Astronaut in 1957: Stratonaut

There is no direct door into the job. Every astronaut arrives as something else first — fighter pilot, engineer, physician, biochemist, geologist — and survives a selection that routinely rejects more than 99.9 percent of applicants: NASA chose 10 from over 12,000 in 2021, and ESA chose its 2022 class from 22,523. Those selected then train for years, learning spacewalking in a 12-metre-deep pool and Russian in a classroom, for a flight that may never come.

This page follows the profession from the Mercury Seven and Gagarin's Vostok through the Moon landings, the Shuttle's scientist-astronauts and a quarter century of continuous life aboard the International Space Station, into today's commercial crews. It covers how people actually get selected, what a day in orbit is scheduled down to five-minute blocks, who reached the top of the corps and how, and how much of the work robots already do.

Through a national or commercial selection, entered from another career. NASA requires a STEM master's degree (or a medical degree, test-pilot school, or doctoral work) plus professional experience or 1,000 hours piloting jets; ESA, JAXA, Canada and China run comparable competitions. Survivors of medical, psychological and interview rounds then complete roughly two years of basic training before becoming eligible for a flight assignment.