Expedition 24 crew members Tracy Caldwell and Doug Wheelock during ISS EVA 1 91027 training

JSC2009-E-226223 (28 Oct. 2009) --- Astronaut Tracy Caldwell, Expedition 23/24 flight engineer, dons a training version of her Extravehicular Mobility Unit (EMU) spacesuit in preparation for a spacewalk training session in the waters of the Neutral Buoyancy Laboratory (NBL) near NASA's Johnson Space Center. Astronaut Shannon Walker, Expedition 24/25 flight engineer, assisted Caldwell.