JSC2010-E-183524 (3 Nov. 2010) --- NASA astronauts Rex Walheim (left), STS-135 mission specialist; and Doug Hurley, pilot, participate in an EVA Thermal Protection System (TPS) overview training session in the TPS/ Precision Air Bearing Facility in the Space Vehicle Mock-up Facility at NASA's Johnson Space Center. STS-135 is planned to be the final mission of the space shuttle program. Photo credit: NASA or National Aeronautics and Space Administration