Mars Cycler
Image from Steve Bowers
The Mars Cycler Valparaiso, a craft that journeyed between Earth and Mars for more than two hundred years, slowly increasing in size with each cycle as extra units were added.

A cycler is a ship or mobile habitat that travels continuously along an orbit or interstellar route in such a way that it makes a regular series of rendezvous with other stations, orbitals, planets, or stars along the way.

Cyclers may be small or large, spartan or luxurious, slow or fast. They may travel within a single solar system; such an interplanetary cycler is also called an Aldrin Cycler, named after Buzz Aldrin, the second human to stand on the Moon, who was also a proponent of the cycler concept. Interplanetary cyclers tend to travel slowly and follow minimum-energy orbits and only rarely approach closely to any particular planet.

Interstellar cyclers are also known as a Schroeder Cycler, named after Karl Schroeder, who was a proponent of the Beamrider concept and also suggested that these craft could follow long circuitous routes that eventually return to their point of origin.

A cycler of either kind may rely upon beamed propulsion or may carry propulsion systems capable of accelerating the ship independently if required. Interplanetary cyclers can take advantage of the Oberth Effect when passing close to a planet, making course corrections possible while using less energy. Interstellar cyclers are usually part of the Beamrider network, and course corrections are achieved through the use of a boostbeam.

Depending on the route and speed, a single cycle may take anywhere from a few months to many millennia. Cyclers often grow in size and sophistication over time, adding new segments and improved technical systems whenever they pass close to a target system.

Cycler and Beamstation
Image from Steve Bowers
The G. David Nordley, an interstellar cycler ship propelled by a beam of smart particles (collected by a magnetic sail created by a superconducting loop at the rear)

One of the most intriguing Cycler routes is that established between the alien High Energy Emission Civilisation HEEC-1 and the xenosophonts known as the Soft Ones. This route passes entirely outside the Terragen Sphere, and no contact has yet been made between the Terragen civilisation and the mysterious Traders who travel this route.
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Development Notes
Text by M. Alan Kazlev
additional material by Steve Bowers
Initially published on 24 September 2001.

Additional Information
More on Mars Cyclers here
Mars cycler