Mission Specialist Tracy Caldwell practices driving an armored personnel carrier as part of emergency exit training.

STS-118 Mission Specialist Tracy Caldwell practices driving an M-113 armored personnel carrier as part of emergency exit training. Seen in the back are Mission Specialist Alvin Drew, Pilot Charlie Hobaugh and educator astronaut and Mission Specialist Barbara R. Morgan. They and other crew members are 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