JSC2011-E-028134 (23 March 2011) --- NASA astronauts Chris Ferguson (left), STS-135 commander; Doug Hurley (right), pilot; and Sandy Magnus, mission specialist, participate in an exercise in the systems engineering simulator in the Avionics Systems Laboratory at NASA's Johnson Space Center. The facility includes moving scenes of full-sized International Space Station components over a simulated Earth. Photo credit: NASA or National Aeronautics and Space Administration