As dawn washes the sky in pink, STS-121 Commander Steven Lindsey is ready for his first flight in the Shuttle Training Aircraft today to practice landing a shuttle in preparation for the July 1 launch of Space Shuttle Discovery. 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