Satnav systems built for Earth used by Blue Ghost lander as it approached the Moon
- Reference: 1741245125
- News link: https://www.theregister.co.uk/2025/03/06/blue_ghost_lugre_module_acquires/
- Source link:
The module is called the Lunar GNSS Receiver Experiment, aka LuGRE, which landed on the surface of the Moon Sunday aboard [1]Blue Ghost , the first privately-built-and-operated spacecraft to successfully touch down on Earth's natural satellite.
On Monday, LuGRE picked up signals from both America's Global Positioning System (GPS) and the EU's Galileo satnav constellations. The instrument then managed to acquire a navigational fix on the lunar surface using those signals, some 225,000 miles from Earth. That's gotta involve some very cool mathematics to achieve that.
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By doing so, it demonstrated that Terran satellite-navigation signals designed to aid earthly roaming can also work on Luna.
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That’s good news because GPS and Galileo are two of several so-called global navigation satellite systems, or GNSS, orbiting our home planet. China, India, and Russia also operate such constellations, meaning there are plenty of satellites for future Moon missions to tap.
"LuGRE shows us that we can successfully acquire and track GNSS signals at the Moon," [5]enthused NASA Space Communications and Navigation program deputy associate administrator Kevin Coggins. "This is a very exciting discovery for lunar navigation, and we hope to leverage this capability for future missions."
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LuGRE also, we're told, received signals from orbiting satnav systems and acquired its position while in transit to the Moon, and while circling it. One of its connections was made while 243,000 miles (391,000 km) from Earth, a new record for the most distant GPS fix that topped the 209,900-mile (336,000 km) hookup achieved by NASA's Magnetospheric Multiscale Mission.
Dump the street directory
NASA engineers track spacecraft using sensors aboard the craft, Earth-based tracking stations, and other tools.
LuGRE’s successful in-transit GNSS positioning suggests future Lunar missions may use more automation.
"Using GNSS signals for navigation can reduce reliance on human operators because these signals can be picked up and used autonomously by the spacecraft, even as far away as the Moon," NASA said.
[7]ESA signs off on contracts for lunar data relay and navigation
[8]Satnav for the Moon could benefit from Fibonacci's expertise
[9]Lockheed Martin launches biz to build lunar satellite network
[10]US Space Force wanted $77M to reinforce GPS – and Congress shot it down
NASA and other space agencies planning to expand human presence to the Moon in the coming decades have been tackling the problem of lunar navigation for some time. Previous experiments have [11]proposed simple approaches such as navigating the Moon's surface using AI trained to triangulate a position based on landmarks, and complex ideas such as creating a [12]fleet of satellites dedicated to a lunar positioning system.
The other Blue Ghost payloads
Along with LuGRE, nine other NASA [13]scientific payloads landed on the Moon aboard Blue Ghost, and several have already [14]begun work.
An Electrodynamic Dust Shield has successfully used electrical forces to shake a little regolith dust that accumulated on the lander. The Lunar PlanetVac has begun to collect and transfer Moon dirt into sample return containers.
Other payloads will probe the Moon's interior heat flow for clues about its formation and ways to capture natural resources for human habitation. The mission will also study Earth's magnetosphere for clues about space weather, and an [15]experimental Radiation Tolerant Computer continues to operate and (hopefully) prove its self-healing powers.
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Blue Ghost’s mission plan calls for it to operate for 14 days, during which time LuGRE will continue to acquire GNSS signals to learn more about the long-term viability of its remote navigation method. ®
Get our [17]Tech Resources
[1] https://www.theregister.com/2025/03/03/blue_ghost_private_moon_success/
[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2Z8mAVM-50EBNIS38RKtnvwAAAZU&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44Z8mAVM-50EBNIS38RKtnvwAAAZU&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33Z8mAVM-50EBNIS38RKtnvwAAAZU&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[5] https://www.nasa.gov/general/nasa-successfully-acquires-gps-signals-on-moon/
[6] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44Z8mAVM-50EBNIS38RKtnvwAAAZU&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[7] https://www.theregister.com/2021/05/21/esa_moonlight/
[8] https://www.theregister.com/2023/07/31/satnav_for_the_moon_paper/
[9] https://www.theregister.com/2023/03/29/lockheed_martin_moon/
[10] https://www.theregister.com/2024/06/13/space_force_gps/
[11] https://www.theregister.com/2022/12/20/nasa_ai_moon_navigation/
[12] https://insidegnss.com/lunar-navigation-a-case-study-analysis/
[13] https://science.nasa.gov/lunar-science/clps-deliveries/to19d-firefly/
[14] https://www.nasa.gov/blogs/missions/2025/03/04/blue-ghost-begins-surface-operations-captures-descent-video-sunrise/
[15] https://www.theregister.com/2025/02/11/nasa_radpc_firefly_moon_mission/
[16] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33Z8mAVM-50EBNIS38RKtnvwAAAZU&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[17] https://whitepapers.theregister.com/
Re: GNSS uses signal time-in-transit to calculate distance
Perhaps a series of prisms could be used to refract the signal to The Dark Side of the Moon ?
