Mission Specialist Rick Mastracchio practices driving an armored personnel carrier as part of emergency exit training.

STS-118 Mission Specialist Rick Mastracchio practices driving an M-113 armored personnel carrier as part of emergency exit training. The astronauts seen behind him are Mission Specialists Alvin Drew, Barbara R. Morgan, Dave Williams (standing) and Tracy Caldwell. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. Williams represents the Canadian Space Agency. The crew is at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton