The criteria for determining who has achieved human spaceflight vary. The Fédération Aéronautique Internationale (FAI) defines spaceflight as any flight above 100 kilometres (62 mi). In the 1960s, the United States Department of Defense awarded the rating of astronaut to military and civilian pilots who flew aircraft higher than 50 miles (80 km). This list follows the FAI criterion.
From the Department of Defense, eight USAF and NASA pilots qualified for the Astronaut Badge by flying the sub-orbital X-15 rocket spaceplane. One of these, Joseph A. Walker, flew the X-15 above 100 km on two flights, becoming the first person to enter space twice. The other pilots did not reach the 100 km FAI limit. However, Joe Engle would later go on to fly on the Space Shuttle, thus exceeding this limit.
There are also nine space travellers who surpassed the 50-mi-border on the sub-orbital SpaceShipTwo (including Richard Branson, founder of Virgin Galactic spaceflight company), and are thus recognized as (commercial) astronauts by the FAA but not by the FAI since they didn't surpass the 100-km-line while one of them (Frederick W. Sturckow) had flown to space in the Space Shuttle already and thus already has been an FAI-recognized astronaut. The rest, therefore, are not recognized as commercial astronauts using FAI criterion.
All other men and women traveled to outer space in non-winged rockets, the orbital Space Shuttle, or the sub-orbital Scaled Composites SpaceShipOne rocket spaceplane.
People who died training for space travel or died during missions that failed to reach the required altitude, such as Christa McAuliffe, can be found in the article on space disasters.
As of July 20, 2021[update], a total of 574 people from 41 countries have gone into space according to the FAI criterion (587 people have qualified when including the US Department of Defense classification). Of those 574, three people only reached a sub-orbital flight, 567 people reached Earth orbit, 24 traveled beyond low Earth orbit and 12 walked on the Moon. Space travelers have spent over 29,000 person-days (or a cumulative total of over 77 years) in space including over 100 person-days of spacewalks. This list does not include animals in space.
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