Astronomers are up in arms, protesting against a proposed constellation of tens of thousands of orbiting mirrors intended to reflect light onto ground-based solar power plants and SpaceX’s envisioned one million orbiting data centers.
The projects, which have been put forward to the U.S. Federal Communications Commission (FCC) for approval, would destroy the night sky as we know it and obscure the views of astronomical telescopes all over the world, hampering scientific progress, according to experts.
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RAS, the oldest astronomical society in the world, has joined the growing army of research institutions filing objections to the FCC against the proposals by SpaceX and California-based startup Reflect Orbital.
SpaceX announced its plans to launch one million data centers to space in January. The company’s founder and CEO, Elon Musk, said on X at that time that moving power-hungry computing infrastructure into space is necessary to fully unleash the powers of AI. Reflect Orbital, founded by former SpaceX intern Ben Nowack, has ambitions to launch 50,000 orbiting mirrors into space, each one about 180 feet (55 meters) wide.
If those plans were to pass, the sky as humankind has known it for millions of years would change beyond recognition.
“If you have a direct view of this, it would be several times as bright as the full moon,” said Massey. “That’s extraordinarily bright.”
Even if seen at an angle, the orbiting mirror would be as bright as Venus, the brightest object in the night sky after the moon.
“Imagine a stream of satellites with that kind of magnitude crossing the sky,” said Massey. “It would absolutely transform our view of the sky.”
Add to that the million proposed SpaceX data centers, which, although dimmer, would also be visible to the naked eye. Due to the vast size of these planned constellations, there would be thousands of shining dots as bright as stars criss-crossing the firmament at any given moment.
Massey estimates the sky would become up to three times brighter as a result of the vast quantity of Reflect Orbital’s sun-reflecting mirrors. That brightening would affect the entire planet, including remote locations that are now considered dark sky sanctuaries, where astronomers build their sky-observing machines.
The European Southern Observatory (ESO), an international astronomy research organization that operates some of the world’s largest telescopes, has also filed objections against the two proposals.
ESO astronomer Olivier Hainaut told Space.com that the Very Large Telescope in Chile would lose up to 10% of pixels in every image if SpaceX’s one million orbiting data centers were to materialize. That number could rise to up to 30% for some kinds of observations.
“That’s a huge loss,” Hainaut said. “We keep our technical losses below 3%, and the total weather losses are about 10%.”
The overall increase in sky brightness caused by the Reflect Orbital mirror constellation would mean astronomers would have to triple exposure times when taking images.
“We wouldn’t be able to observe our faint targets anymore,” Hainaut said. “It would be disastrous.”
Fabio Felchi, a light pollution researcher at Istituto Superiore “Enrico Fermi” Mantova in Italy, told Space.com that “the only option we have to save the starry night as it was for billions of years is to put a limit on the total number of satellites in orbit.”
He added that a safe limit has already been passed and called for “a red-line policy on this, as there is for most other pollutants.”
Noelia Noel, an astrophysicist at the University of Surrey in the U.K., said that the two proposals “mark a critical moment in how we manage humanity’s presence in space.”
“While innovation in satellite technology brings clear societal benefits, scaling to hundreds of thousands or even millions of bright objects — or deliberately illuminating the Earth from orbit — risks fundamentally altering the night sky,” she said. “This would have profound consequences not only for astronomy but also for ecosystems, our cultural heritage, and our collective relationship with the cosmos.”
Some worry that the FCC is in favor of those proposals, as it’s fast-tracking their evaluation without expecting the companies to carry out environmental impact assessments, astronomer and dark sky consultant John Barentine previously told Space.com.
“The presumption now is that the application should be approved and that it should be up to the people who might object to prove that there’s a problem of some kind,” said Barentine. “The fact that they have fast-tracked this application, which has potentially tremendous effects not only for astronomy but for the environment too, and to do so without engaging in a full environmental review, is worrisome.”