Rocket Men. The story of the Project Mercury astronauts. I remember them all. Hotdog test pilots. Combat airmen. Engineers. Officers, gentlemen, and jokesters. They were my heroes, and so they remain: Shepard, Grissom, and Glenn. Then Carpenter, Schirra, and Cooper. And of course, there was one more. But due to heart fibrillation, Slayton didn’t go into space until the Apollo-Soyuz mission in 1975. Yet he served as an administrator for years, from Project Mercury through the early Space Shuttle period.