Editing Trans-lunar injection (section)

== History ==
[[File:Animation of GRAIL-A trajectory.gif |thumb |right |Animation of GRAIL-A{{'s}} trajectory<br />{{legend2|magenta|[[GRAIL|GRAIL-A]]}}{{·}}{{legend2|Lime|[[Moon]]}}{{·}}{{legend2|RoyalBlue|[[Earth]]}}]]
[[File:Animation of Chandrayaan-2 around Earth - Geocentric phase.gif|thumb|right|Animation of Chandrayaan-2{{'s}} trajectory<br />{{legend2|RoyalBlue|Earth}}{{·}}{{legend2|Lime|Moon}}{{·}}{{legend2|Magenta|[[Chandrayaan-2]]}}]]
[[File:Animation of Lunar Reconnaissance Orbiter trajectory around Earth.gif|thumb|right|Animation of LRO trajectory<br />{{legend2|magenta|[[Lunar Reconnaissance Orbiter]]}}{{·}}{{legend2|RoyalBlue|Earth}}{{·}}{{legend2|DarkGoldenrod|Moon}}]]
The first space probe to attempt TLI was the [[Soviet Union]]'s [[Luna 1]] on January 2, 1959 which was designed to impact the Moon. The burn however didn't go exactly as planned and the spacecraft missed the Moon by more than three times its radius and was sent into a heliocentric orbit.<ref>{{cite web|url=https://solarsystem.nasa.gov/missions/luna-01/in-depth/|title=Luna 01|publisher=[[NASA]]|access-date=2019-06-10|archive-date=2020-09-05|archive-url=https://web.archive.org/web/20200905220216/https://solarsystem.nasa.gov/missions/luna-01/in-depth/|url-status=dead}}</ref> [[Luna 2]] performed the same maneuver more accurately on September 12, 1959 and crashed into the Moon two days later.<ref>{{Cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1959-014A|title=NASA - NSSDCA - Spacecraft - Details|website=nssdc.gsfc.nasa.gov}}</ref> The Soviets repeated this success with 22 more [[Luna programme|Luna]] missions and 5 [[Zond program|Zond]] missions travelling to the Moon between 1959 and 1976.<ref>{{Cite web|url=https://nssdc.gsfc.nasa.gov/planetary/lunar/lunarussr.html|title=Soviet Missions to the Moon|website=nssdc.gsfc.nasa.gov}}</ref>

The United States launched its first lunar impactor attempt, [[Ranger 3]], on January 26, 1962, which failed to reach the Moon. This was followed by the first US success, [[Ranger 4]], on April 23, 1962.<ref>{{cite web|url=https://solarsystem.nasa.gov/missions/ranger-4/in-depth/|title=Ranger 4|publisher=[[NASA]]}}</ref> Another 27 US missions to the Moon were launched from 1962 to 1973, including five successful [[Surveyor program|Surveyor]] soft landers, five [[Lunar Orbiter program|Lunar Orbiter]] surveillance probes,<ref name=BeyondEarth>{{cite web|url=https://www.nasa.gov/sites/default/files/atoms/files/beyond-earth-tagged.pdf|title=Beyond Earth|publisher=[[NASA]]}}</ref>{{rp|166}} and nine [[Apollo program|Apollo]] missions, which landed the first humans on the Moon.

