NASA astronauts begin "urgent" repairs

Updated on
The International Space Station (ISS) as seen from NASA space shuttle Endeavour on May 29, 2011.

Two NASA astronauts began "urgent" repairs to the International Space Station's ammonia pump module on Saturday — accomplishing their task ahead of schedule, allowing the duo to make some repairs originally slated for a separate Monday excursion. 

Astronauts Rick Mastracchio and Mike Hopkins successfully carried out the 5 hour and 28 minute long space walk by 12:29 PM Eastern time, according to NASA's Twitter feed, and were scheduled to perform another on Monday to finish installing a new ammonia pump. 

Monday's walk was delayed until Christmas Eve after it was discovered that water may have entered part of Mastracchio's spacesuit during Saturday's walk.

He will reportedly use another spare suit during the next walk on Tuesday.

More from GlobalPost: Stunning NASA video shows comet ISON hurtling toward sun

It's hoped that Tuesday's spacewalk will allow the astronauts to finish installing a new ammonia pump, preventing them from having to conduct another spacewalk on Christmas Day, wrote the Associated Press.

Replacing the faulty 780-pound ammonia pump is a complex undertaking attempted only once before, in 2010. The astronauts who replaced it at that time were on hand at Mission Control to advise Mastracchio and Hopkins in their task.

One of the space suits still in use began to fill with water during a July spacewalk, prompting the crew to construct improvised "snorkels" just in case the problem happens again, wrote the New York Times.

NASA said that the discovery of water from Saturday's repairs was not as serious as July's frightening incident.

NASA live-streamed video of the space walk to their website and provided constant Twitter updates on their progress. 

Here is NASA's weekly video update on the happenings at the International Space Station: