A shuttle training aircraft prepares for takeoff from Kennedy Space Center's Shuttle Landing Facility at dusk.

A shuttle training aircraft, or STA, prepares for takeoff from Kennedy Space Center's Shuttle Landing Facility at dusk. The STA is being used for practice flights by space shuttle Atlantis STS-122 Commander Steve Frick and Pilot Alan Poindexter. The STA is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. Because the orbiter is unpowered during re-entry and landing, its high-speed glide must be perfectly executed the first time. The training is part of terminal countdown demonstration test, or TCDT, activities. The TCDT provides astronauts and ground crews with equipment familiarization, emergency egress training and a simulated launch countdown. On mission STS-122, Atlantis will deliver the European Space Agency's Columbus module to the International Space Station. Columbus is a multifunctional, pressurized laboratory that will be permanently attached to U.S. Node 2, called Harmony, and will expand the research facilities aboard the station. Launch is targeted for Dec. 6. Photo credit: NASA/Kim Shiflett