Shuttle Discovery prepped for final landing
By WILLIAM HARWOOD
CBS News
KENNEDY SPACE CENTER, FL--With no technical problems and windy but acceptable weather expected, the Discovery astronauts are preparing the veteran spaceplane for its 39th and final re-entry Wednesday to close out an extended space station assembly mission.
Commander Steven Lindsey, and his five crewmates -- pilot Eric Boe, entry flight engineer Nicole Stott, Michael Barratt and spacewalkers Stephen Bowen and Alvin Drew -- have two landing opportunities on successive orbits, the first at 11:57 a.m. EST (GMT-5) and the second at 1:34 p.m.
The Spaceflight Meteorology Group at the Johnson Space Center is predicting scattered clouds at 3,000 and 20,000 feet and winds out of 130 degrees at 15 knots with gusts to 23 knots. That translates into a 21-knot headwind on runway 15, 4 knots below NASA's safety limit.
"Winds will be the only thing that are significant in the forecast right now, 130 at 15, peaking at 23," astronaut Charles "Scorch" Hobaugh radioed the crew from mission control. "That gives you a 10-knot cross and a 21-knot headwind. So right now, the weather looks great."
"OK, copy all those words, Scorch," Lindsey replied. "Thanks."
The astronauts plan to close Discovery's cargo bay doors around 8:12 a.m. If the forecast holds up, Lindsey and Boe will shoot for the first landing opportunity, firing the shuttle's orbital maneuvering system braking rockets at 10:52 a.m. for two minutes an 36 seconds to slow the ship by about 194 mph and drop out of orbit for the long glide home.
After a half-hour free fall, Discovery will slip into the discernible atmosphere at an altitude of 76 miles above the south Pacific Ocean at 11:25 a.m., following a northeasterly trajectory back to Florida. The orbiter will pass above Central America and just west of Cuba before crossing the Florida coast near Sarasota.
Lindsey will take over manual control as Discovery nears the Kennedy Space Center and drops below the speed of sound at an altitude of about 50,000 feet. Guiding Discovery through a 252-degree left turn, Lindsey will line up for a steep 21-degree descent to runway 15 where ground crews and NASA managers will be waiting to welcome the astronauts back to Earth.
NASA is not staffing its backup landing sites in California and New Mexico. If the weather or technical problems prevent a re-entry Wednesday, the astronauts will remain in orbit an additional 24 hours and land Thursday, on one coast or the other.
Here are timelines for both Wednesday landing opportunities (in EST):
CBS News
KENNEDY SPACE CENTER, FL--With no technical problems and windy but acceptable weather expected, the Discovery astronauts are preparing the veteran spaceplane for its 39th and final re-entry Wednesday to close out an extended space station assembly mission.
Commander Steven Lindsey, and his five crewmates -- pilot Eric Boe, entry flight engineer Nicole Stott, Michael Barratt and spacewalkers Stephen Bowen and Alvin Drew -- have two landing opportunities on successive orbits, the first at 11:57 a.m. EST (GMT-5) and the second at 1:34 p.m.
The Spaceflight Meteorology Group at the Johnson Space Center is predicting scattered clouds at 3,000 and 20,000 feet and winds out of 130 degrees at 15 knots with gusts to 23 knots. That translates into a 21-knot headwind on runway 15, 4 knots below NASA's safety limit.
"Winds will be the only thing that are significant in the forecast right now, 130 at 15, peaking at 23," astronaut Charles "Scorch" Hobaugh radioed the crew from mission control. "That gives you a 10-knot cross and a 21-knot headwind. So right now, the weather looks great."
"OK, copy all those words, Scorch," Lindsey replied. "Thanks."
The astronauts plan to close Discovery's cargo bay doors around 8:12 a.m. If the forecast holds up, Lindsey and Boe will shoot for the first landing opportunity, firing the shuttle's orbital maneuvering system braking rockets at 10:52 a.m. for two minutes an 36 seconds to slow the ship by about 194 mph and drop out of orbit for the long glide home.
After a half-hour free fall, Discovery will slip into the discernible atmosphere at an altitude of 76 miles above the south Pacific Ocean at 11:25 a.m., following a northeasterly trajectory back to Florida. The orbiter will pass above Central America and just west of Cuba before crossing the Florida coast near Sarasota.
Lindsey will take over manual control as Discovery nears the Kennedy Space Center and drops below the speed of sound at an altitude of about 50,000 feet. Guiding Discovery through a 252-degree left turn, Lindsey will line up for a steep 21-degree descent to runway 15 where ground crews and NASA managers will be waiting to welcome the astronauts back to Earth.
NASA is not staffing its backup landing sites in California and New Mexico. If the weather or technical problems prevent a re-entry Wednesday, the astronauts will remain in orbit an additional 24 hours and land Thursday, on one coast or the other.
Here are timelines for both Wednesday landing opportunities (in EST):
Orbit 202 ground tracks to Kennedy Space Center (Credit: NASA)
Orbit 202 descent to KSC
EST...........EVENT
06:52 AM......Begin deorbit timeline
07:07 AM......Radiator stow
07:17 AM......Astronaut seat installation
07:23 AM......Computers set for deorbit prep
07:27 AM......Hydraulic system configuration
07:52 AM......Flash evaporator cooling system checks
07:58 AM......Final payload deactivation
08:12 AM......Payload bay doors closed
08:22 AM......Mission control 'go' for OPS-3 entry software
08:32 AM......OPS-3 transition
08:57 AM......Entry switch list verification
09:07 AM......Deorbit maneuver update
09:12 AM......Crew entry review
09:27 AM......Commander/pilot don entry suits
09:44 AM......Inertial measurement unit alignment
09:52 AM......Commander/pilot strap in; others suit up
10:09 AM......Shuttle steering check
10:12 AM......Hydraulic system prestart
10:19 AM......Toilet deactivation
10:32 AM......Mission control center 'go' for deorbit burn
10:38 AM......Mission specialists seat ingress
10:47 AM......Single hydraulic power unit start
10:52:09 AM...Deorbit ignition (altitude: 221 miles)
10:54:40 AM...Deorbit burn complete (dT: 02:36; dV: 194 mph
11:25:57 AM...Entry interface (altitude: 76 miles)
11:30:48 AM...1st roll command to right
11:38:04 AM...1st roll right to left
12:44:00 AM...C-band radar acquisition
11:51:11 AM...Velocity less than mach 2.5 (altitude: 83,600 feet)
11:53:23 AM...Velocity less than mach 1 (altitude: 50,900 feet)
11:54:13 AM...252-degree left turn to runway 15 (altitude: 38,800 feet)
11:57:44 AM...Landing
Orbit 203 ground tracks to Kennedy Space Center (Credit: NASA)
Orbit 203 Deorbit to KSC
Deorbit dT: 02:31
Deorbit dV: 188 mph
EST...........EVENT
12:09 PM......MCC 'go' for deorbit burn
12:15 PM......MS seat ingress
12:24 PM......Single APU start
12:29:24 PM...Deorbit ignition (altitude: 223 miles)
12:32:00 PM...Deorbit burn complete (dT: 02:36; dV: 194 mph)
01:01:58 PM...Entry interface (altitude: 76 miles)
01:06:47 PM...1st roll command to right
01:21:10 PM...C-band radar acquisition
01:23:53 PM...1st right to left roll reversal
01:27:34 PM...Velocity less than mach 2.5 (altitude: 84,300 feet)
01:29:43 PM...Velocity less than mach 1 (altitude: 52,700 feet)
01:29:55 PM...328-degree left turn to runway 15 (altitude 50,000 feet)
01:34:10 PM...Landing
