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Session A8: Space Applications for Cislunar and Beyond

Modular and Future-Proof Power, PNT, and Communication Infrastructure Development Options for Lunar Human Exploration and Cislunar Expansion
Taehwan Kim, Theodore Jaeger, Michael Larsen, and Emmanuel Austin, Northrop Grumman
Location: Ballroom B
Date/Time: Wednesday, Jun. 5, 8:55 a.m.

As the DARPA 10-Year Lunar Architecture (LunA-10) RFI envisioned, a thriving lunar economy within the next decade requires rapid scaling of lunar exploration and commerce activities. Such rapid scaling is only supportable by the deployment of modular and future-proof lunar infrastructure sub-systems, which each successive lunar lander can organically integrate. Among the many sub-systems to be delivered and integrated, Power, PNT, and Communication sub-systems are identified as crucial building blocks enabling early human and machine lunar surface explorations near the South pole of the moon under extreme environments.
This paper presents Northrop Grumman Systems Corporation’s (NGSC) vision for modular and future-proof Lunar Power, PNT, and Communications sub-systems, integration options, and preliminary performance bounds.
For these critical initial lunar terrestrial PNT-Communication networks to cover the South Pole region for early human exploration in dark and dangerous terrain, the NGSC terrestrial PNT network architecture includes the following RF-based sub-components:
(i) Portable Cold Rubidium Microwave Atomic master clock with 10 ns/year long-term stability
(ii) S/Ka-band Two-Way Time and Frequency Transfer (TWTFT) and clock ensemble time-keeping Kalman Filters among pseudo-satellite (pseudolite) anchors
(iii) Lunar Rovers (e.g., VIPER), equipped with the NGC space-rated Inertial Measurement Unit (IMU, e.g., LN-200S), potentially with EO/IR sensor fusion/mapping capability as fixed pseudolite anchor nodes with self-navigation and position surveying
(iv) Access to simulations wireless information and power transmission (SWIPT) capabilities. NGSC 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 a RF phased array. SWIPT is made possible using commercial communication waveforms that deliver multi-service power, communications, and PNT (Power+). NGSC's Power+ transmit arrays scaled to 20m in diameter support delivering W/sq. m scale energy to a significant fraction of the moon’s surface from the Low Lunar Orbiter (LLO). If further evolved, a 200m diameter Ka-band system could achieve kW/sq. meter densities over 1000 Km+ link.
(v) Low SWAP-Cost (SWAP-C) and reconfigurable Software Defined Radio (SDR) User Equipment (UE) for PNT, Communications, and Search-Rescue (e.g., emergency beacon) functions. Low SWAP-C UE is enabled by minimizing the data-rate-limited and initial acquisition-challenged Pseudo Random Noise (PRN) waveforms. By maximizing the bandwidth- and power-efficient Chirp Spread Spectrum that Low Power Wide Area Internet-of-Things (IoT) standards have adopted, a 4 Mbps one-way communication data rate with 40 MHz RF bandwidth is feasible while providing full PNT service in a battery-operated SDR. For further power saving, the SDR UE may not maintain a high-quality oscillator to compute its PNT information but rather send a request to the network to obtain its PNT information back.
In the ensuing Cislunar service volume development cycle, the self-positioning and calibrating lunar rover-based terrestrial pseudolite infrastructure is expected to become the reference station network for precision LLO and Cislunar Relay Orbit (RO) constellation orbit and clock determination.
The presentation demonstrates the feasibility of the Cold Rubidium Atomic Clock, the expected pseudolite PNT performance estimate, and the potential PNT contribution of the SDA pLEO constellation with optional Space Looking Antenna to the lunar terrestrial pseudolite network and cislunar RO constellation.



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