Targeting a Mars science orbit from Earth using dual chemical-electric propulsion and ballistic capture

Abstract

Ballistic capture is a relatively novel concept in interplanetary mission design with the potential to make Mars and other targets in the Solar System more accessible. A complete end-to-end interplanetary mission from an Earth-bound orbit to a stable science orbit around Mars (in this case, an areostationary orbit) has been conducted using this concept. Sets of initial conditions leading to ballistic capture are generated for different epochs. The influence of the dynamical model on the capture is also explored briefly. Specific capture trajectories are then selected based on a study of their stabilization into an areostationary orbit. This stabilization uses a combination of a brief high-thrust maneuver at periapsis and a low-thrust control law that spirals down to the final orbit. The captures selected are then targeted from the sphere of influence of the Earth with a low-thrust heliocentric transfer that is optimized using direct transcription and non-linear programming theory. An arrival-departure date grid is constructed with fuel-optimal transfers obtained for all epochs considered.
Finally, a simple study of the escape from Earth is performed for completion. A strategy to quickly escape Earth and avoid radiation damage in the Van Allen belts is defined using high-thrust chemical propulsion, including the computation of gravity losses due to the use of finite burn maneuvers. The result is the preliminary mission design of a mission concept to Mars using a 16-Unit CubeSat that employs ballistic capture and dual chemical-electric propulsion to reach an areostationary orbit. Estimations of the time of flight and fuel consumption for each stage of the mission are obtained.