The 'Catastrophic' Plan to Put 4k Mirrors in Space

An artist's rendering of mirrors beaming sunlight down through the atmosphere. Credit: Reflect Orbital

Astronomers are having a pretty hard go of it, recently. Their state budgets are being cut to the bone, Elon Musk keeps flashing multi-colored lights in their eyes, and now they could have to deal with private industry turning the beloved night into the hated day.

Reflect Orbital has a plan to put 4,000 mirrors into space that could shine four times brighter than the full Moon—from multiple spots at once—in an attempt to keep solar farms productive through the night.

On the one hand, this is exactly the sort of increase in efficiency that the renewable energy industry needs. On the other hand, it's very obviously a problem for any attempt to view the cosmos from the surface of the Earth. Space.com collected a number of reactions from astronomers and NASA officials.

"The central goal of this project is to light up the sky and extend daylight and obviously, from an astronomical perspective, that's pretty catastrophic," said Robert Massey, deputy executive director at the United Kingdom's Royal Astronomical Society.

The issue is light scattering. While Reflect Orbital claims that the beams it would direct toward the Earth are localized to what's approximately a 5-kilometer radius, the real issue is the way the light spreads as it passes through the upper atmosphere. This can reduce visibility through the atmosphere over a large area—though how large an area, we can only speculate.

At 5 kilometers across (or more), the beam would certainly disturb the patterns of local wildlife, as well.

The impact on visibility arises from the same scattering of light from human settlements that already causes light pollution, in which the light scatters and illuminates the atmosphere. Here, the light is traveling in the opposite direction but could accelerate the same effect.

The company claims that the illumination is a "soft, Moon-like glow," and that the mirrors will appear as an extra-bright star in the sky.

One problem with the drastic increase in orbital technologies—the very increase that allows one upstart company to confidently envision launching thousands of satellites—is that not all things can be miniaturized to the same extent.

While we might say that NASA should simply transition to launching its telescopes and antennae into space as well, the power and sophistication of those technologies can be massively greater if they can be made far too large and heavy to realistically launch into orbit.

And, of course, such launches would massively increase the cost of every single new piece of equipment, at a time when NASA is struggling even to afford the projects it already has.