“I think of LunaNet as the big umbrella,” Gramling says. “It’s an architecture that defines the standards to be used for interoperable communications and position, navigation, and timing services. There’s a lot of effort underway to define those standards and document them in a LunaNet interoperability specification.”
“It is a very different paradigm than on Earth, where the United States has GPS, Europe has Galileo or Russia has GLONASS,” he added. “As we are in the early stages, the idea is that we work together as the three partners that are involved in LunaNet so far and establish a system between the three of us.”
In other words, while NASA, ESA and JAXA are working on their separate projects for now, they plan to merge those ideas into a single, operational system. The detailed plans for ESA’s Moonlight Initiative are helpful in imagining what a lunar GNSS constellation might ultimately look like.
As currently planned by ESA, Moonlight would consist of at least five satellites, including a large communications satellite and four smaller navigation satellites, placed in special orbits to optimise coverage at the lunar south pole. This initial configuration would provide 15 reliable and predictable hours of PNT services in the coverage area every 24 hours, but Moonlight is also designed to be scalable, meaning more satellites could be added to expand the service area or to support more complicated missions.
“Moonlight will be a major paradigm shift in exploration,” said Javier Ventura-Traveset, Moonlight Navigation Manager at ESA. “Instead of each lunar mission needing its own complex communications and navigation systems with a heavy reliance on ground support, Moonlight will enable future missions to access broadband communications services and GNSS-like navigation systems directly from lunar orbit, all under a service contract with a commercial provider.”
It’s unclear to what extent China, or any other nation, might collaborate on existing lunar navigation constellation systems, or whether the Moon will end up with multiple versions of GNSS, similar to Earth. Earlier this summer, a team of scientists from the China Academy of Space Technology described A phased plan for a GPS-style constellation in the journal Chinese Space Science and Technology.
“China has expressed interest in developing lunar navigation infrastructure in several international forums and has already launched the Queqiao-2 satellite, a lunar communications relay satellite, this year,” Ventura-Traveset notes. “Like ESA, NASA and JAXA, China is also likely to develop its own lunar navigation constellation. In some of these international forums, China has also expressed interest in pursuing international interoperability.”
The emergence of these multiple competing concepts has led some to question whether they have entered A new “space race” To establish the first lunar version of GPS, Gramling doesn’t see it that way. “I just know that we’re working hard with our partners because we have missions to support in the relatively near term,” he says. “We’re just trying to focus on making sure that, among the partners we’re working with on LunaNet, we have confidence in the services we’re trying to provide and that we’re working together.”
Patla noted that last month, the International Astronomical Union, an organization that mediates a range of astronomical issues, voted on a resolution that Cooperation was emphasized in establishing a lunar time scale and other elements of lunar PNT systems.
“At least in the early stages, collaboration would be cheaper and also beneficial to everyone,” says Patla. “But we don’t know how it will turn out.”