A U.S. company plans to launch giant mirrors into space to reflect sunlight onto Earth on demand, but a new study warns that their brightness could be as intense as 10,000 full Moons and disrupt the night sky for millions of people—far beyond the areas they intend to illuminate.
Reflect Orbital has a dream that sounds like science fiction: selling sunlight from space. Its plan is to deploy a constellation of satellites equipped with mirrors up to 54 meters across, capable of directing beams of light toward specific points on Earth to extend daylight into nighttime or early morning hours. The stated goal is to power solar panels, respond to emergencies, or support military operations, though critics question its real-world usefulness.
Later this year, the company will launch its first prototype, Eärendil-1—a satellite with an 18-meter mirror that will serve as a testbed. The U.S. Federal Communications Commission (FCC) gave its approval last July, but the project has sparked a wave of backlash from astronomers, conservationists, and dark-sky advocates.
A Glow Without Borders
The most recent study, published in Astrophysical Journal Letters and led by astronomer Miroslav Kocifaj of the Slovak Academy of Sciences, has calculated the true reach of these beams. According to their models, a single Reflect Orbital satellite would shine within its impact area (a five-kilometer-diameter circle) with an intensity 40 times greater than the full Moon. At 14 kilometers from the center, its glow would still be comparable to that of our natural satellite.
The scenario becomes even more alarming when projecting the deployment of 400 satellites, as the company intends. In that case, the concentrated light would equal 10,000 full Moons—2.4% of the Sun’s brightness—and its glow would be perceptible up to 80 kilometers away, like a flash on the horizon. This means the visual impact would not be limited to customers who purchase the service but would extend across entire regions, affecting astronomical observation and the nocturnal ecosystem.
Science vs. Industry
Olivier Hainaut, an astronomer at the European Southern Observatory in Germany, endorsed the robustness of Kocifaj’s modeling and noted that his own earlier calculations already pointed to a global increase in sky brightness of up to 300%. Both agree that the damage to astronomy would be irreversible.
For its part, Reflect Orbital’s CEO, Ben Nowack, has pushed back against the criticism. In statements to the media, he assured that the study’s conclusions are based on “inaccurate assumptions” and that the company has designed “safeguards and exclusion zones” to mitigate light scattering. However, Kocifaj counters that the firm has not provided any technical data, numerical models, or figures to support those guarantees, so “there is nothing to interact with technically.”
Eye Hazards and Wildlife Concerns
Reflect Orbital itself has acknowledged in FCC filings that observing its satellite with telescopes over 12 inches—a common tool among amateur and professional astronomers—might not be safe for human eyes, though it qualifies that the risk of serious injury is low due to the intermittent nature of the brightness.
Organizations such as DarkSky International and American Bird Conservancy have formally requested that the FCC revoke its authorization and require a full environmental review. They also warn of possible interference with aviation and negative effects on migratory wildlife and animal behavior patterns.
An Unprecedented Legal Gray Zone
One of the most vexing aspects of the project is its regulation. Currently, there is no international treaty governing this type of space-based reflector. The FCC only has authority over the radio frequencies used to communicate with the satellites, not over the mirrors themselves. As Michelle Hanlon, a space law expert at the University of Mississippi School of Law, explains, the company would need permits from every country or local jurisdiction where it projects its beams—an added layer of legal complexity, especially if the light scatters across borders.
Skies in Dispute
The debate is far from settled. While Reflect Orbital insists on the potential benefits of its technology, the scientific community regrets having to devote effort and resources to calculating an impact they consider avoidable. As astronomer Samantha Lawler of the University of Regina puts it: “It’s a shame that astronomers have to spend our time on this instead of doing astronomy. This is not what we want to invest our lives in.”
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