ISS038-E-017486 (18 Dec. 2013) --- Expedition 38 Flight Engineer Mike Hopkins checks out the spacesuit he will wear outside the International Space Station on Dec. 21. He and fellow astronaut Rick Mastracchio will conduct a series of spacewalks to replace an ammonia pump that is part of the station's coolant system. This will be Hopkins' first spacewalk, while Mastracchio has six previous ones on STS-118 and STS-131.