For the Apollo lunar missions, TLI was performed by the restartable [[J-2 (rocket engine)|J-2]] engine in the [[S-IVB]] third stage of the [[Saturn V]] rocket.  This particular TLI [[combustion|burn]] lasted approximately 350 seconds, providing 3.05 to 3.25&nbsp;km/s (10,000 to 10,600&nbsp;ft/s) of [[Delta-v|change in velocity]], at which point the spacecraft was traveling at approximately 10.4&nbsp;km/s (34150&nbsp;ft/s) relative to the Earth.<ref>{{cite web |url=https://history.nasa.gov/SP-4029/Apollo_18-24_Translunar_Injection.htm |title=Apollo By the Numbers |publisher=[[NASA]]|archive-url=https://web.archive.org/web/20041118103812/https://history.nasa.gov/SP-4029/Apollo_18-24_Translunar_Injection.htm|archive-date=2004-11-18}}</ref> The Apollo 8 TLI was spectacularly observed from the Hawaiian Islands in the pre-dawn sky south of Waikiki, photographed and reported in the papers the next day.<ref>{{cite web |url=https://newspaperarchive.com/independent-star-news/1968-12-22 |title=Independent Star News, Sunday, December 22, 1968 |date=22 December 1968 }} "The TLI firing was begun at PST while the craft was over Hawaii and it was reported there that the burn was visible from the ground."</ref>  In 1969, the Apollo 10 pre-dawn TLI was visible from [[Cloncurry]], [[Australia]].<ref name=ShadowOfTheMoon372>{{cite book |title=[[In the Shadow of the Moon (book)|In the Shadow of the Moon]] |last=French |first=Francis |author2=Colin Burgess |year=2007 |publisher=[[University of Nebraska Press]] |isbn=978-0-8032-1128-5 |page=[https://archive.org/details/inshadowofmoonch0000fren/page/372 372] }}</ref> It was described as resembling car headlights coming over a hill in fog, with the spacecraft appearing as a bright comet with a greenish tinge.<ref name=ShadowOfTheMoon372/>

In 1990 [[Japan]] launched its first lunar mission, using the [[Hiten (spacecraft)|Hiten]] [[satellite]] to fly by the Moon and place the Hagoromo [[Microsatellite (spaceflight)|microsatellite]] in a lunar orbit. Following that, it explored a novel low [[delta-v]] TLI method with a 6-month transfer time (compared to 3 days for Apollo).<ref name="esa">{{cite journal|url=https://www.researchgate.net/publication/245307635|title=Technical Requirements for Lunar Structures |journal=Journal of Aerospace Engineering |author1=Alexander M. Jablonski |author2=Kelly A. Ogden|date=April 2008}}</ref><ref name=BeyondEarth/>{{rp|179}}

The 1994 US ''[[Clementine (spacecraft)|Clementine]]'' spacecraft, designed to showcase lightweight technologies, used a 3 week long TLI with two intermediate Earth flybys before entering a lunar orbit.<ref name="esa"/><ref name=BeyondEarth/>{{rp|185}}

In 1997 [[Asiasat-3]] became the first commercial satellite to reach the Moon's sphere of influence when, after a launch failure, it swung by the Moon twice as a low delta-v way to reach its desired geostationary orbit. It passed within 6200&nbsp;km of the Moon's surface.<ref name="esa"/><ref name=BeyondEarth/>{{rp|203}}

The 2003 ESA [[SMART-1]] technology demonstrator satellite became the first European satellite to orbit the Moon. After being launched into a [[geostationary transfer orbit]] (GTO), it used solar powered ion engines for propulsion. As a result of its extremely low delta-v TLI maneuver, the spacecraft took over 13 months to reach a lunar orbit and 17 months to reach its desired orbit.<ref name=BeyondEarth/>{{rp|229}}

China launched its first Moon mission in 2007, placing the [[Chang'e 1]] spacecraft in a lunar orbit. It used multiple burns to slowly raise its apogee to reach the vicinity of the Moon.<ref name=BeyondEarth/>{{rp|257}}

India followed in 2008, launching the [[Chandrayaan-1]] into a GTO and, like the Chinese spacecraft, increasing its apogee over a number of burns.<ref name=BeyondEarth/>{{rp|259}}

The soft lander ''[[Beresheet]]'' from the [[Israel Aerospace Industries]], used this maneuver in 2019, but crashed on the Moon.

In 2011 the NASA [[GRAIL]] satellites used a low delta-v route to the Moon, passing by the Sun-Earth L1 point, and taking over 3 months.<ref name=BeyondEarth/>{{rp|278}}