William Oefelein left and Commander Mark Polansky are seated getting ready to practice landing the orbiter.

Inside the shuttle training aircraft at the Shuttle Landing Facility, STS-116 Pilot William Oefelein (left) and Commander Mark Polansky are seated in the cockpit, getting ready to practice landing the orbiter. The mission crew is at KSC for the terminal countdown demonstration test, which are prelaunch preparations that include a simulated launch countdown. STA practice is part of the TCDT. 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. Photo credit: NASA/Kim Shiflett