"NASA and the military have a long and storied history."
Those are the words of NASA Administrator Charles Bolden, Jr. in a blog post on the agency's website about hiring veterans at NASA.
"Our earliest astronauts came from the military because we wanted people who had test pilot experience and the willingness to face dangerous situations," he said.
In fact, the first astronauts were specifically chosen for that reason: NASA requested each branch of the military provide a list of military test pilots who might qualify.
In 1959, the "Mercury Seven" astronauts were all military pilots.
Here are some of NASA's most famous astronauts who also had military careers.