Astronauts prep for first spacewalk
05/20/2011 12:49 AM Filed in: STS EVA | STS-134 | Space News | Space Shuttle | International Space Station
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, EV-3, 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):
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.
 |
| The shuttle Endeavour early Friday during work to prepare for the crew's first spacewalk. (Credit: NASA TV) |
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.
 |
| Shuttle commander Mark Kelly helps prepare the spacesuits that will be used by Andrew Feustel and Gregory Chamitoff during a planned six-and-a-half-hour spacewalk. (Credit: NASA TV) |
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)