How Have NASA’s Requirements for Astronaut Candidates Changed?

In June 2017, NASA selected 12 people from a pool of more than 18,300 applicants to begin the two years of training that could allow them to become astronauts. NASA's current application requirements have changed significantly from the late 1950s, when the first search for potential astronauts began. Selected in 1959, the original Mercury 7 were chosen from a field of 500 military candidates. Applicants were required to have a minimum of 1,500 hours of jet aircraft flight time, along with an engineering background. Candidates who were taller than 5 feet 11 inches (1.8 m) were automatically disqualified because they would not be able to fit in the spacecraft.

Into the wild blue yonder:

• The first seven NASA astronauts were “superb physical specimens” with IQs above 130. Gus Grissom, Gordon Cooper, and Deke Slayton were Air Force pilots. Alan Shepard, Scott Carpenter, and Wally Schirra were Navy pilots, and John Glenn was a Marine pilot.
• Neil Armstrong, the first astronaut to walk on the Moon, was accepted in 1962 as part of the second group of candidates. He began his career as a naval aviator, and had two degrees in aeronautical engineering.
• In 1964, NASA began to accept candidates primarily based on education. They wanted “scientist-astronauts” with doctoral degrees or an equivalent amount of professional experience.