Donald Kent "Deke" Slayton (March 1, 1924 – June 13, 1993) was a United States Air Force pilot, aeronautical engineer, and test pilot who was selected as one of the original NASA Mercury Seven astronauts. He went on to become NASA's first Chief of the Astronaut Office and Director of Flight Crew Operations, responsible for NASA crew assignments. Slayton joined the U.S. Army Air Forces during World War II, and flew in Europe and the Pacific. He left the Army after World War II, went on to receive a Bachelor of Science degree in aeronautical engineering from University of Minnesota in 1949, and later joined the Minnesota Air National Guard after working for Boeing as an aeronautical engineer. He joined the United States Air Force, and attended the U.S. Air Force Test Pilot School in 1955. In 1959, he applied to, and was selected as one of the Mercury Seven, NASA's first class of astronauts. Slayton was scheduled to pilot the second U.S. crewed orbital spaceflight, but was grounded in 1962 by atrial fibrillation, an irregular heart rhythm. In March 1972, he was medically cleared to fly and was the docking module pilot of the 1975 Apollo–Soyuz Test Project (ASTP). Slayton continued to work at NASA until 1982. He also helped develop the Space Shuttle. He died from a brain tumor on June 13, 1993, aged 69. Early life and career Donald Kent Slayton was born on March 1, 1924, on a farm near Leon, Wisconsin, to Charles Sherman Slayton (1887–1972) and Victoria Adelia Slayton (; 1895–1970). He was of English and Norwegian descent. From a young age, he worked on the farm to raise sheep and cows, and grow tobacco. Throughout Slayton's childhood, his family's home did not have electricity or indoor plumbing. At the age of five, Slayton was clearing a horse-drawn hay mower when his left ring finger was severed. He attended a two-room elementary school in Leon, and graduated from Sparta High School in 1942, where he boxed, played trombone, and was active in the Future Farmers of America (FFA). World War II The 1941 attack on Pearl Harbor by the Japanese Empire occurred during Slayton's senior year of high school. He initially wished to join the U.S. Navy, but joined the U.S. Army Air Forces when it began accepting high school graduates to fly. After graduation, Slayton moved to San Antonio, Texas, and entered the