NASA noted on December 24, 2013 that the replacement cooling pump on the International Space Station is working nominally. The previous pump had failed, resulting in a five and a half hour spacewalk in Dec 22 to remove it and then a seven and a half hour spacewalk on Dec 24, Christmas Eve, to replace it with a new pump.
“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.”
Commands were sent from Mission Control in Houston to start the new pump. Systems that had been taken offline when the old pump failed are starting to be reactivated, a process that will take several days.
The two spacewalks highlights one of the little mentioned purposes of the ISS, which is to provide a place for astronauts to learn to live and work in space. That involves doing these kinds of repairs. The New York Times also noted that a little bit of ingenuity was involved to make certain that an accident that almost drowned a space walking astronaut in July during which water filled his helmet by creating a makeshift snorkel.
This kind of McGyvering is nothing new in the U.S. space program. The crew of Apollo 13 was obliged to find a way to literally stick a square peg in a round hole to fix a problem buildup of carbon dioxide with just the materials at hand. It is the sort of skill that will become even more necessary for deep space missions, lasting months or even years beyond the reach of help from Earth.