Donald K. "Deke" Slayton. NASA portrait.
Back on July 11, 1962, the Mercury Seven astronaut lineup got a shake-up. Major Deke Slayton (USAF) was re-assigned to take over new operational and planning responsibilities for the astronaut program. He had originally been scheduled to fly the second orbital mission, but Scott Carpenter had flown that mission instead. NASA Doctors had declared Deke was suffering from "Atrial Fibrilation" of the heart. As one astronaut put it, "Don't all our hearts fibrilate?" There was much grief among the astronauts at this decision, but NASA feared such a condition could lead to a medical emergency while in space away from medical help. Deke was a realist, and understood that he could still be of use to NASA. He would eventually resign from the Air Force in 1862, and take up full time administrative work as the head of the astronaut program. He would work extensively with astronaut training programs, detail their schedules and also the flight rotation for missions. And he would never give up on his desire to go into space.
Original Mercury Seven. Slayton is front row, second from left.
Deke was quite a pilot. He had flown B-25 bomber missions over Europe in World War 2, and later flew A-26 missions over the Pacific. His postwar college schooling got him a degree in Aeronautical Engineering, and he became a test pilot for the Air Force, flying the "Century" series of fighter-bombers. His heart condition grounded him from flying.