Continuous Mars Habitation with a Limited Number of Cycler Vehicles

We present cycler and semi-cycler trajectories to transport crews from Earth to a Mars base and back. It is assumed that the Mars base should never be abandoned and that the cycler vehicles safely and comfortably transport twelve people at a time. Since these cycler vehicles involve a significant investment, as few as possible should be built. We examine trades between the number of vehicles, the trajectory V, and the crew mission duration. The trajectory V drives propulsion system requirements and the mission duration affects the crew’s health. One-, two-, and three-vehicle scenarios are presented to sustain the colonization of Mars.