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), a definition recognized by every country. 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 pilots, Joseph A. Walker, flew the X-15 above 100 km on two flights, becoming the first person to enter space twice. However, the other pilots did not reach the 100 km FAI limit.
As of November 6, 201338 countries have gone into space according to the FAI guideline (543 people have qualified when including the US Department of Defense classification). Of the 536, three people completed only a sub-orbital flight, 533 people reached Earth orbit, 24 traveled beyond low Earth orbit and 12 walked on the Moon., a total of 536 people from