Lunar Network Digital Twin

Space communication from its genesis has played a key role in providing secure, high-speed global services that are accessible to most terrestrial users anywhere on Earth. However, with a plethora of upcoming space missions planned for at least the next decade, the Cislunar regime plays a centerpiece in all the missions. A dedicated satellite constellation around the moon and a dedicated relay system in the Cislunar space can greatly enhance the efficiency of accessing Earth, additionally also acting as a sustainable means of cislunar and deep-space communication. This thesis work aims to have an initial design architecture motivation from NASA & ESA’s LunaNet concept on a high-fidelity lunar frozen constellation with supporting relay satellites acting as gateways between Earth and Lunar constellations.

The study focus on designing constellations that could support communication and PNT services for lunar surface and orbiting users. Initial studies are based on providing these services to the high-density terminals on South pole, thus shortlisting to an Elliptical Lunar Frozen Orbit (ELFO) scenario!

Elliptical Lunar Frozen Orbit (ELFO) STK Visualization.

SelenoNet brings together a high-fidelity instantiation of Earth based control ground stations, relay satellite systems in the Cislunar regime and a lunar service constellation systems (Walker or ELFO types) with all levels of relevant interactions needed to support sustainable communication and navigation services to the lunar-based users. Its support for both lunar orbits as well as Earth-Moon L1 Lissajous & Halo orbits with a backend RFC-9174 based BPv7 deep space communication protocol allows a realistic emulation of transreceiving signals between Earth. Moreover, the lunar main constellation has additional navigation data broadcating support that the simulated lunar receivers can actively listen to and estimate their precise point positions, additionally, also running an Extended Kalman Filter (EKF) algorithm to ameliorate the positions for both inertial and non-inertial kinematics.

Position-Navigation-Timing Least Square (orange) and EKF (purple) point position estimates for a stationary user at South pole and a lunar orbiting user. [16sat ELFO navigation constellation.]

Virginia Tech’s SpaceNet emulator (Downs et al., 2025) leveraged to analyze the network perforamance between specified source and destination nodes. The emulator’s flexible support for inertial/non-inertial users and dynamics block allows for near-realistic values of latency and throughput metrics. Figures below show one of the initial experiment of the testbed’s lunar support with the associated Round Trip Time (RTT) plot.

Sea of Tranquality to Schrodinger Basin ping test.

The designing of the constellation was done with particle swarm multi-objective optimization with the objective of maximizing total coverage area, minimizing dilution of precision for south pole and maximizing the career-to-noise density ratio, so that the resultant constellation with sufficient bounds on number of satellites and orbits is capable of providing sufficient quality of service (QoS). The pareto swarm members represent such optimal constellations and with every iteration the swarm closes more towards the optimal phase space. One such optimal constellation is shown below where the white markers represent the satellites with direct line of sight with South pole.

Multi-Objective Particle Swarm Optimization of ELFO constellations for Lunar users

Low Earth Orbit mega-constellations make up a large portion of modern developments in space communications. The ability to simulate and properly research these complex systems is currently being developed to answer questions on the capabilities of the rapidly expanding industry. The development and improvement of a simulation-based platform for satellite network testing can help research efforts to enable industry and government entities to work together in the growing enterprise. The ongoing development of the SpaceNet Testbed is investigated, detailing its use of orbit-based constellation dynamics modeling, software-based emulation, and a hardware-in-the-loop integration design. An overview of the testbed’s software infrastructure design is described alongside details regarding the make-up of its hardware components. Use cases are presented comparing the differences in performance between the satellite network of an actual Starlink mega-constellation currently in orbit and a custom constellation with the same quantity of satellites, but with ideal node spacing and initial orbital positioning. Results of these use cases are then discussed, focusing on the latency of the data traffic and how it differs when varying the testbed’s user-defined configurations. In the future, resiliency testing and ground station to satellite link behavior analysis can be included into the testbed. The testbed has potential to help lead efforts in simulating complex space communication systems.

References

2025