KENNEDY SPACE CENTER, FLA. -- Space shuttle Atlantis STS-122 Commander Steve Frick prepares to practice shuttle landings. He is sitting in the cockpit of a shuttle training aircraft, or STA, at Kennedy Space Center's Shuttle Landing Facility. 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 Internatio