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

JSC2009-E-226239 (28 Oct. 2009) --- Astronaut Tracy Caldwell, Expedition 23/24 flight engineer, attired in a training version of her Extravehicular Mobility Unit (EMU) spacesuit, participates in a spacewalk training session in the waters of the Neutral Buoyancy Laboratory (NBL) near NASA's Johnson Space Center. Divers are in the water to assist Caldwell in her rehearsal, which is intended to help prepare her for work on the exterior of the International Space Station.