The Road to a Moonbase Goes through Advanced Navigation Based on Open Standards

Illustration of ESA’s Moonlight navigation satellites operating in lunar orbit. Image: Thales Alenia Space / Briot

On March 3, Firefly’s NASA-funded Blue Ghost lander became the first spacecraft to get GNSS navigation signal fixes on the Moon. The joint Italian-US LuGRE receiver onboard Blue Ghost locked on to GNSS signals from both American GPS and European Galileo satellites. LuGRE did the same at distances past 400,000 kilometers too when Blue Ghost was in lunar orbit the month prior. The experiment proved that Earth-based GNSS satellites can help future craft autonomously navigate at the Moon, reducing reliance on more expensive Earth-based tracking.

By placing such navigation and communications (navcom) satellites in lunar orbit directly, we can make it even easier for lunar craft to leverage their services with cheaper hardware onboard. NASA hopes to help fund and utilize an initial set of lunar navcom orbiters to not only relieve its bottlenecked Deep Space Network from high demand but also offer some critical redundancy to future missions. ESA plans to deploy a small navcom constellation called Moonlight by 2030, starting with the Lunar Pathfinder communications relay orbiter launching next year. JAXA has similar plans.

Notably, these national space agencies are coordinating on a “LunaNet” standard so that their navcom constellations interoperate—in principle—similar to GPS and Galileo systems. As such, future private and national Moon missions from these countries might be able to tap into a wider navcom network. It’s also how these countries could catch up with China’s growing lead in lunar navcom, which has operational and planned satellites.

But LunaNet’s interoperability will be basic for these initial navcom satellites, which could constrain the US bloc in the next decade from simultaneously operating numerous craft at the Moon in the build up to an Artemis Moonbase. As such, “enhancing the LunaNet Interoperability Specification (LNIS) is necessary to maximize the effectiveness and success rates of complex missions”, says Dr. Peng Hu, a researcher at the Open Lunar Foundation.

Extensions could include network protocols, better security, and resilience for assets that are spread across lunar orbit, the surface, and Earth. To that end, Dr. Hu will perform comparative analysis and simulations to arrive at a lunar navcom configuration that maximizes results across missions with an open, interoperable infrastructure. We can then have repeated precision landings for crew cargo deliveries and even automated science stations. “If some assets fail, having resilience in the network means lower chances of mission failure,” says Dr. Hu. This could incentivize more commercial players and countries to adopt the standard.

Resilience in LunaNet will add a safety net for long-duration crewed Moon missions. If something goes wrong with a US navcom asset, say, another country’s interoperable constellation could step in to ensure safety of human lives. “An open protocol facilitates that,” adds Dr. Hu.