Blue Ghost: Earth’s GPS constellations work on the Moon

Using an engineering test GPS-type receiver built by the Italian Space Agency, engineers have successfully been able to use the GPS-type satellites from two different constellations to pinpoint the location of Firefly’s Blue Ghost lander on the Moon.

The road to the historic milestone began on March 2 when the Firefly Aerospace’s Blue Ghost lunar lander touched down on the Moon and delivered LuGRE, one of 10 NASA payloads intended to advance lunar science. Soon after landing, LuGRE payload operators at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, began conducting their first science operation on the lunar surface.

With the receiver data flowing in, anticipation mounted. Could a Moon-based mission acquire and track signals from two GNSS constellations, GPS and Galileo, and use those signals for navigation on the lunar surface?

Then, at 2 a.m. EST on March 3, it was official: LuGRE acquired and tracked signals on the lunar surface for the first time ever and achieved a navigation fix — approximately 225,000 miles away from Earth.

Obviously, this is a first-time engineering test. A portable version of LuGRE will now have to be developed. However, this success means that any operation on the near side of the Moon will not need the addition of a new GPS-type constellation in lunar orbit. It also will likely simplify the design of any constellation for providing this capability to the far side.

Meanwhile, Blue Ghost continues to operate as planned on the surface, with all instruments functioning and several already collecting data.

Blue Ghost instrument proves Earth-orbiting GPS-type satellites can be used to track location from the Moon

Having now reached lunar orbit in preparation for its landing on March 2, 2025, an engineering test instrument on Firefly’s Blue Ghost lunar lander has now proven that even from that distance spacecraft can use the multiple GPS-type satellites in Earth orbit to track their position.

The Lunar GNSS Receiver Experiment (LuGRE) acquired and tracked Global Navigation Satellite System (GNSS) signals for the first time in lunar orbit – a new record! This achievement, peaking at 246,000 miles, suggests that Earth-based GNSS constellations can be used for navigation in transit to, around, and potentially on the Moon. It also demonstrates the power of using multiple GNSS constellations together, such as GPS and Galileo, to perform navigation. After lunar landing, LuGRE will operate for 14 days and attempt to break another record – first reception of GNSS signals on the lunar surface.

This test is a very big deal. It tells us that operations on the Moon, at least those on the near side, will likely not require a GPS-type infrastructure in lunar orbit, thus allowing a lot of difficult missions to proceed sooner while saving a lot of money and time.

Indian navigation satellite stranded in wrong orbit

Though the GSLV launch rocket worked as planned, putting India’s new navigation satellite in the proper transfer orbit on January 29, 2025, the satellite’s own engines have failed to fire.

Subsequent to the launch, the solar panels on board the satellite were successfully deployed and power generation is nominal. Communication with the ground station has been established. But the orbit raising operations towards positioning the satellite to the designated orbital slot could not be carried out as the valves for admitting the oxidizer to fire the thrusters for orbit raising did not open.

The satellite systems are healthy and the satellite is currently in elliptical orbit. Alternate mission strategies for utilising the satellite for navigation in an elliptical orbit is being worked out. [emphasis mine]

The highlighted sentence suggest India’s space agency ISRO has determined there is no way to raise the orbit to its proper height. With the solar panels deployed and the spacecraft’s orbit having low point that dips into the Earth’s atmosphere, the satellite’s orbit will likely decay relatively quickly. If so, the satellite’s mission will be a failure, not a good way to start what ISRO’s hopes to be its busiest year.

China launches two GPS-type satellites

China today successfully launched two more BeiDou satellites for its GPS-type navigation constellation, its Long March 3B rocket lifting off from its Xichang spaceport in the southwest of China.

No word on where the strap-on boosters and lower stages crashed in China, all using toxic hypergolic fuels.

The leaders in the 2024 launch race:

92 SpaceX
39 China
11 Russia
10 Rocket Lab

American private enterprise still leads the rest of the world combined in successful launches 107 to 61, while SpaceX by itself still leads the entire world, including American companies, 92 to 76.

Researchers figure out how to make the Starlink constellation a GPS-type constellation

Researchers working independent from SpaceX and without any of the company’s proprietary data, have found a way to turn the Starlink internet constellation — now about 3,000 satellites strong — into a method of pinpointing one’s location, thus making it an alternative to GPS-type satellites.

To be clear, no one is accessing Starlink user data here. The sync sequences are just strings of timings and other data that the machines use to stay in touch — the payload data is entirely separate.

In the paper, due to the fact that the signal was being targeted at an actual Starlink user terminal, the location had to be for that terminal too, and they were able to get it within 30 meters. Not better than GPS, obviously, but it could be quicker and eventually more accurate if SpaceX were to give the project its blessing.

A software update that slightly adjusts how the satellites send their signals and a bit of data on correcting for variance between their clocks, and Humphreys suggests Starlink transmissions could be used to locate oneself to within a meter.

You can read the paper here [pdf].

It seems a no-brainer that at some point SpaceX management will recognize the money they can make from this extra capability, and will figure out the best way to produce and sell handheld units. It also appears that there will be profit in allowing others to also tag on.