A California startup’s plan to launch thousands of mirrors into orbit has caused quite a stir among astronomers and wildlife experts. The company, Reflect Orbital, aims to maximize energy output from solar farms by redirecting sunlight toward them at night.

Reflect Orbital recently applied for a Federal Communications Commission (FCC) license to launch a demonstration satellite called EARENDIL-1 in April 2026. Once in orbit, the satellite will unfold a 3,600-square-foot (334-square-meter) mirror designed to direct sunlight down to targeted solar farms on Earth. This would be the first step toward the company’s goal of deploying a constellation of 4,000 such satellites by 2030.

“The cost that this incurs not only on astronomy, but on the entire civilization—plus the ecological impacts—are, in my personal view, not worth the effort,” Siegfried Eggl, an assistant professor of astrophysics at the University of Illinois Urbana-Champaign and co-lead of the IAU’s Center for the Protection of the Dark and Quiet Sky, told Gizmodo.

Reflect Orbital did not respond to Gizmodo’s request for comment by the time of publication. A company spokesperson told Space.com that it intends to conduct an environmental impact assessment before building the constellation.

Would Reflect Orbital’s plan even work?

Reflect Orbital’s website promises that its constellation will deliver “continuous, reliable access to energy, day or night, to increase power generation.” That promise has won the backing of big-wig investors and a $1.25 million Small Business Innovation Research contract from the U.S. Air Force.

On paper, the concept is relatively simple—like using a hand mirror to bounce a spot of sunlight onto the wall. But in practice, this approach may not be as effective as Reflect Orbital hopes, according to astronomers Michael J. I. Brown of Monash University and Matthew Kenworthy of Leiden University.

In a recent article for The Conversation, they explain that due to the Sun’s size and distance, a reflected beam would spread out and be about 15,000 times dimmer than the midday Sun once it reaches Earth’s surface, though that’s still much brighter than the full Moon.

“If a single 54 metre [177-foot] satellite is 15,000 times fainter than the midday Sun, you would need 3,000 of them to achieve 20% of the midday Sun. That’s a lot of satellites to illuminate one region,” Brown and Kenworthy write. Because these satellites would orbit Earth so quickly, it would take well over 4,000 to provide continuous illumination, they add.

And that’s if everything goes according to plan, Eggl said. Imagine, for example, that a piece of space debris or a meteorite impacts one of these mirrors and causes it to tumble. “Once this thing tumbles, you basically have a gigantic lighthouse that is uncontrollably illuminating parts of the Earth,” he explained.

The consequences of light pollution

Darkness is a dwindling resource that astronomers fundamentally depend on. Light pollution poses an increasing threat to their research, with global levels rising roughly 10% per year since the advent of LED lights.

“When you have mirrors that are shining even in the approximate direction of where telescopes are, the sky brightness is going to increase drastically,” Eggl explained. “It will be like having the full Moon up every night, and that will be devastating to astronomy.” This would prevent telescopes from imaging the very faint objects astronomers need to observe.

Light pollution also threatens numerous animal species whose behavior evolved to align with natural day-night cycles. “By effectively extending daylight hours through artificial light and blurring the boundaries between day and night, light pollution interferes with the circadian rhythms, the physiology, and the behavioural patterns of countless species,” David Smith, advocacy and social change manager at invertebrate charity BugLife, told Space.com.

Reflect Orbital’s FCC license application is still pending approval, and Eggl hopes regulators will take the scientific community’s concerns seriously. “But given what they propose, I see no clear way this cannot be extremely disruptive for all sorts of things,” Eggl said.