JOHNSON SPACE CENTER, TX - During a grueling 7 and a half hour spacewalk, Discovery Mission Specialists Rick Mastracchio and Clayton Anderson successfully installed a 1,700-pound ammonia tank on the International Space Station, completing the second of a three-spacewalk coolant tank replacement process that began with the mission's first EVA Friday morning.
STS-131 PHOTO GALLERIES VIDEO FLIGHT DAY SIX EDUCATIONAL EVENT WATCH | DOWNLOAD EVA 2 OVERVIEW WATCH | DOWNLOAD FLIGHT DAY SIX HIGHLIGHTS WATCH | DOWNLOAD FLIGHT DAY SIX ISS FLIGHT DIRECTOR UPDATE WATCH | DOWNLOAD FLIGHT DAY SIX MEDIA INTERVIEWS WATCH | DOWNLOAD FLIGHT DAY SIX MISSION STATUS BRIEFING WATCH | DOWNLOAD FLIGHT DAY SEVEN CREW CHOICE DOWNLINK VIDEO WATCH | DOWNLOAD FLIGHT DAY SEVEN HIGHLIGHTS WATCH | DOWNLOAD ISS/DISCOVERY FLYOVER OF HOUSTON WATCH | DOWNLOAD FLIGHT DAY SEVEN ISS FLIGHT DIRECTOR UPDATE WATCH | DOWNLOAD FLIGHT DAY SEVEN MISSION STATUS BRIEFING WATCH | DOWNLOAD SOLID ROCKET BOOSTER CAMERA REPLAYS WATCH | DOWNLOAD ALL-ACCESS MEMBERS ONLY VIDEO NASA TV COVERAGE OF EVA #2, 1.2 MBPS, PART 1 DOWNLOAD NASA TV COVERAGE OF EVA #2, 1.2 MBPS, PART 2 DOWNLOAD NASA TV COVERAGE OF EVA #2, 1.2 MBPS, PART 3 DOWNLOAD NASA TV COVERAGE OF EVA #2, 1.2 MBPS, PART 4 DOWNLOAD NASA TV COVERAGE OF EVA #2, 1.2 MBPS, PART 5 DOWNLOAD NASA TV COVERAGE OF EVA #2, 1.2 MBPS, PART 6 DOWNLOAD NASA TV COVERAGE OF EVA #2, 1.2 MBPS, PART 7 DOWNLOAD NASA TV COVERAGE OF EVA #2, 1.2 MBPS, PART 8 DOWNLOAD NASA TV COVERAGE OF EVA #2, 1.2 MBPS, PART 9 DOWNLOAD NASA TV COVERAGE OF EVA #2, 1.2 MBPS, PART 10 DOWNLOAD NASA TV COVERAGE OF EVA #2, 1.2 MBPS, PART 11 DOWNLOAD NASA TV COVERAGE OF EVA #2, 1.2 MBPS, PART 12 DOWNLOAD The 7-hour, 26-minute spacewalk, began at 12:30 a.m. CDT, about 45 minutes ahead of schedule. The first task was to unhook and remove the depleted ammonia tank from the station's starboard truss in preparation for its eventual placement in Discovery's payload bay and return to Earth. Mission Specialist Stephanie Wilson and Pilot James P. Dutton Jr. used the station's robot arm Canadarm2 to move the empty tank to one of the mobile equipment carts on the tracks of the truss. There the spacewalkers temporarily stowed it until the third spacewalk Tuesday when it will be moved to Discovery's payload bay. The spent tank will be refurbished for delivery back to the station as a spare on the STS-134 mission in July. The next task was the retrieval of the new ammonia tank assembly (ATA) from its temporary parking spot on the Quest airlock where it had been left during the first spacewalk Friday. It was at this point that Mastracchio and Anderson, attempting to secure the tank to its new location, encountered the only real difficulty of the spacewalk. It took an hour and a half to get the four botls on the tank to line up and torque the proper amount. Finally, the tank was in place and the power connections hooked up to keep the assembly alive and properly conditioned. However, because of the balky bolt delay, connection of the tank's fluid lines was postponed until the Tuesday spacewalk. Scheduled retrieval of debris shields also was postponed. Instead, the astronauts stowed them temporarily on outside the station for retrieval either during the mission's third spacewalk or during a future EVA. With help from Mission Specialist Dorothy Metcalf-Lindenburger, the spacewalk co-ordinator, Mastracchio and Anderson also installed two radiator grapple fixture stowage beams on the P1 Truss. The stowage beams will stow handles that could be used if replacement of a radiator became necessary. Expedition flight engineer Tracy Caldwell-Dyson supported the spacewalkers as the intravehicular (IV) crewmember, including assisting with campout, hygiene break, EMU assistance, hatch closure & leak check. In spite of the bolt difficulties, Mastracchio and Anderson were able to complete most of the tasks scheduled for EVA #2. They transferred the spent ATA to the CETA cart (short for Crew & Equipment Translation Aid) and then stowed the old ATA on the POA (Payload ORU Accommodation). They also successfully attached the new ATA structurally (using 4 bolts) on the S1 truss and mated electrical connectors to the new ATA to apply heater power. Some tasks had to be deferred to a later spacewalk, either during STS-131 or during a future shuttle or station EVA. The most important task that was put off is mating the ammonia tank fluid quick disconnects for NH3 (ammonia) & N2 (nitrogen) on the new ATA, thereby making the new tank a functional part of the station's cooling system. The retrieval of airlock micrometeoroid/orbital debris (MMOD) shields from ESP-2 (External Stowage Platform 2), and relocating a adjustable portable foot restraint(APFR) to the CETA cart were also deferred until later. One more spacewalk remains on tap for STS-131, taking place on Flight Day 9. Tuesday's spacewalk, also by Mastracchio and Anderson, is the last planned for Discovery's mission to the station. It is to begin at 2:11 a.m. and last about 61/2 hours. In addition to relocating the old tank to Discovery's payload bay for return home, the final spacewalk includes retrieval of a light-weight adapter plate assembly from the Columbus module and securing it in the cargo bay, replacing a camera light on the Destiny laboratory, installing two more radiator grapple fixture stowage beams and installing a camera on Dextre, the Special Purpose Dexterous Manipulator. Today's was the 142nd spacewalk for station construction and maintenance. It was the fifth for each astronaut bringing Mastracchio's total spacewalking time to 32 hours, 6 minutes and Anderson's to 32 hours and 4 minutes. (The Spacearium / SpaceflightNews.net)
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