On Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-119 Mission Specialist John Phillips is seated in space shuttle Discovery for a simulated launch countdown as part of the prelaunch preparation known as Terminal Countdown Demonstration Test. The TCDT also includes equipment familiarization. Discovery is targeted to launch on the STS-119 mission Feb. 12. During the 14-day mission, the crew will install the S6 truss segment and solar arrays to the starboard side of the International Space Station, completing the station's truss, or backbone. Photo credit: NASA/Kim Shiflett