to do, the R & R (removal and replacement), the retest that has to be done, how we work all that schedule in.

"But we can tell you pretty much it's not going to be any earlier than the 8th. That doesn't mean we're going to go launch on the 8th, that just means we know right now the 8th is our next available opening."

Earlier Sunday, engineers held out a slight hope of possibly launching Endeavour a day or two earlier if the Air Force would agree to delay the planned May 6 launch of an Atlas 5 rocket carrying a missile early warning satellite. But given the amount of work required to repair the shuttle, that was not a viable scenario.

Launch Director Mike Leinbach said engineers plan to remove the suspect aft load control assembly -- ALCA-2 -- box from Endeavour's cramped engine compartment Monday, install a replacement Tuesday and get into a complex re-test procedure Tuesday night or early Wednesday.

To make a launch at 12:09:17 p.m. EDT (GMT-4) on Sunday, NASA would have to start a fresh three-day countdown around 10:30 a.m. Thursday. Whether the team can complete the ALCA-2 swap-out and re-test in time remains to be seen.

But if Endeavour does not make May 8, launch likely would move to May 10. A launch on May 9 could result in the shuttle undocking from the International Space Station on May 23, the same day a Russian Soyuz crew ferry craft is scheduled to depart. There are no known conflicts for subsequent launch opportunities.

In the meantime, "the team is upbeat," Leinbach said. "A little disappointed, of course, that we couldn't launch. But responding to problems is one of the things we do best around here and the team always likes a good challenge. I'm sure we're going to be really glad when Endeavour's finally on orbit but right now, the team is upbeat and ready to execute the plan that we've laid out."

Endeavour commander Mark Kelly and his crewmates -- pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- flew back to Houston early Sunday aboard a shuttle training aircraft to participate in additional ascent simulations later this week.

"Things happen fast," Johnson said in a Twitter update. "We are now all aboard an STA for return to Houston. Be back in a few days. More to follow."

The astronauts will remain in medical quarantine and spend their nights in crew quarters at the Johnson Space Center until their return to Florida. While NASA limits contact to reduce the possibility of a crew member getting sick in orbit, the astronauts will be able to visit with family members who have been medically cleared.

That presumably would include Kelly's wife, Gabrielle Giffords, whose recovery from a January assassination attempt has generated widespread public interest. Giffords flew to Florida last week to watch Endeavour's launching, but no details about her subsequent plans have been released.

Endeavour was grounded Friday during the final hours of the countdown because of telemetry indicating multiple fuel line heaters used by one of the shuttle's three hydraulic power units were not activating normally. The heaters are needed to keep the lines from freezing and possibly rupturing in flight.

The shuttle is equipped with three auxiliary power units, providing the hydraulic muscle to move the ship's engine nozzles, wing elevons, rudder, tail fin speed brake, body flap, landing gear brakes and nose wheel steering system. The shuttle can safely fly with a single APU, but flight rules require full redundancy for a countdown to proceed.

Likewise, each of the shuttle's three APUs is equipped with redundant heater "strings" and only one channel is required for normal operation. But again, the flight rules require redundancy to protect against a subsequent failure that could knock the system out of action.

Early Saturday, engineers ruled out a problem with the fuse panel in the shuttle's cockpit that routes power to the APU circuitry. That left two possible culprits: one or more faulty heater control thermostats or the aft load controller assembly, or ALCA-2, avionics box the heater circuitry runs through.

To find out if a faulty thermostat was to blame, engineers working in Endeavour's cramped engine compartment Saturday afternoon sprayed compressed air on APU No. 1's B-channel heater thermostats to lower their temperature enough to find out whether they would cycle on or not. They did not, but that could have been the result of a wiring problem or a bad connector. Additional tests were carried out overnight and no such problems were found.

Engineers met early Sunday and recommended replacing the ALCA-2 box.

"The box will come out tomorrow and we'll send it down to our malfunction lab for a detailed inspection," Leinbach said. "The new box goes in on Tuesday. ... And then after that, we get into the re-test Tuesday night, Wednesday, that kind of timeframe. It's going to be a full two days of re-test."

The shuttle's electrical system features three main circuits, or buses, for redundancy. As a result, three aft load control assemblies are present in the engine compartment.

Each 50-pound box includes dozens of power switches that route electricity to components in nine major systems, including the auxiliary power units, the environmental control and life support system, solid-fuel booster electronics, the shuttle's main engines, its orbital maneuvering system rockets and flight control systems.

The box is located just forward of a right-side engine compartment access door and Leinbach said the replacement operation was not particularly difficult. An ALCA was changed out during a 1995 shuttle launch campaign and engineers will use the same procedures for Endeavour.

The issue for NASA is the time needed to complete testing to make sure the myriad subsystems downstream of the box are receiving power as required.

"Anytime you break connection to a box like this, you essentially invalidate all the testing we did up to that point," Leinbach said. "You could take the tack of saying all you're doing is replacing the box and everything downstream of that box should be fine. Well, that's true, But our requirements, the way we do business is whenever we break a connection we go back and retest it.

"That's just the prudent thing to do and the way our requirements are set. So we have to retest every one of those nine systems. The details within those systems, you could probably write a thesis on how many individual tests there are within those nine systems. And that's why it takes so long."

Assuming NASA sticks with a May 8 launch, Endeavour would dock with the International Space Station around 9 a.m. on May 10 and the mission's primary payload, a $2 billion particle physics detector, would be attached to the lab complex the next day.

The mission's four spacewalks would be carried out May 12, 14, 16 and 18, before undocking around 2 a.m. on May 20. If that schedule holds up, landing back at the Kennedy Space Center would be expected around 6:30 a.m. on May 22.

But NASA managers plan to extend Endeavour's mission by two days, if possible, to give the shuttle crew time to help their space station counterparts with needed internal maintenance. In that case, undocking would slip to May 22 and landing would be expected before dawn on May 24.

The Russians plan to bring three station crew members back to Earth aboard a Soyuz ferry craft on May 23. Because of that, NASA does not expect to have a launch opportunity for Endeavour on May 9. A launch on May 9, plus two extension days, would result in the shuttle and the Soyuz undocking on the same day. Because of sleep-shifting and a variety of other issues, dual undocking operations cannot be accommodated.

CBS NEWS Coverage of Breaking Space News

09:50 AM EDT, 05/01/11: NASA rules out Monday launch try; avionics swap-out ordered

By WILLIAM HARWOOD
CBS News

Engineers have traced an electrical problem blamed for grounding the shuttle Endeavour Friday to an avionics box in the ship's engine compartment, officials said Sunday. Replacing the box will delay launch past Monday, but NASA managers have not yet determined when another attempt might be possible.

An Air Force Atlas 5 rocket carrying a missile early warning satellite is scheduled for launch May 6 with a second day available as a backup. NASA cannot launch Endeavour between May 5 and 7 because the Air Force Eastern Range, which provides tracking and telemetry support for all rockets launched from the East Coast, needs 24 hours between missions to reconfigure equipment.

Whether the Air Force might agree to delay the Atlas launch to make way for Endeavour is not yet known, but work to replace and retest the avionics box is expected to take several days. It appears unlikely NASA could complete that work in time for a launch by May 4, the last available day before the Atlas cutout.

Barring a delay for the Atlas, Endeavour's launch could move to May 8 or, if the Air Force launch slips a day, to May 10. A May 9 launch date is not available for the shuttle because undocking from the International Space Station would come on the same day a Russian Soyuz is scheduled to depart.

Endeavour was grounded Friday during the final hours of the countdown because of telemetry indicating multiple fuel line heaters used by one of the shuttle's three hydraulic power units were not activating normally. The heaters are needed to keep the lines from freezing and possibly rupturing in flight.

The shuttle is equipped with three auxiliary power units, providing the hydraulic muscle to move the ship's engine nozzles, wing elevons, rudder, tail fin speed brake, body flap, landing gear brakes and nose wheel steering system. The shuttle can safely fly with a single APU, but flight rules require full redundancy for a countdown to proceed.

Likewise, each of the shuttle's three APUs is equipped with redundant heater "strings" and only one channel is required for normal operation. But again, the flight rules require redundancy to protect against a subsequent failure that could knock the system out of action.

Early Saturday, engineers ruled out a problem with the fuse panel in the shuttle's cockpit that routes power to the APU circuitry. That left two possible culprits: one or more faulty heater control thermostats or the aft load controller assembly, or ALCA-2, avionics box the heater circuitry runs through.

To find out if a faulty thermostat was to blame, engineers working in Endeavour's cramped engine compartment Saturday afternoon sprayed compressed air on APU No. 1's B-channel heater thermostats to lower their temperature enough to find out whether they would cycle on or not. They did not, but that could have been the result of a wiring problem or a bad connector. Additional tests were carried out overnight and no such problems were found.

Engineers met early Sunday and recommended replacing the ALCA-2 box. It's not yet clear how long that work might take.

"Due to additional troubleshooting required for APU 1 heater issue, Monday's launch attempt has been scrubbed," the launch team was told early Sunday. "Currently in work to secure from launch countdown operations at this time. No new launch date has been determined."

CBS NEWS Coverage of Breaking Space News

-- Posted at 03:24 PM EDT, 04/30/11: Engineers troubleshoot electrical glitch
-- Updated at 05:55 PM EDT, 04/30/11: Thermostats fail to respond in initial low-temperature tests; more troubleshooting planned

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Engineers troubleshooting an electrical glitch that grounded the shuttle Endeavour Friday have verified that a cockpit fuse panel is working normally, officials said Saturday, indicating the problem likely is either an open circuit in a hydraulic system fuel line heater thermostat or trouble inside an avionics box in the shuttle's aft engine compartment.

Initial thermostat tests were consistent with a problem in the avionics box, but engineers could not immediately rule out a connector problem or some other wiring issue elsewhere in the system.

If the problem can be isolated to an open circuit in a suspect thermostat, a replacement possibly could be installed in time to support a second launch attempt Monday, at 2:34:00 p.m. EDT (GMT-4). But if the problem is traced to the aft load control assembly -- ALCA-2 -- avionics box that routes power to the heaters, launch likely would be delayed until at least May 8, after the planned May 6 launch of an Atlas rocket carrying an Air Force missile early warning satellite.

And that assumes the problem can be traced to a fault in ALC-2.

The problem cropped up Friday during the final hours of Endeavour's countdown to launch on its 25th and final mission. Telemetry showed that multiple fuel line heaters used by auxiliary power unit No. 1 were not activating normally. The heaters are needed to keep the lines from freezing and possibly rupturing in flight.

The shuttle is equipped with three APUs, providing the hydraulic muscle to move the ship's engine nozzles, wing elevons, rudder, tail fin speed brake, body flap, landing gear brakes and nose wheel steering system. The shuttle can safely fly with a single APU, but flight rules require full redundancy for a countdown to proceed. Likewise, each of the shuttle's three APUs is equipped with redundant heater "strings" and only one channel is required for normal operation. But again, the flight rules require redundancy to protect against a subsequent failure that could knock the system out of action.

To find out if a faulty thermostat was to blame, engineers working in Endeavour's cramped engine compartment Saturday afternoon sprayed compressed air on APU No. 1's B-channel heater thermostats to lower their temperature enough to find out whether they would cycle on or not. The initially tested thermostats did not respond, but that could be the result of a wiring problem or a bad connector. Additional tests were planned overnight.

If no obvious culprits are found -- and engineers were not optimistic -- the problem likely is the result of a fault in ALCA-2, a box that contains multiple electronic switches for a variety of subsystems. Replacing ALCA-2 is a complex job requiring extensive retest.

NASA managers and engineers plan to review the troubleshooting Sunday morning to determine a course of action. But without an obvious "smoking gun," the chances of a launching Monday appear slim.

Endeavour's countdown currently is holding at the T-minus 11-hour mark. If a Monday launch is possible, the countdown would resume at 10:07 p.m. Sunday. Fueling would begin at 5:09 a.m. Monday and the crew would begin strapping in at 11:14 a.m. to await launch at 2:34:00 p.m.

The Spaceflight Meteorology Group at the Johnson Space Center is predicting scattered clouds at 3,000 feet and winds out of 100 degrees at 14 knots with gusts to 20, violating NASA's crosswind limits for an emergency landing.

The forecast for Tuesday calls for acceptable weather while the outlook for Wednesday calls for high crosswinds and a chance of showers within 20 nautical miles of the runway.

CBS NEWS Coverage of Breaking Space News

03:40 PM EDT, 04/30/11: Shuttle engineers troubleshoot electrical glitch

By WILLIAM HARWOOD
CBS News

Engineers troubleshooting an electrical glitch that grounded the shuttle Endeavour Friday have verified that a cockpit fuse panel is working normally, officials said Saturday, indicating the problem likely is either an open circuit in a hydraulic system fuel line heater thermostat or a controller assembly in the shuttle's aft engine compartment.

If the problem can be isolated to an open circuit in a suspect thermostat, a replacement likely could be installed in time to support a second launch attempt Monday, at 2:34:00 p.m. EDT (GMT-4). If the problem is traced to the aft load control assembly -- ALC-2 -- avionics box that routes power to the heaters, launch likely would be delayed until at least May 8, after the planned May 6 launch of an Atlas rocket carrying an Air Force missile early warning satellite.

And that assumes the problem can be traced to a fault in ALC-2.

The problem cropped up Friday during the final hours of Endeavour's countdown to launch on its 25th and final mission. Telemetry showed that multiple fuel line heaters used by auxiliary power unit No. 1 were not activating normally. The heaters are needed to keep the lines from freezing and possibly rupturing in flight.

The shuttle is equipped with three APUs, providing the hydraulic muscle to move the ship's engine nozzles, wing elevons, rudder, tail fin speed brake, body flap, landing gear brakes and nose wheel steering system. The shuttle can safely fly with a single APU, but flight rules require full redundancy for a countdown to proceed.

Likewise, each of the shuttle's three APUs is equipped with redundant heater "strings" and only one channel is required for normal operation. But again, the flight rules require redundancy to protect against a subsequent failure that could knock the system out of action.

To find out if a faulty thermostat was to blame, engineers working in Endeavour's cramped engine compartment planned to spray compressed air on the thermostats in APU No. 1's B-channel heater string to lower their temperature. If a thermostat is working normally, the lower temperature should cause it to activate.

If not, the problem likely is the result of a fault in ALC-2, a box that contains multiple electronic switches for a variety of subsystems. Replacing ALC-2 is a complex job requiring extensive retest.

NASA managers and engineers plan to review the troubleshooting Sunday morning to determine a course of action.

Endeavour's countdown currently is holding at the T-minus 11-hour mark. If a Monday launch is possible, the countdown would resume at 10:07 p.m. Sunday. Fueling would begin at 5:09 a.m. Monday and the crew would begin strapping in at 11:14 a.m. to await launch at 2:34:00 p.m.

The Spaceflight Meteorology Group at the Johnson Space Center is predicting scattered clouds at 3,000 feet and winds out of 100 degrees at 14 knots with gusts to 20, violating NASA's crosswind limits for an emergency landing.

The forecast for Tuesday calls for acceptable weather while the outlook for Wednesday calls for high crosswinds and a chance of showers within 20 nautical miles of the runway.

CBS NEWS Coverage of Breaking Space News

-- Posted at 12:46 PM EDT, 04/29/11: Hydraulic system glitch grounds shuttle Endeavour
-- Updated at 01:35 PM, 04/29/11: Launch delayed at least 72 hours; quotes and details
-- Updated at 2:30 PM, 04/29/11: President Obama lands at Cape Canaveral
-- Updated at 7:05 PM, 04/29/11: President tours space center, meets with shuttle crew; engineers assess repair options

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--An electrical glitch with the shuttle Endeavour's hydraulic power system forced NASA managers to scrub Friday's planned launch on a space station assembly mission, disappointing thousands of spectators and spoiling a visit by President Obama and his family.

It also was a disappointment to commander Mark Kelly's wife, Gabrielle Giffords, who flew to Florida Wednesday to watch the launching as she recovers from a January assassination attempt.

"So, a disappointing day for team Endeavour and the astronauts," said Launch Director Mike Leinbach. "But as we always say in this business, we will not fly this machine until it's ready. And today, it was not ready to go."

NASA managers do not yet know what it will take to resolve the problem, but they are hopeful a faulty thermostat in a heater circuit is to blame. If so, the shuttle could be ready for another launch attempt as early as Monday at 2:33:56 p.m.

But if the problem requires a cockpit fuse panel swap out, or installation of a replacement electrical box in the shuttle's aft engine compartment, Endeavour's launch on its 25th and final mission could be delayed until May 9 or 10, after the planned May 6 launch of an Atlas rocket carrying a missile early warning satellite.

Because of a conflict with the planned undocking of a Russian Soyuz spacecraft from the International Space Station at the back end of the shuttle's mission, "we'd probably move to the 9th, maybe even the 10th as our first launch attempt on the other side of Atlas," Moses said.

"We're going to have to go do some homework there and talk to the Russians about exactly the right way to deconflict that," he said. "But we're not going to do too much on that just yet because we think we've still got a shot in front of Atlas."

President Obama and his family toured tornado-damaged Tuscaloosa, Ala., early Friday and continued on to Florida, landing at the Cape Canaveral Air Force Station as planned shortly after 2 p.m. The first family then boarded a Marine helicopter and flew to the nearby Kennedy Space Center, flying past launch pad 39A for a bird's eye view of Endeavour.

The president and his party toured an orbiter processing hangar, getting a close-up look at the shuttle Atlantis, before moving onto the Launch Control Center where he met with Endeavour's crew, Giffords and other astronaut family members.

Obama enjoyed "a great tour of Atlantis over it the Orbiter Processing Facility, came over to the LCC (Launch Control Center) and met with the crew," said spaceport Director Robert Cabana, a former shuttle commander. "The crew is in great spirits, he had a long conversation with them. Then he met with the crew families and talked to some folks along the way."

The president's meeting with Giffords was not recorded and a few minutes later, Obama flew on to Miami.

Endeavour's problem cropped up during fueling when engineers noticed apparent problems with two heater thermostats used by one of the ship's auxiliary power units. Space shuttles are equipped with three APUs to provide the hydraulic muscle needed to move wing flaps, main engine nozzles, landing gear brakes and other critical systems.

While a shuttle can safely fly with a single APU, NASA flight rules require all three to be operating normally at launch to ensure redundancy. In this case, the concern was the possibility a fuel line could freeze, leaving APU No. 1 just one failure away from a shutdown.

As engineers were assessing the problem, Kelly and his crewmates -- pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- were preparing for launch, going through final medical checks and donning their pressure suits before heading to the launch pad.

But they knew a potentially serious issue was under discussion and a few minutes after noon, Leinbach called off the countdown and ordered a scrub. The "astrovan" carrying Kelly and his crewmates stopped at the Launch Control Center, paused briefly for a call from Leinbach, then turned around and headed back to crew quarters.

Engineers, meanwhile, drained Endeavour's external tank and held meetings to review data from the ship's hydraulic power system.

"The exact problem was a thermostat on one of the fuel lines for that auxiliary power unit and we need to keep those lines warm to prevent them from freezing on orbit," Leinbach said. "So we have two thermostats, two heaters for each fuel line for each APU."

"And on auxiliary power unit No. 1, one of those two heater units failed and the trouble shooting we did on it proved it was a hard failure, we were not able to get it to come to life no matter what we did.

"We tried to let the line cool down just by normal means to see if the thermostat on that heater would kick in. That did not happen. We tried to command the heater from the cockpit of the orbiter, that did not happen either. So we know we had a hard failure in that heater string for that one auxiliary power unit. There was another heater upstream of that that's also exhibiting some funny behavior."

It is possible the "signature" can be explained by a single faulty thermostat. If so, engineers should be able to install a replacement in time for a second launch attempt Monday.

"If there's a thermostat that's failed such that it might have an open circuit in it, not necessarily a short circuit but just an open, that would open up to ground," said Mike Moses, chairman of NASA's Mission Management Team.

"These things are wired together such that all the heaters on the front half of that string share a common ground. ... So a single failure on one thermostat could still cause this problem."

That's the best-case scenario for NASA.

"The troubleshooting involves taking in a can of (compressed air) and spraying it on the thermostat to see if we can force a lower temperature on the thermostat and have it kick on," Leinbach said. "If that works, we might have just a thermostat that's out of kilter and we can replace that thermostat and we'll be in good shape.

"If it's more than that, then it could be in a box called the LCA. the load control assembly, which is essentially a box full of switches. If there's something wrong in that box and we have to change out that box, that's a much more extensive job. It would take us quite some time to do that."

Engineers hope to climb in the aft compartment Saturday afternoon to begin troubleshooting. A final decision on how to proceed is expected by midday Sunday at the latest.

CBS NEWS Coverage of Breaking Space News

-- Posted at 12:46 PM EDT, 04/29/11: Hydraulic system glitch grounds shuttle Endeavour
-- Updated at 01:35 PM, 04/29/11: Launch delayed at least 72 hours; quotes and details
-- Updated at 2:30 PM, 04/29/11: President Obama lands at Cape Canaveral

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Problems with the shuttle Endeavour's hydraulic power system forced NASA managers to scrub Friday's planned launch on a space station assembly mission, disappointing thousands of spectators and spoiling a visit by President Obama and his family.

It also was a disappointment to commander Mark Kelly's wife, Gabrielle Giffords, who flew to Florida Wednesday to watch the launch as she recovers from a January assassination attempt.

It's not yet clear how long it will take to repair Endeavour, but launch is off until at least Monday, at 2:33:56 p.m. EDT (GMT-4), and possibly longer.

The problem cropped up as Kelly and his crewmates -- pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- were suiting up for launch.

Two heaters on one of the shuttle's three hydraulic power units failed, raising the possibility that temperature in propellant lines to drop below acceptable limits. The "astrovan" carrying the astronauts to launch pad 39A was stopped at the launch control center while engineers continued discussing the issue.

A few minutes later, Launch Director Mike Leinbach called off the countdown, ordering a scrub. The astrovan turned around and headed back to crew quarters.

President Obama and his family toured tornado damage in Alabama early Friday and continued on to Florida, landing at the Cape Canaveral Air Force Station as planned shortly after 2 p.m. The first family then boarded a Marine helicopter and flew to the nearby Kennedy Space Center, flying past launch pad 39A for a bird's eye view of Endeavour.

The president planned to tour a processing hangar where the shuttle Atlantis is being readied for launch June 28 and to meet with NASA officials, possibly including Giffords and other family members.

Engineers, meanwhile, drained Endeavour's external tank and held meetings to review data from the ship's hydraulic power system.

The auxiliary power units, or APUs, provide the hydraulic power to move the shuttle's engine nozzles, wing flaps and landing gear brakes. Engineers suspect a blown fuse may be to blame but it's not yet clear what caused that or what might be needed to fix it.

"The exact problem was a thermostat on one of the fuel lines for that auxiliary power unit and we need to keep those lines warm to prevent them from freezing on orbit," Leinbach said. "So we have two thermostats, two heaters for each fuel line for each APU."

"And on auxiliary power unit No. 1, one of those two heater units failed and the trouble shooting we did on it proved it was a hard failure, we were not able to get it to come to life no matter what we did.

"We tried to let the line cool down just by normal means to see if the thermostat on that heater would kick in. That did not happen. We tried to command the heater from the cockpit of the orbiter, that did not happen either. So we know we had a hard failure in that heater string for that one auxiliary power unit. There was another heater upstream of that that's also exhibing some funny behavior."

As a result, engineers believe a failure occurred in or near a load control assembly, or LCA, in the shuttle's aft engine compartment. The data indicate "we probably have a short in that box or in one of the electrical lines to that box or from that box," Leinbach said. "We're not quite sure yet, we won't know until we get into the aft of the orbiter and do some detailed troubleshooting."

"But the issue is, we didn't want to commit to flight with only one of two heaters on those auxiliary power unit fuel lines because of the chance if you lost that one good one on orbit, you run the very high risk of freezing the fuel in that line and therefore the auxiliary power unit would not function and therefore you wouldn't have full hydraulic power, which is a case you never want to get into for re-entry."

After draining Endeavour's external tank, engineers will open the aft engine compartment to gain access to the suspect hardware.

"Probably tomorrow afternoon we'll get into the aft, start putting in our platform set to get to this load control assembly, which is down inside the aft quite a ways and so it's going to take us a bit of time to get in and do that," Leinbach said. "And then once we're in the avionics bay we'll be able to do our troubleshooting."

Endeavour's launch window extends through May 4. If the shuttle is not off the ground by then, the team will stand down for three days to reload liquid oxygen and hydrogen fuel cell reactants and to give the Air Force time to launch an Atlas 5 rocket carrying a military missile early warning satellite. The shuttle launch window would re-open around May 8 and extend through May 29.

CBS NEWS Coverage of Breaking Space News

-- Posted at 12:46 PM EDT, 04/29/11: Hydraulic system glitch grounds shuttle Endeavour
-- Updated at 01:35 PM, 04/29/11: Launch delayed at least 72 hours; quotes and details

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Problems with the shuttle Endeavour's hydraulic power system forced NASA managers to scrub Friday's planned launch on a space station assembly mission, disappointing thousands of spectators and spoiling a planned visit by President Obama and his family.

It also was a disappointment to commander Mark Kelly's wife, Gabrielle Giffords, who flew to Florida to watch the launch as she recovers from a January assassination attempt.

It's not yet clear how long it will take to resolve the problem, but launch is off until at least Monday, at 2:33:56 p.m. EDT (GMT-4), and possibly longer.

The problem cropped up as Kelly and his crewmates -- pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- were suiting up for launch.

Two heaters on one of the shuttle's three hydraulic power units failed, raising the possibility that temperature in propellant lines to drop below acceptable limits. The "astrovan" carrying the astronauts to launch pad 39A was stopped at the launch control center while engineers continued discussing the issue.

A few minutes later, Launch Director Mike Leinbach called off the countdown, ordering a scrub. The astrovan turned around and headed back to crew quarters.

President Obama and his family planned to visit the Kennedy Space Center as planned, but no details were immediately available.

The auxiliary power units, or APUs, provide the hydraulic power to move the shuttle's engine nozzles, wing flaps and landing gear brakes. Engineers suspect a blown fuse may be to blame but it's not yet clear what caused that or what might be needed to fix it.

"The exact problem was a thermostat on one of the fuel lines for that auxiliary power unit and we need to keep those lines warm to prevent them from freezing on orbit," Leinbach said. "So we have two thermostats, two heaters for each fuel line for each APU."

"And on auxiliary power unit No. 1, one of those two heater units failed and the trouble shooting we did on it proved it was a hard failure, we were not able to get it to come to life no matter what we did.

"We tried to let the line cool down just by normal means to see if the thermostat on that heater would kick in. That did not happen. We tried to command the heater from the cockpit of the orbiter, that did not happen either. So we know we had a hard failure in that heater string for that one auxiliary power unit. There was another heater upstream of that that's also exhibing some funny behavior."

As a result, engineers believe a failure occurred in or near a load control assembly, or LCA, in the shuttle's aft engine compartment. The data indicate "we probably have a short in that box or in one of the electrical lines to that box or from that box," Leinbach said. "We're not quite sure yet, we won't know until we get into the aft of the orbiter and do some detailed troubleshooting."

"But the issue is, we didn't want to commit to flight with only one of two heaters on those auxiliary power unit fuel lines because of the chance if you lost that one good one on orbit, you run the very high risk of freezing the fuel in that line and therefore the auxiliary power unit would not function and therefore you wouldn't have full hydraulic power, which is a case you never want to get into for re-entry."

After draining Endeavour's external tank, engineers will open the aft engine compartment to gain access to the suspect hardware.

"Probably tomorrow afternoon we'll get into the aft, start putting in our platform set to get to this load control assembly, which is down inside the aft quite a ways and so it's going to take us a bit of time to get in and do that," Leinbach said. "And then once we're in the avionics bay we'll be able to do our troubleshooting."

Endeavour's launch window extends through May 4. If the shuttle is not off the ground by then, the team will stand down for three days to reload liquid oxygen and hydrogen fuel cell reactants and to give the Air Force time to launch an Atlas 5 rocket carrying a military missile early warning satellite. The shuttle launch window would re-open around May 8 and extend through May 29.

CBS NEWS Coverage of Breaking Space News

-- Posted at 06:50 AM EDT, 04/29/11: Weathering storms, Endeavour fueled for launch
-- Updated at 09:45 AM EDT, 04/29/11: Fueling complete; hydrogen vent line working normally
-- Updated at 10:30 AM EDT, 04/29/11: Progress supply ship docks with space station
-- Updated at 12:35 PM EDT, 04/29/11: LAUNCH SCRUB!

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Problems with the shuttle Endeavour's hydraulic power system forced launch controllers to scrub Friday's planned launch on a space station assembly mission, disappointing thousands of spectators and spoiling a visit by President Obama and his family.

It also was a disappointment to commander Mark Kelly's wife, Gabrielle Giffords, who flew to Florida to watch the launch as she recovers from a January assassination attempt.

It's not yet clear how long it will take to resolve the problem, but launch is off until at least Sunday, at 2:59:38 p.m. EDT (GMT-4). The forecast calls for an 80 percent chance of good weather, but it's not yet clear whether the problem can be resolved in time.

The problem cropped up as Kelly and his crewmates were suiting up for launch. Two heaters on one of the shuttle's three hydraulic power units failed, allowing the temperature in propellant lines to drop below acceptable limits.

The auxilliary power units, or APUs, provide the hydraulic power to move the shuttle's engine nozzels, wing flaps and landing gear brakes. Engineers suspect a blown fuse may be to blame but it's not yet clear what caused that or what might be needed to fix it.

"Our NASA launch director Mike Leinbach has made the decision ... that we're not able to resolve this situation with the APU heaters in time to make a launch attempt today," said NASA launch commentator George Diller. "There's not a way to do the kind of troubleshooting we need to do and sill be able to stay in a count configuration. So we will be scrubbing for today.

"Right now, it will be at least a 48-hour scrub turnaround while we try to get a better handle on understanding what the problem is. As we've been able to piece it together, there will be some entry into the aft (engine compartment) to do that troubleshooting."

But it's not at all clear whether the problems can be resolved in time for a launching Sunday.

Endeavour's launch window extends through May 4. If the shuttle is not off the ground by then, the team will stand down for three days to reload liquid oxygen and hydrogen fuel cell reactants and to give the Air Force time to launch an Atlas 5 rocket carrying a military missile early warning satellite. The shuttle launch window would re-open around May 8 and extend through May 29.

CBS NEWS Coverage of Breaking Space News

-- Posted at 06:50 AM EDT, 04/29/11: Weathering storms, Endeavour fueled for launch
-- Updated at 09:45 AM EDT, 04/29/11: Fueling complete; hydrogen vent line working normally
-- Updated at 10:30 AM EDT, 04/29/11: Progress supply ship docks with space station

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--The shuttle Endeavour's external tank has been loaded with a half-million gallons of liquid oxygen and hydrogen rocket fuel and forecasters are hopeful low clouds will break up as a front moves through, clearing the way for launch on NASA's next-to-last shuttle mission.

Endeavour's fueling began at 6:22 a.m. and the tank went into "stable replenish" mode three hours later, at 9:24 a.m.. There were no problems with a 7-inch gaseous hydrogen vent line attached to the side of the tank that delayed the previous shuttle launching.

The only technical problem under discussion early today was a slight pressure differential between the propellant tanks in the shuttle's right-side orbital maneuvering system rocket pod. After troubleshooting, engineers decided to open a crossfeed valve to equalize pressures between the left and right rocket pods.

Forecasters monitoring fast-moving storm cells south of the Kennedy Space Center during the later stages of fueling said it appeared the bad weather would stay away from the launch pad, although low clouds and blustery winds at the shuttle's emergency runway could cause problems later.

But for now, the forecast remains 70 percent "go" for a launching at 3:47:55 p.m. EDT (GMT-4).

NASA originally hoped to launch Endeavour April 19, but the flight was delayed to make way for the launch and docking of a Russian Progress supply ship that blasted off from the Baikonur Cosmodrome in Kazakhstan on Wednesday. The unmanned supply ship glided to a smooth linkup with the space station at 9:28 a.m. Friday.

Endeavour's crew -- commander Mark Kelly, pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- got up at 6 a.m. After breakfast and final medical checks, Kelly and Johnson will get a weather update before donning their bright orange pressure suits and heading to launch pad 39A around noon to begin strapping in for launch.

Kelly's twin brother Scott, who just got back from a long-duration stay aboard the International Space Station, joked Thursday night in a Twitter feed that he was "ready if replacement is required." Kelly's wife, Arizona Rep. Gabrielle Giffords, flew to Florida Wednesday, her first major trip since an assassination attempt in January. President Barack Obama and his family are scheduled to fly in later today, landing at the nearby Cape Canaveral Air Force Station.

Thunderstorms pounded Florida's Space Coast late Thursday, delaying work to roll a protective gantry away from the shuttle to clear the way for fueling. But the storms dissipated enough before midnight to permit the rotating service structure to be pulled away about five hours behind schedule. Engineers worked through the early morning hours to make up lost time and fueling began on schedule at 6:22 a.m.

"Launch teams are not working any issues right now that would prevent us from launching on time at 3:47 p.m. Eastern today," NASA spokesman Allard Beutel said just before fueling began. "Currently, forecasters are calling for a 70 percent of good weather for this afternoon's launch."

The three-hour fueling procedure began when ultra-cold liquid hydrogen and oxygen began flowing through transfer lines to inlets on either side of the shuttle's aft engine compartment. Before entering the tank, the propellants circulate through the ship's three main engines to acclimate the propulsion system plumbing to cyrogenic temperatures.

Here is a timeilne for the remainder of today's countdown (in EDT):

HH...MM...SS...EDT...........EVENT

Fri  04/29/11

04...25...00...11:17 AM......Final crew weather briefing
04...15...00...11:27 AM......Crew suit up begins
03...50...00...11:52 AM......Resume countdown (T-minus 3 hours)

03...45...00...11:57 AM......Crew departs Operations and Checkout building
03...15...00...12:27 PM......Crew ingress
02...25...00...01:17 PM......Astronaut comm checks
02...00...00...01:42 PM......Hatch closure
01...30...00...02:12 PM......White room closeout

01...10...00...02:32 PM......Begin 10-minute built-in hold (T-minus 20m)
01...00...00...02:42 PM......NASA test director countdown briefing
01...00...00...02:42 PM......Resume countdown (T-minus 20m)

00...59...00...02:43 PM......Backup flight computer to OPS 1
00...55...00...02:47 PM......KSC area clear to launch

00...49...00...02:53 PM......Begin final built-in hold (T-minus 9m)
00...24...00...03:18 PM......NTD launch status verification
00...09...00...03:38:55 PM...Resume countdown (T-minus 9m)

00...07...30...03:40:25 PM...Orbiter access arm retraction
00...05...00...03:42:55 PM...Launch window opens
00...05...00...03:42:55 PM...Hydraulic power system (APU) start
00...04...55...03:43:00 PM...Terminate LO2 replenish
00...04...00...03:43:55 PM...Purge sequence 4 hydraulic test
00...04...00...03:43:55 PM...IMUs to inertial
00...03...55...03:44:00 PM...Aerosurface profile
00...03...30...03:44:25 PM...Main engine steering test
00...02...55...03:45:00 PM...LO2 tank pressurization
00...02...35...03:45:20 PM...Fuel cells to internal reactants
00...02...30...03:45:25 PM...Clear caution-and-warning memory
00...02...00...03:45:55 PM...Crew closes visors
00...01...57...03:45:58 PM...LH2 tank pressurization
00...00...50...03:47:05 PM...SRB joint heater deactivation
00...00...31...03:47:24 PM...Shuttle GPCs take control of countdown
00...00...21...03:47:34 PM...SRB steering test
00...00...07...03:47:48 PM...Main engine start (T-6.6 seconds)
00...00...00...03:47:55 PM...SRB ignition (LAUNCH)

CBS NEWS Coverage of Breaking Space News

6:40 AM EDT, 04/29/11: Shuttle fueling begins; weather 70 percent 'go' for launch

By WILLIAM HARWOOD
CBS News

Thunderstorms pounded Florida's Space Coast late Thursday, delaying work to ready the shuttle Endeavour for blastoff Friday afternoon. But the storms passed a protective gantry was retracted and engineers began pumping rocket fuel into the ship's external tank on schedule.

"Launch teams are not working any issues right now that would prevent us from launching on time at 3:47 p.m. Eastern today," NASA spokesman Allard Beutel said just before fueling began. "Currently, forecasters are calling for a 70 percent of good weather for this afternoon's launch."

The protective rotating service structure was pulled away from Endeavour just before midnight, nearly five hours later than planned because of thunderstorms from an approaching cold front. Working through the early morning hours, engineers made up lost time and after assessing the latest forecast, NASA's Mission Management Team gave the team permission to begin pumping a half-million gallons of supercold liquid oxygen and hydrogen rocket fuel into Endeavour's external tank on time at 6:22 a.m. EDT (GMT-4).

Forecasters expect low clouds to dissipate as the day wears on, clearing out in time for Endeavour's planned 3:47:55 p.m. launch time. But brisk crosswinds are expected at the shuttle's emergency runway, setting up what could be a down-to-the-wire countdown. The forecast calls for scattered clouds at 4,000 feet, winds out of the north-northeast at 12 knots gusting to 18.

Endeavour's crew -- commander Mark Kelly, pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- got up at 6 a.m. After breakfast and final medical checks, Kelly and Johnson will get a weather update before donning their bright orange pressure suits and heading to launch pad 39A around noon to begin strapping in for launch.

Kelly's twin brother Scott, who just got back from a long-duration stay aboard the International Space Station, joked Thursday night in a Twitter feed that he was "ready if replacement is required." Kelly's wife, Arizona Rep. Gabrielle Giffords, flew to Florida Wednesday, her first major trip since an assassination attempt in January. President Barack Obama and his family are scheduled to fly in later today, landing at the nearby Cape Canaveral Air Force Station.

The three-hour fueling procedure began when ultra-cold liquid hydrogen and oxygen began flowing through transfer lines to inlets on either side of the shuttle's aft engine compartment. Before entering the tank, the propellants circulate through the ship's three main engines to acclimate the propulsion system plumbing to cyrogenic temperatures.

If all goes well, the tank will be topped off and the system will transition to "stable replenish" mode around 9:22 a.m.

Engineers will be paying close attention to a seven-inch gaseous hydrogen vent line attached to the side of the external tank as the hydrogen section is filled. NASA has had problems with leaks in the vent line but managers are confident the system will work normally this time around.

