Trans-lunar injection
A trans-lunar injection (TLI) is a propulsive maneuver, which is used to send a spacecraft to the Moon. Typical lunar transfer trajectories approximate Hohmann transfers, although low-energy transfers have also been used in some cases, as with the Hiten probe.[1] For short duration missions without significant perturbations from sources outside the Earth-Moon system, a fast Hohmann transfer is typically more practical.
A spacecraft performs TLI to begin a lunar transfer from a low circular
Free return
In some cases it is possible to design a TLI to target a
Such free return trajectories add a margin of safety to human spaceflight missions, since the spacecraft will return to Earth "for free" after the initial TLI burn. The Apollos 8, 10 and 11 began on a free return trajectory,[3] while the later missions used a functionally similar hybrid trajectory, in which a midway course correction is required to reach the Moon.[4][5][6]
Modeling
Patched conics
TLI targeting and lunar transfers are a specific application of the
Restricted circular three body (RC3B)
More realistically, however, the spacecraft is subject to
Further accuracy
More detailed simulation involves modeling the Moon's true orbital motion; gravitation from other astronomical bodies; the non-uniformity of the Earth's and Moon's gravity; including solar radiation pressure; and so on. Propagating spacecraft motion in such a model is numerically intensive, but necessary for true mission accuracy.
History
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.[9] Luna 2 performed the same maneuver more accurately on September 12, 1959 and crashed into the Moon two days later.[10] The Soviets repeated this success with 22 more Luna missions and 5 Zond missions travelling to the Moon between 1959 and 1976.[11]
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.[12] Another 27 US missions to the Moon were launched from 1962 to 1973, including five successful Surveyor soft landers, five Lunar Orbiter surveillance probes,[13]: 166 and nine Apollo missions, which landed the first humans on the Moon.
For the Apollo lunar missions, TLI was performed by the restartable
In 1990
The 1994 US Clementine spacecraft, designed to showcase lightweight technologies, used a 3 week long TLI with two intermediate Earth flybys before entering a lunar orbit.[17][13]: 185
In 1997
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.[13]: 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.[13]: 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.[13]: 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.[13]: 278
See also
- Astrodynamics
- Comparison of super heavy lift launch systems
- Low energy transfer
- Trans-Earth injection
- Trans-Mars injection
References
- ^ "Hiten". NASA.
- ^ Schwaninger, Arthur J. (1963). Trajectories in the Earth-Moon Space with Symmetrical Free Return Properties (PDF). Technical Note D-1833. Huntsville, Alabama: NASA / Marshall Space Flight Center.
- ^ Mansfield, Cheryl L. (May 18, 2017). "Apollo 10". NASA.
- ^ "APOLLO 12". history.nasa.gov.
- ^ Ways to the Moon (PDF) (Report). p. 93.
- ^ "Launch Windows Essay". history.nasa.gov.
- ^ Henri Poincaré, Les Méthodes Nouvelles de Mécanique Céleste, Paris, Gauthier-Villars et fils, 1892-99.
- ^ Victor Szebehely, Theory of Orbits, The Restricted Problem of Three Bodies, Yale University, Academic Press, 1967.
- ^ "Luna 01". NASA. Archived from the original on 2020-09-05. Retrieved 2019-06-10.
- ^ "NASA - NSSDCA - Spacecraft - Details". nssdc.gsfc.nasa.gov.
- ^ "Soviet Missions to the Moon". nssdc.gsfc.nasa.gov.
- ^ "Ranger 4". NASA.
- ^ a b c d e f g h "Beyond Earth" (PDF). NASA.
- ^ "Apollo By the Numbers". NASA. Archived from the original on 2004-11-18.
- ^ "Independent Star News, Sunday, December 22, 1968". 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."
- ^ ISBN 978-0-8032-1128-5.
- ^ a b c Alexander M. Jablonski1a; Kelly A. Ogden (2006). "A Review of Technical Requirements for Lunar Structures – Present Status". Journal of Aerospace Engineering.
{{cite journal}}
: CS1 maint: numeric names: authors list (link)
This article incorporates public domain material from websites or documents of the