Astronaut in 1959: The Mercury Seven

About two years of basic training covers spacecraft systems, spacewalking in a giant pool, robotics, jet flying, wilderness survival and the Russian language. Graduation only makes you eligible: a specific mission then adds 18–30 months of dedicated training across Houston, Star City, Cologne and Tsukuba. Counting the prior degrees and career, most astronauts fly 15–20 years after leaving school.

Not anymore. The first generation was drawn almost entirely from military test pilots — NASA's 1959 Mercury selection screened only them. Since the Shuttle era created mission specialists in 1978, roughly half of most astronaut classes have been civilian engineers, scientists and physicians. Pilots still fill command seats, but ESA's 2022 class included an astrophysicist, a neuroscientist-pilot and a medical doctor.

Less superhuman than people assume. Modern limits mostly ensure you fit the suits and seats — Soyuz-era seats accepted heights of roughly 150–190 cm — with vision correctable to 20/20 (NASA has accepted laser eye surgery since 2007), controlled blood pressure and no disqualifying conditions on a long-duration flight physical. ESA went further in 2022, selecting parastronaut John McFall, a leg amputee.