Editing Spaceflight (section)

== Types ==
=== Uncrewed ===
[[File:Pathfinder01.jpg|thumb|''[[Sojourner (rover)|Sojourner]]'' takes its [[Alpha particle X-ray spectrometer]] measurement of [[Yogi Rock]] on Mars.]]
[[Image:messenger.jpg|thumb|The ''[[MESSENGER]]'' spacecraft at Mercury (artist's interpretation)]]
{{Main|Uncrewed spacecraft}}
{{excerpt|Uncrewed spacecraft|only=paragraphs}}

=== Human ===
{{Main|Human spaceflight}}
[[File:ISS-20 Robert Thirsk at the Minus Eighty Degree Laboratory Freezer.jpg|thumb|[[International Space Station|ISS]] crew member stores samples.]]

The first human spaceflight was [[Vostok 1]] on April 12, 1961, on which [[astronaut|cosmonaut]] [[Yuri Gagarin]] of the [[USSR]] made one orbit around the Earth. In official Soviet documents, there is no mention of the fact that Gagarin parachuted the final seven miles.<ref>[https://web.archive.org/web/20020419041313/http://www.astronautix.com/flights/vostok1.htm Vostok 1]. Astronautix.com. Retrieved on 2011-10-05.</ref> As of 2020, the only spacecraft regularly used for human spaceflight are [[Soyuz spacecraft|Soyuz]], [[Shenzhou spacecraft|Shenzhou]], and [[Crew Dragon]]. The U.S. [[Space Shuttle]] fleet operated from April 1981 until July 2011. [[SpaceShipOne]] has conducted three human suborbital space flights.

=== Sub-orbital ===
{{Main| Sub-orbital spaceflight}}
[[Image:X-15 flying.jpg|thumb|The [[North American X-15]] in flight. X-15 flew above {{cvt|100|km}} twice and both of the flights were piloted by [[Joseph A. Walker|Joe Walker (astronaut)]].]]

On a [[sub-orbital spaceflight]] the spacecraft reaches space and then returns to the atmosphere after following a (primarily) ballistic trajectory. This is usually because of insufficient [[specific orbital energy]], in which case a suborbital flight will last only a few minutes, but it is also possible for an object with enough energy for an orbit to have a trajectory that intersects the Earth's atmosphere, sometimes after many hours. [[Pioneer 1]] was NASA's first [[space probe]] intended to reach the Moon. A partial failure caused it to instead follow a suborbital trajectory to an altitude of {{convert|113854|km|mi|sp=us}} before reentering the Earth's atmosphere 43 hours after launch.

The most generally recognized boundary of space is the [[Kármán line]] {{cvt|100|km}} above sea level. (NASA alternatively defines an astronaut as someone who has flown more than {{cvt|50|mi|km|order=flip}} above sea level.) It is not generally recognized by the public that the increase in potential energy required to pass the Kármán line is only about 3% of the orbital energy (potential plus kinetic energy) required by the lowest possible Earth orbit (a circular orbit just above the Kármán line.) In other words, it is far easier to reach space than to stay there. On May 17, 2004, [[Civilian Space eXploration Team]] launched the GoFast rocket on a suborbital flight, the first amateur spaceflight. On June 21, 2004, [[SpaceShipOne]] was used for the first [[Private spaceflight|privately funded]] [[human spaceflight]].

=== Point-to-point ===
Point-to-point, or Earth to Earth transportation, is a category of [[sub-orbital spaceflight]] in which a spacecraft provides rapid transport between two terrestrial locations.<ref name="nsp_ete">
{{cite web
 |url=https://www.nasaspaceflight.com/2020/12/earth-to-earth-supersonic-airliners/
 |title=Preparing for "Earth to Earth" space travel and a competition with supersonic airliners
 |last=Burghardt 
 |first=Thomas
 |date=December 26, 2020
 |website=NASA Spaceflight
 |access-date=January 29, 2021
 |quote=The most prevalent concept for suborbital Earth to Earth transportation comes from none other than Elon Musk and SpaceX. Primarily designed for transporting large payloads to Mars for the purpose of colonization, the next generation Starship launch system offers a bonus capability for transporting large amounts of cargo around Earth.
}}
</ref> A conventional airline route between [[London]] and [[Sydney]], a flight that normally lasts [[Non-stop flight#Future of ultra long-haul|over twenty hours]], could be traversed in less than one hour.<ref>{{cite web | url=http://www.spacex.com/sites/spacex/files/making_life_multiplanetary_transcript_2017.pdf | title=Becoming a Multiplanetary Species | date=29 September 2017 | series=68th annual meeting of the International Astronautical Congress in Adelaide, Australia | publisher=SpaceX | access-date=15 April 2018 | archive-date=8 August 2018 | archive-url=https://web.archive.org/web/20180808022709/http://www.spacex.com/sites/spacex/files/making_life_multiplanetary_transcript_2017.pdf | url-status=dead }}</ref> While no company offers this type of transportation today, [[SpaceX]] has revealed plans to do so as early as the 2020s using [[SpaceX Starship|Starship]]. Suborbital spaceflight over an intercontinental distance requires a vehicle velocity that is only a little lower than the velocity required to reach low Earth orbit.<ref>{{cite web|first=David |last=Hoerr |url=http://www.thespacereview.com/article/1118/1 |title=Point-to-point suborbital transportation: sounds good on paper, but… |work=The Space Review |date=May 5, 2008 |access-date=November 5, 2013}}</ref> If rockets are used, the size of the rocket relative to the payload is similar to an Intercontinental Ballistic Missile (ICBM). Any intercontinental spaceflight has to surmount problems of heating during atmospheric re-entry that are nearly as large as those faced by orbital spaceflight.

