Deke Slayton was an American astronaut who was instrumental in the early years of the U.S. space program. He was one of the original Mercury Seven astronauts selected in 1959 and served as the backup pilot for the first American orbital flight, Freedom 7, piloted by Alan Shepard. Slayton was also the backup commander for the Gemini 3 mission. Despite his substantial contributions to space exploration, he was grounded due to a heart condition and never flew in space. He passed away on June 13, 1993.
