TODAY | December 24, 2013
>> a lot of people on christmas eve dash out to the mall and do wrapping. others walk in space ichl.s it's incredible what we're watching right now.
>> it is. it's what nasa hopes to be the last space walk to wrap up repair at the international space station . tom costello is going to walk us through what's happening right now.
>> reporter: good morning. the same two astronauts that completed saturday's space walk on are this job. he is inside controlling the robotic arm again today. but the two on the outside have already left the station and while nasa stresses nothing in space is routine but it's very confident this urgent repair job should be wrapped up today. above the earth, two astronauts stepping back into space to replace a critical cooling pump that failed two weeks ago forcing the space station to conserve power and rely on one cooling pump.
>> i don't know if you believe in miracles but i got the hinch pin on the first try.
>> reporter: saturday's space walk went so well.
>> we're about an hour and a half ahead.
>> reporter: nasa was able to scrub the second of three planned space walks . instead, they're planning to finish the job today. mike hopkins on his second space walk out on the canada arm to move the large replacement cooling unit into the spot they cleared on saturday.
>> you can't move them around with your fingertip. you have to wrestle them and hold them and actually move them a very substantial distance from their storage slots down the side of the space station to where they need to be installed.
>> reporter: all told it should take about six hours. today's walk delayed a day so the more senior could switch suits. after an exhausting walk on saturday.
>> do you want to take it inside or what.
>> reporter: he accidentally let a small amount of water leak into a part of his suit designed to disapate heat.
>> it was an accident. they reset the switch.
>> reporter: nothing like the water problems that caused an italian astronaut to nearly drowned in his helmet last july.
>> they hope to run a test on the system to make sure they do have this cooling system back up and running and this is inside the space station and on the outside is where the work is being done. very important and especially for willie's kids, mission control expects no conflicts between the space station and santa's flight. a short time ago they reported the skies are all clear for santa.
>> way to bury the lead, tom. most important thing.