STS-135 crew during Space Station Mockup Training

JSC2011-E-021694 (25 Feb. 2011) --- NASA astronauts Chris Ferguson (left), STS-135 commander; Doug Hurley (second left), pilot; and Rex Walheim (right foreground), mission specialist, participate in a training session in the Space Vehicle Mock-up Facility at NASA's Johnson Space Center. Photo credit: NASA or National Aeronautics and Space Administration