Flight Engineers Chris Cassidy (left) and Luca Parmitano participate in a "dry run" in the International Space Station's Quest airlock in preparation for the first of two spacewalks in July 2013. ... more 
Flight Engineers Chris Cassidy (left) and Luca Parmitano participate in a "dry run" in the International Space Station's Quest airlock in preparation for the first of two spacewalks in July 2013. Flight Engineer Karen Nyberg (center) assists. less 
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SPACE.com | Photo By NASA
Tue, Jul 9, 2013 7:10 AM EDT