Optimal injection into Quasi-Satellite Orbits around Phobos: application to MMX mission

The Japan Aerospace Exploration Agency is aiming to launch in 2024 the Martian Moons eXploration mission. The main scientific objective is to survey the two Martian moons and to return a sample from the surface of Phobos. As nominal scientific orbits, several Quasi-Satellite Orbits around Phobos have been computed and adopted in consideration of the complex dynamical environment characteristic of the Mars--Phobos system. This paper explores the performance capability of a multi-impulsive control strategy to inject the MMX probe into a host of QSOs around Phobos, after a heliocentric journey from the Earth. A perturbation analysis in the vicinity of Phobos is performed using several gravitational models of increasing fidelity. Results show that the CR3BP is a suitable model for this analysis. Finally, a control strategy for the multi-impulsive transfer to Phobos QSOs is presented and, starting from a grid of initial states, optimal QSO injection trajectories are evaluated and discussed.