Who are astronauts?

Short answer

Astronauts are professionals selected and trained by a space agency or company to crew spacecraft and work in orbit. They typically come from military aviation, engineering, science or medicine. Since 1961, more than 700 people have flown to space, most on short-duration missions in low orbit.

Published: September 23, 2026 · Updated: September 23, 2026 · Edited by Above Ten Thousand · Editorial policy

Cockpit, Lunar Module, Apollo, Mockup

Where they come from

The typical profile combines solid technical training with operational experience under pressure. The first groups, in the 1960s, were drawn almost exclusively from military test pilots: candidates used to flying prototypes and making split-second decisions. With the arrival of the shuttle and orbital stations, the corps opened up to scientists, engineers and doctors, since much of the work involves operating experiments and maintaining complex systems.

Today's selection rounds typically require an advanced degree in science, engineering or medicine, several years of professional experience or thousands of flight hours in jets, and passing a demanding medical exam. Competition is fierce: the latest NASA and ESA selections received tens of thousands of applications for barely a dozen slots.

What they do and what they're called

Once selected, candidates undergo around two years of basic training — spacecraft systems, robotics, languages, survival training, diving to rehearse spacewalks — before becoming eligible for a crew assignment. Within a mission there are commanders and pilots, responsible for the vehicle, and mission specialists, in charge of experiments, maintenance and activities outside the spacecraft.

The name varies by tradition. Russia has spoken of cosmonauts since Yuri Gagarin's flight in 1961; China officially uses *hangtianyuan*, though the Western press popularized "taikonaut." The total number of people who have flown to space exceeds 700 and grows slowly; in recent years it has been joined by a different group, passengers on commercial suborbital and orbital flights, who are not part of any professional astronaut corps.