Here is a timeilne for the remainder of today's countdown (in EDT; best viewed with fixed-width font):

HH...MM...SS...EDT...........EVENT

Fri  04/29/11

09...20...00...06:22 AM......Resume countdown (T-minus 6 hours)

09...20...00...06:22 AM......LO2, LH2 transfer line chilldown
09...10...00...06:32 AM......Main propulsion system chill down
09...10...00...06:32 AM......LH2 slow fill
08...40...00...07:02 AM......LO2 slow fill
08...35...00...07:07 AM......Hydrogen ECO sensors go 'wet'
08...30...00...07:12 AM......LO2 fast fill
08...20...00...07:22 AM......LH2 fast fill
06...25...00...09:17 AM......LH2 topping
06...20...00...09:22 AM......LH2 replenish
06...20...00...09:22 AM......LO2 replenish

06...20...00...09:22 AM......Begin 2-hour 30-minute built-in hold (T-minus 3 hours)
06...20...00...09:22 AM......Closeout crew to white room
06...20...00...09:22 AM......External tank in stable replenish mode
06...17...00...09:25 AM......Ascent flight control team on console
06...05...00...09:37 AM......Astronaut support personnel comm checks
05...35...00...10:07 AM......Pre-ingress switch reconfig
05...12...00...10:30 AM......NASA TV launch coverage begins
04...25...00...11:17 AM......Final crew weather briefing
04...15...00...11:27 AM......Crew suit up begins
03...50...00...11:52 AM......Resume countdown (T-minus 3 hours)

03...45...00...11:57 AM......Crew departs Operations and Checkout building
03...15...00...12:27 PM......Crew ingress
02...25...00...01:17 PM......Astronaut comm checks
02...00...00...01:42 PM......Hatch closure
01...30...00...02:12 PM......White room closeout

01...10...00...02:32 PM......Begin 10-minute built-in hold (T-minus 20m)
01...00...00...02:42 PM......NASA test director countdown briefing
01...00...00...02:42 PM......Resume countdown (T-minus 20m)

00...59...00...02:43 PM......Backup flight computer to OPS 1
00...55...00...02:47 PM......KSC area clear to launch

00...49...00...02:53 PM......Begin final built-in hold (T-minus 9m)
00...24...00...03:18 PM......NTD launch status verification
00...09...00...03:38:55 PM...Resume countdown (T-minus 9m)

00...07...30...03:40:25 PM...Orbiter access arm retraction
00...05...00...03:42:55 PM...Launch window opens
00...05...00...03:42:55 PM...Hydraulic power system (APU) start
00...04...55...03:43:00 PM...Terminate LO2 replenish
00...04...00...03:43:55 PM...Purge sequence 4 hydraulic test
00...04...00...03:43:55 PM...IMUs to inertial
00...03...55...03:44:00 PM...Aerosurface profile
00...03...30...03:44:25 PM...Main engine steering test
00...02...55...03:45:00 PM...LO2 tank pressurization
00...02...35...03:45:20 PM...Fuel cells to internal reactants
00...02...30...03:45:25 PM...Clear caution-and-warning memory
00...02...00...03:45:55 PM...Crew closes visors
00...01...57...03:45:58 PM...LH2 tank pressurization
00...00...50...03:47:05 PM...SRB joint heater deactivation
00...00...31...03:47:24 PM...Shuttle flight computers take control of countdown
00...00...21...03:47:34 PM...Booster steering test
00...00...07...03:47:48 PM...Main engine start (T-6.6 seconds)
00...00...00...03:47:55 PM...Booster ignition (LAUNCH)

CBS NEWS Coverage of Breaking Space News

02:30 PM EDT, 04/28/11: Storm front slows, shuttle launch now 70 percent 'go'

By WILLIAM HARWOOD
CBS News

A storm front that wreaked havoc across the southeastern United States overnight Wednesday will reach the Florida space coast Thursday night, but forecasters expect the sky will clear in time for the shuttle Endeavour's launch Friday on a long-awaited space station assembly mission.

Shuttle weather officer Kathy Winters said the front slowed and lost energy as it moved toward Florida, but rain showers and possible thunderstorms were expected in the area Thursday evening as engineers roll a protective gantry away and prepare the shuttle for fueling.

The three-hour fueling procedure is scheduled to begin at 6:22 a.m. EDT (GMT-4) Friday and Winters said she was optimistic conditions would improve enough overnight to keep the countdown on schedule. She put the odds of good weather for launch at 70 percent, down from the 80 percent "go" forecast issued Wednesday.

Commander Mark Kelly, pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori plan to strap in around 12:30 p.m. Friday to await liftoff at 3:47:52 p.m.

President Barack Obama planned to tour tornado-damaged sites in Alabama Friday before flying to the Kennedy Space Center for Endeavour's launch. Kelly's wife, Rep. Gabrielle Giffords, injured in an assassination attempt Jan. 8, arrived at the spaceport Wednesday.

More than a half-million spectators are expected to gather along area roads and beaches to watch NASA's next-to-last shuttle launch, the 25th and final flight for Endeavour.

NASA Test Director Jeff Spaulding told reporters Thursday that Endeavour's countdown was proceeding smoothly with no technical problems of any significance.

"Everything's going well out at pad A," he said. "We don't have any issues right now that we're tracking."

The weather forecast was not as clear cut.

"As we get into the late afternoon and into the evening hours, we are expecting the front that's been working its way through the southeast U.S. the last couple of days causing all that severe weather, we're expecting that to move down into central Florida," Winters said.

"The front should move through in the overnight hours and the weather will probably be done somewhere around 10 or 11 p.m. So that's not probably going to cause too much of a delay. We'll still be able to get to tanking tomorrow morning."

As the morning wears on, low clouds are expected to break up, but Winters said that will depend on the timing. There is a chance of low ceilings that could cause problems at launch time as well as possibly high crosswinds at the shuttle's emergency runway.

"As we go into launch time, we expect the clouds to scatter out," Winters said. "But we are a little bit more concerned (than Wednesday). A ceiling could linger in the area so we did increase the probability of KSC weather prohibiting launch from 20 percent yesterday to 30 percent due to me fact that the front is a little bit slower.

"So I wouldn't be surprised if tomorrow we are red during the countdown for ceiling and then we expect the conditions to improve by launch time."

The forecast for Saturday calls for a 70 percent chance of acceptable weather, improving to 80 percent "go" by Sunday.

CBS NEWS Coverage of Breaking Space News

03:50 PM EDT, 04/27/11: Shuttle countdown on track; Giffords flies to Florida for launch

By WILLIAM HARWOOD
CBS News

The shuttle Endeavour's countdown is proceeding smoothly toward launch Friday with no technical problems of any significance and forecasters predicting an 80 percent chance of good weather. Rep. Gabrielle Giffords, the gravely wounded wife of shuttle commander Mark Kelly, flew to Florida from Houston Wednesday, her first major trip since an assassination attempt in January.

President Barack Obama also plans to attend Endeavour's launching, landing aboard Air Force One at the nearby Cape Canaveral Air Force Station Friday. The president and his family will visit a shuttle processing hangar before Endeavour's planned takeoff at 3:47:52 p.m. Obama is scheduled to fly to Miami later in the afternoon.

As for Giffords, "we treat that just like a crew family visit," said MIke Moses, director of shuttle integration at the Kennedy Space Center. "She needs a little extra care and attention. There's going to be a lot of extra, outside attention placed on it, but from a what-we're-doing (standpoint), she's NASA family and we're treating her just like we do all the rest of the crew families."

Crew families typically watch shuttle take offs from the roof of the Launch Control Center 3.4 miles from the pad. And that's where President Clinton and wife Hillary watched former Sen. John Glenn's 1998 shuttle launch. A crane was parked by the building Wednesday and workers could be seen hauling material of some sort to the roof.

With only two flights left before the shuttle program comes to an end, large crowds are expected around the Kennedy Space Center to watch Endeavour's 25th and final liftoff. Launch Director Mike Leinbach said Brevard County law enforcement officials estimated some 400,000 spectators turned out for the shuttle Discovery's final flight in February. Between 500,000 and 750,000 spectators are expected for Endeavour's launch.

"What local law enforcement has told us is that whatever drive delay we experienced for (Discovery's) launch, it's going to be about 50 percent longer this time going home," Leinbach said. "It's going to be tough to get home. But when you think about why the people are coming, to experience something that's uniquely American and be able to see one of the last two flights, that gives me a lot of pride."

Forecasters are predicting an 80 percent chance of good weather Friday for Endeavour's launching. The only concern is possibly high crosswinds at the emergency runway where Kelly and pilot Gregory Johnson would have to attempt a landing if a main engine failed early in flight.

Shuttle weather officer Kathy Winters said a front is expected to move through the area Thursday , bringing possibly severe thunderstorms to the Kennedy Space Center that night. Lightning could hold up plans to retract a protective gantry, but Leinbach said the countdown could accommodate a four- to five-hour delay with no impact on fueling and launch.

"That really shouldn't be a problem for us," he said.

If all goes well, engineers will begin pumping liquid oxygen and hydrogen rocket fuel into Endeavour's external tank around 6:22 a.m. Friday. Kelly, Johnson and their crewmates -- Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- will strap in around 12:30 p.m. to await liftoff.

"We're not working any significant issues at all," Leinbach said. "The team's upbeat. I talked to the firing room this morning, and they're all excited about the mission, about the countdown, the president showing up. We're dealing with that, it's a little bit of a challenge for us, but the team is not distracted by that."

CBS NEWS Coverage of Breaking Space News

05:04 PM, 04/26/11: STS-134 mission preview

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--With just two flights remaining and thousands of layoffs looming, NASA is readying the shuttle Endeavour for launch Friday on its 25th and final mission, a four-spacewalk voyage to deliver supplies, spare parts and a $2 billion particle physics detector to the International Space Station.

Playing out against a backdrop of uncertainty about the future of American manned space flight, Endeavour's launch on NASA's next-to-last shuttle flight has generated intense public interest in the wake of a Jan. 8 assassination attempt that left Rep. Gabrielle Giffords, wife of shuttle commander Mark Kelly, gravely injured with a gunshot wound to the head.

Recovering in Houston, Giffords faces a long, difficult rehabilitation and an uncertain prognosis. But Kelly says his wife is making steady progress and will attend the launching in Florida. When told her medical team had approved the trip, Kelly told the CBS Evening News, she pumped her fist and said "awesome."

Joining the national surge of interest in Giffords' story and Kelly's decision to remain in place as Endeavour's commander, President Barack Obama and his family also plan to attend the launching, making him only the third sitting president to witness a manned space launch.

Giffords, her entourage and the First Family will watch from a secure location near the launch control center 3.4 miles from launch pad while several hundred thousand area residents and tourists jam nearby roads and beaches for a chance to see one of NASA's final two shuttle launchings as the 30-year-old program draws to a close.

"It's been an incredible success over a long period of time and it brings a capability that certainly we're not going to replace with the next vehicle," Kelly said. "So it's sad to see it go. (But) I think it's probably the right time to retire the shuttle and move on to something else so we can get out of low-Earth orbit and start to explore the solar system again."

Using a repaired external tank that was damaged during Hurricane Katrina, Endeavour's launch on the 134th shuttle mission is targeted for 3:47:52 p.m. EDT on Friday, April 29, roughly the moment Earth's rotation carries pad 39A into the plane of the space station's orbit. To catch up with the lab complex, the shuttle must take off within five minutes of that "in-plane" moment.

Joining Kelly on Endeavour's upper flight deck will be pilot Gregory "Box" Johnson, European Space Agency flight engineer Roberto Vittori and Michael Fincke, a space station veteran who has logged nearly a full year in space during two earlier expeditions aboard the space station.

Strapped in on the shuttle's lower deck will be station veteran Gregory Chamitoff and Andrew Feustel, who helped repair the Hubble Space Telescope during a 2009 shuttle mission. All six shuttle fliers are space veterans, but it's the first shuttle flight for Fincke, who rode Russian Soyuz spacecraft for his first two missions.

Lost in the glare of the Giffords story, Endeavour's mission is among the most ambitious of the final half-dozen or so flights to complete the assembly of the International Space Station. Carrying 15 tons of cargo, shuttle mission STS-134 will complete the U.S. segment of the lab complex after 12 years of construction. A final flight by the shuttle Atlantis in late June is devoted primarily to stocking the lab with supplies.

"It is an extremely complex mission," said shuttle Program Manager John Shannon. "It's a long period of time docked to the station, four EVAs, a tremendous amount of activity internal to the ISS, we're going to put a world-class experiment on the ISS and get it all hooked up.

"I think the missions we are executing now in complexity are the most difficult missions that not just NASA, but any nation has ever flown in space. And I would include Apollo in that discussion. I think the missions we do right now are more complicated than what we were doing even during the moon landings."

Assuming an on-time liftoff, Kelly plans to guide Endeavour to a docking at the space station's forward port around 1:25 p.m. on May 1. A pallet of spare components will be robotically bolted to left side of the station's power truss a few hours later. The next day, the 7.5-ton Alpha Magnetic Spectrometer will be attached to the right side of the power truss.

Using a massive magnet to bend the trajectories of high-energy cosmic rays -- charged particles from supernovas, neutron stars, black holes and other cosmic enigmas -- scientists will look for evidence of antimatter and as-yet-undetected dark matter, believed to make up a quarter of the mass of the universe.

AMS may even find evidence of strange particles made up of quarks in different arrangements than those found on Earth. Or something completely unexpected.

The AMS "really probes the foundations of modern physics," said Sam Ting, a Nobel Laureate who manages the multinational experiment. "But to my collaborators and I, the most exciting objective of AMS is to probe the unknown, to search for phenomena which exist in nature but yet we have not the tools or the imagination to find."

AMS will operate autonomously after it is connected to station power, beaming down a continuous stream of data for at least 10 years and possibly longer if the lab is funded past 2020.

With AMS in place, Fincke, Feustel and Chamitoff, working in alternating two-man teams, plan to carry out four spacewalks May 3, 5, 7 and 9 to retrieve one materials science exposure experiment and to install another; to refill the ammonia coolant reservoir in the station's far left-side solar array; to re-lubricate a solar array rotary joint; to install a robot arm attachment fitting on the Russian Zarya module; and to perform needed maintenance.

They also plan to test an innovative new technique for removing nitrogen from their bloodstreams prior to one spacewalk, a protocol to prevent the bends that is less time consuming and potentially disruptive than the established technique.

If all goes well, Endeavour will undock from the station around 6:18 p.m. on May 11. Then, testing new sensors and software under development for NASA's Orion deep space exploration capsule, the shuttle crew will re-rendezvous with the station, pulling within about 1,000 feet before breaking off and departing the area.

Landing back at the Kennedy Space Center is targeted for 9:22 a.m. on Friday, May 13. But if Endeavour is in good shape after docking, NASA managers plan to extend the flight one or two days to give the crew more time to help their station colleagues with needed maintenance. If two days are added, the landing would be expected around 8:40 a.m. on May 15.

It is not yet known where President Obama, his family or Giffords will view the launching. NASA normally reserves the top floor of a United Space Alliance office building near the huge Vehicle Assembly Building for guests of the agency administrator, providing an unobstructed view of the launch pad a few miles away.

President Bill Clinton and wife Hillary watched the launch of former Sen. John Glenn aboard the shuttle Discovery in 1998 from the roof of the nearby launch control center where the families of shuttle crews typically gather.

In any case, NASA and Brevard County officials are bracing for large crowds as tourists and area residents turn out to witness the shuttle program's next-to-last launching. During Discovery's final launch in February, tourism officials estimated more than 300,000 shuttle watchers jammed area roads an beaches, generating major traffic jams across the county.

Even larger crowds are expected for Endeavour's launching. If bad weather or technical problems delay launch inside of four hours, NASA managers may be forced to order a 48-hour slip because of expected traffic snarls that would make it difficult for engineers to "safe" the shuttle, get home for needed rest and then get back to the space center in time for a 24-hour recycle.

Obama's presence for Endeavour's launching is fitting, not just to show support for Kelly and Giffords as she continues her difficult recovery, but also because of his administration's drive to reshape America's manned space program.

While expressing support for the Bush administration's post-shuttle moon program during the 2008 presidential campaign, Obama has since ordered NASA to scrap the Constellation program and to focus instead on helping private industry develop commercial space taxis to ferry U.S. astronauts to and from low-Earth orbit after the shuttle fleet is retired.

At the same time, the administration gave into congressional demands for immediate work on a new-heavy lift rocket to propel new crew capsules like Lockheed Martin's Orion spacecraft, originally designed for moon missions, on deep space voyages to nearby asteroids and, eventually, Mars.

But exploration is a long-term goal and the targets and mission architectures are not yet defined. In the near term, the focus is on operating the space station, retiring the shuttle and developing commercial manned spacecraft to take it's place.

It will take private industry at least three to four years to develop new orbital spacecraft and until then, NASA will be forced to rely on Russian Soyuz vehicles, at an average cost of about $55 million a seat, to get astronauts to and from the station.

While many NASA insiders agree with the need to replace the space shuttle with a less expensive more up-to-date spacecraft, virtually everyone laments the political decisions and compromises that resulted in a multi-year gap between the shuttle's retirement and the debut of whatever vehicle will replace it.

As it is, the shuttle's highly trained work force is being phased out as NASA winds down the program.

Through earlier layoffs and attrition, United Space Alliance, the shuttle prime contractor, has reduced its workforce in Florida, Texas and Alabama from around 10,500 in October 2009 to a current level of around 5,600. In late July or early August, the company will implement another major reduction, eliminating between 2,600 and 2,800 jobs across the company. Of that total, 1,850 to 1,950 job losses are expected in Florida, 750 to 800 in Texas and 30 to 40 in Alabama.

"We have been stepping down our workforce over the last, really, three years," Shannon told reporters last month. "Back in late 2006, the shuttle program had 14,000 contractors. We're currently down to just over 6,000 contractors. We had 1,800 civil servants at that time, we're just over 1,000 at this time.

"So it's been this gradual phase down. We're at a point now where it's primarily operations and sustaining engineering for the different elements that are left, and we require those out to the end of the program."

And the end is clearly at hand.

Only two more shuttle flights are on the books -- Endeavour's mission and a final flight by the shuttle Atlantis in late June. A small transition team, made up of only a few hundred managers and engineers, will be responsible for decommissioning the orbiters after their final flights, removing components that might be used in follow-on programs and preparing the ships for eventual museum duty.

Discovery will be sent to the Smithsonian Air and Space Museum's Steven F. Udvar-Hazy Center near Washington. Atlantis will remain at the Kennedy Space Center and Endeavour will be displayed at the California Science Center in Los Angeles.

ENDEAVOUR'S FINAL FLIGHT -- A CONVOLUTED TRAIL

In January 2004, responding to a recommendation from the Columbia Accident Investigation Board, President Bush ordered NASA to complete the International Space Station and retire the shuttle fleet by the end of fiscal 2010. The president said the money saved would help finance development of new rockets and spacecraft designed to carry astronauts back to the moon by around 2020. The goal was the establishment of Antarctica-style lunar bases.

NASA managers then prioritized the remaining shuttle payloads to ensure completion of the space station with a reduced number of flights. One payload -- the Alpha Magnetic Spectrometer -- was dropped from the manifest to make room for more critical space station components.

Ting and the project's supporters never gave up hope and even while developing plans for the possible use of an unmanned rocket, they continued lobbying for an additional shuttle flight to ferry the particle detector to the space station. Their arguments swayed several key lawmakers, including Sen. Bill Nelson, a Florida Democrat who flew aboard the shuttle in 1986.

During a swing through Florida in the midst of the 2008 presidential campaign, Obama said he would support an additional shuttle flight as well as the Constellation moon program NASA was developing to carry out the Bush administration's 2004 directives.

After the election, Obama came through on his promise to add an additional shuttle flight to ferry AMS into space. But the administration chartered a blue-ribbon panel in 2009 to re-assess NASA's manned space program in light of lower long-range budget projections.

