Dave Williams signals success after driving an M-113 armored personnel carrier as part of emergency exit training.

STS-118 Mission Specialist Dave Williams, who represents the Canadian Space Agency, signals success after driving an M-113 armored personnel carrier as part of emergency exit training. Behind him are, at left, Pilot Charlie Hobaugh and, right, Mission Specialist Tracy Caldwell. 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