Create a controllable, semi-opaque particle cloud at Sun–Earth L1 that trims incoming solar irradiance by ~1.5–2% without blocking starlight for astronomy along other lines of sight.

Micron-scale grains from lunar regolith (silicates, glass), plus options like carbon dust or hollow glass microspheres; sort by size/charge for predictable dynamics.

Ion-tug or solar-sail freighters deliver feedstock to an L1 staging hub; in-situ power from solar arrays.

Multiple injectors launch crossing ballistic streams through a target volume near L1; streams refresh the cloud continuously instead of trying to “hold” grains static.

Grains lightly charged at injectors; weak electrostatic/EM fields near the hub nudge trajectories (steer, don’t trap) while radiation pressure and gravity set the flow.

Photometers and laser tomography measure optical depth and shape; closed-loop control adjusts injector rates, grain size distributions, and field strengths.

Modulate injector rates and grain sizes to vary the effective optical depth by region and season (e.g., 0.5–2% TSI reduction envelopes).

Natural divergence clears the cloud if injectors stop; failsafes bias charges/fields to disperse down-sun rapidly if needed.

Start with a 1-km demonstrator to validate persistence, metrology, and closed-loop control, then scale injector count and throughput.