Live somewhere that doesn’t get much sunlight? That could soon be changing. The FCC has approved a startup’s plan to launch a satellite that reflects sunlight down to Earth after dark. The company, Reflect Orbital, wants to use a steerable mirror that it would put in orbit to cast a beam of sunlight onto the ground at night. Eventually, it wants to add about 50,000 such satellites, according to IFLScience. The first satellite, Eärendil-1, will be launching in the next few months.
The concept is as such: a reflective mirror that steers a beam of sunlight roughly three miles wide onto a spot on the ground at night. Reflect Orbital says the technology could deliver sunlight to solar power plants after dark and light up disaster areas. Critics say the same reflected light would go a long way past its target.
The FCC’s own approval acknowledges the pushback but sets it aside. The commission wrote that federal law directs it to encourage new technologies and services, and it called the demonstration satellite a potentially groundbreaking technology in the public interest. It also concluded that the harms raised on the record were unrelated to its role in authorizing radio spectrum, that it lacked authority to review those operations, and that the harms were unlikely to occur.
An earlier round of public comments on the plan drew about 1,800 responses, most of them negative. They cited light pollution, safety, and harm to astronomy. Before the approval, Dark Sky International had called on the FCC to require a full environmental review of the proposals, which the commission did not do.
What Scientists Say the Mirror Could Do
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The American Astronomical Society laid out specific risks in its filing to the FCC. Deputy Director of Public Policy Roohi Dalal wrote that the satellite could cause eye damage to amateur astronomers looking through reasonably sized telescopes, temporarily flash-blind drivers and pilots, and interfere with research at federally funded observatories. Those were the society’s stated concerns about a single satellite, not the full constellation.
The wider problem astronomers raise is that light does not stay where it is aimed. Sunlight scatters as it passes through the atmosphere, which is why the daytime sky is blue; so a satellite reflecting sunlight down at night would brighten the sky over a broad area rather than a single point. The European Southern Observatory’s Olivier Hainaut ran simulations of a 50,000-satellite version and found it could make dark-sky sanctuaries as bright as suburbs and erase the few stars still visible from cities. He described the potential effect on ground telescopes as losing all of their data.
Why One Satellite Sets Up a Larger Fight
The approval covers a single demonstration satellite, but scientists worry about the precedent it establishes. It signals what one company from one country can be permitted to put in orbit, even when the effects could reach observers worldwide, and Reflect Orbital has said it envisions tens of thousands more. Astronomers argue that without clear regulation for reflective satellites, later expansion becomes harder to stop once the first is flying.
The Vera Rubin Observatory recently began its decade-long Legacy Survey of Space and Time, and the Extremely Large Telescope and the Giant Magellan Telescope are under construction, all of them ground-based projects that depend on dark skies. A separate analysis published last week estimated that around 100,000 faint satellites may be the maximum before ground-based astronomy becomes unworkable. The FCC has said that looking into these particular risks is beyond its scope. It’s very possible that this mirror could come to fruition after all.