STS-115 Mission Specialist Joseph Tanner is ready to practice driving the armored personnel carrier.

STS-115 Mission Specialist Joseph Tanner is ready to practice driving the M-113 armored personnel carrier. Behind him is seen Mission Specialist Steven MacLean, who represents the Canadian Space Agency. The STS-115 crew are at NASA's Kennedy Space Center for Terminal Countdown Demonstration Test activities such as the M-113 training. They will also practice emergency egress from the launch pad and take part in a simulated launch countdown. Liftoff of mission STS-115 aboard Space Shuttle Atlantis is scheduled in a window beginning Aug. 27. Photo credit: NASA/Cory Huston