Failed Coolant Pump Stowed In Shuttle

A failed cooling system pump is now nestled in the cargo bay of shuttle Atlantis, ready for a return to Earth and a root-cause failure analysis deemed important to the long-term health of the International Space Station.

Space station astronauts Mike Fossum and Ron Garan bolted the pump to a girder in the back of the Atlantis payload bay about two hours and 15 minutes after the start of the final shuttle-era spacewalk -- the 160th performed in the assembly and maintenance of the $100 billion orbiting outpost.

"The pump module is part of Atlantis for the ride home," NASA Flight Commentator Rob Navias said.

The ammonia pump failed last July 31, knocking out half of the cooling capacity on the U.S. side of the International Space Station. The system is key to quelling heat generated by the operation of space station systems and science experiments.

Three spacewalks were required to removed and replace the fail pump. Engineers on Earth want to examine the pump, determine the root cause of the failure and refurbish the pump for a future return to the outpost. Three spares are current stowed on the station.

The astronauts now are removing an experiment package from the same cargo bay girder. The robotic refueling demonstration kit will be moved to an equipment pallet where the two-armed Canadian robot Dextre can work with it after the departure next week of the Atlantis astronauts.

Fossum will climb aboard the station's robot arm and take hold of the bulky experiment package. Then arm operator Sandra Magnus will hoist him up to the platform. Garan will climb hand-over-over up to Dextre, which is anchored on the outside of the U.S. Destiny lab. Then the two will work together to bolt the technology demonstration kit to the platform.

The spacewalk began about 40 minutes late, but Fossum and Garan now are back on schedule. The excursion is slated to last about another four hours.