How they do that RIGHT NOW, is for instance, the Chinese probe on the back side of the moon, would be useless without the ability to communicate with Earth, so they have a sat that goes around the lunar equator and THAT communicates with the probe, records the latest data set and when it gets around to LOS with Earth, it squirts the data. Nice thing about Lunar sats is the gravity at about 1/6th of Earth means the orbital velocity is that much lower than Earth and that means the sat will be in LOS (Line Of Sight) of earth 6 times longer than a comparable sat around Earth which would have only about 45 or so minutes depending on altitude.
Of course we have sats 22,000 miles up, geosynchronous orbits that means it always stays in one place directly above a certain point on Earth so a TV or data sat can have ground stations that don't need to move around much to get data lock.
That would not work very will on the moon, I guess you could put one in an orbit that is near the terminator where it could have LOS to both the Chinese rover on the backside but it would be tricky finding the right altitude and the problem there is if the orbit is not high enough the moon itself would shadow the signals coming and going to the rover so that probably would not work.
You can't pick the altitude if you want geosync orbit, or in this case Lunasync orbit.
Because the gravity of the moon is about 1/6 Earth, the lunasync orbit would be a lot closer to the lunar surface so I imagine the view would be blocked where you could only use that sat if you were near the terminator because say 90 degrees away from the sat would most likely put the moon in the way so there would be no LOS.
So they just use a sat that has some altitude, not lunarsync but like I said, picks up the data when it is floating around the backside and is in LOS.
So it is a technical challenge but it can and IS being done as we speak by the Chinese.
They have taken photos of the rover and vicinity, not sure what they call it but you can google Chinese lunar backside rover or some such.
I'll see if I can find a link.
Well that took at LEAST one minute🙂
It is called Yuto-2.
I know about this stuff because for one thing I was an Apollo technician, Apollo Tracking and Timing was my job before Nixon killed the whole program.
I have done a lot of microwave tower work, one on Andros Island in the Bahamas where there is a British submarine base I worked at, AUTEC, a very interesting place to work and they flew me down in helicopter to the microwave tower which was 200 feet tall and the footprint of a house, huge! And the wind on top actually moved the whole top a few inches which surprised me the first time I was assigned the job of flying downsite to do maintenance.
AUTEC stands for Atlantic Underwater TEst Center. Like I said, VERY interesting place to work.
Another job I did for a few years was in Thailand, at NKP airforce base, used to be US but we gave it back to the Thais so it is theirs now, about 400 miles north of Bankok.
I worked on a now obsolete tech called Space diversity Troposcatter, TWO microwave dishes shooting RF next to each other about 10 meters (30 odd feet) apart and that allowed very reliable microwave communications out to a few hundred miles. A single dish has too many dropouts to be used reliably for communications, but 2 side by side fixes that.
I also have the top level amateur radio license called 'amateur extra class
which gives me more bandwidth to talk on.
One contact I remember to this day: I threw a wire out my second story window, maybe 20 feet long and on 20 meters (14 megahertz) back when there was a nice bunch of sunspots which makes for world wide communications, I talked to McMurdo Station in Antarctica, that was thrilling. I suggested a chess game which I knew they played in the dark time, months of no sunlight. But the signal died out before I could get one going.