Two spacewalks later, an equipment malfunction on the outside of the International Space Station (ISS) has been fixed.

The faulty pump module, located on the truss - or backbone - of the station, stopped working Dec. 11 after reaching a preset temperature limit. The module controls the flow of ammonia through cooling loops and radiators on the outside of the orbiting lab, removing excess heat as the station orbits the Earth - an orbit that brings with it a 400 degree Fahrenheit fluctuation.

Shortly after the pump module stopped working, NASA officials issued a statement saying that both the crew and station were in stable condition and not in any immediately danger. However, the glitch did "remove redundancy, which could make a second failure a far more serious concern."

ISS Mission Operations Integration Manager Kenny Todd said in a statement Dec. 12: "Everything we can do is being done. The system is good and stable. The crew is in good shape. All the right folks on the ground are looking at the problem and trying to assess exactly what the root cause is and what our options are to continue moving forward."

Flight engineers Mike Hopkins and Rick Mastracchio, both from NASA, removed the pump module Dec. 22 during a spacewalk that lasted more than 5 hours. Two days later, the duo retrieved a replacement from an external storage unit and installed it during a more than 7-hour spacewalk. Flight controllers in the Mission Control Center at NASA's Johnson Space Center restarted the new pump that same night.

Despite the new module being fully functional, the system will need time to finish reintegrating both it and the loop it's tied to. During this time, electrical systems that normally depend on it will be either powered back up or moved from their place of temporary support on a second loop. This process is expected to last well into the weekend.

The broken piece of equipment, meanwhile, has been moved into storage where it can remain indefinitely.