While many people may spend Christmas Eve doing last-minute gift shopping, two American astronauts have a more challenging matter to attend to Tuesday.


In orbit more than 200 miles above the planet, Flight Engineers Rick Mastracchio and Mike Hopkins are set to embark on a spacewalk to repair part of the International Space Station's cooling system.

It will be the second Christmas Eve spacewalk in history, according to NASA.

The two engineers will be carrying out the second in a series of expeditions needed to replace a malfunctioning pump, which circulates ammonia through loops outside the station to keep equipment cool.

The pump developed problems December 11, when an internal valve stuck in an incorrect position. The space station's life support system remains up and running, but operations were cut back as a result of the failure, NASA said.

The two astronauts spent about five and half hours outside the space station on Saturday working to remove the problematic pump. They are scheduled step out again Tuesday at 7:10 a.m. ET to install a new one.

If everything goes according to plan, the repair job will be completed Tuesday.

Spacesuit problem

Mastracchio will be using a different spacesuit after a small amount of water leaked into the cooling system of the one he wore on Saturday.

NASA said the issue with the suit, which happened at the end of the spacewalk, was unrelated to a problem experienced in July, when water pooled in an Italian astronaut's helmet, causing a spacewalk to be cut short.fb.com/vaderv