NASA - National Aeronautics and Space Administration

JSC2011-E-040202 (2 March 2011) --- NASA astronaut Chris Ferguson, STS-135 commander, departs from the Moffett Field (Calif.) flight operations center for his trip home to Houston after he and his crew trained in the Vertical Motion Simulator (VMS) at NASA's Ames Research Center in Mountain View, March 2, 2011. Photo credit: NASA Photo/Houston Chronicle, Smiley N. Pool

JSC2011-E-040205 (2 March 2011) --- A NASA T-38 jet trainer piloted by astronaut Chris Ferguson, STS-135 commander, takes off from Moffett Field in California for a flight home to Houston after Ferguson and his crew trained in the Vertical Motion Simulator (VMS) at NASA's Ames Research Center in Mountain View, March 2, 2011. Photo credit: NASA Photo/Houston Chronicle, Smiley N. Pool

JSC2011-E-040211 (10 March 2011) --- NASA astronaut Rex Walheim, STS-135 mission specialist, prepares to train in the Neutral Buoyancy Laboratory (NBL) near NASA's Johnson Space Center in Houston March 10, 2011. Photo credit: NASA Photo/Houston Chronicle, Smiley N. Pool

JSC2011-E-040215 (10 March 2011) --- A bank of video screens shows the progress of a simulated spacewalk as the crew of STS-135 trains in the Neutral Buoyancy Laboratory near NASA's Johnson Space Center in Houston March 10, 2011. Photo credit: NASA Photo/Houston Chronicle, Smiley N. Pool

JSC2011-E-040269 (24 March 2011) --- The crew members of STS-135 are briefed by trainers before they participate in a post-insertion training session in the Full-Fuselage Trainer in the Space Vehicle Mock-up Facility at NASA's Johnson Space Center in Houston March 24, 2011. Photo credit: NASA Photo/Houston Chronicle, Smiley N. Pool

JSC2011-E-043685 (29 April 2011) --- NASA astronaut Rex Walheim, STS-135 mission specialist, participates in an ingress/egress timeline training session in the Space Vehicle Mock-up Facility at NASA's Johnson Space Center. Photo credit: NASA

JSC2011-E-043688 (29 April 2011) --- NASA astronaut Chris Ferguson, STS-135 commander, signs his name on hardware during an ingress/egress timeline training session in the Space Vehicle Mock-up Facility at NASA's Johnson Space Center. Photo credit: NASA

JSC2011-E-043692 (29 April 2011) --- NASA astronaut Rex Walheim, STS-135 mission specialist, signs his name on hardware during an ingress/egress timeline training session in the Space Vehicle Mock-up Facility at NASA's Johnson Space Center. Photo credit: NASA

JSC2011-E-043693 (29 April 2011) --- A close-up view of the STS-135 crew members' signatures placed on hardware during an ingress/egress timeline training session in the Space Vehicle Mock-up Facility at NASA's Johnson Space Center. Photo credit: NASA

JSC2011-E-043696 (29 April 2011) --- NASA astronauts Rex Walheim (center) and Sandy Magnus, both STS-135 mission specialists, participate in an ingress/egress timeline training session in the Space Vehicle Mock-up Facility at NASA's Johnson Space Center. Photo credit: NASA