Controversial startup's plan to 'sell sunlight' using giant mirrors in space would be 'catastrophic' and 'horrifying,' astronomers warn

It’s tricky business. The idea has to be plausible enough to attract investors, but implausible enough not to get looked at too closely by clever investors. Similarly, you have to drum up enough publicity to get interest, but not enough to get scrutiny.

Get the balance wrong and you get Theranos.

I'm gonna start a startup called startup starter and my business plan will be selling business plans to startups that are flashy enough to attract VC money so you can siphon off as much as possible before the business folds.

That's the main hurdle.

Re-finding this was a pain in the ass because I didn't save it. https://lemmy.world/post/19485246/12219336

Editing to add some more meandering. Now this is even longer than the first one.

In addition to surface area limitations, there's also a pretty obvious line of sight problem in that if your satellite is positioned such that its shiny side is facing the sun, by definition it must be facing the same direction as the Earth's currently lighted side. The further past the dusk line onto the dark side of the Earth you're trying to hit the further you have to rotate your mirror until ultimately the surface of it is perpendicular to the incoming sunlight. This is the angle of incidence, in optical terms, and it reduces the effective reflection not only off of the mirror proportionally to the increase in angle (in a roughly geometric manner, I believe) but also where that reflected beam of light hits the ground at its oblique angle. In real terms, it will be impossible to hit any target more than a few degrees past the dusk line with any meaningful amount of energy. Insofar as this harebrained scheme could possibly hit the ground with any amount of energy at all.

The diagram (which is surely not to scale) on these idiots' website seems to depict a mirror in orbit around the Earth that's about the size of Massachusetts, which is orbiting at a height that'd put it somewhere in the vicinity of the Van Allen belt, which is also a bad idea (no radio communication for you!) and would result in an orbital period of around 2.5 hours. If so, that means your mirror is whizzing over the surface at something like 14,000 MPH, and you would have some kind of line of sight to it from the ground for maybe 25% of its orbit. So even with the best will in the world and absolutely mathematically perfect rotation control it'll only be able to remain on a surface target for about 37 minutes at most, most of which would be while it's uselessly passing through the Earth's shadow and is reflecting no sunlight at all, and for the remaining handful of minutes with its effective output tapering off to uselessness as it sets over the opposite horizon.

"I'll just position my mirrors in a geostationary orbit," says Mr. Clever. "Then I'll have line of sight to a big chunk of the surface and my satellite won't move relative to it."

Well, the further you park your mirrors from the surface, the harder they are to aim. You can't have it both ways. A geostationary orbit is about 22,000 miles from the surface, a distance from which even the tiniest error in alignment will result in you hitting the wrong target. You can use some middle school trig to calculate this for yourself: At a distance of 22,000 miles, an alignment error of just 0.01 degrees will result in the centerline of your beam missing the target by four miles, which in terrestrial terms is what we refer to as kind of a lot. Maintaining an alignment precision that high especially taking into account gravitational perturbation by the moon, etc., is a rather tall order. To maintain targeting precision within 223 feet, which is probably already unacceptable, you need a constant alignment precision of 0.0001 degrees, and you need to hold it there 100% of the time.

I don't care how big your rocket is, that's not happening.

All of this also assumes perfectly flat and 100% reflective surfaces on the mirrors, which never degrades or gets scuffed up or punctured by space debris. Which is also impossible.

To recap:

• You can't reflect any more energy than strikes the surface area of your mirrors, end of story. The mirrors will be tiny, relative to the size of the Earth, and the Earth is huge, relative to the size of any mirror we can launch.
• The efficacy of your mirrors diminishes geometrically with how far you must angle them relative to the direction of incoming sunlight.
• Most of the time your mirrors will either be in the Earth's shadow, where they are useless, or over the already illuminated side of the Earth, where they're pointless. In easily achievable low Earth orbits, their time on target will be very short.
• Positioning the orbits high enough to mitigate either problem will make aiming mathematically impossible, and also magnify any imperfections in focus, which are certain to be vast. That won't work either.

TL;DR: The whole thing won't work.

Weaponization or dangerous rays are not among the challenges facing space-based solar.

Contrary to appearances in fiction, most designs propose beam energy densities that are not harmful if human beings were to be inadvertently exposed, such as if a transmitting satellite's beam were to wander off-course. But the necessarily vast size of the receiving antennas would still require large blocks of land near the end users. The service life of space-based collectors in the face of long-term exposure to the space environment, including degradation from radiation and micrometeoroid damage, could also become a concern for SBSP.

People don't hate DST, they want permanent DST.

Ah ha, exactly

Well, those are for the fire. You know, can't burn someone alive at the stake if you have no fire.

ah you may have missed my meaning there. I was concerned about sunlight going somewhere in the middle of the night. Things need it to be dark. Since both the article and other commenters had already addressed the issues to people I thought I would bring up that its an environmental disaster as well

The difference is that the most under invested real economy promises little to no profits because of saturation, while these techbros are always ready to promise the moon from the sky. Nothing gets done and less flashy industries stay uncompetitive.

given the enormous capital cost of doing anything in space ever, I don't think they'd even do that

We’re definitely spaceballs

Total recall gives me instant flashbacks to the mutant scene, the cool part and the creepy part.

Moonraker was eugenics and nerve gas. Die Another Day was big space mirror.

Red Dwarf did this in an Episode as well where the new AI decides he's not crew and no longer has a subscription to air.

To a lesser extent, so did the Lorax's Aloysius O'Hare.

Even cheaper to just launch the billionaire funders as payload.

Then you need method of power transmission, usually microwaves or lasers, both come with energy losses. With microwaves you need a reliever and those can get about the size of a solar farm.

If I understand correctly, those mirrors will reflect sun rays, that would otherwise be wasted across the universe, to earth.

So, you are fundamentally wrong. The very idea is to reflect sunlight that wouldn't otherwise hit the planer. This WILL add extra energy to the planet.

Even if they used sunlight that bounces off earth, they would still cause issues, just a little less serious. This is because they would be trapping energy that tries to leave the earth.

Literally a screenshot from their website

Are you being serious? I can't tell, but if you are, that's not how this works.

You either steal energy from somewhere/someone to redirect it around the planet where it's dark, or, you add energy from what is not hitting the planet in the first place.

You can't have a situation where you aren't stealing someone's sunlight and you aren't adding sunlight

This is past soviet collapse and a literal monetary venture the whole point was to use it to sell access to it for the few rich places that could possibly want that, thats capitalist theres literally no use for it except for use in trying to increase wealth for a smaller group that has access to the technology and can suddenly control natural resources without even colonizing or genociding a place to get it they can starve countries or have a permanent advantage at the cost of the rest of society

New rule. All CEOs must now always be shirtless so we can all confirm that they don't have a third nipple.

If the mirrors are reflecting light into a dark part of earth, they are taking it away from a place that's experiencing daylight.

Not any more, there’s a blanket

Life on earth depends on day and night cycles. This would cause an environmental disaster. So many animals would get fucked up.