When all was said and done, Obama ordered NASA to stop work on Constellation and to focus instead on development of private-sector rockets and a new heavy-lift system for deep space exploration. He also approved a five-year extension to keep the space station operational through 2020.

When AMS was designed, the instrument featured a powerful cryogenically cooled superconducting magnet. Designed to operate for three years, NASA originally planned to bring the detector back to Earth when it ran out of coolant, making space for a follow-on experiment.

When AMS was put back on the post-Columbia manifest, it was penciled in as the last mission. But planners revised the schedule to maximize space station resupply and AMS ended up scheduled for launch in July 2010. A final flight by the shuttle Discovery was planned for the following September.

In late 2009 and early 2010, when it was becoming clear the administration was going to support a five-year extension to the life of the space station, Ting began re-thinking the AMS mission. The cryogenically cooled magnet, while more powerful than an uncooled magnet used during an AMS test flight, would run out of coolant in three years.

By switching back to the uncooled magnet and adding additional detectors and computer processors, the team could achieve the same resolution as the super-cooled magnet. And the uncooled magnet could operate through the life of the space station.

"We had built a superconducting magnet based on the assumption ... that we would be on space station for three years and space station would be deorbited in 2015," Ting said. "So we test the magnet. The magnet would last 28 plus or minus six months, close to three years. But now at the end of last year (2009) we learned space station would go to 2020 and maybe even go to 2028. So after three years, AMS would become a museum piece. And so we quickly decided to change to a permanent magnet."

The permanent magnet, which flew a test mission aboard the shuttle in 1998, is five times less powerful than the superconducting magnet originally envisioned. But it requires no maintenance and testing shows its magnetic field has not changed in 12 years.

Because of the weaker field, "we put in more detectors ... to increase the measurement accuracy," Ting said. "And so the detector resolution with the permanent magnet is not compromised."

Replacing the magnet and adding the additional detectors forced NASA to delay Endeavour's launch until after Discovery's flight, first to November, then December and eventually February. Then, problems with suspect ribs, or stringers, in Discovery's external tank ultimately delayed that flight to February 2011 and Endeavour's launch to mid April.

While all of that was going on, NASA managers were lobbying for permission to convert a stand-by launch-on-need rescue flight for Endeavour's crew into a full-blown space station mission to deliver a final load of supplies. That flight, by the shuttle Atlantis, is scheduled for launch June 28. While a dedicated rescue flight will not be available for Atlantis' crew, NASA developed plans for the three-man one-woman crew to fly back aboard Russian Soyuz spacecraft if anything goes wrong with Atlantis.

Funding for the Atlantis mission was included in the compromise continuing resolution that is keeping the government in operation through the end of fiscal 2011.

Atlantis will use an external tank that is similar in design and history to the one used by Discovery. The aluminum alloy used in that tank's stringers was from a batch that did not meet strength requirements. Built-in stress, coupled with exposure to cryogenic temperatures during fueling, caused cracks to develop, requiring extensive repairs.

Similar repairs have been carried out on the tanks used by Endeavour and Atlantis. But Endeavour's tank is of a different vintage.

"ET-122 was in one of our production cells down at Michoud (Louisiana) when Hurricane Katrina hit and several small chunks of concrete were dislodged from the room and fell on the tank, damaging the foam," Shannon said. "We kind of put that tank to the side while we were doing normal processing.

"I asked the team several years ago to go back and look at ET-122 and see if it was a viable flight tank. All the foam in that area was dissected. The LOX tank, they did eddy current (testing), they did all kinds of non-destructive analysis on it. It was a very good tank, so they replaced that foam, they went to the intertank area, there was one stringer that had been nicked, they took that stringer off, put a new one on, re-foamed that area."

The foam insulation on the tank is nearly 10 years old. To make sure it was still up to the rigors of launch, "they did pull tests all over the tank, they did assessments to make sure it's a good tank and safe to fly," Shannon said. "Then they did all of the return-to-flight modifications that we had done on tanks after Columbia."

"We have a lot of confidence in ET-122," he said. "It doesn't look real pretty because we did some foam patches, it looks a little more like the hail-damaged tank that we flew, which I think was ET-120. But from all out testing and experience, we have high confidence in that tank."

TRAGEDY IN TUCSON

At the start of 2011, as NASA was closing in on the root cause of the cracks in Discovery's tank, the agency was rocked by news that Giffords, a Democrat representing Arizona's 8th Congressional District, had been shot in the head Jan. 8 at point blank range during a public meeting in front of a Tucson supermarket.

Giffords was one of 20 people hit when Jared Loughner, a 22-year-old college dropout, allegedly opened fire with a semi-automatic pistol. Six were killed, including a federal judge and a 9-year-old girl.

"It was extremely terrible," said Johnson, Endeavour's pilot. "The news reports, for a period of time believed that (Giffords) had been killed. We had socialized as a crew just a few short weeks prior, and my daughter had spent some time with Gabby on a one-on-one level. She was devastated."

President Obama flew to Arizona for a memorial service, telling friends and family members "there is nothing I can say that will fill the sudden hole torn in your hearts."

"But know this: The hopes of a nation are here tonight. We mourn with you for the fallen. We join you in your grief. And we add our faith to yours that Representative Gabrielle Giffords and the other living victims of this tragedy will pull through."

One week after the assassination attempt, NASA announced that Kelly, who had flown to Tucson the day of the shooting, would be taking a leave of absence. Rick Sturckow, a veteran shuttle commander, took his place in crew training exercises and simulations.

But one month later, Kelly announced he would resume training to command Endeavour, saying his wife "would be very comfortable with the decision I made."

"Her days are filled, from the time she gets up at eight o'clock until after 6 p.m., with six hours of speech, occupational and physical therapy," Kelly told reporters in March. "So she's got very busy days, and meals in between.

"And I started to think about STS-134, about the mission, my crew, the fact that I've been training for it for nearly a year and a half. And considering a bunch of other factors, including what Gabrielle would want me to do and what her parents and her family and my family would like, I ultimately made the decision that I would like to return and command STS-134."

Chief astronaut Peggy Whitson supported Kelly's decision.

"Mark had to make the first part of this decision," she said. "We weren't going to ask him to command 134 unless he felt comfortable and ready to do that. In addition to feeling comfortable, he has an incredible support group, which made us more comfortable with the fact that he had folks to help him through this process and that it would make it a doable thing for him to perform the mission."

Asked about critics who might question his decision to spend time away from his wife at a critical point in her recovery, Kelly said "they don't understand a few things."

"They don't know her very well, so they don't know what she would want," he said. "She is a big supporter of my career, a big supporter of NASA. She really values the mission of NASA. What we do and what the nation gets from that are very high on her list of things she really treasures about this country. So I think they don't understand that, and they also don't understand her condition or the support system that I have in place.

"I think if they had more details about those things, you'd probably have less people being critical. But I think in any decision there's a lot of interest in, you're going to have people on both sides."

Kelly told the CBS Evening News the week before launch that Giffords was "very excited" about the pending trip to Florida.

"It's going to be a little bit more complicated than your average person," he said. "But I've got folks in my office that have been focused on that. And, you know, she has some security and certainly there are some medical needs that need to be met, but we've been planning it for a couple weeks now. It's not anything too significant."

Kelly said earlier he still feels angry from time to time about what happened to his wife and the other victims of the Tucson shootings.

"When a traumatic event happens, there are those different steps that you go through," he said. "I think I very quickly got to 'angry' on the first day this happened. I can't remember what step two was, but I think I skipped right over that one. At times, I'm angry about what happened to her. ... It's really an unfortunate, tragic situation."

But he said that anger played no role in his decision to resume training.

"Absolutely not," he said. "What I use to evaluate whether I want to come back to be commander of this mission has nothing to do with being angry and everything to do with what is right for NASA first, and then for me and my family."

WORLD-CLASS SCIENCE, COMPLEX FLIGHT PLAN

Endeavour's initial launch window opens April 29 and extends through May 4. If the shuttle is not off the ground by then, the team will stand down for three days to reload liquid oxygen and hydrogen fuel cell reactants and to give the Air Force time to launch an Atlas 5 rocket carrying a missile early warning satellite. The shuttle launch window would re-open around May 8 and extend through May 29.

NASA had planned to launch Endeavour on April 19, but earlier this month the fight was delayed 10 days because of a conflict with the launch and docking of a Russian Progress supply ship. The delay put the shuttle launch on the same day as the British royal wedding of Prince William and Kate Middleton.

Asked if NASA considered an additional delay to avoid a conflict with the royal wedding, Bill Gerstenmaier, chief of space operations for NASA, said "we work beta (angle) constraints and we work launch range constraints. I haven't yet put on our manifest charts 'wedding constraints.' So we didn't factor that into our thinking."

As with all post-Columbia flights, Endeavour's ascent will be monitored by batteries of launch pad cameras, radar and long-range trackers, on the lookout for any signs of foam insulation falling from the external tank that could damage the shuttle's fragile heat shield.

Debris poses the biggest threat during the first two minutes and 15 seconds of flight when the dense lower atmosphere can cause lightweight insulation to come to a near standstill in a fraction of a second. The accelerating space shuttle can then slam into it at a high relative velocity.

A phenomenon known as "cryo pumping" can cause foam to pop off later in ascent when liquefied air trapped under the foam near the top of the liquid hydrogen tank warms and expands as the fuel level drops during the climb to space. But testing and flight experience show cryopumping typically happens well after the aerodynamically sensitive period.

Given the history of Endeavour's "hurricane tank," mission managers expect to see more foam insulation falling away during the climb to space than usual because not all of the post-Columbia tank improvements were carried out for the repaired tank.

"This tank doesn't have some of the modifications to it that other tanks have had, so we expect to see some foam loss," Gerstenmaier said. "If you remember, we used to lose foam around the LH2 ice frost ramps on the hydrogen tank because there was a little alignment pin that would allow some cryo pumping and ingestion around the ice frost ramps which could cause some foam to come off in those areas.

"We fully expect this to occur on this tank," he said. "It'll again be late losses of foam, but we expect to see some foam losses in that area."

Kelly and company plan to close out their first day in space setting up a computer network, downlinking photos of the external tank, breaking out equipment and testing the ship's robot arm.

The next day, Johnson, Fincke and Vittori will use the robot arm and an instrumented extension boom to carry out a detailed inspection of Endeavour's reinforced carbon carbon nose cap and wing leading edge panels to make sure the most critical elements of the shuttle's heat shield came through the climb to space in good shape. Laser scans and high-resolution photographs will be beamed down to NASA's Damage Assessment Team for detailed analysis.

While the heat shield inspection is underway, Fincke, Feustel and Chamitoff will check out their spacesuits and the tools they'll use during the mission's four spacewalks. The crew also will break out and test the rendezvous tools they will use during final approach to the space station.

The terminal phase of the rendezvous will begin about three hours before docking on fight day three when Kelly and Johnson will fire the ship's maneuvering jets to begin closing the final nine miles between the two spacecraft. Approaching from behind, Kelly will pause at a point 600 feet directly below the space station. He then will oversee a slow computer-assisted back flip maneuver that will expose the orbiter's belly to the station.

As black heat shield tiles on the shuttle's underside come into view, station flight engineer Paolo Nespoli and Catherine "Cady" Coleman, working in the Russian Zvezda command module, will snap hundreds of photographs using cameras equipped with 400-mm and 800-mm telephoto lenses capable of spotting even minor damage and defects.

With the rendezvous pitch maneuver complete, Kelly will manually guide Endeavour up to a point about 400 feet directly in front of the station with the shuttle's nose pointed toward deep space and it's open payload bay facing the lab's forward port. With the two spacecraft flying in formation at more than 5 miles per second, Kelly will carefully move in for a docking.

Joining Nespoli and Coleman to welcome the shuttle crew aboard will be Expedition 27 commander Dmitri Kondratyev, Ronald Garan and Russian cosmonauts Andrey Borisenko and Alexander Samokutyaev.

After a brief "meet and greet" in the forward Harmony module, the shuttle crew will get a routine safety briefing before splitting up and getting to work.

The major item on the post-docking agenda is installation of External Logistics Carrier No. 3 on the upper left side of the station's power truss.

Mounted in Endeavour's cargo bay just in front of the Alpha Magnetic Spectrometer, ELC-3 tips the scales at just over 14,000 pounds, loaded with large components that will become part of the station's extensive spare parts inventory for use down the road, after the shuttle fleet is retired. Three other ELCs were attached to the station during two earlier shuttle missions, two on the right side of the power truss and one on the lower left.

ELC-3 is carrying 10 spare remote power control module circuit breakers, two spare S-band antenna assemblies, an ammonia tank loaded with 600 pounds of coolant, a high-pressure oxygen tank for the station's airlock and a spare arm for a Canadian cargo manipulator that can be attached to the station's main robot arm. It is also carrying a suite of small military experiments.

Fincke and Vittori, operating the shuttle's robot arm, will pull ELC-3 from Endeavour's cargo bay three hours after docking and hand it off to Johnson and Chamitoff, operating the space station's robot arm. From there, the station arm will move ELC-3 to the upper attachment point on the port side of the power truss.

Once in position, a motorized clamp will lock ELC-3 in place and an umbilical will deliver power to component heaters and electronics.

Getting ELC-3 attached is "absolutely critical because there's no other way to get the big spares on board without the orbiter," said space station Flight Director Derek Hassmann. "It's amazing the amount of inventory we have on orbit in terms of critical pump modules, in terms of communications equipment, in terms of high pressure gas tanks for the airlock. I would say we're in an excellent position for shutle retirement. We've made tremendous progress over the past five or six years, first in identifying the plan and getting all the tons of hardware on orbit."

ELC-3 must be unloaded from the shuttle first because of center-of-gravity re-entry and landing constraints. If ELC-3 cannot be unberthed for some reason, the spare parts pallet and the AMS will be returned to Earth.

But no such problems are expected and if all goes well, the astronauts will turn to their primary payload on flight day four.

Feustel and Vittori will pull the Alpha Magnetic Spectrometer out of the shuttle's cargo bay using Endeavour's robot arm. As with ELC-3, the AMS will be handed off to the station arm, operated by Johnson and Chamitoff. They will move the particle detector to the upper right side of the power truss and robotically lock it in place.

Power and data cables will be remotely connected. No other crew interaction is required and data collection will begin almost immediately.

"Not too long ago, Steve Hawking, a very well known physicist, came to spend an afternoon with me at Geneva (where we were) assembling the detector," Ting said. "He asked me a question. He said, why do you do AMS on the station, not with a satellite? I told him it's really not possible to do a very, very precise, very sophisticated state-of-the-art detector to study the origin of the cosmos without the space station. Because space station can provide support of large weight and enormous amount of power. So without a space station, AMS would not have been possible."

Using the same magnet that flew on a shuttle test mission in 1998, the AMS will record subtle shifts in the trajectories of incoming charged particles to look for evidence of antimatter left over from the big bang birth of the cosmos and to search for clues about the nature of mysterious dark matter and evidence for new forms of matter that have been predicted but never seen.

Built at CERN, the European Organization for Nuclear Research, and managed by the U.S. Department of Energy, the $2 billion AMS is an international collaboration between 16 nations, 60 institutes and some 600 physicists. Ting, a soft-spoken Chinese-American physicist who shared the 1976 Nobel Prize in physics, is a tireless advocate.

"The largest accelerator on Earth is 16 miles in circumference, the large Hadron Collider, LHC," he said. "In LHC there are four big experiments. Thousands and thousands of physicists work there trying to understand the beginning of the universe, what is the origin of mass, why different particles have different masses.

"The cost of ISS is about 10 times more than the LHC. The LHC has four experiments. On the space station, to study particle physics, the origin of the universe, (we only have) AMS. And that's why we're very grateful to the United States House of Representatives and the Senate, which passed the resolution to support NASA to have an additional flight to put us in space."

The Large Hadron Collider is capable of generating energies as high as 7 trillion electron volts. To put that in perspective, 1 trillion electron volts is roughly equivalent to the energy of a single flying mosquito. But in particle physics, that energy is concentrated in a single sub-atomic particle and particles from deep space can have energies as high as 100 million trillion electron volts.

"This means that no matter how accelerators are here on Earth, you cannot compete with the cosmos," Ting said.

One of the many mysteries AMS was designed to explore is what happened to the anti-matter that must have been created in the big bang. Scientists believe equal amounts of matter and anti-matter were produced, but a slight imbalance -- or some other factor -- resulted in a universe dominated by normal matter. Or at least a nearby universe made up of normal matter.

"If the universe comes from a big bang, before the big bang it is vacuum," Ting told reporters recently. "Nothing exists in vacuum. So in the beginning, you have (negatively charged) electron, you must have a (positively charged) positron so the charge is balanced. So you have matter, you must have antimatter, otherwise we would not have come from the vacuum.

"So now the universe is 14 billion years old, you have all of us, made out of matter. The question is, where is the universe made out of antimatter? With this experiment, the reason we designed it to such a large size with so many layers of repetitive position detectors is to search for the existence of antimatter to the age of the observable universe, anti-helium, anti-carbon.

"We can distinguish this particle from billions of ordinary particles," he said. "If you think about it, this is not a trivial job. In the city of Houston during the rainy season, you have about 10 billion raindrops per second. If you want to find one that's a different color, it's somewhat difficult. This illustrates the precision this detector is going to achieve."

Dark matter, the mysterious, as-yet-undetected material believed to provide the glue -- gravity -- needed to hold galaxies and clusters of galaxies together, is believed to make up a quarter of the universe compared to the 4 percent made up of the normal matter familiar to human senses. The rest is believed to be in the form of dark energy, a repulsive force that appears to be speeding up the expansion of the universe.

While AMS cannot directly detect dark matter, it can detect the particles that would be produced in dark matter collisions.

AMS also will be on the lookout for so-called "strangelets," sub-atomic particles made up of quarks in different combinations than particles found on Earth. There are six types of quarks -- known as up, down, top, bottom, charm and strange -- but protons and neutrons making up normal matter seen on Earth are made up of just two -- different combinations of up quarks and down quarks.

"The smallest particle are called quarks," Ting said. "We know six quarks exist. But it's very, very strange. All the material on Earth is made up of just two, up and down. We know in the accelerator, six types exist, but on Earth you only see the first two. So the simple question you want to ask is, where's the material made out of three types of quarks? Up, down and strange? It's a very simple question, but a very, very important question."

Whatever AMS discovers, scientists will have plenty of data to work with. Some 25,000 particle detections per second are expected when the instrument is up and running.

"We're gathering data at seven gigabits per second," said Trent Martin, the AMS project manager at the Johnson Space Center in Houston. "We can't send that huge amount of data down through the space station data system, it's just too much.

"So the onboard computers actually go through a process of condensing that data down to just the data that we're truly interested in, compressing it as much as possible. We send down data on average at about six megabits per second, constantly for the entire time that AMS is on. The computers can store up data and we can burst it down at a much higher rate."

Asked to speculate on what AMS might discovery, Ting declined, saying "Most physicists who predict the future normally end up regretting it."

"My responsibility and the responsibility of my senior collaborators is to make sure the instrument is correct," he said. "Because the detector is so sensitive, everything we measure is something new. We want to make sure it's done correctly."

FOUR COMPLEX SPACEWALKS ON TAP

A few hours after the AMS installation, Feustel and Chamitoff will seal themselves in the space station's Quest airlock and spend the night at a reduced pressure of 10.2 pounds per square inch. The "camp out" procedure is a standard protocol to help remove nitrogen from the spacewalkers' bloodstreams and prevent the bends when working in NASA's low-pressure spacesuits.

