Discovery astronauts Al Drew and Steve Bowen suited up early Feb. 28 for a six to seven hour spacewalk outside the International Space Station.
NASA's Steve Bowen suits up for a spacewalk with help from European Space Agency astronaut Paulo Nespoli, left, and NASA's Mike Barratt, foreground. Photo Credit/NASA TV
During the outing, which was scheduled to get under way shortly after 11 a.m., EST, the two men will retrieve a failed thermal control system pump. The bulky pump was left on the station's inboard starboard solar power system truss, following a July 31 failure.
The pump was replaced in early August with a spare by spacewalking station astronauts Doug Wheelock and Tracy Caldwell Dyson. Drew and Bowen plan to move the 780-pound pump to a storage platform on the station's airlock. There, it will be stowed until it can be returned on board NASA's hoped-for STS-135 mission, using Atlantis, over the summer.
Once on the ground, the pump will undergo a failure analysis.
Without a fully-functioning thermal control system, the station cannot sustain a full time six person crew, or the many science experiments that are planned.
Discovery’s crew docked with the station on Feb 26, two days after lifting off. The six shuttle astronauts will remain at the orbital outpost for seven to eight days.