this post was submitted on 06 Nov 2025
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Controversial startup's plan to 'sell sunlight' using giant mirrors in space would be 'catastrophic' and 'horrifying,' astronomers warn (www.livescience.com)
submitted 3 days ago by themachinestops@lemmy.dbzer0.com to c/technology@lemmy.world
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https://archive.ph/3WZrp

California-based startup Reflect Orbital aims to build a swarm of 4,000 giant mirrors in low Earth orbit to "sell sunlight" to customers at night. Experts warn that the mirrors could mess with telescopes, blind stargazers and impact the environment.

Reflect Orbital, which was founded in 2021, has recently taken the first step in a scheme to sell sunlight at night by bouncing solar rays off giant "reflectors" that can redirect the vital resource almost anywhere on our planet. By doing this, the company aims to extend daylight hours in specific locations, thus allowing paying customers to generate solar power, grow crops and replace urban lighting.

But experts say it is a wildly impractical plan that should never get off the ground. What's more, the resulting light pollution could devastate ground-based astronomy, distract aircraft pilots and even blind stargazers.

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[–] toddestan@lemmy.world 2 points 1 day ago

If I had to build such a system, instead of a few satellites with really big mirrors I'd instead have a massive number of small satellites with smaller mirrors. Obviously then any area I'd want to light up, I'd have to hit with a number of the satellites - probably dozens at least or even hundreds of them for decent sized area. That would at least alleviate a few of the problems - aiming would be easier. As satellites move out of range new satellites would be moving in range. Long shadows from the angle of satellite near the edge of their range wouldn't be as much of a problem as I'd be hitting any spot from a variety of angles. That the satellites would be useless for about 75% of their orbit I could make up for by launching even more satellites.

Of course, it would still be hugely impractical and there would still be major limitations. I'm still not sure how you could manage the aiming - the satellites would have to be continuously adjusting their aim to track their target. Reaction wheels can only do so much and using thrusters you'd burn through propellant like crazy. Launching the required array of satellites would be outrageously expensive and you'd need thousands of them. Eventually something would go wrong - you'd have a collision or one would break up and you'd Kessler yourself right out of business.