ZERO-MOMENTUM POINT ANALYSIS AND EPHEMERIS TRANSITION FOR INTERIOR EARTH TO LIBRATION POINT ORBIT TRANSFERS

The last decade has seen a significant increase in activity within cislunar space. The quantity of missions to the Lunar vicinity will only continue to rise following the collab- orative effort between NASA, ESA, JAXA and the CSA to construct the Gateway space station. One significant engineering challenge is the design of trajectories that deliver space- craft to orbits in the Lunar vicinity. In response, this study employs multi-body dynamics to investigate the geometry of two-maneuver transfers to Earth-Moon libration point or- bits. Zero-Momentum Points are employed to investigate transfer behavior in the circular- restricted 3-body problem. It is found that these points along stable invariant manifolds indicate changes in transfer geometry and represent locations where transfers exhibit limit- ing behaviors. The analysis in the lower-fidelity model is utilized to formulate initial guesses that are transitioned to higher-fidelity, ephemeris models. Retaining the solution geometry of these guesses is prioritized, and adaptations to the transition strategy are presented to circumvent numerical issues. The presented methodologies enable the procurement of desir- able trajectories in higher-fidelity models that reflect the characteristics of the initial guess generated in the circular restricted 3-body problem.