Donald Kent "Deke" Slayton (March 1, 1924 – June 13, 1993), (Major, USAF) was an American World War II pilot, aeronautical engineer, test pilot who was selected as one of the original NASA Mercury Seven astronauts, and became NASA's first Chief of the Astronaut Office.
After joining NASA, Slayton was selected to pilot the second U.S. manned orbital spaceflight, but was grounded in 1962 by atrial fibrillation, an irregular heart rhythm. He then served as NASA's Director of Flight Crew Operations, making him responsible for crew assignments at NASA from November 1963 until March 1972. At that time he was granted medical clearance to fly, and was assigned as the docking module pilot of the 1975 Apollo–Soyuz Test Project, at age 51 becoming the oldest person to fly in space at the time. This record was surpassed in 1983 by 53-year-old John Young and in 1998 by Slayton's fellow Project Mercury astronaut John Glenn, who at the age of 77 flew on Space Shuttle mission STS-95.
Slayton died at the age of 69 on June 13, 1993, from a malignant brain tumor.
He is also known as '''Donald Kent 'Deke' Slayton''' and Donald Kent 'Deke' Slayton.