Another Mercury astronaut, Deke Slayton (1924-1993) was meant to be the second American in Earth orbit, but was grounded because of an irregular heartbeat. He stayed on at NASA to supervise his fellow astronauts and was returned to flight status in 1972. In 1975, after sixteen years as head of the astronaut office, Slayton made it into space for the historic first docking of an American and a Russian spacecraft, a step that was a long stride on the road to end the Cold War.
