Ephemeris refinement of low-energy Earth–Moon transfers via an astrodynamic model chain

Interest in the exploitation of the cislunar environment is growing exponentially. The establishment of lunar outposts and orbiting gateways is pivotal to enable the next generation of human exploration in the solar system. This paper investigates the refinement process of prototype Earth–Moon transfers, originally designed in the Earth–Moon, Sun-perturbed bi-circular restricted four-body problem, into the full ephemeris. Reference bi-impulsive trajectories, extracted from a dataset of locally optimal solutions, serve as seeds for the generation of flyable cruises to the Moon in the real environment. Complex transfer geometries pose challenges in refinement. A meticulous search for a suitable departure calendar epoch is necessary to facilitate the process. Moreover, passage through an intermediate astrodynamic model, such as the elliptic one, further favors convergence to the high-fidelity representation. As a new era of lunar exploration approaches, this work demonstrates the flyability of complex Earth–Moon transfers within the real solar system, and elucidates the process of achieving such trajectories. • Early-stage trajectories must be refined into an ephemeris-based model. • Lunar orbital eccentricity disrupts interior transfers and requires compensation. • Solar attraction is crucial for exterior Earth–Moon transfers. • Continuation into the elliptic system favors refinement toward the ephemeris model.