NASA - National Aeronautics and Space Administration

JSC2011-E-029041 (21 March 2011) --- NASA astronauts Rex Walheim (right) and Sandy Magnus, 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. EVA instructors John Ray (left foreground) and Art Thomason assisted Walheim and Magnus. STS-135 is planned to be the final mission of the space shuttle program. Photo credit: NASA or National Aeronautics and Space Administration

JSC2011-E-029042 (21 March 2011) --- NASA astronauts Rex Walheim (second left) and Sandy Magnus, 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. EVA instructors John Ray (left foreground) and Art Thomason assisted Walheim and Magnus. STS-135 is planned to be the final mission of the space shuttle program. Photo credit: NASA or National Aeronautics and Space Administration

JSC2011-E-029044 (21 March 2011) --- NASA astronauts Rex Walheim (left) and Sandy Magnus, 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. EVA instructors John Ray (right background) and Art Thomason assisted Walheim and Magnus. STS-135 is planned to be the final mission of the space shuttle program. Photo credit: NASA or National Aeronautics and Space Administration

JSC2011-E-029049 (21 March 2011) --- NASA astronaut Rex Walheim (foreground), STS-135 mission specialist, participates in an extravehicular activity (EVA) hardware training session in the Neutral Buoyancy Laboratory (NBL) near NASA's Johnson Space Center. EVA instructor Art Thomason assisted Walheim. STS-135 is planned to be the final mission of the space shuttle program. Photo credit: NASA or National Aeronautics and Space Administration

JSC2011-E-029056 (21 March 2011) --- NASA astronauts Rex Walheim (right) and Sandy Magnus, 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. EVA instructors John Ray (left foreground) and Art Thomason assisted Walheim and Magnus. STS-135 is planned to be the final mission of the space shuttle program. Photo credit: NASA or National Aeronautics and Space Administration

JSC2011-E-029062 (21 March 2011) --- NASA astronaut Sandy Magnus, STS-135 mission specialist, participates in a training session in the Neutral Buoyancy Laboratory (NBL) near NASA's Johnson Space Center. Crew instructors assisted Magnus. STS-135 is planned to be the final mission of the space shuttle program. Photo credit: NASA or National Aeronautics and Space Administration

JSC2011-E-029068 (21 March 2011) --- NASA astronaut Chris Ferguson, STS-135 commander, is pictured during a 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

JSC2011-E-029070 (21 March 2011) --- NASA astronaut Doug Hurley, STS-135 pilot, participates in a 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

JSC2011-E-029071 (21 March 2011) --- NASA astronaut Doug Hurley, STS-135 pilot, is pictured during a 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

JSC2011-E-029074 (21 March 2011) --- NASA astronaut Chris Ferguson, STS-135 commander, participates in a 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