NASA has confirmed two astronauts have successfully replaced a malfunctioning external cooling pump, which is now restarted and running, on the International Space Station (ISS).
According to a NASA news release, the new cooling pump was fully functional and being used in the ISS' system Wednesday. The pump was located on the "truss," or backbone, of the ISS.
"Flight controllers in the Mission Control Center at NASA's Johnson Space Center in Houston successfully restarted the new pump Tuesday night," according to the release.
Rick Mastracchio and Michael Hopkins performed spacewalks on Dec. 21 and Dec. 24, but did not need a third one, tentatively scheduled for Thursday.
The cooling loop, one of two, malfunctioned about two weeks ago. Although the backup cooling loop was functional, NASA said repairs for the primary one were urgent, but not immediately threatening to the astronauts aboard. NASA then scheduled a series of spacewalks to repair the malfunctioned pump.
Mastracchio and Hopkins performed their first spacewalk Dec. 21 and completed their tasks well ahead of schedule, but ran into a suit issue that delayed their next mission. They performed their second and final spacewalk Dec. 24, repairing the pump that was fully operational by the next day.
According to NASA's news release, "The pump module controls the flow of ammonia through cooling loops and radiators outside the space station, and, combined with water-based cooling loops inside the station, removes excess heat into the vacuum of space."
Two weeks ago, the pump automatically shut down when it had reached a pre-set temperature limit. Mastracchio and Hopkins found the pump to be degraded and in need of a replacement. They removed it on the first spacewalk and installed the spare on the second.
NASA reported that electrical systems that normally run on cooling loop A, the one that malfunctioned, have been running on loop B. Over the weekend, they will gradually switch back to loop A.