The primary goals of the first spacewalk are to retrieve a materials science space exposure experiment mounted on ELC-2; to install a replacement; and to hook up ammonia line jumpers to set up a pipeline from an ammonia coolant tank near the center of the power truss to the outboard left-side solar array.

The Materials International Space Station Experiments -- MISSE -- are the size of suitcases.

"It's a space exposure experiment," Chamitoff said in a NASA interview. "Basically they're like large suitcases with lots of samples inside, and those samples can be everything from materials to paints to coatings to electronic equipment to biological samples, and they can come from different organizations.

"The idea is to expose these things to the harsh environment of space for a long period and see what happens -- if the seeds will still germinate, if a paint material will protect what's below it, see if a circuit can still work and to help us design better systems for the future.

"There are two experiments out there that are a part of MISSE 7," Chamitoff said. "We're going to retrieve those, close (them) up, take them back, put them in the shuttle cargo bay, and then we take new ones out of the cargo bay, MISSE 8, and we install them up on the truss. They'll be out there for six months to a year before they come in."

The spacewalkers then will turn their attention to preparations for topping off the ammonia coolant supply in the port six, or P6, solar array segment.

Each of the station's four sets of solar arrays are equipped with radiators that use circulating ammonia to carry away heat generated by batteries and electronics subsystems. Engineers have been monitoring a small leak in the P6 coolant system and during the crew's second spacewalk, the astronauts will top off the coolant in the P6 radiator panels. But first, Feustel and Chamitoff must hook up the jumpers to complete what amounts to a long hose running from an ammonia storage tank on the P1 truss segment all the way out to P6.

"We have to sort of connect a lot of ammonia hoses between a lot of segments including one that jumps across the rotating solar alpha rotary joint, which normally can't have a hose running across (it). It has to spin freely.

"We're going to go out and we're going to connect all these hoses and then vent them basically so that they're filled with N2, the nitrogen. We're going to vent them so that they're ready to be used for the ammonia fill on the next EVA."

After the line is vented, the segment crossing the solar alpha rotary joint -- the P3/P4 jumper -- will be disconnected so the outboard arrays can rotate as required to track the sun. Those jumpers will be reconnected during the second spacewalk when the ammonia fill will take place.

After the jumper work, Chamitoff and Feustel will install a new wireless antenna that can be used by external experiments and other payloads.

"There are experiments and payloads outside the space station (that) need to communicate to the data system and they're installing a couple of antennas and all the wiring for that to enable those pieces of equipment or experiments to communicate to internal systems," Chamitoff said.

"It's a lot of wiring. It's a little messy with long wires and it takes a while but that's going to be in the front of the space station near the shuttle. The thing that's maybe a little interesting about that is just that in order for us to do that, they have to disable some things internally. We may lose communication. We may have to wave through the window and say everything's OK, and then go down and finish the work and come back and say everything's OK. We'll see how that goes but it should be interesting."

The next day -- flight day six -- Johnson and Coleman, operating the space station's robot arm, will pull the shuttle heat shield inspection boom out of Endeavour's cargo bay and hand it off to the shuttle's arm, operated by Feustel and Vittori. The boom will be used later in the misson to inspect the shuttle's heat shield again. After the handoff, the astronauts will take a half day off to relax and catch their collective breath.

Fincke will join Feustel for the second spacewalk on flight day seven. There are two primary objectives: to fill the P6 ammonia radiator with coolant and to lubricate the port solar alpha rotary joint drive gear and bearing race.

"Building on the success of EVA 1, we hope, we're going to go out, and we have two main jobs for EVA No. 2. Both of them are for the long-duration maintenance of the International Space Station," Fincke said in a NASA interview. "Since we're the last shuttle-based EVA, we're doing things in advance for routine preventative maintenance just like with our automobiles."

Feustel will focus on making the final connections to permit six to eight pounds of ammonia to flow outboard from the P1 ammonia tank assembly to the P6 radiator, including reconnecting the P3/P4 jumper across the solar alpha rotary joint, or SARJ. It will take about 10 minutes to top off the radiator. After that, Fuestel will vent the line with nitrogen to remove any residual ammonia. Two ventings are required, one lasting 17 minutes and one about four minutes.

NASA has a history of problems with ammonia quick-disconnect fittings, and there are more than a half-dozen connections required for the P6 radiator fill. If either spacewalker gets ammonia on his suit, NASA will implement a "bake out" protocol to make sure any ammonia ice crystals sublimate away in direct sunlight, before the astronauts re-enter the space station.

"This isn't your household cleaner ammonia," Fincke said, "this is high-grade industrial ammonia so we have to be super careful not to get it on us or to spill it because it's quite dangerous if we brought it back inside. But we're going to recharge the ammonia lines. ... There's a series of jumpers that we have to go across, including the rotating solar alpha rotary joint, so we have some jumpers, a series of hoses that will fully charge our ammonia system.

"While Drew's doing that, I get to do a lubrication job, add some grease, some Braycote, to our solar alpha rotary joint," Fincke said. "We found the original design had some extra friction that we weren't expecting and it started to grind our joint. So since then, every couple years, (we've) started to add some grease on it and it rotates great. However, we won't have that ability so much in the future, so while Drew's working with the ammonia system I'll be lubricating the outside of the solar alpha rotary joint so it can last another five to ten years, no problem."

When the SARJ work is complete and the astronauts have verified that all tools, tethers and jumpers are inboard of the port SARJ, commands will be sent to rotate the solar arrays through 200 degrees. The 45-minute procedure will spread the grease already applied and bring the other side of the gear and race into position for lubrication.

While the array is slowly rotating, Feustel will install a lens cover on a camera used by the Canadian Special Purpose Dexterous Manipulator, or Dextre, a robot arm attachment fitting that in some cases can take the place of a spacewalking astronaut. With the lens cover in place, Feustel plans to lubricate the snares used by Dextre to hold components in place.

While Feustel is working with Dextre, Fincke will install two grapple bar stowage beams that will provide a temporary mounting point for radiator panels if replacement operations are ever required.

Finally, Fincke and Feustel will apply a final bead of grease to the SARJ race ring before re-installing six covers and heading back to the airlock.

The day after the second spacewalk, the astronauts will take another half-day off before Fincke and Feustel prepare for the mission's third spacewalk.

But this time around, the astronauts will not camp out in the Quest airlock to help remove nitrogen from their bloodstreams. Instead, they will test a new protocol known as the "in-suite light exercise" pre-breathe protocol, or ISLE for short.

Extensive testing on the ground indicates spacewalkers can remove nitrogen by simply performing light exercise the morning of the excursion while breathing pure oxygen. By avoiding the overnight campout, astronauts will not be isolated before a spacewalk and a fire alarm or other problem will not force them to open the airlock and delay a long-planned spacewalk.

"It doesn't require the overnight campout that was used for most of the previous EVAs on the last several flights," said Hassmann. "In terms of complexity, in terms of the quality of life for the crew, this ISLE protocol is a pretty significant upgrade because we don't have that point the night before where the two EVA crew has to go in the airlock, and we shut the hatch, and they're forced to spend the night in the airlock.

"With this in-suit light exercise, or ISLE, protocol, the night before an EVA looks exactly like any other night during the mission. They wake up, they don't have to stay on the portable breathing apparatus, they don't have to stay on the oxygen masks. So up until the point where they actually begin the EVA prep the morning of, it looks just like any other day.

"We think this is an improvement over the campout protocol," he said. "And of course, the main thing we're after here is crew safety. All of these crew protocols are designed to prevent the bends. Leading up to this, we put the ISLE protocol through all the standard medical reviews and tests that both the campout and exercise pre-breathe protocols have been subjected to, and everybody's comfortable it's completely safe. We think it offers some significant advantages."

The third spacewalk, on flight day nine, is devoted primarily to attaching a power and data grapple fixture -- a robot arm anchor fitting -- to the side of the Russian Zarya module, along with a video signal conditioner and associated cabling. The equipment will allow the station's robot arm to base itself on the Russian segment of the space station for maintenance work down the road.

"We've just added this EVA, and this involves installing a power and data grapple fixture, or a base, for Canadarm 2," Feustel said. "So the Canadarm space station arm has a capability of walking around the space station from end to end to do different tasks. The Russian segment doesn't really have any of those bases for the arm to walk on to.

"This is an opportunity for us to actually attach one of these base station mechanisms onto what we call the FGB or Functional Cargo Block portion of the space station to allow the arm to walk onto that position and do some tasks in areas that it wouldn't have been able to reach previous to this."

In addition to mounting the PDGF and the video signal conditioner, Fincke and Feustel also will route power and data cables from the U.S. segment of the station to the new equipment.

The day after the third spacewalk -- flight day 10 -- the astronauts will carry out an inspection of the shuttle's nose cap and wing leading edge panels to look for any signs of damage that might have occurred since launch due to impacts with space debris or micrometeoroids.

This so-called late inspection, using the shuttle's robot arm and heat shield inspection boom, normally is carried out after the shuttle undocks from the station. But Endeavour's orbiter boom sensor system, or OBSS, will be left behind aboard the station to give the lab's robot arm an extension, providing the capability to reach areas that would otherwise be inaccessible.

After the late inspection, the crew will review procedures for a fourth and final spacewalk by Fincke and Chamitoff the next day to mount the OBSS on the station's power truss. If the ISLE protocol works and no problems develop, Fincke and Chamitoff may use it again for EVA No. 4. Otherwise, they will use the normal camp out procedure.

After exiting the Quest airlock, the astronauts will set up foot restraints on the power truss and take the OBSS boom from the shuttle's robot arm, operated by Johnson, known by his nickname Box. After mounting the boom on attachment fixtures, Fincke will demate electrical connectors leading to a no-longer-needed laser scanner and heat shield inspection camera.

Then they will remove the grapple fixture on the other end of the boom that was used by the shuttle's robot arm and replace it with a fixture designed for the station arm.

"That boom will be left behind on the space station with the idea that at some point if the space station has to do some work, it would give the robotic arm more reach if it could use this boom as well," Chamitoff said. "We have left it up there before, we have the mechanisms in place to leave it up there.

"We'll be attaching that boom to the truss, locking it in place. Normally the shuttle arm grabs that boom at the end, and the station arm has a grapple fixture in the middle, but if we're going to use it on the station at some future point, you want to be able to grab it from the end. The grapple fixture at the end is not the right kind and we have to change it so it'll be kind of fun for Mike.

"Because we're kind of tearing this thing apart in a way, we're taking off that end, replacing it with a station grapple fixture, and we have to cut some wires and pull this thing off completely and while we're doing that I'll be on the station robotic arm and Box will be flying me around. That'll be an exciting task to do."

After wrapping up work to stow the OBSS, the astronauts will perform minor maintenance on the Dextre manipulator, unlatch a spare arm mounted on ELC-3 and install a protective handling fixture to the spare high-pressure oxygen tank.

The day after the final spacewalk -- flight day 12 -- the combined crews will wrap up equipment transfers, finish moving science samples from the station to the shuttle and hold a joint crew news conference. Then the two crews will bid each other farewell and close the hatches between Endeavour and the space station.

The next morning, Endeavour will undock to wrap up its final station visit.

A FINAL TEST BEFORE RE-ENTRY TO CLOSE OUT A 25-FIGHT CAREER

With Johnson at the controls, the shuttle is scheduled to undock four hours after crew wakeup on flight day 13. After pulling straight away in front of the station, Johnson will kick off a one-lap fly-around, loop up over, behind, below and back in front of the lab complex.

At that point, the shuttle normally departs the area for good. But Endeavour's crew plans to test software and new sensors designed for use on the Orion capsule Lockheed Martin is designing for possible deep space exploration.

The Sensor Test for Orion Relative Navigation Risk Mitigation experiment -- STORRM -- will operate in the background during Endeavour's approach to the station on flight day three, collecting data that will allow engineers to calibrate the system.

After Endeavour's one-lap fly around after undocking, Johnson and Kelly will guide the shuttle through another looping rendezvous sequence to put the new equipment to the test.

"The orbiter will undock and back away and do a full one lap fly-around like we normally do," said shuttle flight director Gary Horlacher. "We'll do the nominal sep 1 burn and the sep 2 burn will put us on the STORRM re-rendezvous trajectory. So we're going to phase out above station and behind it and STORRM will be taking data all the way out until the sensors drop lock outside 20,000 feet.

"Then we'll go ahead and do an orbit lowering burn, which is going to bring us down below the space station and get us set up for the trajectory to mimic the Orion approach to the space station. This approach is called a co-elliptic approach, so this burn down here is going to put us in a co-elliptic trajectory under the space station and then we'll be catching back up to it and do the terminal phase initiation burn, which will bring us back up towards station.

"It's designed to have us stall out about 1,000 feet below and 300 feet behind the space station," he said. "And then orbital mechanics will pull us down and away. STORRM sensors will continue to take data until the sensors drop lock. And when we get outside that range, we'll go ahead and call the docked mission complete and then we'll get our nominal water dumps accomplished and get the ship prepared to come back home."

The astronauts will pack up and test the shuttle's re-entry systems the next day, stowing gear and breaking down their computer network. Kelly and Johnson will take turns flying a shuttle flight simulator to practice landing procedures, and the crew will handle a final round of media interviews.

Landing currently is planned for flight day 15 -- Friday, May 13, assuming an April 29 liftoff. But NASA managers likely will extend the flight at least one and possibly two days to give the shuttle crew more time to help their station colleagues carry out maintenance on the station's life support system.

"We're going to lift off with a 14-day planned mission," said Mike Moses, the shuttle integration manager at the Kennedy Space Center. "We have two extension days in addition to the two weather and systems wave-off days that we keep for deorbit and landing contingencies. So we have two mission extension days this time.

"After we get docked to station, probably around flight day five or so, the mission management team ... will take a look at where we're at. The mission ops team has a really good plan where those two extra days will go in. We'll probably add those two days, taking it to a 16-day mission. But we won't do that until we get in orbit and see what we've got.

If two extension days are added, landing would slip to flight day 17, or May 15 for an April 29 launch.

And that will be the end of the line for Endeavour.

"Three out of six of us have flown on Endeavour," Kelly told reporters. "It's pretty close to my heart because it's the first space shuttle I flew on in 2001. I'm glad it's the one I'm going to fly on last, it's the baby of the fleet, it's coming up on 19 years in service, the 25th flight. Twenty five's a good round number to end on."

On April 12 -- the 30th anniversary of the first shuttle flight -- NASA Administrator Charles Bolden ended months of speculation by announcing the museums that had been chosen to display the shuttles after the final mission.

"We want to display the vehicles as realistically as possible, but the thought that it's going to be a flyable orbiter is just not true," Shannon said. "There's a lot of safety issues where you have toxic chemicals and things, and we've got to take that plumbing off and we're not going to replace it. We'll either safe it in place, if we can't safe it in place, you just remove it.

"The main engines are an extremely valuable asset, and I want to save all of our block 2 SSMEs. We have a plan to store them in a purged, safe environment along with all of the ground systems required to maintain them until we decide what to do with the next program. So what we did is, we went and really searched the facilities for excess hardware that we could build up into some main engines. So we'll have nine engines we'll put into each of the vehicles that are older technology engines, but they're real nozzles that flew, they're real combustion chambers, real pumps. And so we'll take out the really good engines we'd like to save for the next program, we'll put in rebuilt engines that we kind of scrapped together, and that is what will be displayed."

Shannon said NASA also hopes to cobble together enough spare parts to build a few stand-alone engines that can be put on display by the orbiters "so people can see how big and how complex they really are. I'm also trying to save the OMS engines, the smaller orbital maneuvering system engines on the back. Same reason, if we can use them in a future program, I think they are very valuable assets. We don't have a lot of spares on those, so those are probably going to be mocked up."

During the decommissioning phase, engineers are going to take the opportunity to inspect or remove components that are buried in the shuttle and have not been inspected since construction began decades ago. The hydraulic actuators that move the shuttle's elevons, for example, are prime candidates for removal.

"I had some pretty good debates with the ground operations team about the difficulty in going to get some of these things," Shannon said. "But from an engineering standpoint, this is a once-in-a-lifetime opportunity to go see how a reusable vehicle actually weathered this many cycles, this many times on orbit, this much time in ground processing. So we'll go get representative actuators, we're going to get main engine flow liners, things that basically you started with it, then you built the orbiter around it.

"It's very invasive to go in and get them, but I've asked the team to go in there and do that. We'll send those out to our labs. That's kind of the next legacy of the shuttle program is to give you a lot of material knowledge, a lot of design knowledge in how things work over a long period of time."

The shuttle will look the same to the public, but "we're going to put on some hardware so we can save some of the higher value hardware, we're going to safe it so that the public's not exposed to anything dangerous, and we'll remove some things the public would never see."

"To me, it's more important to get that engineering knowledge out of these vehicles than it is to have total accuracy in a museum."

CBS NEWS Coverage of Breaking Space News

02:25 PM EDT, 04/26/11: Endeavour astronauts arrive; countown begins

By WILLIAM HARWOOD
CBS News

The shuttle Endeavour's crew flew to Florida Tuesday for the start of their countdown to blastoff Friday on a long-awaited mission to deliver supplies, spare parts and a $2 billion cosmic ray detector to the International Space Station. Forecasters are predicting an 80 percent chance of good weather.

Arriving in sleek T-38 jet trainers, commander Mark Kelly and his five crewmates -- pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- landed at the shuttle runway just before 1 p.m. EDT (GMT-4) after a flight from Houston.

One hour later, at 2 p.m., engineers in the nearby launch control center started Endeavour's countdown, setting the stage for launch of NASA's next-to-last shuttle mission at 3:47:52 p.m. Friday. It will be Endeavour's 25th and final mission since its maiden voyage in May 1992.

"We're really happy to be here today," Kelly told reporters at the shuttle runway. "We got a chance to take a look at the orbiter as flew over. ... It's great to see Endeavour all ready to go again. Endeavour has had a pretty amazing career. It's been flying now for 18 years. This is going to be Endeavour's 25th flight and me and my crew are excited to be a part of it."

Kelly's wife, Arizona Rep. Gabrielle Giffords, plans to arrive later this week to watch Endeavour's launching. Giffords, shot in the head Jan. 8 in Tucson, has been recovering in Houston. This will be her first major trip away from the hospital.

"I'm personally looking forward to my wife, Congresswoman Gabrielle Giffords, getting here pretty soon, to be here in time for our launch on Friday," Kelly said. "It's something she's been looking forward to for a long time. She's been working really hard to make sure that her doctors would permit her to come, and she's more than medically ready to be here. She's excited about making this trip."

Kelly thanked the thousands of engineers and technicians who worked on Endeavour over the years, joking that "we're going to take Endeavour out for a couple of more, probably five or six million more miles."

"After 25 flights, we will hopefully land here on this runway and then Endeavour is done with its service to the country," he said. "Over the years, Endeavour's had thousands and thousands of very dedicated KSC government an contractor employees working on it. We want to thank every one of them for the hard work that they've done to get this vehicle ready time and time again. ... My crew and I are really excited to be a part of that. We're looking forward to launching on Friday."

NASA Test Director Jeremy Graeber said engineers were not tracking any significant issues going into the countdown and shuttle weather officer Kathy Winters said forecasters are predicting generally good weather through the weekend. The only concern is possibly high crosswinds from a front expected to move through the area Thursday night.

She said the models indicate an 80 percent chance of acceptable weather Friday, dropping to 79 percent on Saturday and moving back up to 80 percent "go" on Sunday.

