A cycler is a potential spacecraft on a closed transfer orbit that would pass close to two

celestial bodies An astronomical object, celestial object, stellar object or heavenly body is a naturally occurring physical entity, association, or structure that exists in the observable universe. In astronomy, the terms ''object'' and ''body'' are often us ...

at regular intervals. Cyclers could be used for carrying heavy supplies,

life support Life support comprises the treatments and techniques performed in an emergency in order to support life after the failure of one or more vital organs. Healthcare providers and emergency medical technicians are generally certified to perform basic ...

and radiation shielding.

Free return trajectory

A free-return trajectory is a symmetrical orbit past the moon and Earth that was first analysed by Arthur Schwaniger

Lunar cycler

A ''lunar cycler'' or ''Earth–Moon cycler'' is a cycler orbit, or spacecraft therein, which periodically passes close by the Earth and the Moon, using gravity assists 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.

Mars cycler

A ''Mars cycler'' or ''Earth–Mars cycler'' is a spacecraft trajectory that encounters the Earth and Mars on a regular basis, or a spacecraft on such a trajectory

Interstellar cycler

An ''interstellar cycler'' or ''Schroeder cycler'', a theoretical spacecraft trajectory that encounters two or more stars on a regular basis, or a spacecraft on such a trajectory

References

Space Spacecraft {{spacecraft-stub fr:Cycler