A lunar cycler or Earth–Moon cycler is a
cycler
A cycler is a potential spacecraft on a closed transfer orbit that would pass close to two celestial bodies at regular intervals. Cyclers could be used for carrying heavy supplies, life support and radiation shielding.
Free return trajectory
A ...
orbit, or
spacecraft
A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, p ...
therein, which periodically passes close by the
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
and the
Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
, using
gravity assist
In orbital mechanics and aerospace engineering, a gravitational slingshot, gravity assist maneuver, or swing-by is the use of the relative movement (e.g. orbit around the Sun) and gravity of a planet or other astronomical object to alter the p ...
s and occasional
propellant-powered corrections to maintain its trajectories between the two. If the fuel required to reach a particular cycler orbit from both the Earth and the Moon is modest, and the travel time between the two along the cycler is reasonable, then having a spacecraft in the cycler can provide an efficient and regular method for space transportation.
History
Buzz Aldrin
Buzz Aldrin (; born Edwin Eugene Aldrin Jr.; January 20, 1930) is an American former astronaut, engineer and fighter pilot. He made three spacewalks as pilot of the 1966 Gemini 12 mission. As the Lunar Module ''Eagle'' pilot on the 1969 A ...
first suggested the use of cycler orbits in 1985 for the life support equipment and logistical supplies necessary for extensive human exploration of the Moon and Mars. He also presented his thoughts on the benefits of using cycler spacecraft at the Space 88 Symposium in Albuquerque during a panel discussion on "Approaching the Construction Problems in Space." These trajectories must have the characteristic that they can be easily targeted for either launch or destination planet and that the times between encounters yield a reasonable stay time on the destination and provide for both routine and emergency return on a fairly regular basis.
See also
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Free-return trajectory
In orbital mechanics, a free-return trajectory is a trajectory of a spacecraft traveling away from a primary body (for example, the Earth) where gravity due to a secondary body (for example, the Moon) causes the spacecraft to return to the primar ...
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Interstellar cycler
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Mars cycler
A Mars cycler (or Earth–Mars cycler) is a kind of spacecraft trajectory that encounters Earth and Mars regularly. The term Mars cycler may also refer to a spacecraft on a Mars cycler trajectory. The Aldrin cycler is an example of a Mars cycler. ...
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Spaceflight
Spaceflight (or space flight) is an application of astronautics to fly spacecraft into or through outer space, either with or without humans on board. Most spaceflight is uncrewed and conducted mainly with spacecraft such as satellites in or ...
References
{{Reflist
Spaceflight concepts
Missions to the Moon