Bull, John Sumter (1934– )

US astronaut. He was selected as an astronaut in 1966, but resigned two years later for health reasons. He worked at NASA's Ames Research Center 1973–85, conducting simulation and flight-test research on advanced flight systems for aircraft. In 1986 he began managing NASA's autonomous systems technology for space applications. He retired from NASA in 1989 and became a consultant in aerospace research and technology.