In which mission was Slayton scheduled to pilot the second U.S. crewed orbital spaceflight?
Mercury-Atlas 7
Gemini 3
Apollo 11
Skylab 2
Answer
Mercury-Atlas 7 was the mission in which Slayton was scheduled to pilot the second U.S. crewed orbital spaceflight. However, due to a heart condition, he was medically disqualified and replaced by Scott Carpenter.
Reaching for the Stars: The Deke Slayton Astronaut Challenge