JSC2011-E-003204 (18 Jan. 2011) --- NASA astronauts Rex Walheim, STS-135 mission specialist; and Mike Fossum (foreground), Expedition 28 flight engineer and Expedition 29 commander; use the virtual reality lab in the Space Vehicle Mock-up Facility at NASA's Johnson Space Center to train for some of their duties aboard the space shuttle and space station. This type of computer interface, paired with virtual reality training hardware and software, helps to prepare crew members for dealing with space station elements. STS-135 is planned to be the final mission of the space shuttle program. Photo credit: NASA or National Aeronautics and Space Administration