STS-116 Pilot William Oefelein is suited and ready to begin practice flights on the shuttle training aircraft.

STS-116 Pilot William Oefelein (right) is suited and ready to begin practice flights on the shuttle training aircraft (STA) two days before launch. 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. Launch of Space Shuttle Discovery on mission STS-116 is scheduled for 9:35 p.m. Dec. 7. On the mission, the STS-116 crew will deliver truss segment, P5, to the International Space Station and begin the intricate process of reconfiguring and redistributing the power generated by two pairs of U.S. solar arrays. The P5 will be mated to the P4 truss that was delivered and attached during the STS-115 mission in September. Photo credit: NASA/Kim Shiflett