It's not just any military background, though. Most of them are former pilots. Astronaut Candidates must have 1,000 hours of "pilot-in-command" time in a jet ai

It's not just any military background, though. Most of them are former pilots. Astronaut Candidates must have 1,000 hours of "pilot-in-command" time in a jet aircraft, or 3 years of professional related experience. The former is usually obtained through the military. A civilian would have to complete training equivalent to that of a military pilot before actually being cleared for a mission. One-third of military pilots don't, though it's entirely possible the civilian could. However, it probably makes more sense to train those individuals who have already shown they can perform under similar conditions.