DETERMINING MARS PARKING ORBITS THAT ENSURE TANGENTIAL PERIAPSIS BURNS AT ARRIVAL AND DEPARTURE

For a manned Mars mission, many previous interplanetary studies have a rbitrarily assumed that the required parking orbit can be achieved wit h tangential periapsis burns at both Mars arrival and departure withou t considering the actual arrival and departure orbital geometries. As a consequence of this assumption, a misleading estimate of up to 50% o f the initial low-Earth-orbit mass may result for the mission. In this paper, a method is presented that finds Mars parking orbits that allo w tangential periapsis burns at both arrival and departure. This metho d accounts for the actual geometry at both arrival and departure betwe en the hyperbolic asymptotes and the orbital plane, along with the pre cession effects caused by the oblateness of Mars. Thus, realistic DELT AV values (and hence initial low-Earth-orbit masses) are obtained for these orbits. The results obtained from the present method compare ver y well with a trajectory integration program and require CPU times of only about 1 min. Therefore, because of its computational efficiency a nd accuracy, the present method would be an ideal tool to use in preli minary mission design, since it provides the opportunity to incorporat e realistic Mars parking orbits effects.