Astronauts aboard the International Space Station (ISS) spent their Christmas Eve conducting a rare space walk to swap out a failing part in the craft's cooling system.

The pump was successfully restarted Tuesday night, a NASA news release reported.

The damaged piece was a pump module, which "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," NASA reported.

The astronauts removed the degraded pump module during a Dec. 22 spacewalk that took five hours and 28 minutes to complete. The new piece was retrieved and replaced during a seven and a half hour spacewalk that took place on Christmas Eve, Dec. 24.

The cooling problem aboard the ISS started about two weeks ago and NASA had all nonessential functions of the craft shut down; the agency holds that the six astronauts on board were never in any danger, the Wall Street Journal reported.

NASA suspected a manufacturing glitch since the pump module was only three years old.

"it's like Christmas morning opening up a little present here," astronaut Rick Mastracchio said while looking through his tool box during the spacewalk, the Wall Street Journal reported. Mike Hopkins also worked to replace the part during the spacewalk while Japanese ISS inhabitant Koichi Wakata worked a robotic arm from the inside of the ship that helped move the 780-pound pump.

Now that the cooling system problem has been fixed, the ISS astronauts plan to participate in some Christmas festivities. The ISS is decorated for the holiday, and the crew plans to spend time speaking with their families, Space.com reported.

"Of course, all six of us will get together and have a special meal, and everyone will pull out whatever special foods we have that are appropriate for the holidays," Mastracchio said, Space.com reported. "And we'll just spend time together as a crew and good friends, enjoying each other's company."

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