"Overall, our main concern for launch day is going to be crosswinds," she said. "There's just a 20 percent chance of KSC weather prohibiting launch. The main thing is we just want to get that frontal system through us on Thursday evening and still be able to complete all our pre-launch operations."

Engineers plan to pump liquid oxygen and hydrogen aboard the orbiter starting at 11:30 a.m. Wednesday to power the shuttle's electricity producing fuel cells, a procedure that should be complete by around 6 p.m. After an eight-hour hold, main engine preparations will get underway along with checkout of various avionics systems.

A 13-hour 20-minute hold will begin at 10 a.m. Thursday, during which communications links will be activated and checked out. A protective gantry will be pulled away from the shuttle starting around 7 p.m. Thursday, exposing the orbiter to view.

If all goes well, engineers will begin pumping a half-million gallons of supercold liquid oxygen and hydrogen rocket fuel into Endeavour's external tank around 6:22 a.m. Friday. Kelly and his crewmates plan to don their pressure suits and head to the pad to begin strapping in a few minutes before noon.

As with most space station flights, Endeavour's launch is timed for the middle of a 10-minute window, roughly the moment Earth's rotation carries pad 39A into the plane of the space station's orbit. A detailed countdown timeline is posted on the Fight Data File page, along with an updated launch windows chart and other useful data. The STS-134 flight plan and the mission television schedule are posted separately.

CBS NEWS Coverage of Breaking Space News

06:30 PM EDT, 04/19/11: Shuttle Endeavour cleared for April 29 launch

By WILLIAM HARWOOD
CBS News

NASA managers attending an executive-level flight readiness review Tuesday formally cleared the shuttle Endeavour for launch April 29 on its 25th and final mission, a four-spacewalk flight to deliver supplies, spare parts and a $2 billion particle physics detector to the International Space Station.

Bill Gerstenmaier, chief of space operations at NASA headquarters in Washington, said the vote to proceed with the 134th and next-to-last shuttle mission was unanimous.

"We reviewed everything," he said. "We're ready to go fly."

Endeavor commander Mark Kelly, pilot Gregory Johnson, European Space Agency flight engineer Roberto Vittori and spacewalkers Andrew Feustel, Michael Fincke and Gregory Chamitoff will fly to the Kennedy Space Center next Tuesday for the start of the shuttle's countdown to launch. Liftoff is targeted for 3:47:49 p.m. EDT on April 29, roughly the moment Earth's rotation carries launch complex 39A into the plane of the space station's orbit.

It is not yet known whether Kelly's wife, Arizona Rep. Gabrielle Giffords, will attend the launching or if so, when she might arrive. Giffords is recovering from a gunshot wound to the head and her medical team in Houston has not yet indicated whether her condition will permit travel.

In any case, Endeavour's initial launch window opens April 29 and extends through May 4. If the shuttle is not off the ground by then, the team will stand down for three days to reload liquid oxygen and hydrogen fuel cell reactants and to give the Air Force time to launch an Atlas 5 rocket carrying a military communications satellite. The shuttle launch window would re-open around May 8 and extend through May 29.

NASA had planned to launch Endeavour on April 19, but earlier this month the fight was delayed 10 days because of a conflict with the launch and docking of a Russian Progress supply ship. The delay put the shuttle launch on the same day as the British royal wedding of Prince William and Kate Middleton.

Asked if NASA considered an additional delay to avoid a conflict with the royal wedding, Gerstenmaier said "We work beta (angle) constraints and we work launch range constraints. I haven't yet put on our manifest charts 'wedding constraints.' So we didn't factor that into our thinking."

Assuming an on-time liftoff, Kelly plans to guide Endeavour to a docking at the space station's forward port around 1:30 p.m. on May 1. The $2 billion Alpha Magnetic Spectrometer, designed to sift high energy particles from deep space to look for antimatter and clues about the formation and evolution of the universe, will be attached to the lab's power truss the day after docking.

Four spacewalks are planned for May 3, 5, 7 and 9 to carry out a variety of maintenance chores. Undocking is scheduled for May 11 with landing back at the Kennedy Space Center around 9:30 a.m. on Friday, May 13. If there are no major problems, however, mission managers hope to extend the flight an additional two days, giving the shuttle crew time to help with needed maintenance.

"We're going to lift off with a 14-day planned mission," said Mike Moses, the shuttle integration manager at the Kennedy Space Center. "We have two extension days in addition to the two weather and systems wave off days that we keep for deorbit and landing contingencies. So we have two mission extension days this time.

"After we get docked to station, probably around flight day five or so, the mission management team ... will take a look at where we're at. The mission ops team has a really good plan where those two extra days will go in and we'l probably add those two days, taking it to a 16-day mission. But we won't do that until we get in orbit and see what we've got."

Assuming the extension days are approved, landing would be expected around 8:40 a.m. on May 15.

Whenever it gets back, Endeavour will be "safed" and decommissioned before work to ready the orbiter for permanent display at the California Science Center in Los Angeles. The shuttle Discovery, which completed its final mission in March, already is undergoing that process before its eventual display near Washington at the Smithsonian National Air and Space Museum's Steven F. Udvar-Hazy Center.

NASA plans to follow Endeavour's flight with a final launch by the shuttle Atlantis on June 28. The goal of that flight, the orbiter's 33rd mission, is to deliver a final load of needed supplies and equipment to stock the station before the transition to unmanned resupply missions by smaller U.S. and Russian cargo craft. Atlantis will be put on permanent display at the Kennedy Space Center visitor's complex.

CBS NEWS Coverage of Breaking Space News

12:22 AM, 04/09/11: Government shutdown averted in last-minute deal

By WILLIAM HARWOOD
CBS News

With just one hour to go before a government shutdown would have gone into effect, lawmakers reached a compromise late Friday after agreeing to the largest annual spending reduction in U.S. history. The compromise means NASA and other federal agencies will remain open and work to process the shuttle Endeavour for launch April 29 on a space station assembly mission will continue on schedule.

"We have agreed to an historic amount of cuts for the remainder of this fiscal year, as well as a short-term bridge that will give us time to avoid a shutdown while we get that agreement through both houses and to the President," House Speaker John Boehner and Senate Majority Leader Harry Reid said in a joint statement.

"We will cut $78.5 billion below the President's 2011 budget proposal, and we have reached an agreement on the policy riders. In the meantime, we will pass a short-term resolution to keep the government running through Thursday. That short-term bridge will cut the first $2 billion of the total savings."

With a shutdown looming, NASA and other federal agencies had put plans in place to close down non-critical operations and to furlough thousands of federal employees starting at midnight Friday. NASA managers said earlier in the week that space station operations would continue in near-normal fashion, but work to ready Endeavour for launch would be halted.

Because of a recent launch delay from April 19 to April 29, NASA has about nine days of contingency time in the shuttle's processing flow and agency officials said a work stoppage and furlough would not have an impact on launch unless a shutdown extended beyond around April 18.

With the late night compromise -- and assuming new spending legislation is passed next week -- shuttle processing will continue apace.

"Tomorrow, I'm pleased to announce that the Washington Monument, as well as the entire federal government, will be open for business," President Barack Obama said late Friday. "And that's because today, Americans of different beliefs came together again.

"In the final hours before our government would have been forced to shut down, leaders in both parties reached an agreement will allow our small businesses to get the loans they need, our families to get the mortgages they apply for and hundreds of thousands of Americans to show up for work, and take home their paychecks on time, including our brave men and women in uniform."

Additional details are available on the CBS News Political Hotsheet web page.

CBS NEWS Coverage of Breaking Space News

06:11 PM, 04/07/11: NASA braces for possible government shutdown

By WILLIAM HARWOOD
CBS News

Bracing for a potential government shutdown, NASA managers are assessing shuttle launch processing and putting plans in place to continue near-normal operation of the International Space Station if a workforce furlough is ordered.

Work to ready the shuttle Endeavour for launch April 29 on a mission to deliver supplies, spare parts and a $2 billion particle physics experiment to the space station would be curtailed for the duration of a furlough, although a skeleton crew would remain in place to monitor the spacecraft and ensure its safety.

But as of Thursday, Endeavour's processing flow included nine days of contingency time and NASA officials said the April 29 launch date likely would not be affected unless a furlough extended beyond April 18 or thereabout.

"Launch processing will not be affected by a government shutdown unless it's lengthy," an agency official said. "We're looking at a line in the sand for day-to-day slip of around April 18. If the furlough is a week or less, we don't anticipate any impact. If it's longer than a week, we're going to have to assess that."

A stopgap spending bill expires at midnight Friday. If lawmakers do not agree on compromise funding for the rest of fiscal 2011, or approve another short-term stopgap bill, a federal shutdown will go into effect.

If so, flight controllers at the Johnson Space Center in Houston would continue operating the International Space Station in near-normal fashion and NASA's Mission Management Team would participate in an already planned meeting Monday with the agency's international partners. Less critical support staff would be on call but not report to work.

Shuttle processing at the Kennedy Space Center would come to a virtual standstill. But thanks to a recent delay, no immediate launch date impact would be expected.

Endeavour had been scheduled for launch April 19, but NASA announced April 4 that the 134th shuttle flight would be delayed 10 days because of a conflict with the arrival of a Russian Progress supply ship at the space station. The slip to April 29 gives the space agency more of a cushion than usual to cope with unexpected problems and delays.

NASA plans to close out the shuttle program by launching the Atlantis on June 28 on a final space station resupply mission. As with Endeavour, the June launch target likely would not be affected unless a government shutdown extended beyond nine or 10 days. After that, both flights likely would begin facing delays.

A furlough would have an immediate impact on NASA's public affairs operation, including plans for in-flight media interviews with the space station crew and agency coverage of celebrations in Russia to mark the 50th anniversary of Yuri Gagarin's April 12, 1961, launch on the first manned space mission.

Likewise, a news conference April 12 at the Kennedy Space Center to announce which museums will eventually display NASA's three space shuttles would be put on hold.

CBS NEWS Coverage of Breaking Space News

10:25 AM, 04/04/11: Shuttle launch delayed to April 29

By WILLIAM HARWOOD
CBS News

Launch of the shuttle Endeavour on a mission to the International Space Station has been delayed 10 days to April 29 because of a conflict with the already planned launch and docking of an unmanned Russian Progress supply ship.

"Following discussions among the International Space Station partners on Sunday, NASA has targeted the launch of space shuttle Endeavour's STS-134 mission for (3:47:47) p.m. EDT on Friday, April 29," NASA said in a statement posted on its shuttle web site. "The delay removes a scheduling conflict with a Russian Progress supply vehicle scheduled to launch April 27 and arrive at the station April 29."

An executive-level flight readiness review to assess Endeavour's launch processing is planned for April 19.

Endeavour commander Mark Kelly and his five crewmates had hoped to blast off April 19, but that would have required the Russians to delay the Progress arrival until after the shuttle departed on May 1. But the Russians decided a docking delay could not be accommodated and the shuttle launch was delayed instead.

Endeavour's flight has generated intense media interest in the United States because of Kelly's decision to press ahead with the mission in the wake of the attempted assassination of his wife, Rep. Gabrielle Giffords, an Arizona Democrat, in January. Giffords is recovering in Houston from a gunshot wound to the head and Kelly has said he hopes she will be able to attend his launching in Florida.

The fight would have generated widespread interest in any case because it is Endeavour's 25th and final mission and the next-to-last flight on NASA's shuttle manifest before the fleet is retired. As it now stands, news organizations will have to split their resources to cover the shuttle launch and the British royal wedding of Prince William and Kate Middleton.

The primary goals of Endeavour's mission are to deliver critical supplies and equipment to the International Space Station, along with a $2 billion particle physics experiment called the Alpha Magnetic Spectrometer. Four spacewalks also are planned to carry out needed maintenance on the lab complex.

Assuming an on-time launch April 29, Kelly will guide Endeavour to a docking at the space station's forward port around 1 p.m. on May 1. The AMS will be attached to the lab's right-side solar power truss the next day. The flight plan calls for spacewalks on May 3, 5, 7 and 9 before undocking just after 6 p.m. on May 11. Landing back at the Kennedy Space Center would be targeted for around 9:30 a.m. on Friday May 13.

One wild card in the flight plan is the possibility of a Soyuz undocking and fly-around to photograph the space station with Endeavour still attached.

NASA asked the Russians to consider a similar fly-around during the shuttle Discovery's recently-completed mission, but the Russians declined because of a short planning cycle and the need to use an upgraded Soyuz making its first flight. If a fly around is added to Endeavour's mission, the flight will be extended.

CBS NEWS Coverage of Breaking Space News

07:30 PM, 03/24/11 Update: Kelly remains hopeful injured wife can attend shuttle launch

By WILLIAM HARWOOD
CBS News

Astronaut Mark Kelly told reporters Thursday he believes there is a "pretty good chance" his wife, Rep. Gabrielle Giffords, will be able to attend his launching April 19 aboard the shuttle Endeavour.

While he declined to participate in pre-flight one-on-one media interviews, Kelly opened a crew news conference by providing an update on the Arizona Democrat's condition as she recovers from a gunshot wound to the head.

"As her doctors described in their last press conference March 11, she's doing remarkably well," Kelly said. "She's improving every day and in the realm of brain injuries, that is very significant and pretty rare. She's starting to walk, talk more every day and she's starting to process some of the tragedy that we all went through in January. She's going through that as we speak. Despite that, she remains in a very good mood.

"She spends most of her day in therapy, enjoys brief visits from friends and colleagues, she was really happy to see my (twin brother Scott Kelly) last week after he returned from space. She gets staff briefings from her staff when they're in town on what's going on with her office, in the district and what's going on in Congress."

Giffords was shot in the head Jan. 8 in Tucson. She is undergoing therapy at The Institute for Rehabilitation and Research, part of the Memorial Hermann hospital system in Houston. Kelly said he sees his wife every morning before he leaves for work and when he comes back in the evening after training.

"I've said on a few occasions that I'd like her to attend the launch," he said. "She wants to attend, she's been looking forward to this for a long time. As one of NASA's biggest supporters in Congress, she was really looking forward to having the opportunity to be there.

"I think there's a pretty good chance that's going to happen. We still don't know for sure, and I'm just awaiting final approval from her doctors."

Kelly said he withdrew from round-robin media interviews because he wanted to focus attention on Endeavour's 25th and final mission and not on personal family matters.

He appeared at ease during the crew news conference and gave short but polite answers to the few personal questions that came his way. He said he would be willing to talk about his wife's recovery in more detail at a later date, but added any such interviews would be arranged by Giffords' staff, not NASA.

Asked how difficult it has been to focus on training while coping with his wife's recovery, Kelly said his previous experience -- Endeavour's flight is his fourth mission -- was a clear advantage.

"I think it would have been really challenging if this was my first shuttle flight or if it was even my first flight as commander of the space shuttle," he said. "But (having previous) experience certainly makes it very manageable, to be able to handle what's going on in my personal life and focusing on the mission.

"I've given this mission everything I would have if the events of January did not happen. So I'm very focused, we're very prepared as a crew. ... We're getting pretty close to the end and we're ready to do this, and excited about it."

The primary goals of Endeavour's four-spacewalk mission are to deliver a $2 billion particle physics experiment to the International Space Station, along with critical supplies, equipment and a pallet of spare parts that will be stored on the station's main power truss.

But the objectives of the flight have been overshadowed by the Giffords' shooting and intense public interest in its aftermath.

"It was a shock to the whole crew," Endeavour pilot Gregory H. Johnson told CBS News Thursday. "Gabby was a part of our crew as a spouse and everybody in the immediate families of the crew members, we all knew each other and it had a great impact emotionally, for example, on my 13-year old daughter. ... She was devastated."

The Endeavour astronauts all wore blue "awareness" wristbands with Giffords' nickname imprinted

"The bracelet reminds us of the ordeal the world has been through on this," Johnson said. "I think it's amazing that she survived. ... But I think it's even more miraculous the tenacity and the improvement that she's made in such short periods of time.

"It would be wonderful if she could be well enough to attend the launch, I don't think that's well understood yet, but it would be great. And we're hopeful she'll continue improving over the next couple of years and get her job back."

CBS NEWS Coverage of Breaking Space News

05:15 PM, 03/23/11 Update: Mark Kelly abruptly opts out of pre-flight media interviews

By WILLIAM HARWOOD
CBS News

Astronaut Mark Kelly, scheduled to command the shuttle Endeavour's 25th and final mission next month, abruptly removed himself from planned round-robin media interviews Thursday, citing a reluctance to discuss his personal life and that of his wife, Arizona Rep. Gabrielle Giffords, NASA officials announced Wednesday.

The unprecedented decision came one day after Kelly's twin brother Scott, who returned to Earth March 16 after a 159-day stay aboard the International Space Station, stopped a round of interviews in progress Tuesday morning because of repeated questions about Giffords' condition and her progress recovering from a gunshot wound to the head.

The Arizona Democrat was gravely injured during a shooting spree in Tucson in January. She is recovering in Houston and during a Feb. 4 news conference, Mark Kelly announced he planned to command Endeavour as scheduled. But he would not discuss his wife's recovery or what input she might have had on his decision to fly aboard the shuttle.

"I just don't want to go into details about her condition," Kelly told reporters. "Then people speculate on prognosis. It's just something I don't want to address. We had a discussion but beyond that, it's not something I feel comfortable talking about."

Asked if his wife might attend his launching, Kelly said "absolutely! I have every intention that she'll be there for the launch. I've already talked to her doctors about it. There really shouldn't be any reason why she can't go to the launch."

Kelly's flight -- and Giffords' possible appearance at the Kennedy Space Center for launch -- has generated widespread interest and fueled higher participation than usual in traditional pre-flight briefings planned for Thursday at the Johnson Space Center in Houston.

Kelly conducted several media interviews on his own in the aftermath of the shooting. But the planned interviews Thursday were the first making him available to a large number of reporters.

Before every shuttle flight, NASA holds briefings to help reporters understand the content of a mission and to provide an opportunity for one-on-one round-robin interviews with the crew. It is the only opportunity most reporters have to chat with shuttle crew members for preview stories and backgrounders.

A NASA spokesman said no other shuttle astronaut had ever declined to participate in the one-on-one interviews and dozens of reporters and photographers were expected to be on hand Thursday. Why Kelly waited until the day before the long-planned interviews to make his decision was not known.

"As you may know, Mark Kelly has expressed concern, from his past media experience and recent interviews conducted with his brother Scott, that it is difficult to get the media to focus attention on his mission rather than personal family matters," a NASA spokesman said. "He made a request to NASA to cancel these media interviews."

Kelly will participate in a crew news conference and his crewmates -- pilot Gregory H. Johnson, Michael Fincke, Roberto Vittori, Andrew Feustel and Gregory Chamitoff -- will participate in the one-on-one interview sessions as planned. A morning network-only event with the entire crew was canceled.

It remains to be seen whether reporters will honor expected requests not to ask about Giffords during the crew news conference Thursday or what Kelly might do if questions are, in fact, asked.

It also remains to be seen whether Kelly will participate in a traditional launch pad question-and-answer session at the Kennedy Space Center March 31 during training before a dress-rehearsal countdown April 1.

As for Scott Kelly's decision to interrupt his own interviews Tuesday, leaving several news organizations with empty slots in their morning talk show schedules, the NASA spokesman cited a similar reluctance to field repeated questions about Giffords.

"He stopped his (interviews) because of the media, despite being requested by both public affairs and by Scott himself to focus on his flight aboard the station and not on his sister-in-law's condition, the media continued to ask question about his family members. Scott decided to opt out of the rest of the interviews."

