ISS039-E-013152 (17 April 2014) --- Inside the Quest airlock of the International Space Station, NASA astronauts Steve Swanson (left) and Rick Mastracchio, both Expedition 39 flight engineers, participate in a dress rehearsal for an upcoming spacewalk during which they are to replace a failed backup computer relay box in the S0 truss.
Photographer Koichi Wakata
Date April 17, 2014