Night Sky Threat
Astronomers Warn 1.7 Million Proposed Satellites Could Permanently Brighten Night Sky
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Key Points
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Reflect Orbital plans involve deploying 50,000 large, mirror-like satellites that would beam sunlight onto Earth's night side; the beams would span at least five kilometers across the surface and the satellites could appear up to four times as luminous as the full Moon within those beams.
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ESO researchers warn that the night sky could remain usable only if the number of faint satellites stays around 100,000 or fewer; higher counts would significantly hamper optical astronomy.
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SpaceX has proposed as many as 1 million solar-powered satellites to function as orbiting data centers, a concept that could radically alter the appearance of the night sky.
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Public engagement on the FCC proposals has been unusually high, with about 1,800 public comments for Reflect Orbital and roughly 1,500 for SpaceX, even though regulators have yet to rule.
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Hugh Lewis of the University of Birmingham describes the issue as a 'global effect' and notes that the brightness of some large satellites presents significant challenges for mitigation in astronomy.
A new study published July 1, 2026 warns that plans to launch 1.7 million satellites could destroy ground-based astronomy as we know it. The European Southern Observatory says the proposals — from companies including SpaceX and Reflect Orbital — would have "devastating consequences" for scientists who study the night sky, according to Phys.org.
Right now, about 14,000 to 15,000 active satellites orbit Earth. The new proposals would increase that number by more than 100 times. ESO astronomer Olivier Hainaut put it bluntly: "We can reach conditions where basically, there is no point in operating the telescopes anymore because all the data will be corrupted. All. 100 percent."
The Two Proposals Driving Astronomers to Sound the Alarm
SpaceX filed a plan in January 2026 to put 1 million satellites into orbit. The company wants to use them as "orbiting data centers" to handle AI computing, according to Courthouse News. Reflect Orbital filed its own plan in July 2025 for 50,000 mirror-equipped satellites designed to bounce sunlight back toward Earth.
The Reflect Orbital satellites are especially alarming to researchers. Each mirror could appear four times brighter than a full Moon within its 5-kilometer beam on the ground. Outside those beams, the mirrors could still raise the overall brightness of the night sky by 10% or more, according to Universe Today. Hugh Lewis of the University of Birmingham says the brightness of these large satellites presents challenges that are extremely hard to fix.
ESO Sets a Hard Limit: 100,000 Satellites or Science Suffers
The ESO study draws a clear line. If the total number of faint satellites — those at magnitude 7 or dimmer — stays around 100,000 or fewer, optical astronomy can survive. Above that threshold, the damage becomes severe, according to Phys.org. The 1.7 million total in current proposals blows past that limit by more than 17 times.
Wide-field telescopes face the worst risk. The Vera C. Rubin Observatory, built to spot faint asteroids and distant galaxies, could have most of its images made unusable by satellite streaks. Even the Very Large Telescope could lose 10% of data per image — and possibly 100% during wide-field surveys. ESO's Betty Kioko said simply: "For optical astronomy, this is an existential threat."
FCC Reviews the Plans While Scientists Flood the Comment Box
The FCC fast-tracked SpaceX's application just days after it was filed in January 2026. The public comment period for both proposals closed on March 9, 2026. The response was unusually large. Reflect Orbital drew about 1,800 public comments. SpaceX drew roughly 1,500. The FCC has not yet ruled on either proposal, according to Courthouse News.
Major scientific groups have formally asked the FCC to reject both plans. The International Astronomical Union and the American Astronomical Society both filed opposition. But experts note a key gap: U.S. law gives the FCC power over radio frequencies and orbital debris. There is currently no binding law — in the U.S. or internationally — that covers optical light pollution from space, according to Insider Paper.
Industry Says It's Green Energy; Scientists Say It's Inescapable Pollution
Reflect Orbital CEO Ben Nowack defends the mirrors as a clean-energy tool. "Sunlight is the most abundant energy source in the solar system," he said, framing the satellites as a way to boost solar farms at night. SpaceX argues its orbiting data centers run on 100% solar power and cut the need for water-heavy ground cooling systems used by AI facilities, according to Newsy Today.
Astronomers reject that trade-off. They point out that unlike city light pollution — which can be escaped by building telescopes in remote deserts — orbital light pollution is global and inescapable. Hugh Lewis calls it a "global effect." A single regulatory decision by the FCC, researchers warn, could permanently alter the night sky for every person on Earth, according to RFI.
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