"Sweet" news on station: spare coolant pump is healthy

A new coolant pump spacewalkers installed this morning outside the International Space Station is working fine, NASA mission controllers reported.

"Oh sweet, that's awesome news," lead spacewalker Doug Wheelock radioed.

Wheelock and partner Tracy Caldwell Dyson were about three hours into their spacewalk when Mission Control's thermal systems officer confirmed that the ammonia pump's pressures were good and a drive shaft spun properly during a brief "bump test."

The pump is a spare that had been resting on a platform outside the station for four years before being installed and turned on.

But the spacewalkers' repairs are not complete. Wheelock now is beginning to mate four fluid lines that will allow ammonia to flow from a tank to the pump.

The first step is to disconnect two lines from a temporary jumper box (left) attached on an earlier spacewalk to maintain proper pressure while the failed pump was being removed.

If all goes well, NASA hopes to have the coolant loop serving the station's starboard side back up and running normally by Thursday. For now only one loop, on the port side, is active, so systems are turned off to prevent overheating.