Nightly News | December 22, 2013
>>> we now know why nasa decided to delay a second space walk by two american astronauts making those critical repairs to the international space station . it is because of a problem with one of their space suits . we get details from nbc's kerry sanders .
>> this is a good stopping point.
>> reporter: after a 5:28 space walk , astronaut rick returned to the space station 's air lock and discovered something that wasn't supposed to be. water had entered his space suit sublimator. a design to dissipate excess heat .
>> there's always been water in the suit. the difference is they had devices that got rid of it. this time it accumulated. they really don't know why.
>> reporter: nasa postponed a second space walk tomorrow until tuesday so a spare space suit can be reconfigured for him. meantime colonel mike hopkins reported no problems with water which is especially notable because he was wearing the same space suit an italian astronaut wore last july when a malfunction filled the helmet with water. the helmets now have makeshift snorkels and absorb dlenlt pads in case the water reappears. nasa says the water that developed inside the space suit in july that the water detected yesterday are not the same problem.
>> okay, rick, pull back.
>> reporter: on tuesday the astronauts will continue their repair mission to replace a cooling pump that malfunctioned.
>> the space station is running with only a single cooling system which means it is vulnerable to that one cooling system having a failure.
>> reporter: tonight the astronauts look forward to the next space walk . they're preparing for what they hope is routine and dry. kerry sanders , nbc news, miami.