I am a hobbyist working on a climate change adaptation idea that is a variation of orbital sun shades. It would project soil/material from the moon to provide targeted shading for whatever part of earth needs it most, mitigating some issues and helping land be healed. One aspect of the project (The Eclipse Project, TEP for short) is that the soil would be collected back on the moon for reuse after being projected from the moon. I am curious how efficient this system would be for transporting mined material from one part of the moon to another as compared to using delivery drones or a fixed system like rails. I am still in the early stages and do not have any hard math but I am confident about some aspects that could help in determining efficiency.

1) Mass drivers (the method currently at the top of projection methods) can be up to 80-90% energy efficient. 2) Soil would be launched in 5-15lb units shot at between 2.5 to 4 km/second (To account for both escape velocity and the desired speed of the material. Slower is better in that it reflects more material.) 3) Once the material is traveling through space it does not require any energy input. 4) While collecting the soil as it lands may be difficult the current idea is large metal dishes. When the material begins to make contact it will create a static charge which will attract the soil to the dish until it can be collected. 5) The goal is for 95% of material to make it to its destination (the clouds of soil would be knocked off course by space material sometimes and some will miss the dish). The dish would be a safe distance from anything that could be damaged but a short fixed method could be constructed for the final part of the journey. 6) Transport on the moon would require a lot of detours around craters and other obstacles.

This would only be efficient for transporting material a long way and it would take ~30 days tops (yes I know this is longer than a moon’s orbit), but most of the time soil could be delivered in around 15-20 days. However, this would share considerable resources between the mining project and TEP and TEP could dispose of the unused material by projecting it via another array to create more shade.

I think this could make lunar colonization easier because the material could be collected anywhere before being sent via TEP to a central location for refinement and/or use or distribution to earth while sharing resources between projects. Any thoughts, comments, or links to resources would be appreciated.

EDIT: please note this would be a secondary purpose of TEP, not its primary objective. The mathematics to determine the efficiency may show conventional means being more efficient to a point but at some point projecting 60LB of material per minute per projector (A conservative amount) would be more efficient than hundreds of drones traveling hundreds of miles. The point of this question is to determine that line.

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    $\begingroup$ To the TEP idea as a solution for climate change: launching 10 lbs of material from the Moon takes about 10 MJ, plus the energy used to send material to the Moon, build the launch site, collect the material, and process it. launch it. I wonder if the Lunar energy needed to do all that would be better beamed to Earth to mitigate climate change directly by reducing fossil fuel use and powering carbon capture. And then there's the potential for use as an orbital bombardment weapon, accidental or otherwise. $\endgroup$ – Schwern Dec 27 '19 at 18:45
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    $\begingroup$ The material name you're after is "regolith" $\endgroup$ – Starfish Prime Dec 27 '19 at 19:14
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    $\begingroup$ Catching a meteorite shower travelling at multiple kilometres per second sound like an interesting challenge, even leaving aside the rest of the issues. It seems pointless as well as being hazardous, technically challenging and therefore expensive. $\endgroup$ – Starfish Prime Dec 27 '19 at 19:19
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    $\begingroup$ I think it would be more efficient to manufacture thin-film sunshades from regolith rather than using it by itself to provide shade. Using this system for moon-to-moon transport just seems like extra steps, minimizing delivery distance of construction materials for any building project is always a priority and sending the cheapest material (regolith) on the most expensive ride doesn't seem cost effective $\endgroup$ – Dragongeek Dec 27 '19 at 22:18
  • $\begingroup$ To Schwern, TEP would only be more efficient energy-wise at a certain distance. even if it took 30 MJ compare that with a donor rover, if it takes more than 30 MJ to get that 10 pounds 100 miles then that 100 miles start becoming the point where TEP may before efficient. At 1000 miles it may take more and more costly material to use drones, not to mention more moving parts means more points of failure along the entire stretch. At a certain distance, TEP would be less material and less energy. TEP may be more expensive but sharing resources would split the costs. $\endgroup$ – T.A. McKay Dec 28 '19 at 20:40

"Drones" usually refer to quadcopters--which will do absolutely nothing in space or on the moon.

Also, I can't imagine how you're planning to catch your blobs of regolith. At the speeds it will be approaching you'll need a very strong (which means very heavy) catcher to avoid being smashed. There's no gravity to hold it down, it's just going to splash back off your catcher.

I think you need to seriously redesign your idea.

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    $\begingroup$ "Drone" is almost always used to refer to unmanned aerial vehicles, which was certainly the origin of the term. Trying to expand the usage of the term into other contexts is pointless, confusing, and a bit of an uphill struggle. That said, in context it would be clear that the UAVs in question could not be propellor quadcopters. It seems reasonable to assume that the questioner is not an idiot. $\endgroup$ – Starfish Prime Dec 28 '19 at 9:57
  • $\begingroup$ I have been using 'drone' as a term for a mostly Autonomous vehicle. Please let me know if there is a better term. The effect of static on loose material in space is pretty large. As regolith contains a lot of metal if it was being fired into a large hole of regolith, like a lunar crater, or a metal dish it would generate a lot of static. Gravity is ~17% of the earth which allows for some help, though the lack of atmosphere makes it harder. Shooting tons of material in a sputtering stream at one point would allow the material that floats up to collect with incoming regolith minimizing loss. $\endgroup$ – T.A. McKay Dec 28 '19 at 21:00
  • $\begingroup$ I do acknowledge that there are design obstacles. This community has been welcoming and helped me with a few points. I will continue to post questions and help others with answers where I can. Just because there is a problem, however, doesn't mean I should quit without trying. This project has a lot of potential, the question is if realizing that potential is worthwhile. Combining resources makes that far more likly and is thus worthy if a looksie into. $\endgroup$ – T.A. McKay Dec 28 '19 at 21:03
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    $\begingroup$ @T.A.McKay I don't think we have the ability to drive autonomously over the moon for substantial distances unless you build roads first. And you're way overestimating the effect of static--yes, it works well on dust which is really tiny, you're talking large masses. $\endgroup$ – Loren Pechtel Dec 29 '19 at 15:28
  • $\begingroup$ @Loren Pechtel, the regolith would be ground down to gravel size. Between the small size of the material, the ability for regolith to absorb some of the impacts, gravity, and static I would be surprised if significant amounts of material would escape something several dozen meters tall. It is something to look into. Autonomous vehicles are easier to program for the moon than earth roads. So, while we don't have the ability ATM if we had a reason to give it a good attempt we could probably have that in a few years without too many issues. The technology exists it just hadn't been adapted. $\endgroup$ – T.A. McKay Dec 29 '19 at 17:29

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