Boffins propose fiber-optic network for the Moon Researchers at the Woods Hole Oceanographic Institute in the US are proposing the deployment of a fiber-optic network on the Moon to probe our natural satellite's interior by detecting seismic waves. In the research journal Seismological Research Letters, the boffins note that understanding the composition of the Moon and its …
Sorry, but it just doesnt sound very realistic as a solution. Anything that requires multiple landings and cables laid for a 100km on the Moon, is not going to happen in any time frame we care about. I wonder if someone just bought shares in a Fibre Optic Cable Manufacture... :P
Why wouldnt you just deploy something along the lines of the Seismometer deployed with the InSight mission to Mars. It basically mapped the internals of Mars to a degree that everyone seems happy with and also detected marsquakes, meteorite impacts, and if I remember correctly was even able to pick up the effect of the Moons passing by!
Since one already exists, getting CNES to build another one using the same tech, should be (relatively speaking) cheap. It does mean dealing with the French though.... ;)
(Disclaimer: I worked on a different instrument on the InSight mission...)
100km of fibre doesn't just give you data from 100km away; you can get data from any point along the fibre -- so it's more like 100km of seismometers, which is a lot of instrument.
Not that makes it easier to deploy, mind, ...
(Recently I saw something similar pulled off comms fibre on the west coast of NZ ... you could see/detect cars driving along a nearby road)
It doesn't need to be that long. Here's a live one in Iceland recording the earthquakes as they happen in Svartsengi volcano earthquakes before and after an eruption. I think it is no more than 10 km long. It is buried into the ground, so I don't know how they are going to solve that problem on the Moon. Unless they do this when manned travel starts again to the Moon. Its complicated and I don't think the technical solution for this is ready for the Moon. It is going to need an upgrade.
https://www.youtube.com/live/bLbxEMEDZGw?si=rpsg4zd6pN9XLu8I
No you leave the cable drum on earth and just attach the fibre to the rocket so as it takes off it unspools the fibre and drags it along behind as it transits to the moon, then when it orbit a the appropriate time it releases the cable to float down the lunar surface... simples
This is an interesting idea, perhaps predominantly because it would involve validating a lot of multi-purpose technologies.
* We know we can get >15tonnes to the surface of the moon, because Apollo did it (launch is the issue currently).
* We have modern tech that can more or less get stuff there upright as well - Odysseus had an insane hardware fault where they didn't install wiring to the altimeters. The fact that landed just using the optical cameras with nothing more than a bent leg is top-flight boffinry (but sack the head of production FFS). Meanwhile, SLIM was playing in hard-mode, deliberately aiming for a sloped landing site.
* The Apollo Lunar Rovers each did 30km, though the (non-rechargeable) battery was notionally good for 90km, and had a top speed of 10kph (though Eugene Cernan managed 18kph on Apollo 17). So the idea of a ground vehicle covering 100km is totally feasible, particularly if you're happy for it to trundle at a couple of km per day slowly paying out fibre.
None of this is easy, but it's eminently achievable.
There's two obvious mission architectures here.
1. Land a rover with a cable spool, which drops a termination/reflector box (with one end of the cable attached) and then trundles off, spooling out fibre behind it. It can then run DAS to the reflector when it gets to where it's going (or when the drivetrain fails).
2. The more sophisticated version is to drop a fixed lander (with a Mars Insights-style seismometer). You also land a rover with cable spool capable of the above mission.
If either landing fails, you still have something. But ideally, the rover backs up to the lander and plugs the cable terminator into a power/data receptacle on the lander. It then trundles off. Using a multi-strand cable, you now have a redundant DAS rig - either the rover can shine light down one strand, or the lander can bounce down to the rover. They could even use it to communicate (in the event, say, of a radio failure on either end).
Those are both arguably the same mission - e.g. you could have an Apollo LM size craft that deploys a rover after landing, or a really big rover-lander which leaves quite a chunky fixed station behind. Or in the first instance, the reflector box has a small solar panel, radio and DAS unit in case the rover dies. Hypothetically, you could also drop off other instruments en route - mass allowing.
In either case, it's a valuable exercise in deploying infrastructure on another planet with high levels of automation and robotics, which could serve future manned bases, a far-side radio telescope, etc.
All this requires a comms relay network of course, because we can't keep soaking up time on the Deep Space Network talking to research cube sats around the moon at the expense of missions like Webb and Voyager...
I suppose there might be an issue hiding here -- is it really sufficient to just leave the unspooled fibre lying on the surface? Or would it be better (or even necessary) to bury it, or (perhaps) to at least fix it securely to the ground at intervals?
Hmm.
Heh. I was more thinking about how well the fibre would be coupled to the small ground movements it's being used to detect.
Fair point. From what we know of the moon's surface, it's fairly uniformly (though not deeply) covered in soft regolith (apart from steeper slopes and outcrops). A teeny v-shaped trenching tool could probably carve a small (<10mm) channel with a soft roller behind to smoosh the regolith back over, just enough to ensure ground contact/coupling. It would require some careful design to ensure a bit of sharp rock didn't get pressed over the fibre and damage it (maybe not a roller, just a plough-arrangement to push regolith over the top of the fibre, lightly burying it without direct compaction). It wouldn't need to be continuous of course - no wind to push it around, so getting "mostly" good contact should be sufficient.
It certainly requires careful choice of landing site and rover course.
Lightly burying it might also take the edge off the intense solar radiation and heat/cold cycles, slowing down degradation (not that the glass would be a problem, but the coating would inevitably degrade with sun exposure).
Monitoring the amount of impacts attracted to the moon as it revolves around us would be very interesting ... we can't detect normal meteoric impacts on 71% of our planet because they just splash in the sea and the moon may be attracting many well away from us as they approach us both. Looking at the moon it seems to have been hit more then we have - is it just revolving us and cleaning our orbit space for us?
Astronomers have been dreaming of putting a radio telescope on the dark side of the moon also. Of course, construction of such a telescope is one huge challenge, but getting the data back to earth is also a challenge as the moon blocks radio waves (the very reason astronomers want the radio telescope there in the first place - to escape the noise of Earth's radio emissions). A fiber-optic cable stretching from the telescopes "around the edge" of the moon back to the"edge" visible from earth would be very useful to those scientists too.
So the inhabitants of Earth's large natural satellite - Lunarians? Lunatics? - have requested cat videos?
Speaking facetiously, it sounds interesting. I'm wondering how they'd get the radio telescope to the moon first. A fibre network for relaying observations back to Earth, would be small potatoes after that.
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