Assisted by space station robotic arm drivers Scott Kelly and Mike Barratt, spacewalkers Steve Bowen and Alvin Drew attached an 800-pound ammonia pump module to External Stowage Platform 2 on the outside of the Quest airlock. The failed pump module will remain there until it can be brought back to Earth for engineering analysis at a future date. The spacewalkers also installed a tool to safely vent the remaining ammonia from the pump module into space.
The pump module failed in July 2010 and was removed from its original truss location during an Aug. 11, 2010, spacewalk by Doug Wheelock and Tracy Caldwell-Dyson. It had been temporarily stored on the mobile base system payload orbital replacement unit accommodation (POA) for about 6.5 months.