Design and Development of Fault Tolerant Lunar Satellite Network and Navigation Architecture

Abstract

Space communication and navigation infrastructure has been a vital part in contributing to human civilization commercially and in achieving scientific endeavors in space exploration. The recent surge of attention towards the cislunar and lunar domains, along with scheduled missions until the next couple of decades, demands an understanding of space systems interactions for a sustainable, fault-tolerant lunar architecture. The LunaNet concept is a collaborative work between NASA, ESA and JAXA space agencies, representing the initial framework of interoperable standards and protocols for delivering communications and position, navigation, timing (CandPNT) services to users around the Moon. With LunaNet currently in the initial stages of the development phase, this thesis work aims to determine optimal CandPNT design architectures based on the communication and navigation performance of a stable Elliptical Lunar Frozen Orbit (ELFO) service constellation along with the Earth-Moon relay constellation models. The tradeoff space for the service constellations were explored with the sequential quadratic programming formulation and a multi-objective particle swarm heuristic search formulation to select diverse set of CandPNT designs. A simulation framework, termed SelenoNet, is designed to digitally model interactions within the CandPNT designs in a high-fidelity lunar environment to facilitate space network topology instantiation for emulating IP packets and BPv7 bundle transfers between lunar users and with Earth. Due to independent node instantiation of service satellites and users, SelenoNet can emulate satellite navigation broadcasts with Signal-In-Space errors (SISE) and clock errors to accurately determine precise point positioning for surface and orbiting lunar users. SelenoNet's high-fidelity cislunar propagator is validated using the Ansys Systems Tool Kit (STK) High Precision Orbit Propagation (HPOP) solutions. The resultant optimal constellations' CandPNT performance is evaluated and compared in SelenoNet to inform additional strategic performance for lunar surface ground stations, CandPNT design sensitivity and combinations of orbiting relay designs to maintain the quality of service (QoS).