Mixed Low-Thrust Invariant-Manifold Transfers to Distant Prograde Orbits Around Mars

Transfers from Earth to Mars have been extensively studied in the literature, with the prevalent approaches being two-body patched-conics-based trajectory optimization or three-body halo-to-halo transfers augmented by lowthrust coasting arcs. In this work, a new transfer method is suggested. The main idea is to combine manifold theory with low-thrust propulsion in order to reach distant prograde orbits about Mars. The most prominent feature of the said distant prograde orbits is the associated hyperbolic structure, permitting a free capture by coasting on the stable manifold without any additional injection maneuvers. The preliminary design process includes identification of Martian distant prograde orbits via a numerical continuation of known orbits in Hill’s three-body problem and derivation of a three-phase coupled restricted three-body transfer comprising an Earth-escape stage, a heliocentric orbit, and a Martian rendezvous.Adirect nonlinear programming-based low-thrust optimization in a full-ephemeris model including the Earth, the moon, and Mars is used to improve the preliminary design and evaluate the performance of the suggested transfer method.