By the second half of the Sixties, with almost half a million American troops in Vietnam, many of the astronauts were developing itchy feet to return to active military service. “We were uncomfortable wearing the hero image,'' wrote Gene Cernan, “while our buddies were bleeding, being captured and dying in a real shooting war for which we had been trained.'' Some of them, indeed, approached Deke
Slayton, NASA’s Chief of the Astronaut Office, with a view to taking leave of absence from NASA, and returning to the front line. They were free to leave, if they wished, Slayton told them, but he offered no guarantees of a job when they returned.