TODAY | May 11, 2013
>>> two astronauts making a repair on the international space station . tom costello joins us live.
>> reporter: this is not a life or death emergency but certainly an urgent repair they need to make to the international space station . we have live pictures from nasa tv to show you as the astronauts are preparing to leave the station to begin these repairs. on thursday, the astronauts onboard the station noticed flakes of ammonia leaking from the station's port truss and if you look closely at the video of the ammonia leaking you can actually see the flakes dripping down. now, the port truss makes up the back bone of the international space station . look very closely. you can see those flakes kind of dripping away. this is actually one of the oldest components to the space station 's truss. it was put in place back in 2000 . nasa quickly determined that the ammonia leak was coming from a coolant pump. so they shut down one coolant system. while the station is operating normally, if they lose another pump they'd have to start shutting down some noncritical systems. so astronauts chris cassidy and tim marshburn are going to try to replace the pump with the ammonia leak. hopefully that will end the story and everything will go just fine. nasa never likes to rush anything but they did put the space walk together rather quickly because they want to stop the leak as soon as possible and because they want to get the space walk expertise of tom marshburn who is scheduled to return to earth on monday on soyuz. and so the plan is to swap out the pump box on the, one of the eight solar panels that supply the electricity to the station and hopefully everything will be back to normal. back to you, erica.
>> we are hoping for that. lots of normal. tom costello,