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.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
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.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
As is depressingly common, that linked article really gives no information, just that the experiment was able to receive signals. Was it able to actually determine a location from them? And with what accuracy? Going forward, it will be very interesting to see what the limits are. Obviously it will be of no use on the far side, but will it be equally effective near the lunar poles vs the equator? Will effectiveness change based on the inclination of the lunar orbit? I suspect being able to use the existing systems is going to be helpful, but not nearly enough to enable not making some kind of LPS network.
David Eastman: FYI, I linked to a NASA press announcement, so no one should expect more information. More to the point, that information will only become available when the principal scientists running this instrument publish their paper on their results, probably in about a year.
For example, one question I am certain they will address is whether data of a near side orbital track will be precise enough to extrapolate through the entire orbit. I suspect it will.
I still think 3 to 6 mini sats in orbit around the Moon will be needed,
For one we will need them for communications arrays and at the same time they can be a lunar positioning system.
And it will cost less than all the work and research that would go into using the Earth gps system on the moon.
Here is a link to the Institute of Navigation
https://www.ion.org/publications/abstract.cfm?articleID=19375
More:
https://www.isprs.org/
I agree that….it would be helpful if we knew more about just exactly what kind of positioning Firefly and NASA got from this. How precise was it? How long did it take?
I agree with Pzatchok, in any case, that….at least in the medium term, we are going to need some sort of lunar positioning system. Not just for orbital and ground use on Far Side (which obviously will not have line of sight with Earth orbit positioning systems), but also for operations where only lower power transmitters will be in use. An astronaut in an EVA suit. A small drone. A cubesat in orbit. And so on.
But for now, this is a useful capability we have uncovered. And CLPS missions in the next couple of years can and will certainly take advantage.