Perilune Rendezvous Method of Earth-NRHO Transfer Orbit for Cargo Transportation Mission to Gateway

Abstract

As a post-ISS mission, the construction of Gateway in lunar orbit is planned, and a cargo supply mission to Gateway is also being considered by JAXA. NRHO is a candidate orbit for Gateway, and several methods for the transfer trajectory from Earth are being researched. This study proposes a new transfer technique, the Perilune Rendezvous Method (PRM). With this method, a deceleration maneuver during a lunar swing-by inserts a spacecraft into an elliptical lunar orbit. Then, the spacecraft can enter the NRHO with a small velocity increment by waiting for when the orbital plane coincides with the NRHO. Compared with the Lunar Fly-by Method (LFM) adopted by NASA for manned flight missions, the PRM can reduce the required ΔV, but the transition requires a longer period. This method expands the options for cargo supply and manned flight missions. In this paper, the transfer trajectory from Earth to the NRHO is designed using both methods. Furthermore, the results of the ΔV optimization analysis are compared with the velocity increment and the transition period as variables. This leads to a discussion of the Jacobi integrals of the analysis against the theoretical minimum velocity increment.