CIS-SIM Facility: The Galileo-based European Navigation and Communication Constellation Simulator for the Cis-lunar Society

Abstract

ESA's Lunar Communication and Navigation Service (LCNS) programme aims to catalyse upcoming lunar missions, including NASA's Lunar Gateway, by offering a turnkey communication and navigation service solution. The service shall be enabled by a lunar satellite constellation and offered to customers with spacecrafts in lunar orbit, lunar orbital descent and for lunar surface operations. To be able to develop, test and operate this lunar Navigation and Communication (navcom) infrastructure and the technology enabling and improving it, it is of importance to have a representative simulation environment as early as possible in the programme. Amongst others, such a simulation environment can be used to evaluate the navcom signals and mission concepts, to train operators and service customers, to troubleshoot anomalies of the deployed lunar infrastructure, to conduct test campaigns of orbital/surface mission scenarios (e.g for ESA's Moon Village, Lunar Gateway, etc.), and to develop advanced Position Navigation and Timing (PNT) solutions (e.g. lunar Precise Point Positioning (PPP) corrections, terrestrial GNSS signal augmentation, etc.). We therefore suggest beginning with the development of the CIS-SIM Facility, representing a global first for a lunar navigation and communication constellation simulator, by reusing major components of flight-proven ground segment software of an active GNSS, namely Galileo. Its main purpose is to simulate the satellite constellation in the lunar orbit environment, to model the navcom signal propagation/distribution, and to allow simulated monitoring and control of the satellite platforms as well as their navcom payloads. Therefore, the design herein presented is a holistic and hybrid solution, being a navcom signal service volume simulator and a spacecrafts constellation simulator in one facility. The facility is a key infrastructure for the development of future cis-lunar navigation and communication technologies and lowers the barriers for their potential translunar application. It brings commercial and scientific space activities together and helps legacy and new market entrants to participate in the lunar industrialization process. Within this paper, we introduce to the overall topic and in particular to ESA's LCNS programme. We elaborate on the CISSIM facility design with its core elements. We then showcase the potential for extensions by exemplary outlining three options and conclude the paper with the future outlook of the project.