CBS NEWS Coverage of Breaking Space News

11:40 AM, 03/14/11 Update: Worker killed in launch pad mishap

By WILLIAM HARWOOD
CBS News

A United Space Alliance worker at launch complex 39A, where the shuttle Endeavour is being processed for launch April 19, was killed in a fall early Monday, a NASA spokesman said. An investigation is underway and all work at the pad has been suspended for the rest of the day.

The mishap occurred around 7:40 a.m. EST (GMT-4). Allard Beutel, a NASA spokesman at the Kennedy Space Center, said emergency crews responded but the worker "could not be revived." The family was notified, but no other details were immediately available. The victim was not identified.

Endeavour was hauled to the launch pad late last week for work to ready the ship for launch April 19 on its 25th and final mission. Endeavour's flight, and a final mission by the shuttle Atlantis in late June, are the only missions left on NASA's shuttle manifest as the agency retires the fleet and shifts its focus to developing new commercial launch vehicles.

NASA has been laying off the shuttle contractor workforce in stages as the program's retirement approaches and another round is expected in the next few weeks. NASA managers have praised the workforce in recent weeks for maintaining its focus on safety during a particularly turbulent period.

Endeavour's flight has generated more interest than usual because of commander Mark Kelly's decision to fly with his crew and his hope that his wife, Rep. Gabrielle Giffords, can attend the launching. The Arizona Democrat was shot in the head in January and is recovering in Houston.

CBS NEWS Coverage of Breaking Space News

03:45 PM, 03/11/11 Update: Shuttle Endeavour hauled to launch pad

By WILLIAM HARWOOD
CBS News

With the shuttle Discovery just back from its 39th and final space flight Wednesday, the shuttle Endeavour was hauled to launch pad 39A overnight Thursday for work to ready the ship for blastoff April 19 on its 25th and final voyage.

The 3.2-mile trip from the Vehicle Assembly Building to the ocean-side launch stand began at 7:55 p.m. EST (GMT-5) Thursday. Powerful spotlights illuminated Endeavour as a squat crawler-transporter carried it past hundreds of Kennedy Space Center workers who turned out to witness what should be the orbiter's last trip to the pad.

"Those are the people who have sweated over Endeavour for the last two decades and they are the people who have enabled us to be here tonight," said Gregory H. Johnson, pilot of mission STS-134. "So I was happy to be talking to them and sharing the experience."

Before departing to hitch a brief ride on Endeavour's crawler-transporter, Johnson said he was pleased to see "lots of moms, lots of dads" viewing the shuttle's rollout. "It's an inspiration for me seeing the kids out there," he said.

Endeavour's slow trip to the pad was completed around 3:49 a.m.

Joining Johnson for the 134th shuttle mission will be commander Mark Kelly, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori.

Kelly's wife, Arizona Rep. Gabrielle Giffords, was shot in the head in January and is undergoing therapy at Memorial Hermann-Texas Medical Center in Houston. Kelly told reporters last month that he expected his wife to attend Endeavour's launching and doctors said Friday there is a good chance she will be able to make the trip.

"The goal is for her to witness the launch in April," Dr. Gerard Francisco, the chief medical officer, told reporters Friday.

But a final decision will depend on the progress of her recovery.

"Our number one concern is that it will be safe and appropriate for her to do that," Francisco said. "We are still planning, we have a lot of options we are considering at this point."

NASA managers plan to hold an executive-level flight readiness review on April 8 to assess Endeavour's ground processing and to set an official launch date. The current target is 7:48:53 p.m. on April 19.

The primary goals of the flight are to deliver a $2 billion particle physics experiment to the International Space Station, along with needed supplies, science gear and a pallet of spare parts that will be stored on the lab's power truss. Working in two-man teams, Fincke, Chamitoff and Feustel also plan to carry out four spacewalks to service massive rotating solar array drive mechanisms and to perform a variety of maintenance tasks.

But for Johnson, the most exciting moment likely will be Endeavour's thundering climb to space.

"The ascent is pretty spectacular," he said. "I trained almost 10 years before I got to go on my first space shuttle flight. ... All that simulation didn't prepare me for the spectacle of launch. It was like sensory overload with the light and the sound, you could feel it, you could almost taste it.

"As the space shuttle launched off the pad, I was like a deer staring into the headlights for a second. I said 'wait a second, I'm the pilot, I have a job to do here' and got my wits about me. But it was quite the experience!"

If all goes well, Endeavour's countdown will begin at 8 p.m. on April 16. Assuming an on-time launch, Kelly will guide Endeavour to a docking at the space station's forward port around 4:38 p.m. on April 21. The primary payload, the Alpha Magnetic Spectrometer, will be attached to the right side of the station's power truss the next day.

The day after that -- April 23 -- Feustel and Chamitoff plan to carry out the first of the crew's four planned spacewalks. Feustel and Fincke will stage the next two EVAs on April 25 and 27 followed by a final excursion by Fincke and Chamitoff on April 29.

Endeavour is scheduled to undock from the space station around 9:50 a.m. on May 1. Landing back at the Kennedy Space Center is expected around 2:40 p.m. on May 3.

NASA plans to close out the shuttle program with a final space station resupply flight by the Atlantis. Launch is targeted for June 28.

CBS NEWS Coverage of Breaking Space News

12:45 PM, 02/28/11 Update: Shuttle Endeavour hauled to VAB for March 10 rollout to pad

By WILLIAM HARWOOD
CBS News

With the shuttle Discovery orbiting overhead on its 39th and final flight, the shuttle Endeavour was hauled from its processing hangar to the Kennedy Space Center's Vehicle Assembly Building Monday for attachment to an external tank a set of solid-fuel boosters.

If all goes well, Endeavour will be carried to pad 39A March 10 for work to ready the ship for blastoff April 19 on its 25th and final mission.

The primary goals of the 134th shuttle mission at to deliver a $2 billion particle physics detector to the International Space Station, along with supplies, spare parts and science gear.

Endeavour's external tank has been modified to prevent the sort of cracks in rib-like stringers that grounded Discovery for three-and-a-half months.

Discovery's tank appeared to work well during launch last Thursday and there were no known problems with the repaired stringers near the top of the "intertank" compartment where cracks were found after a Nov. 5 launch scrub.

Several pieces of foam insulation fell from Discovery's tank during the climb to space, but the shedding occurred well after the time when the dense lower atmosphere can cause high impact velocities. Engineers have found no signs of any significant heat shield damage.

The analysis is not yet complete, but it does not appear any additional work will be needed for Endeavour's tank.

If all goes well, the shuttle's primary payload -- the Alpha Magnetic Spectrometer -- will be taken to the launch pad March 24 for installation in Endeavour's cargo bay.

Shuttle commander Mark Kelly, pilot Gregory H. Johnson, Michael Fincke, Roberto Vittori, Andrew Feustel and Gregory Chamitoff plan to strap in for a dress-rehearsal countdown April 1 that will set the stage for launch.

CBS NEWS Coverage of Breaking Space News

12:50 p.m. EST, 2/4/11 Update: Kelly to resume training for April shuttle flight

By WILLIAM HARWOOD
CBS News

Astronaut Mark Kelly will resume training to command the shuttle Endeavour for its final mission in April, NASA announced Friday, rejoining his crew one month after a Tucson shooting spree that left his wife, Rep. Gabrielle Giffords, critically injured with a gunshot wound to the head.

With Giffords undergoing recovery and rehabilitation in Houston, Kelly will rejoin his crew Monday and resume preparations for shuttle mission STS-134, a flight to deliver critical supplies and a $2 billion physics experiment to the International Space Station.

"I am looking forward to rejoining my STS-134 crew members and finishing our training for the mission," Kelly said in a NASA statement. "We have been preparing for more than 18 months, and we will be ready to deliver the Alpha Magnetic Spectrometer to the International Space Station and complete the other objectives of the flight. I appreciate the confidence that my NASA management has in me and the rest of my space shuttle crew."

Whether Kelly could resume training in time for Endeavour's April flight has been an open question for weeks given the severity of Giffords' wound and the demands of her recovery. With Kelly's concurrence, NASA earlier named veteran shuttle commander Frederick Sturckow to train with Endeavour's crew with the understanding that he would fly in Kelly's place if necessary.

Giffords reportedly is making steady progress with rehabilitation in Houston, but NASA's press release did not go into Kelly's reasons for pressing ahead with mission training, saying only that he planned to report to work Monday.

Chief astronaut Peggy Whitson said NASA is "glad to have Mark back."

"He is a veteran shuttle commander and knows well the demands of the job," she said. "We are confident in his ability to successfully lead this mission, and I know I speak for all of NASA in saying 'welcome back'."

Kelly, Whitson and veteran astronaut Brent Jett, director of flight crew operations at the Johnson Space Center, were scheduled to participate in a news conference at 3 p.m. EST Friday to discuss Kelly's decision and upcoming training for the flight.

Endeavour is scheduled for launch on the 134th shuttle mission around 7:48 p.m. EDT on April 19. If all goes well, Kelly and his crewmates -- pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European astronaut Roberto Vittori -- will dock with the space station two days later.

Along with moving the Alpha Magnetic Spectrometer to a permanent mounting pointing point on the station's main power truss, the crew also plans to stage four maintenance spacewalks and deliver critical supplies and equipment.

Assuming an on-time launch, Endeavour will undock from the station May 1 and land back at the Kennedy Space Center the afternoon of May 3.

NASA managers hope to launch the shuttle Atlantis on the shuttle program's final flight around the end of June to deliver a final load of supplies and equipment to the space station. NASA's fiscal 2011 budget includes authorization for the flight and a four-man crew is in early training, but the mission has not yet been funded.

CBS NEWS Coverage of Breaking Space News

01:40 PM, 01/13/11: Backup commander named to replace Kelly in near-term training for April shuttle flight

By WILLIAM HARWOOD
CBS News

Veteran shuttle commander Frederick Sturckow will replace Mark Kelly in near-term training for a flight aboard the shuttle Endeavour in April, NASA announced Thursday. With Kelly's wife, Rep. Gabrielle Giffords, in critical condition in Tucson with a gunshot wound to the head, the substitution will free Kelly to remain at her bedside while ensuring his crewmates complete critical flight training.

NASA officials said Kelly, who endorsed the decision, remains the designated commander of shuttle mission STS-134. Sturckow, a veteran of four previous shuttle missions, will begin training with Endeavour's crew next week.

"I recommended to my management that we take steps now to prepare to complete the mission in my absence, if necessary," Kelly said in a NASA statement. "I am very hopeful that I will be in a position to rejoin my STS-134 crew members to finish our training."

Peggy Whitson, chief of the astronaut office at the Johnson Space Center in Houston, said Kelly "is still the commander of STS-134."

"He is facing many uncertainties now as he supports Gabrielle, and our goal is to allow him to keep his undistracted attention on his family while allowing preparations for the mission to progress. Designating a backup allows the crew and support team to continue training, and enables Mark to focus on his wife’s care."

No shuttle commander has ever been replaced this close to flight. There have, however, been several cases where other crew members were replaced due to illnesses or other issues.

Astronaut David Griggs, scheduled to serve as pilot of shuttle mission STS-33, was replaced after he was killed June 17, 1989, flying a vintage aircraft. Jeff Ashby was replaced as the pilot of STS-85 in 1997 because his wife had terminal cancer. And astronauts Gus Loria and Carlos Noriega were replaced aboard shuttle missions in 2002 and 2004 respectively because of undisclosed medical issues.

Earlier Thursday, NASA managers reviewed processing timelines and signed off on target launch dates for the next two space shuttle missions.

As expected, the agency hopes to launch the shuttle Discovery on mission STS-133, a flight to deliver needed supplies and a cargo storage module to the International Space Station, at 4:50:13 p.m. EST on Feb. 24. That target date assumes engineers complete repairs to structural ribs, or stringers, in the ship's external tank in time to move the shuttle back out to the launch pad around the end of the month.

Assuming an on-time launch, the flight plan calls for Discovery to dock with the space station around 1 p.m. on Feb. 26. Two spacewalks are planned, one on Feb. 28 and another on March 2, before undocking three days later and landing back at the Kennedy Space Center around noon on March 7.

Launch of the shuttle Endeavour on mission STS-134, a flight to deliver a $2 billion physics experiment to the station, is now targeted for liftoff at 7:48:34 p.m. EDT on April 19, setting up a docking two days later. Four spacewalks are planned for April 23, 25, 27 and 29. Landing at the Kennedy Space Center is planned for around 2:30 p.m. on May 3.

Only one additional shuttle flight is planned, a space station resupply mission with Atlantis that currently is targeted for launch June 28. NASA managers hope to fly that mission later in the summer if the budget permits, to leave the station as well supplied as possible before the fleet is retired.

CBS NEWS Coverage of Breaking Space News

5 PM, 1/8/11: Reb. Gabrielle Giffords shot

By WILLIAM HARWOOD
CBS News

Rep. Gabrielle Giffords, 40, an Arizona Democrat married to veteran astronaut Mark Kelly, was shot in the head during a public meeting outside a Tucson supermarket Saturday. More than a dozen bystanders also were shot -- and some reportedly killed, including a 9-year-old child, officials said -- when a lone gunman allegedly opened fire.

Scheduled to command the shuttle Endeavour in April, Kelly immediately flew to Tucson from Houston, MASA officials said. His twin brother Scott, in orbit commanding the International Space Station, was informed of the shooting by flight controllers at the Johnson Space Center.

"She's in critical condition," said Peter Rhee, a surgeon at the University of Arizona trauma center where 10 gunshot victims were taken. "The neurosurgeons have finished operating on her and I can tell you ... I'm very optimistic about recovery."

He said he was optimistic "because she was following commands. She was shot one time, in the head, through and through. I can't tell you right now, obviously, for forensic purposes what direction (the bullet went). But she was shot through and through on one side of the head. It went through her brain."

Asked if he was optimistic about a full recovery, Rhee said "we cannot tell what kind of recovery, but I'm about as optimistic as it can get in this situation."

President Obama said in a statement the shooting was "an unspeakable tragedy."

"While we are continuing to receive information, we know that some have passed away, and that Representative Giffords is gravely wounded," he said. "We do not yet have all the answers. What we do know is that such a senseless and terrible act of violence has no place in a free society. I ask all Americans to join me and Michelle in keeping Representative Giffords, the victims of this tragedy, and their families in our prayers."

The shooting occurred in front of a Safeway supermarket in Tucson where Giffords was hosting an event called "Congress on Your Corner" intended to let members of the 8th Congressional District to meet their congresswoman.

According to The New York Times, a former emergency room doctor who witnessed the shooting said the gunman approached Giffords from behind, "held a gun about a foot from her head and began firing."

"He must have got off 20 rounds," the witness told the Times. The gunman was tackled by bystanders and later was identified as Jared Laughner. Police said he used a pistol with an extended magazine.

Some initial media reports said Giffords was killed, but other officials later said she was alive, in surgery and in critical condition. By 4 p.m., officials were saying she was expected to survive, which Rhee later confirmed.

"I am horrified by the senseless attack on Congresswoman Gabrielle Giffords and members of her staff," said Speaker of the House John Boehner, R-Ohio. "An attack on one who serves is an attack on all who serve. Acts and threats of violence against public officials have no place in our society. Our prayers are with Congresswoman Giffords, her staff, all who were injured, and their families. This is a sad day for our country."

Elected to the House in 2006 and only the third Arizona woman to serve in Congress, Giffords was considered a centrist Blue Dog Democrat and a supporter of the military and immigration control. She is a member of the House Committee on Armed Services, the Committee on Foreign Affairs and the Committee on Science and Technology.

Giffords was unusually accessible and held scores of public meetings, prompting the Arizona Republic to dub her "the Energizer rabbit with a brain." The Washington Post quoted former Labor Secretary Robert Reich as saying "I wouldn't be surprised if she's the first or second female president of the United States. She's of that caliber."

In her capacity as chairwoman of the Subcommittee on Space and Aeronautics, Giffords played a key role in recent debate over NASA's future direction and was widely respected for her thorough knowledge of the issues. She married Kelly, veteran of three shuttle flights, in November 2007.

An ardent supporter of the manned space program, Giffords questioned the Obama administration's decision to scuttle the Constellation moon program, an initiative promoted by President Bush, and the Ares rockets NASA was designing to replace the space shuttle.

The administration's change of course was based in large part on a report by a presidential panel led by aerospace executive Normal Augustine that concluded the Constellation program was not sustainable given realistic budget expectations. The panel supported a shift to commercial launch providers in the near term and development of a new heavy lift rocket for deep space exploration in the long term.

But the Augustine panel also said NASA would need significant additional funding to make any manned space option viable.

Giffords was critical of the Augustine panel's options, saying "I thought we were going to take a hard, cold, sobering look at the Constellation program and tell us exactly what we needed to do here in Congress, with our budget, in order to maximize the chances of success. But that's not what I see."

"Instead of focusing on how to strengthen the exploration program in which we've invested so much time -- four years, billions of dollars -- we have a glancing attention to Constellation, even referring to it in the past tense in your summary report and instead spending the bulk of the time crafting alternative options that do little to illuminate the choices that I think are really confronting the Congress and the White House.

"So where does that leave us? I think in place of a serious review of potential actions that could be taken to strengthen and improve the Constellation program, we've been given a set of alternatives that in some sense look almost like cartoons, lacking detailed costs, schedule, technical, safety, other programmatic specifics that can't be subjected to the rigorous and comprehensive analysis and validation that NASA's required to go over.

"So I guess I'll ask my colleagues on this committee, what are we going to do with this report? I know that we are going to see more details. But in the absence of mismanagement or technological show stoppers ... none of which the Augustine panel has indicated has occurred in this program, can any of us in good conscience recommend canceling the exploration systems development programs that Congress has funded and supported over the past four years?"

Giffords said she did not see "the logic of scrapping what the nation has spent years and billions of dollars to develop."

"And for the nation's sake, I hope we can break this cycle of false starts that was mentioned by many of my colleagues before," she said. "The future of America's human spaceflight is really at risk. And I'm hoping before the panel is dismantled we can get some real, solid numbers ... so we can make the decisions as to what to do with our future in manned spaceflight."

Giffords strongly disagreed with a compromise later put forward by the Senate, and ultimately approved by the administration, that called for an additional shuttle flight and immediate development of a new heavy lift rocket to replace the shuttle. The rocket's specifications are not yet defined.

Speaking on the House floor before a key vote Sept. 30, Giffords said the legislation "lacks serious budgetary discipline" and includes an "unfunded mandate to keep the shuttle program going through all of fiscal year 2011 even after the shuttle is retired, which NASA estimates will cost the agency more than half a billion dollars."

Giffords criticized the proposed heavy lift rocket as a launcher designed "not by our best engineers, but by our colleagues over on the Senate side. By NASA's own internal analysis, they estimate this rocket will cost billions more than the Senate provides."

"In short, the Senate bill forces NASA to build a rocket that doesn't meet its needs, with a budget that's not adequate to do the job and on a schedule that NASA's own analysis says is unrealistic," Giffords said. "That is not my idea of an executable and sustainable human spaceflight program."

CBS NEWS Coverage of Breaking Space News

12:38 PM, 09/28/10 Update: External tank for February shuttle flight arrives at KSC

By WILLIAM HARWOOD
CBS News

External tank No. 122, damaged by Hurricane Katrina, refurbished and slated for use by the shuttle Endeavour in February on what is currently the final planned space shuttle mission, was offloaded from its transport barge at the Kennedy Space Center Tuesday and moved into the Vehicle Assembly Building for processing.

"It's kind of a sentimental day," said Alicia Mendoza, tank and booster vehicle manager at Kennedy. "We're excited to have the tank here and offloaded. It's always such a quick process and gets everybody's adrenaline going. And, at the same, it's kind of sad because it is the last tank.

