The Lunar GPS: Overcoming Challenges for Successful Exploration Foundation
GISTDA, Geo-informatics and Space Technology Development Agency
Delivering values from space
Space agencies worldwide are gearing up for ambitious lunar missions, driven by the promise of scientific discovery and the potential for economic growth. However, past missions have faced limitations, hindering their success rates. As plans for future exploration take shape, addressing these challenges becomes paramount.
The Moon is the closest celestial body to Earth, which holds a high value of scientific discoveries, creating a solid foundation for the space economy, and the beginning of sustainable deep-space exploration. Yet, the absence of crucial services such as navigation and communication satellite constellations in lunar orbit has hindered previous missions.
The introduction of NASA's lead Artemis program, and the International Lunar Research Station or ILRS, led by ROSCOSMOS and CNSA, shows that humanity will soon be back on the Moon for an extended period of exploration. This means that navigation satellites like the GPS, GNSS, and Galileo constellations in Earth orbit, as well as the communication satellites, must be up and ready to also support astronauts on the lunar surface as well.
The European Space Agency or ESA is currently developing the Moonlight initiative, to expand navigation and communication satellite coverage to the Moon. With a minimum of 3-4 satellites in an orbit which provides 24-7 coverage above the lunar south pole, which will be crucial for future crewed surface operations.
At the same time, NASA also developed the Lunar Communications Relay and Navigation Systems, or LCRNS, to support human and robotics operations on the Moon. Especially with the upcoming Artemis program, which is planned for a crewed lunar landing in September 2026.
Both the Moonlight and LCRNS are part of the LunaNet project, as well as JAXA's Lunar Navigation Satellite System or LNSS. These three projects are planned to alleviate landing site constraints, reduce latency in communications, and increase the overall science return.
Moreover, the China National Space Administration or CNSA also planned to build its constellation of satellites in lunar orbit, known as the Queqiao program. Currently, two Queqiao satellites are in orbit to support Chinese missions on the far side of the Moon, with two Tiandu satellites launched to demonstrate the necessary technology required for the constellation.
All of the above constellations of satellites will play a crucial role in locating all spacecraft and missions on the Moon with precision, as well as providing navigation and communication with ground-based mission control. This will help reduce the cost of research, and construction, as well as the mass needed for navigation and communication instruments aboard the future spacecraft, making the Moon more accessible to everyone.
However, the team that develops constellation satellites around the Moon will face considerable technical issues. For example, the Moon clocks run faster than one on Earth by around 58.7 microseconds per day, as well as the development of a common 'Selenocentric Reference Frame' to be used by everyone while exploring the Moon.
GISTDA, or the Geo-Informatics and Space Technology Development Agency, is proudly supporting the development of the Thai space industry. We are currently developing the THEOS-3 Earth observation satellite, which will be entirely built by Thai engineers, as well as providing the National Satellite Assembly, Integration and Test Center (AIT), to be a facilitator and support the overall growth of the space economy.