I’m working on an alternate approach to the concept of using a solar shield to shade the earth from the Sun (to help with climate change adaptation). It would use streams of lunar soil from multiple different lunar locations to overlap the shading effects on a specific targeted area for a designated period of time.
The soil would be aimed so as to intercept the moon’s orbit to be recollected (preventing loss of material). Each line of shade would be unnoticeable to someone on the ground (blocking <0.5% of solar radiation) but overlapping lines for long periods of time would create a noticeable effect for ground surface temperatures.
I know the slowest speeds possible would provide the greatest shading effect and increasing the speed of the projectiles decreases the effectiveness. I also know technology will be a limitation based on costs. My question is, do orbital mechanics also limit the window for the period of time soil could be projected and still land back on the moon? I assume the target window is at least a few days because the target gets closer at the same rate the launch platform gets further away but that's not the kind of assumption I want to rely on.
CLARIFICATION The usage of TEP with 6 origin points for soil would create 6 intercepting lines create 6 long rectangular shadows blocking ~0.5%-1% of light. But the shadows would overlap in an area, creating a stronger shadow around ~3%-6% of light. If you can combine fire from 2 different days to double that overlapping effect, you could block ~6%-12% of light (before accounting for a loss of efficiency). If you could do this across 10 days you wouldn't just increase efficiency you would drastically lower the costs for initial testing and return on investment. Thus the incredible distances in space become an asset that acts as both a stepping stone and a force multiplier with diminishing returns. The goal of this question is to determine how theoretically feasible it is to extend that force-multiplying range and how far it might be.
Also, the image is by no means accurate. Think of it as a really bad napkin drawing.