"It kind of brings home reality that it is the last tank that we will be receiving here at KSC for the shuttle program," she said. "So almost kind of nostalgic. We're not going to really see this again."

The milestone came just three days before more than 1,100 Florida shuttle workers faced layoffs Friday, part of NASA's ongoing push to retire the shuttle program after two, or possibly three, more flights.

As it now stands, only two missions are officially planned. Discovery is scheduled for launch Nov. 1 on a space station resupply mission and Endeavour is targeted for takeoff Feb. 26 to deliver a $2 billion particle physics experiment to the lab complex.

But NASA's fiscal 2011 budget, under debate in Washington, may include funding for a final flight by shuttle Atlantis next June to deliver one last load of supplies and equipment.

NASA already was processing Atlantis for launch on a possible emergency rescue mission in case of a problem that might strand Endeavour's crew in orbit. Four astronauts were named earlier this month to fly the launch-on-need mission, if necessary. If not, NASA wants to turn that mission into an actual flight, relying on Russian Soyuz spacecraft to provide rescue service if Atlantis suffers a major problem that might prevent a safe re-entry.

The solid-fuel boosters needed for the launch-on-need flight were delivered in May and external tank No. 138 was shipped to Florida in July.

At that time, NASA managers intended to launch Endeavour with ET-138 and to use ET-122 with Atlantis. But earlier this month, managers decided to swap tanks, assigning the Katrina-damaged ET-122 to Endeavour and ET-138 to Atlantis.

ET-122 was undergoing post-Columbia processing at Lockheed Martin's Michoud Assembly Facility in New Orleans in 2005 when Hurricane Katrina ripped open the roof above the tank's vertical processing cell. Concrete panels fell into the processing bay, damaging the foam insulation on the upper part of the external tank. But an inspection revealed no structural damage.

In 2008, NASA decided to repair the tank and a team of about workers stripped off and replaced damaged foam. Most of the damage was found on the left side of the tank in the quadrant opposite where the shuttle attaches.

CBS NEWS Coverage of Breaking Space News

9:20 PM, 08/26 Update: $2 billion space station particle detector delivered to Kennedy Space Center

By WILLIAM HARWOOD
CBS News

A $2 billion 7.5-ton physics experiment bound for the International Space Station aboard the last planned shuttle flight in February arrived at the Kennedy Space Center Thursday after a busy summer of work to replace the magnet at the heart of the costly particle detector.

With Nobel laureate Samuel Ting, the lead scientist of the AMS project looking on with shuttle commander Mark Kelly and his crew, an Air Force C-5 transport jet taxied to a stop at the Shuttle Landing Facility after a flight from Geneva where the payload was assembled and tested.

If all goes well, Kelly and his crewmates will blast off Feb. 26 aboard the shuttle Endeavour to deliver the Alpha Magnetic Spectrometer to the International Space Station. Endeavour's flight is the final shuttle mission currently planned, although NASA managers hope to get funding for one final space station resupply mission next June.

"This is our main payload for this mission," Kelly said at the shuttle runway. "It's also, as far as I can tell, the most expensive piece of the space station that will be installed. So it's pretty exciting for us to be part of this crew and part of this mission.

"The space shuttle was designed to build a space station. And it did not get the opportunity to do that for the first 20 years of its life. Over the last 10 years, it's been very successful assembling this very complex laboratory in space. I think it's fitting that on its last assembly mission, which will be our flight, STS-134, the space station is going to be complete."

Kelly promised Ting that his crew planned to do "everything we can to get AMS successfully installed" on the station's main power truss.

"So Sam, I give you our guarantee we're not going to break it!" Kelly said. "It'll get installed on the truss and hopefully be working before we depart."

The Alpha Magnetic Spectrometer, an international project managed by the U.S. Department of Energy, NASA, the European Space Agency, and other government and academic institutions, is designed to study subatomic particles from deep space in search of antimatter and phenomena that might help explain dark matter, the unseen material making up 90 percent of the matter in the known universe.

The trajectories of high energy cosmic ray particles entering the AMS will be deflected by the instrument's intense magnetic field. Scores of detectors will precisely measure such deflections, allowing scientists to figure out the properties of the subatomic particles in question.

"At the moment there was a big bang, there must be equal amounts of matter and antimatter," Ting said. "Now antimatter has been found in accelerators. The question is, is there a universe far, far, far away made out of antimatter? That is one example. The second example is we know 90 percent of the matter in the universe we cannot see. We know it exists. ... This experiment will provide the most sensitive search for the dark matter."

In the wake of the 2003 Columbia disaster and a decision by the Bush administration to complete the International Space Station and retire the shuttle by 2010, the AMS payload was dropped from NASA's manifest in favor of higher-priority space station components.

But supporters of the project never gave up hope and after intense lobbying, the Obama administration agreed to fund an shuttle flight to deliver the AMS to the space station.

"The largest (particle) accelerator on Earth is 16 miles in circumference, the Large Hadron Collider, LHC," Ting told reporters, referring to the new accelerator built by the European Organization for Nuclear Research, or CERN. "In the LHC, there are four big experiments, thousands and thousands of physicists work there trying to understand the beginning of the universe, what is the origin of mass, why different particles have different masses.

"The cost of ISS is about 10 times more than the LHC," Ting said. "The LHC has four experiments. On the space station, to study particle physics, the origin of the universe, only has AMS. And that's why we're very grateful to the United States House of Representatives and the Senate, which passed the resolution to support NASA to have an additional flight to put us in space."

That flight originally was planned for July, but the AMS team decided to replace the cryogenically-cooled magnet at the heart of the device after the Obama administration cleared NASA to operate the space station through at least 2020.

"We had built a superconducting magnet based on the assumption ... that we would be on space station for three years and space station would be deorbited in 2015," Ting said. "So we tested the magnet. The magnet would last 28 (months), plus or minus six months, close to three years.

"But now at the end of last year, we learned space station would go to 2020 and maybe even go to 2028. So after three years, AMS would become a museum piece. And so we quickly decided to change to a permanent magnet."

A less powerful magnet tested during an earlier shuttle flight was pressed into service in place of the superconducting magnet.

"The magnetic field of the permanent magnet from the first flight, it has not changed at all," Ting said. "And so because the permanent magnet has a weaker field, you need to put in more detectors. Since it always had 400 percent redundancy, it was easy for us to put in the detectors.

"Now we have put in more detectors and over the past two weeks we tested extensively in the accelerator at CERN and found the resolution, the sensitivity, is exactly the same as the superconducting magnet."

But the work to swap out the magnets, along with launch conflicts with other station-bound missions, forced NASA to delay Endeavour's flight from July to February.

CBS NEWS Coverage of Breaking Space News

2:20 PM, 7/8/10, Update: External tank for final planned shuttle mission heads to Florida

By WILLIAM HARWOOD
CBS News

The external tank for the final planned shuttle mission was rolled out of Lockheed Martin's Michoud Assembly Facility Thursday to begin the 900-mile voyage to the Kennedy Space Center for launch next February.

Wrapping up 37 years of tank deliveries in support of the shuttle program, Lockheed Martin employees, joined by senior NASA managers, lawmakers and company officials, gathered for a departure ceremony to mark the completion of ET-138. Many of the workers were wearing black T-shirts with the words "Finish Strong" on the back.

"Everyone of you should be proud, as I know you are," said Joanne Maguire, Lockheed Martin executive vice president for space systems. "The accomplishments of the external tank team are the stuff of legend. The challenges and hardships you've overcome have been monumental and our respect for, and gratitude to you, is immeasurable.

"We have two more missions to fly before we bring to a close one of America's most iconic human spaceflight programs. I have every confidence this team will rally together, as they have through thick and thin, to safely and successfully conclude the space shuttle program even as we prepare for what comes next. Whatever that might be. This team is a team we have counted on for decades to do the heavy lifting, figuratively and literally, and it is my firm commitment and hope that we can continue to rely on you going forward."

The tank will travel by barge across the Gulf of Mexico from New Orleans, around the tip of Florida and up the coast to the Kennedy Space Center where it will be prepared for launch Feb. 26 with the shuttle Endeavour.

Sen. David Vitter, a Louisiana Republican, attended the ET-138 rollout and took the opportunity to criticize the Obama administration's post-shuttle space policy, which includes a shift to commercial manned launch operations and a multi-year gap between the shuttle's retirement and the debut of whatever spacecraft replaces it.

"I for one am extremely concerned about those proposals and plans for NASA," Vitter said. "Because quite frankly, if we stay on that radical new path - and it is a radical new plan for NASA - it will mean two things. Here at Michoud, it will turn that gap into a cliff, and I'm fighting to prevent that from happening. And for the nation, I truly think it will give up our leadership in manned spaceflight, probably for the rest of our lifetimes.

"Now, call me old fashioned, but I think NASA should be about space flight," Vitter said, prompting applause. "Call me old fashioned, but I don't want NASA just to be the fourth or the fifth or the sixth climate change research agency. And call me old fashioned, but I certainly don't want its primary purpose to be outreach to Muslim countries to make them feel good about their scientists."

The last comment, loudly cheered by the assembled workers, was a clear dig at NASA Administrator Charles Bolden, who told the Al-Jazeera network last week that President Obama had told him that one of NASA's primary objectives was to "reach out to the Muslim world and engage much more with dominantly Muslim nations to help them feel good about their historic contribution to science, math and engineering."

Vitter concluded his remarks by saying "the good news is there are many folks in Congress, Republicans and Democrats, who feel as I do. So this battle is not over by a long shot."

While Endeavour's flight is the last officially planned shuttle mission, NASA plans to prepare the shuttle Atlantis for launch on a possible rescue flight in case of any major problems with Endeavour that might prevent a safe re-entry.

The tank for the stand-by mission, ET-122, was damaged in Hurricane Katrina, but it has since been repaired and is in the final stages of assembly. Shipment to the Kennedy Space Center is expected in September.

NASA managers are studying the possibility of actually launching Atlantis on a final space station resupply mission if a rescue flight is not needed. By launching the shuttle with a reduced crew of four, Russian Soyuz spacecraft could be used for possible rescue duty, eliminating the need for a second shuttle stand-by mission.

Shuttle program managers are studying cost projections and potential savings to see how far they can stretch current funding. The shuttle program normally costs about $200 million a month to operate and even with projected savings, sources say additional money almost certainly will be required to cover a final mission with Atlantis.

A decision is expected by early August.

CBS NEWS STS-133 STATUS REPORT: 04

2:55 PM, 7/6/10, Update: United Space Alliance announces shuttle layoffs

By WILLIAM HARWOOD
CBS News

With only two shuttle flights remaining on NASA's manifest, prime contractor United Space Alliance plans to lay off about 15 percent of its 8,100-strong space shuttle workforce Oct. 1, company officials announced Tuesday.

Eight hundred to 1,000 jobs will be lost at the Kennedy Space Center in Florida, with another 300 to 400 in Texas and 10 in Alabama. Another 743 USA jobs were lost in two earlier rounds of layoffs.

"Our workforce has known for several years that the space shuttle program has been scheduled to end, but layoffs are always difficult for everyone involved," Virginia Barnes, USA President and chief executive officer, said in a statement. "The accomplishments of this team are unmatched in human spaceflight. We acknowledge the tremendous talent and commitment of our teammates and congratulate them on their achievements."

NASA plans to launch the shuttle Discovery Nov. 1 on a mission to deliver critical supplies and equipment to the International Space Station. The final currently planned flight, using the shuttle Endeavour, is scheduled for launch Feb. 26.

Both of those flights are covered by the shuttle program's current budget and a congressional pledge for an additional $600 million that originally was intended to cover program costs through the end of the calendar year. Shuttle managers now say they can stretch current funding to cover Endeavour's flight in February.

NASA managers are lobbying for a third and final space station resupply mission with the shuttle Atlantis in the June 2011 timeframe. Atlantis is being processed for stand-by duty as an emergency rescue vehicle for Endeavour's crew, but if a rescue flight is not needed, NASA would like to launch Atlantis on a final resupply mission.

By launching Atlantis with a crew of four, NASA would not need a second shuttle for stand-by duty. Instead, a four-person crew could seek safe haven aboard the space station, if necessary, and get back to Earth aboard Russian Soyuz spacecraft.

Shuttle program managers are studying cost projections and potential savings to see how far they can stretch current funding. The shuttle program normally costs about $200 million a month to operate and even with projected savings, sources say additional money almost certainly will be required to cover a final mission with Atlantis.

NASA managers are expected to make a decision in August. A USA spokeswoman said the Atlantis mission, whether it is added or not, will not affect the current round of projected layoffs.

CBS NEWS STS-133 STATUS REPORT: 03

12:25 PM, 7/1/10, Update: Shuttle target dates reset for Nov. 1 and Feb. 26

By WILLIAM HARWOOD
CBS News

After assessing payload processing issues and projected traffic to and from the International Space Station, NASA managers Thursday formally retargeted the program's final two missions for launches Nov. 1 and Feb. 26.

The shuttle Discovery, which had been scheduled for launch Sept. 16 on mission STS-133, is now targeted for liftoff at 4:33 p.m. EDT on Nov. 1. The primary goals of the two-spacewalk mission are to deliver spare parts and supplies, along with a modified cargo transfer module that will be permanently attached to the station to provide additional storage space.

The shuttle Endeavour, which had been targeted for launch around Nov. 26, was reset for takeoff at 4:19 p.m. EST on Feb. 26, 2011. The goal of that mission is to deliver the $1.5 billion Alpha Magnetic Spectrometer to the station, along with a pallet of critical spare parts that will be mounted on the lab's power truss.

NASA managers asked engineers to reassess the launch dates with an official "change request" that went out June 22. At that time, the proposed target dates were Oct. 29 for STS-133 and Feb. 28 for STS-134.

The STS-133 slip was required to complete preparations of critical spares that will be launched in the Permanent Multi-Purpose Module, or PMM, including a pump package, a robotic test article known as "Robonaut" and a heat exchanger. Other hardware required for the Alpha Magnetic Spectrometer and spares for the station's life support system also were on tight schedules.

Two Russian launches planned for October forced NASA to consider the Oct. 29 target. Then, during the review process, planners realized the target date was in conflict with an already scheduled air show and maintenance planned at the Air Force Range that provides tracking and telemetry support for all rockets launched from Florida. As a result, agency managers settled on Nov. 1.

Assuming the schedule holds up, commander Steven Lindsey pilot Eric Boe, station veterans Nicole Stott and Michael Barratt and spacewalkers Alvin Drew and Timothy Kopra, another station veteran, will blast off from pad 39A at 4:33 p.m. on Nov. 1. Docking with the International Space Station would be expected around 12:52 p.m. on Nov. 3.

The PMM would be installed on Nov. 4, followed by spacewalks with Kopra and Drew on Nov. 5 and 7. Undocking would be targeted for 7:13 a.m. on Nov. 10 with landing back at the Kennedy Space Center on tap around 12 p.m. Friday, Nov. 12.

Endeavour's launching on mission STS-134 originally was scheduled for July, but the flight was delayed to late November after a decision to replace the magnet at the heart of the Alpha Magnetic Spectrometer. The AMS payload will not be delivered to the Florida space center until late August and three months of on-site processing are required before launch.

A late-November/early December launch was ruled out because of conflicts with other planned station launches. Temperature constraints related to the station's orbit prevented a launch in January and range conflicts with other unmanned missions pushed the approved launch date to Feb. 26.

Endeavour will be commanded by veteran Mark Kelly. His crewmates are pilot Gregory Johnson, Hubble veteran Andrew Feustel, European Space Agency astronaut Roberto Vittori and station veterans Gregory Chamitoff and Mike Fincke.

NASA originally planned to end shuttle operations by the end of fiscal 2010, launching Endeavour in July followed by Discovery in mid September. But Congress already had promised an additional $600 million to cover shuttle costs through the end of the calendar year to avoid the sort of schedule pressure blamed in part for the Challenger and Columbia mishaps.

NASA managers then came up with additional savings, permitting operations through February or March without additional appropriations.

The shuttle Atlantis is being processed to serve as an emergency rescue vehicle for Endeavour's crew. But if a rescue flight is not needed, NASA managers believe the standby shuttle could be launched with a crew of four, relying on Russian Soyuz capsules to ferry the crew members home if a major problem blocked a safe re-entry.

Concerned about the near-term lack of a large rocket to deliver heavy payloads after the shuttle fleet is retired, NASA managers want to take advantage of the boosters and external tank being prepared for Atlantis' rescue mission that otherwise would go to waste.

But additional funding would be required and it's not yet clear whether NASA has the necessary political support. A decision is expected in August.

CBS NEWS STS-133 STATUS REPORT: 02

5:55 PM, 6/22/10, Update: NASA begins two-week review of proposed shuttle launch date changes

By WILLIAM HARWOOD
CBS News

NASA managers Tuesday asked shuttle engineers to assess retargeting the final two space shuttle missions, moving launch of a mid-September flight with Discovery to Oct. 29 and a late November flight by Endeavour to Feb. 28. The changes would give engineers more time to optimize payloads bound for the International Space Station and avoid launch conflicts with other flights to the lab complex.

The status of a proposed final fight of the shuttle Atlantis next June to deliver a final load of supplies and equipment remains unresolved. Bill Gerstenmaier, director of space operations at NASA headquarters, said earlier this year he hoped to have a decision by the end of this month, but officials said Tuesday the discussion had been deferred to the August timeframe.

A decision on delaying the next two missions, however, is expected July 1, after a two-week review.

Assuming an Oct. 29 target date, Discovery would blast off at 5:44 p.m. and dock with the station the afternoon of Oct. 31. Two spacewalks would be carried out Nov. 2 and 4. Discovery would undock the morning of Nov. 7 and land back at the Kennedy Space Center the afternoon of Nov. 9.

Shuttle mission STS-133 will be commanded by former chief astronaut Steven Lindsey. His crewmates are pilot Eric Boe, station veterans Nicole Stott and Michael Barratt and spacewalkers Alvin Drew and Timothy Kopra, another station veteran.

Endeavour, commanded by Mark Kelly, would blast off around 5:31 p.m. on Feb. 28 to deliver critical supplies and a $1.5 billion physics experiment to the space station. Joining Kelly for mission STS-134 will be pilot Gregory Johnson, Hubble veteran Andrew Feustel, European Space Agency astronaut Roberto Vittori and station veterans Gregory Chamitoff and Mike Fincke.

NASA originally planned to end shuttle operations by the end of fiscal 2010, launching Endeavour in July and Discovery in mid September. But problems with the Alpha Magnetic Spectrometer scheduled for launch aboard Endeavour forced program managers to delay the July flight to the end of November.

Congress earlier promised an additional $600 million to cover shuttle costs through the end of the calendar year to avoid the sort of schedule pressure blamed in part for the Challenger and Columbia mishaps.

NASA managers then came up with additional savings, permitting operations through February or March without additional appropriations. Delaying Discovery to late October and Endeavour to late February will give engineers more time to optimize the equipment and spare parts being launched to the station.

Atlantis is being processed to serve as an emergency rescue vehicle for Endeavour's crew. But if a rescue flight is not needed, NASA managers believe the standby shuttle could be launched with a crew of four, relying on Russian Soyuz capsules to ferry the crew members home if a major problem blocked a safe re-entry.

Concerned about the near-term lack of a large rocket to deliver heavy payloads after the shuttle fleet is retired, NASA managers want to take advantage of the boosters and external tank being prepared for Atlantis' rescue mission that otherwise would go to waste.

But additional funding would be required and it's not yet clear whether NASA has the necessary political support.