Mercury Seven
Deke Slayton
Grounded Mercury astronaut who ran crew assignments for a decade, then finally flew on Apollo-Soyuz.
Deke Slayton was selected among the Mercury Seven but was grounded by a heart murmur before he could fly. Rather than leave, he became NASA’s Director of Flight Crew Operations — the man who chose every Gemini and Apollo crew, including who would be first on the Moon.
Restored to flight status after 13 years, Slayton finally reached orbit at age 51 as docking module pilot on the Apollo-Soyuz Test Project in 1975, the oldest rookie astronaut in history at the time.