Donald ('Deke') Slayton was one of the original Mercury Seven astronauts selected in 1959, and the only one not to make a Mercury flight. He flew on the Apollo-Soyuz Test Project (ASTP) in 1975.

 

Slayton received a BS in aeronautical engineering from the University of Minnesota in 1949, joined the Air Force in 1942, and received his wings a year later. During World War II, he flew combat missions over Europe and Japan, then became an aeronautical engineer with Boeing in Seattle. He was recalled to active duty in the Minnesota Air National Guard in 1951 and remained in the Air Force, going on to attend the Air Force Test Pilot School at Edwards Air Force Base before becoming an experimental test pilot there. After being selected by NASA, Slayton was assigned to fly the second Mercury orbital mission, but was grounded by an irregular heartbeat. He stayed with NASA to supervise the astronaut corps, first as chief of the Astronaut Office and then as director of flight crew operations. He eventually overcame his heart problem and was restored to flight status in 1972. Three years later, on 17 July 1975, Slayton made it into space aboard the ASTP after 16 years as an astronaut. For the next two years, Slayton was manager of the Space Shuttle approach and landing tests at Edwards. From 1977, until he retired from NASA in 1982, he was manager for orbital flight tests. Later, he became president of Space Services, Inc., a company that develops rockets for suborbital and orbital launch of small commercial space payloads.