Mars cycler

Abstract: Trajectories that regularly encounter Earth and Mars but use small or no propulsive maneuvers are known as cycler trajectories, or cyclers. For cyclers that repeat after two Earth-Mars synodic periods, several variations are possible. A detailed investigation is presented of a simple two synodic period cycler, along with several promising variations using combinations of one year and half-year phasing orbits. Analysis is included for both the circular co-planar model and with actual Earth and Mars ephemerides.

Abstract: We construct a cycler (with acceptable transfer times and moderate encounter velocities) by patching a series of three-synodic-period semicycler trajectories together. The cycler employs high-efficiency low-thrust propulsion for trajectory maintenance and correction (thus making it a "powered" cycler). Even though the propellant usage is not insignificant, we believe that this cycler still compares favorably with ballistic cyclers (that is, cyclers that do not require deterministic maneuvers), which require four (or more) vehicles, especially when considering the long-term cost to supply and maintain each vehicle. An attractive feature of this cycler is that both short inbound and outbound legs occur within each semicycler segment, thus reducing the number of required vehicles (which provide transfer opportunities every synodic period) to only three.

Abstract: Sun-orbiting spacecraft trajectories that repeatedly encounter Earth and Mars may play a central role in a future Earth-Mars transportation system. Such orbits are known as Earth-Mars cycler trajectories (cyclers). By using gravity-assist maneuvers at Earth or Mars, many cyclers can avoid using large amounts of propellant. The known cyclers were found using heuristics or numerical searches. We describe a new, systematic method for constructing and evaluating cyclers. Our method reveals that previously known cyclers, such as the Aldrin cycler and the Versatile International Station for Interplanetary Transport cyclers, belong to a larger family of cyclers. Our cycler construction method also reveals some previously unknown cyclers. For example, we identify a new cycler that repeats every two synodic periods and has a low V ∞ at Earth and Mars (5.65 and 3.05 km/s, respectively).

Abstract: Earth-Mars cycler trajectories (cyclers) repeatedly encounter Earth and Mars. A systematic approach to constructing and evaluating such trajectories is described.