A captain in the US Navy, Jeffrey Ashby received the MS in aviation systems from the University of Tennessee Space Institute (Tullahoma, Tennessee) in 1993. In 1994 he was selected by NASA as an astronaut and reported to the Johnson Flight Center in March 1995. He was chosen to serve as a pilot on the crew of the STS-93 (Space Shuttle Columbia) in 1999. The five-day mission featured the deployment of the Advanced X-ray Astrophysics Facility (AXAF). The purpose of the AXAF is to allow scientists to conduct comprehensive studies of exotic phenomena in the universe, including exploding stars, quasars, and black holes.