Discovery spacewalker Steve Bowen , center, works outside the International Space Station from the outstretched Canadian robot arm. Photo Credit/NASA
Discovery spacewalkers Steve Bowen and Al Drew marched through a long list of maintenance tasks outside the International Space Station on Wednesday, adding to the unfolding success of the storied shuttle orbiter’s final flight.
They vented a failed thermal control system circulation pump that NASA’s station managers hope to return to Earth this summer aboard Atlantis.
Bowen and Drew retrieved the 780 pound pump from the station’s right side solar power system truss during Monday’s spacewalk. The pump assembly broke down on July 31, creating a temporary power shortage aboard the orbiting science lab.
The motor assembly contained a small amount of hazardous ammonia coolant that was vented prior to a possible trip back to Earth.
The spacewalkers devoted the remainder of Wednesday’s 6 ½ hour spacewalk to a range of maintenance tasks. They installed a video camera on DEXTRE, the Canadian robot hand, and external lighting on a tool cart. They adjusted insulation in several locations, collected tool bags and carried out some troubleshooting on a loose radiator support beam.
Inside the station, Discovery’s Nicole Stott, Mike Barratt and Steve Lindsey coordinated the spacewalk timeline and shared operation of the station’s robot arm.
Meanwhile, the station’s six U. S., Russian and Italian astronauts continued their efforts to off load much of the five tons of cargo delivered by Discovery.
Discovery lifted off for a 39th and final time on Feb. 24.
Since docking with the station two days later, the astronauts have transferred an equipment storage module and an external spare parts rack to the station.