Long dwell time orbits for lander-based Mars missions

This paper deals with the possibility of retrieving orbits around Mars able to provide long dwell times over a given area of the planet, without needing expensive orbital corrective manoeuvres. After a general description of the fundamental principles associated with the obtainment of the repeating ground track orbits which satisfy the aforesaid requirement, the concepts have been applied to Mars to gain trajectories which make it possible to maximise the daily contact time between a probe orbiting around the planet and a lander on the surface. The lander has been considered as equipped with an antenna of 0.5 m of diameter, working in the bands C, X, Ku, and the cases of both fixed and mobile antennas have been taken into account.