STS-135 crew during Ingress/Egress Timeline training in building 9NW space station mockups

JSC2011-E-043699 (29 April 2011) --- NASA astronaut Chris Ferguson (left), STS-135 commander; along with astronauts Rex Walheim and Sandy Magnus, both 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