Joint Age and Coverage-Optimal Satellite Constellation Relaying in Cislunar Communications with Hybrid Orbits

TL;DR

This paper proposes a hybrid satellite constellation design for cislunar communication that optimizes age and coverage, outperforming traditional configurations through multi-objective genetic algorithms.

Contribution

It introduces a novel hybrid Earth-Moon satellite constellation considering lunar and Earth rotation, optimizing for minimal age and maximal coverage using NSGA-II.

Findings

Significantly reduces average Age of Information (AoI).

Improves coverage of lunar surface regions.

Outperforms traditional Walker Star and Delta constellations.

Abstract

With the ever-increasing lunar missions, a growing interest develops in designing data relay satellite constellations for cislunar communications, which is challenged by the constrained visibility and huge distance between the earth and moon in pursuit of establishing real-time communication links. In this work, therefore, we propose an age and coverage optimal relay satellite constellation for cislunar communication by considering the self-rotation of the earth as well as the orbital motion of the moon, which consists of hybrid Earth-Moon Libration 1/2 (EML1/L2) points Halo orbits, ordinary lunar orbits, and Geostationary Earth Orbit (GEO) satellites. In particular, by minimizing both the number of satellites and the average per-device Age of Information (AoI) while maximizing the coverage ratio of specific lunar surface regions, a multi-objective optimization problem is formulated and solved by using a well-designed Nondominated Sorting Genetic Algorithm-II (NSGA-II). The simulation results demonstrate that our proposed hybrid constellation significantly outperforms traditional Walker Star and Delta constellations in terms of both AoI and the coverage of communication.