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Spacewalking Astronauts Hunt for Space Station Ammonia Leak

NASA astronaut Chris Cassidy (striped spacesuit) holds an ammonia pump control box during a spacewalk to hunt for an ammonia leak outside the International Space Station on May 13, 2013. The spacesuit of astronaut Tom Marshburn can be seen behi

Spacewalk to repair ISS

Repairs to the International Space Station began on Saturday morning as

members of the crew suit up and head outside to track down the source of

the ammonia leak discovered on May 9.