Missions to Earth and Mars using a lunar launch facility

Many space agencies are working on solutions for manned operations on the Moon, both on its surface and in cislunar space. In such a scenario, with stable human presence, a launch facility would be needed and launch vehicles could take advantage of the benefits of the lunar environment. In the present paper missions to Earth (to a geostationary orbit) and to Mars (to an areostationary orbit), from a lunar launch facility, has been studied. The trajectories are analysed by using an ephemeris model, taking into account four attractive bodies (Earth, Moon, Sun and Mars). In the first phase of the two missions, the launcher places the spacecraft on a circular lunar orbit by using liquid, solid or hybrid propulsion systems. The latter solution is analysed assuming in situ propellant production using aluminum and oxygen, elements in which the moon is very rich. In the second phase of both the missions, a minimum energy trajectory is studied, which, exploiting the Luni-Solar perturbations, allows the spacecraft to escape the gravitational field of the Moon. In the mission to Earth, this manoeuver puts the spacecraft on a very high and inclined elliptical orbit. The last phase involves a circularization manoeuvre towards the GEO and transfers are studied for two different initial inclinations, using an electric engine. In the mission to Mars, the escape impulse is used to leave both the Earth-Moon and Sun-Earth systems. The interplanetary phase is analysed for several transfer final times and considering an electric engine with variable specific impulse. Finally, the performance of a lunar launch facility is compared to that of a traditional Earth facility, showing great advantages are obtained in terms of payload ratio.