NASA astronaut training in free fall on a KC-135 aircraft flight. The astronaut is Dr Robert L. (Bobby) Satcher Jr. (born 1965). Satcher trained as a doctor and a surgeon before beginning his astronaut training in 2004. He has also studied engineering. He completed his astronaut candidate training in February 2006. This free fall flight involves flying the aircraft in a parabolic trajectory to simulate the free fall conditions found in Earth orbit. The aircraft interior is padded to prevent injuries. Each period of free fall lasts about 25 seconds, and each flight includes 40 to 80 parabolas. Photographed on 13 October 2004.