# Would mass drivers be able to transport base material on the moon more efficiently than drones?

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.

• 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. Dec 27, 2019 at 18:45
• The material name you're after is "regolith" Dec 27, 2019 at 19:14
• 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. Dec 27, 2019 at 19:19
• 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 Dec 27, 2019 at 22:18
• 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. Dec 28, 2019 at 20:40