Modular Power, PNT, and Communication Infrastructure Development Options for Cislunar Space Exploration

The US Defense Advanced Research Projects Agency (DARPA) 10-Year Lunar Architecture (LunA-10) announcement (DARPA, 2023) envisions a thriving lunar economy that necessitates rapid scaling of lunar exploration and commerce activities within the next decade. This rapid scaling, facilitated by the deployment of modular lunar infrastructure subsystems, can bring about a paradigm shift in cislunar space exploration. Among these subsystems, power, position navigation timing (PNT), and communication systems are identified as critical infrastructures for early human and machine lunar surface exploration. This paper presents a pivotal NGC trade study for modular power, low to medium data rate (<4 Mbps), and low size, weight, and power (SWaP) mobile joint communications-PNT (Comms-PNT) and Lunar Search and Rescue (LunarSAR) subsystem options, and preliminary performance bounds. These early critical lunar terrestrial Power, Comms-PNT, and LunarSAR network subsystems and their key subcomponents listed below are envisioned to begin covering the South Pole region. The terrestrial Comms-PNT modular subsystems are not just designed to be expandable but also to be adaptable, ensuring that they can evolve to meet the changing PNT and geo-referencing control segment assets per National Aeronautics and Space Administration (NASA) Lunar Communications Relay and Navigation Systems services requirements document (LCRNS SRD) (NASA 2022a & 2022b) to support future LunaNet specification (NASA 2023) for cislunar spacecraft and installations. (i) Portable Cold Rubidium Microwave Atomic master clocks below ten ns/year long-term frequency stability design options (ii) Stable-oscillator enabled Deep-integrating GNSS Software-Defined Radio (SDR), potentially co-processing Lower Lunar Orbiter (LLO) transmitted Comms-PNT signal. The LLO Comms-PNT signal is proposed to be compatible with Low SWaP terrestrial Comms-PNT and LunarSAR (CPSR) signals. The CPSR signals are proposed and designed per the IEEE Internet-of-Things (IoT) low rate and low power real-time location system (RTLS) concept, but with higher range, two-way accuracy, data rate, and LLO Doppler agility, authentication, and commercial crypto considerations. (iii) S/Ka-band Two-Way Time and Frequency Transfer (TWTFT) and distributed timekeeping Kalman Filters (TKF) for CPSR mesh network synchronization (iv) Access to simultaneous wireless information and power transmission (SWIPT) capabilities. NGC is currently maturing technologies that support space-based wireless power transfer, enabled by the invention of a modular tile that harvests solar energy and redirects it using an RF-phased array (v) Optional Lunar Rovers equipped with the space-rated Inertial Measurement Unit (IMU, e.g., LN-200S in Mars Rover programs), with EO/IR sensor fusion/mapping capability as expandable CPSR anchor nodes with self-calibration, and position surveying features for LCRNS two-way orbit-clock determination