A California startup\u2019s 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.<\/p>\n
Reflect Orbital recently applied<\/a> 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\u2019s goal of deploying a constellation of 4,000 such satellites by 2030.<\/p>\n \u201cThe cost that this incurs not only on astronomy, but on the entire civilization\u2014plus the ecological impacts\u2014are, in my personal view, not worth the effort,\u201d Siegfried Eggl, an assistant professor of astrophysics at the University of Illinois Urbana-Champaign and co-lead of the IAU\u2019s Center for the Protection of the Dark and Quiet Sky, told Gizmodo.<\/p>\n Reflect Orbital did not respond to Gizmodo\u2019s request for comment by the time of publication. A company spokesperson told Space.com<\/a> that it intends to conduct an environmental impact assessment before building the constellation.<\/p>\n Would Reflect Orbital\u2019s plan even work? <\/p>\n Reflect Orbital\u2019s website<\/a> promises that its constellation will deliver \u201ccontinuous, reliable access to energy, day or night, to increase power generation.\u201d That promise has won<\/a> the backing of big-wig investors and a $1.25 million Small Business Innovation Research contract<\/a> from the U.S. Air Force.<\/p>\n On paper, the concept is relatively simple\u2014like 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.<\/p>\n In a recent article for The Conversation, they explain<\/a> that due to the Sun\u2019s size and distance, a reflected beam would spread out and be about 15,000 times dimmer than the midday Sun once it reaches Earth\u2019s surface, though that\u2019s still much brighter than the full Moon.<\/p>\n \u201cIf 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\u2019s a lot of satellites to illuminate one region,\u201d 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.<\/p>\n And that\u2019s 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. \u201cOnce this thing tumbles, you basically have a gigantic lighthouse that is uncontrollably illuminating parts of the Earth,\u201d he explained.<\/p>\n The consequences of light pollution <\/p>\n Darkness is a dwindling resource<\/a> that astronomers fundamentally depend on. Light pollution poses an increasing threat to their research, with global levels rising<\/a> roughly 10% per year since the advent of LED lights.<\/p>\n \u201cWhen you have mirrors that are shining even in the approximate direction of where telescopes are, the sky brightness is going to increase drastically,\u201d Eggl explained. \u201cIt will be like having the full Moon up every night, and that will be devastating to astronomy.\u201d This would prevent telescopes from imaging the very faint objects astronomers need to observe.<\/p>\n