Gets her coat, the pink one, of course
Re: GNSS uses signal time-in-transit to calculate distance
Very very good.
That deserves a pint.
Re: GNSS uses signal time-in-transit to calculate distance
Obvious one is no coverage on the 'dark' far side of the moon.
That would be my question, though not quite all of the dark side depending on GNSS orbit height above Earth to take a peek slightly to the side of what we see from Earth itself.
Re: GNSS uses signal time-in-transit to calculate distance
My initial thought was that the satellites will be transmitting a directional beam towards earth, so very surprised that they could receive anything 200000 miles off the back of them. But then realised that the satellites on the other side of earth will be pointing in the correct direction (and presumably the beam width is such that they reach around the planet) - the extra ~28000 miles won't make much difference but the signals are likely to be a lot stronger.
And the calculations will be exactly the same regardless of distance from the satellites, but the required accuracy will be a lot looser (greater tolerances) and the angular differences will be smaller (needing higher precision in the calculations)
Overall, I have to say "bravo" to the team that decided to try it.
Re: GNSS uses signal time-in-transit to calculate distance
In cases where signals are reaching around the planet, I wonder what corrections need to me made for refraction, etc. I know from experience that GNSS signals coming straight down to earth can be disrupted/refracted/whatever as they come down through the atmosphere, so don't always travel in a straight line (in a previous life I worked on something which performed calculated the amount of inaccuracy introduced by such things, and did some jiggery pokery to correct for it). In a case where the signal is coming around the planet then that could be a lot more atmosphere to travel through.
How?
The Lunar PlanetVac has begun to collect and transfer Moon dirt into sample return containers.
I would like to know how that works.
As the surface of the Moon is already in a vacuum, what system are they using to suck up stuff from the surface and transfer it to the containers?
Enquiring minds need to know.
Re: How?
From what I have read elsewhere, they are using a blast of compressed gas to persuade the loose regolith to board the PlanetVac once the attachment is flush with the surface
https://www.nasa.gov/missions/artemis/clps/nasa-lander-to-test-vacuum-cleaner-on-moon-for-sample-collection/
Precision?
Looking at the references there's an absence of information about accuracy. The way GPS works is that your position is on a sphere around each sat with radius given by the measured range. With 4 or more sats that problem can be solved to give your position. The accuracy is best if the directions to each sat are widely spaced, which they generally are on Earth.
However on the Moon all those sats are in more or less the same direction. The maximum angle subtended at the Moon by GPS sats at opposite ends of their orbit is only about 8 degrees. I hope that experiment can collect sufficient data before it freezes to death to give some estimate of expected position errors. I expect the time errors will be a lot less though.
Signal strength
The signal strength received would be interesting
Interesting that there's no word LuGRE was designed and built in Italy
What's this, the new MAGA bending by The Register?
"The LuGRE payload is a collaborative effort between NASA’s Goddard Space Flight Center in Greenbelt, Maryland, the Italian Space Agency, their industry partner Qascom, and Politecnico di Torino."
https://www.nasa.gov/general/nasa-successfully-acquires-gps-signals-on-moon/
I wonder if Garmin will release maps for the moon
Ah, I can see it now:
Braking burn...
Pitch-over...
Final descent...
Almost there...
AAAAAANNNDDD......
"Recalculating. Recalculating."
"When possible, make a U-turn."
Turn left at the next Crater...
How long before the first Rover is destroyed after trying to follow the Navi's instructions, and ends up falling into a crater that the Navi insists is not there?
"Go straight for 500m"
" I cant, there's a bloody big crater in the way!"
"Go straight."
"I cant! There's a crater."
"Overriding controls. Go Straight!"
"Ahhhh!!!!"
GNSS uses signal time-in-transit to calculate distance
.. but probably has a much cooler acronym ..
so extra distance makes the calculation more relaxed, leisurely.. not like the knife fighting range that earth focused operations have to work at.
There is an upper limit - which is probably the 'word' length that is used to measure against synchronisation.
There would also be design issues to overcome - machine built to broadcast down towards earth may not send a strong signal in the other direction - or it could be fully unidirectional, i dont know.
Obvious one is no coverage on the 'dark' far side of the moon.