=== Orbital ===
{{Main| Orbital spaceflight}}
[[File:S68-27366.jpg|thumb|upright|Apollo 6 heads into orbit.]]
A minimal [[orbital spaceflight]] requires much higher velocities than a minimal sub-orbital flight, and so it is technologically much more challenging to achieve. To achieve orbital spaceflight, the tangential velocity around the Earth is as important as altitude. In order to perform a stable and lasting flight in space, the spacecraft must reach the minimal [[orbital speed]] required for a [[orbit|closed orbit]].

=== Interplanetary ===
{{Main|Interplanetary spaceflight|Interplanetary mission}}

[[Interplanetary spaceflight]] is flight between planets within a single [[planetary system]]. In practice, the use of the term is confined to travel between the planets of the [[Solar System]]. Plans for future crewed interplanetary spaceflight missions often include final vehicle assembly in Earth orbit, such as NASA's [[Constellation program]] and Russia's [[Kliper]]/[[Parom]] tandem.

=== Interstellar ===
{{Main|Interstellar travel}}

''[[New Horizons]]'' is the fifth spacecraft put on an escape trajectory leaving the [[Solar System]]. ''Voyager 1'', ''Voyager 2'', ''Pioneer 10'', ''Pioneer 11'' are the earlier ones. The one farthest from the Sun is ''[[Voyager 1]]'', which is more than 100 [[Astronomical unit|AU]] distant and is moving at 3.6 AU per year.<ref>{{cite web|url=http://www.heavens-above.com/solar-escape.asp
 |title=Spacecraft escaping the Solar System
 |publisher=Heavens-Above GmbH
 |url-status=dead  |archive-url=https://web.archive.org/web/20070427184732/http://www.heavens-above.com/solar-escape.asp |archive-date=April 27, 2007 }}</ref> In comparison, [[Proxima Centauri]], the closest star other than the Sun, is 267,000 AU distant. It will take ''Voyager 1'' over 74,000 years to reach this distance.<!-- This still borders on original research, but is at least consistent with cited sources. --> Vehicle designs using other techniques, such as [[nuclear pulse propulsion]] are likely to be able to reach the nearest star significantly faster. Another possibility that could allow for human interstellar spaceflight is to make use of [[time dilation]], as this would make it possible for passengers in a fast-moving vehicle to travel further into the future while aging very little, in that their great speed slows down the rate of passage of on-board time. However, attaining such high speeds would still require the use of some new, advanced method of [[Spacecraft propulsion|propulsion]]. [[Dynamic soaring]] as a way to travel across interstellar space has been proposed as well.<ref name="SA-20221206">{{cite news |last=Mcrae |first=Mike |title='Dynamic Soaring' Trick Could Speed Spacecraft Across Interstellar Space |url=https://www.sciencealert.com/dynamic-soaring-trick-could-speed-spacecraft-across-interstellar-space |date=6 December 2022 |work=[[ScienceAlert]] |accessdate=6 December 2022 }}</ref><ref name="FST-20221128">{{cite journal |last1=Larrouturou |first1=Mathias N. |last2=Higgns |first2=Andrew J. |last3=Greason |first3=Jeffrey K. |title=Dynamic soaring as a means to exceed the solar wind speed |date=28 November 2022 |journal=  Frontiers in Space Technologies|volume=3 |doi=10.3389/frspt.2022.1017442 |arxiv=2211.14643 |bibcode=2022FrST....317442L |doi-access=free }}</ref>

=== Intergalactic ===
{{Main|Intergalactic travel}}

Intergalactic travel involves spaceflight between galaxies, and is considered much more technologically demanding than even interstellar travel and, by current engineering terms, is considered [[science fiction]]. However, theoretically speaking, there is nothing to conclusively indicate that intergalactic travel is impossible. To date several academics have studied intergalactic travel in a serious manner.<ref name="burruss">{{cite journal | first1 = Robert Page | last1 = Burruss | first2= J. | last2= Colwell | title = Intergalactic Travel: The Long Voyage From Home | journal = The Futurist | date=September–October 1987 | volume= 21 | issue= 5 | pages = 29–33}}</ref><ref>{{cite journal | author= Fogg, Martyn | title= The Feasibility of Intergalactic Colonisation and its Relevance to SETI | journal= Journal of the British Interplanetary Society | volume= 41 | number= 11 | date= November 1988 | pages= 491–496 | url= https://www.academia.edu/4166742 | bibcode= 1988JBIS...41..491F }}</ref><ref>{{cite journal | author= Armstrong, Stuart | author2= Sandberg, Anders | url= http://www.fhi.ox.ac.uk/wp-content/uploads/intergalactic-spreading.pdf | title=Eternity in six hours: intergalactic spreading of intelligent life and sharpening the Fermi paradox | journal= Acta Astronautica | year= 2013 | volume= 89 | page= 1 | publisher= Future of Humanity Institute, Philosophy Department, Oxford University| doi= 10.1016/j.actaastro.2013.04.002 | bibcode= 2013AcAau..89....1A }}</ref>