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

By: Richard M

Richard M — Mon, 24 Feb 2025 16:00:24 +0000

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.

By: Jeff Wright

Jeff Wright — Mon, 24 Feb 2025 08:31:01 +0000

Here is a link to the Institute of Navigation
https://www.ion.org/publications/abstract.cfm?articleID=19375

More:
https://www.isprs.org/

By: pzatchok

pzatchok — Mon, 24 Feb 2025 04:31:56 +0000

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.

By: Robert Zimmerman

Robert Zimmerman — Sun, 23 Feb 2025 19:01:47 +0000

In reply to David Eastman. 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.

By: David Eastman

David Eastman — Sun, 23 Feb 2025 18:31:22 +0000

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.