In this Saturday, May 11, 2013 photo made available by NASA, astronaut Chris Cassidy and Tom Marshburn, not pictured, perform a space walk to inspect and replace a pump controller box on the ... more 
In this Saturday, May 11, 2013 photo made available by NASA, astronaut Chris Cassidy and Tom Marshburn, not pictured, perform a space walk to inspect and replace a pump controller box on the International Space Station after an ammonia coolant leak was discovered. (AP Photo/NASA) less 
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Associated Press | Photo By NASA
Wed, May 15, 2013 8:26 PM EDT