In this image provided by NASA astronaut Nicole Stott, Expedition 20 flight engineer, participates in the STS-128 mission's first session of extravehicular activity on the International Space Station ... more 
In this image provided by NASA astronaut Nicole Stott, Expedition 20 flight engineer, participates in the STS-128 mission's first session of extravehicular activity on the International Space Station Sept. 1, 2009. Two deployed radiators are visible behind Stott. The International Space Station has a radiator leak in its power system. The outpost's commander calls the situation serious, but not life-threatening. The six-member crew on Thursday May 9, 2013 noticed white flakes of ammonia leaking out of the station. (AP Photo/NASA) less 
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Associated Press | Photo By NASA
Fri, May 10, 2013 4:55 AM EDT