JSC2011-E-029038 (21 March 2011) --- NASA astronauts Sandy Magnus and Rex Walheim, both STS-135 mission specialists, participate in an extravehicular activity (EVA) hardware training session in the Neutral Buoyancy Laboratory (NBL) near NASA's Johnson Space Center. STS-135 is planned to be the final mission of the space shuttle program. Photo credit: NASA or National Aeronautics and Space Administration