LuGRE becomes first system to acquire GNSS signals on the Moon

When NASA and the Italian Space Agency (ASI) successfully acquired and tracked Global Navigation Satellite System (GNSS) signals on the Moon’s surface at approximately 07:00 UTC on March 3, 2025, the Lunar GNSS Receiver Experiment (LuGRE) became the first technology demonstration to achieve this milestone.

The experiment was carried out using Firefly Aerospace’s Blue Ghost lunar lander, marking an important step in enabling autonomous navigation for future lunar missions, including NASA’s Artemis program.

The LuGRE payload, developed in collaboration with NASA’s Goddard Space Flight Center, ASI, and industry partner Qascom, successfully tracked signals from two satellite constellations, GPS (United States) and Galileo (European Union).

The receiver achieved a navigation fix on the Moon, approximately 384 400 km (238 855 miles) from Earth, demonstrating that GNSS signals can support precise positioning, velocity, and timekeeping in deep space environments.

LuGRE acquired the highest altitude GNSS signal ever recorded at 337 690 km (209 900 miles) from Earth during its transit to the Moon on January 21, surpassing the previous record held by NASA’s Magnetospheric Multiscale (MMS) mission.

This altitude record continued to rise as LuGRE reached lunar orbit on February 20 at a distance of 391 000 km (243 000 miles) from Earth. The achievements confirm the feasibility of using GNSS signals for spacecraft navigation in cislunar space, the region between Earth and the Moon.

LuGRE was delivered to the lunar surface as one of 10 NASA payloads onboard the Blue Ghost lander, which successfully landed in the Mare Crisium region of the Moon on March 2. Shortly after, the payload operators at NASA’s Goddard Space Flight Center began the first science operations. The receiver continuously tracked and downlinked GNSS data, validating its ability to operate in the lunar environment.

Traditional spacecraft navigation relies on Earth-based tracking stations combined with onboard sensors. The successful demonstration of GNSS signal tracking on the Moon suggests that future lunar missions can reduce reliance on ground-based tracking by utilizing autonomous GNSS-based navigation.

“On Earth, we can use GNSS signals to navigate in everything from smartphones to airplanes. Now, LuGRE shows us that we can successfully acquire and track GNSS signals at the Moon. This is a very exciting discovery for lunar navigation, and we hope to leverage this capability for future missions,” Kevin Coggins, deputy associate administrator for NASA’s Space Communications and Navigation (SCaN) Program, noted.

The LuGRE system consists of a high-gain L-band antenna, a low-noise amplifier, and a weak-signal GNSS receiver capable of acquiring GPS L1 C/A and L5 signals, as well as Galileo E1 and E5a signals. The receiver can track signals as weak as 23 dB-Hz, an important capability for lunar distances where GNSS signals are weaker than in Earth’s orbit.

The receiver produces pseudorange, Doppler, and carrier phase measurements and performs real-time navigation using least-squares point solutions and an extended Kalman filter. LuGRE can record raw in-phase and quadrature (I/Q) baseband samples, which can be downlinked for further processing and analysis on Earth.

LuGRE’s high-gain antenna was in a stowed position during the transit phase, only allowing signal acquisition when the lander was oriented correctly. The spacecraft’s cold-gas thrusters enabled periodic realignments to allow GNSS tracking. The total transit operation budget allowed for 15 hours of Earth-pointing time for GNSS data collection.

NASA’s SCaN Program provided funding and oversight for the LuGRE mission, while ASI contributed the payload hardware and testing. LuGRE is part of NASA’s Commercial Lunar Payload Services (CLPS) initiative, which contracts private companies like Firefly Aerospace to deliver scientific instruments to the Moon.

Scientific investigations using LuGRE data include characterizing GNSS signal strength and availability at lunar distances, evaluating navigation performance using onboard processing, and calibrating models for future lunar GNSS receivers. The data collected will support future lunar exploration, including Orion, Gateway, and robotic and crewed landers.

References:

¹ NASA Successfully Acquires GPS Signals on Moon – NASA – March 4, 2025