JSC2011-E-059636 (21 June 2011) --- NASA astronaut Chris Ferguson, STS-135 commander, participates in safety training in the M113 personnel carrier during the Terminal Countdown Demonstration Test (TCDT) at NASA?s Kennedy Space Center on June 21, 2011. TCDT serves as the prelaunch countdown rehearsal for the final space shuttle mission, which is scheduled for launch on July 8. The M113 would be used in the event of an emergency at the pad forcing the crew to evacuate. Photo credit: NASA Photo/Houston Chronicle, Smiley N. Pool