Spacewalker Steve Bowen, center, secures a broken pump motor to the space station's airlock while perched on the robot arm. Al Drew, lower right, looks on. Photo Credit/NASA TV
Discovery astronauts Steve Bowen and Al Drew successfully relocated a bulky thermal control system pump motor outside the International Space Station on Monday, during the first of two spacewalks they plan this week.
The 780 pound pump, which circulates a liquid coolant, stopped working on July 31.
NASA would like to return the pump to Earth for a failure analysis aboard the shuttle Atlantis, which is currently planned to conduct the last flight of the shuttle program. The mission is tentatively scheduled for late June.
Without sufficient external cooling, the station cannot generate the solar power required to sustain a fulltime crew of six on the station or scientific research. Station engineers are concerned spare pumps already on the station may be prone to a similar failure.
The bad pump motor was replaced with an on board spare during a series of hastily planned spacewalks in early August that limited the disruption of regular station operations to several days.
The broken pump was left at the worksite until it could be retrieved.
Bowen and Drew relocated the pump to an external storage platform on the station’s airlock. Bowen shouldered the broken pump while riding the tip of the station’ robot arm.
“Very nice work with that,” Discovery crew mate Nicole Stott, who choreographed the work from inside the station, told the two men, as they neared the end of the four hour task.
Before the spacewalk ended, Bowen and Drew planned to open a metal canister supplied by the Japanese Aerospace Exploration Agency as part of an educational project called Message in a Bottle. After “filling” the bottle with the vacuum of space, they will close the container, which is inscribed with the signatures of astronauts. The container will become part of a traveling display.
The spacewalkers will return to the pump during a second spacewalk on Wednesday to vent the device of residual ammonia coolant.
Discovery’s six astronauts docked with the space station on Saturday for seven to eight days of assembly activities, cargo transfers and external maintenance.
Soon after the linkup, the shuttle crew moved an external spare parts rack from Discovery’s payload bay to the station.
On Tuesday, they plan to use the station’s robot arm to extract a 21-foot-long equipment storage module from Discovery’s cargo bay and move it to the station’s Unity module.
Fashioned from the 10-year-old, Italian-buiilt Leonardo transfer module, the new storage compartment will hold research equipment and other supplies.