Design of halo orbit constellation for lunar global positioning and communication services

A lunar global positioning–navigation–timing (PNT) and communication system can greatly support the exploration and exploitation of the Moon. In this study, the application of the stable orbits of the L ${}_1$ and L ${}_2$ halo families and the unstable orbits of L ${}_3$ in the Earth–Moon system is analyzed, and a design is proposed. L ${}_3$ halo orbits are considered for a continuous line-of-sight satellite infrastructure for the Earth–Moon communication, thereby providing an opportunity for ground stations on the Earth to participate in lunar missions even if they do not directly see the Moon. In this study, a constellation of 26 satellites distributed over a lunar segment, made of four halo orbits of L ${}_1$ and L ${}_2$, and a terrestrial segment, made of two halo orbits of L ${}_3$, is designed; this constellation facilitates global and continuative Earth–Moon communication and provides accurate and continuous lunar PNT service. According to a station-keeping analysis in the framework of the elliptical restricted three-body problem, the maintenance cost for approximately 60 d was 0.76 m/s for the lunar segment and 0.02 m/s for the terrestrial segment.