STS-115 Mission Specialists Heidemarie Stefanyshyn-Piper and Joseph Tanner are taking the culmination of Terminal Countdown Demonstration Test activities.

Inside Atlantis' cockpit, STS-115 Mission Specialists Heidemarie Stefanyshyn-Piper and Joseph Tanner are taking part in a simulated launch countdown, the culmination of Terminal Countdown Demonstration Test activities. The TCDT is a prelaunch preparation for the mission that is scheduled to lift off in a window opening Aug. 27. During their 11-day mission to the International Space Station, the STS-115 crew will continue construction of the station and attach the payload elements, the Port 3/4 truss segment with its two large solar arrays.