Edit: This is real proposal, by an outfit called Reflect Orbital. I thought it might be a given that people reading knew this, but just in case I figure I ought to mention it anyway.

It’s a venture capital scam. I’ve commented on this startup’s deeply moronic idea several times, but the takeaway is that the math doesn’t work. These guys failed their middle school science classes and are desperately hoping all of their deep pocketed investors did as well. The allure of seeking rent on a natural resource is powerful, though, and of course everyone saw that episode of the Simpsons where Mr. Burns blocks out the sun with his giant disk. So here we are regardless.

You can’t reflect any more sunlight onto the Earth’s surface than you have surface area of satellites in orbit, and compared to the surface area of the Earth — even the relatively piddling fraction of its potential surface area with owners who might actually pay for such a service — you’d need an absurd number of satellites with enormous footprints, all in stable orbits where keeping them on target on the surface would not be feasible. But even one highly reflective satellite can handily fuck with somebody looking through a telescope, so it’s still a dick move even though it self-evidently won’t even begin to accomplish its stated purpose.

The Russians already tested such an idea and the results were underwhelming. Illumination over a relatively small area on the order of regular old moonlight is already a pretty piss-poor use of launch fuel when you can accomplish the same results much more easily and cheaply with, you know, terrestrial electric lights. Which we already have. In abundance. Reflect Orbital’s proposal that you’d be able to drive solar panels or even grow crops with the things are laughable. For reference, the Znamya satellite only managed to shine a dim patch of light onto the surface for around six minutes, during which the spot raced across most of Europe before the thing was no longer in a position to maintain an acceptable angle of incidence and then passed into the Earth’s shadow. The notion of keeping something like that acceptably on target for any useful length of time is laughable, and even then you’d need a whole horde of them all aimed at the same spot to get even part of the way towards the equivalent of daytime illumination.

And putting enough of anything in orbit in order to block out sunlight on anything approaching a meaningful portion of the Earth’s surface is right out.