Editing Human spaceflight (section)

==== Post-Apollo era ====
[[File:Apollo-Soyuz-Test-Program-artist-rendering.jpg|thumb|Artist's rendering of an [[Apollo CSM]] about to dock with a [[Soyuz spacecraft]]]]

In 1969, Nixon appointed his vice president, [[Spiro Agnew]], to head a Space Task Group to recommend follow-on human spaceflight programs after Apollo. The group proposed an ambitious [[Space Transportation System]] based on a [[Space Shuttle design process|reusable Space Shuttle]], which consisted of a winged, internally fueled orbiter stage burning liquid hydrogen, launched with a similar, but larger [[RP-1|kerosene]]-fueled booster stage, each equipped with airbreathing jet engines for powered return to a runway at the [[Kennedy Space Center]] launch site. Other components of the system included a permanent, modular space station; reusable [[space tug]]; and [[NERVA|nuclear]] interplanetary ferry, leading to a [[human mission to Mars|human expedition to Mars]] as early as 1986 or as late as 2000, depending on the level of funding allocated. However, Nixon knew the American political climate would not support congressional funding for such an ambition, and killed proposals for all but the Shuttle, possibly to be followed by the space station. [[Space Shuttle|Plans for the Shuttle were scaled back]] to reduce development risk, cost, and time, replacing the piloted fly-back booster with two reusable [[Space Shuttle Solid Rocket Booster|solid rocket booster]]s, and the smaller orbiter would use an expendable [[Space Shuttle external tank|external propellant tank]] to feed its hydrogen-fueled [[Space Shuttle main engine|main engine]]s. The orbiter would have to make unpowered landings.

[[File:Space Shuttle Atlantis landing at KSC following STS-122 (crop).jpg|thumb|[[Space Shuttle orbiter]], first crewed orbital spaceplane]]

In 1973, the US launched the [[Skylab]] sortie space station and inhabited it for 171 days with three crews ferried aboard an Apollo spacecraft. During that time, President [[Richard Nixon]] and Soviet general secretary [[Leonid Brezhnev]] were negotiating an easing of Cold War tensions known as [[détente]]. During the détente, they negotiated the [[Apollo–Soyuz]] program, in which an Apollo spacecraft carrying a special docking adapter module would rendezvous and dock with [[Soyuz 19]] in 1975. The American and Soviet crews shook hands in space, but the purpose of the flight was purely symbolic.

The two nations continued to compete rather than cooperate in space, as the US turned to developing the Space Shuttle and planning the space station, which was dubbed ''[[Space Station Freedom|Freedom]]''. The USSR launched three [[Almaz]] military sortie stations from 1973 to 1977, disguised as Salyuts. They followed Salyut with the development of ''[[Mir]]'', the first modular, semi-permanent space station, the construction of which took place from 1986 to 1996. ''Mir'' orbited at an altitude of {{convert|354|km|nmi|abbr=off|sp=us}}, at an [[orbital inclination]] of 51.6°. It was occupied for 4,592 days and made a controlled reentry in 2001.

The Space Shuttle started flying in 1981, but the US Congress failed to approve sufficient funds to make ''Space Station Freedom'' a reality. A fleet of four shuttles was built: ''[[Space Shuttle Columbia|Columbia]]'', ''[[Space Shuttle Challenger|Challenger]]'', ''[[Space Shuttle Discovery|Discovery]]'', and ''[[Space Shuttle Atlantis|Atlantis]]''. A fifth shuttle, ''[[Space Shuttle Endeavour|Endeavour]]'', was built to replace ''Challenger'', which was destroyed in [[Space Shuttle Challenger disaster|an accident during launch]] that killed 7 astronauts on 28 January 1986. From 1983 to 1998, twenty-two Shuttle flights carried components for a [[European Space Agency]] sortie space station called [[Spacelab]] in the Shuttle payload bay.<ref name=StoryShuttle>{{cite book |title=The Story of the Space Shuttle |author=David Michael Harland |publisher=[[Springer Science+Business Media|Springer]] Praxis |date=2004 |page=[https://archive.org/details/storyofspaceshut0000harl/page/444 444] |isbn=978-1-85233-793-3 |author-link=David M. Harland |url=https://archive.org/details/storyofspaceshut0000harl/page/444 }}</ref>

[[File:Buran on An-225 (Le Bourget 1989) (cropped).JPEG|thumb|''[[Buran programme|Buran]]''-class orbiter, Soviet equivalent of the Space Shuttle orbiter]]

The USSR copied the US's reusable [[Space Shuttle orbiter]], which they called ''[[Buran programme|Buran]]''-class orbiter or simply ''Buran'', which was designed to be launched into orbit by the expendable [[Energia (rocket)|Energia]] rocket, and was capable of robotic orbital flight and landing. Unlike the Space Shuttle, ''Buran'' had no main rocket engines, but like the Space Shuttle orbiter, it used smaller rocket engines to perform its final orbital insertion. A single uncrewed orbital test flight took place in November 1988. A second test flight was planned by 1993, but the program was canceled due to lack of funding and the [[dissolution of the Soviet Union]] in 1991. Two more orbiters were never completed, and the one that performed the uncrewed flight was destroyed in a hangar roof collapse in May 2002.