Navigating to the Moon Along Low-Energy Transfers

TL;DR

This paper develops a navigation strategy for lunar missions using low-energy transfer trajectories, incorporating advanced filtering techniques to ensure accurate orbit determination and successful lunar capture.

Contribution

It introduces an optimal filtering approach for navigation along weak stability boundary transfers, demonstrating the effectiveness of the unscented Kalman filter in this context.

Findings

Unscented Kalman filter meets accuracy and computational requirements.

Lunar weak capture is demonstrated for all trajectories in the capture corridor.

A minimum fuel strategy extends spacecraft lifetime around the Moon.

Abstract

This paper presents a navigation strategy to fly to the Moon along a Weak Stability Boundary transfer trajectory. A particular strategy is devised to ensure capture into an uncontrolled relatively stable orbit at the Moon. Both uncertainty in the orbit determination process and in the control of the thrust vector are included in the navigation analysis. The orbit determination process is based on the definition of an optimal filtering technique that is able to meet accuracy requirements at an acceptable computational cost. Three sequential filtering techniques are analysed: an extended Kalman filter, an Unscented Kalman filter and a Kalman filter based on high order expansions. The analysis shows that only the unscented Kalman filter meets the accuracy requirements at an acceptable computational cost. This paper demonstrates lunar weak capture for all trajectories within a capture corridor defined by all the trajectories in the neighbourhood of the nominal one, in state space. A minimum f'v strategy is presented to extend the lifetime of the spacecraft around the Moon. The orbit determination and navigation strategies are applied to the case of the European Student Moon Orbiter.