A startup aiming to run solar farms at night by reflecting sunlight from space has sparked controversy among astronomers who rely on dark skies.
California-based Orbital recently requested a license from the Federal Communications Commission to launch a demo satellite in 2026. The startup says it plans to launch dozens more over the next two years, with a goal of having about 4,000 satellites in orbit by 2030.
Reflecting Orbital’s plans, it has secured the backing of investors including Sequoia Capital and tech billionaire Baiju Bhatt. But while its mission is to extend solar farms’ operating hours, astronomers say doing so comes at the expense of their research.
“Illuminating the ground at night with 4,000 bright satellites of this kind is potentially catastrophic for cutting-edge ground-based optical astronomy,” says Anthony Tyson, chief scientist at the Rubin Observatory, which will launch the Sky survey next year.
Reflection Orbital says the redirected light from its first demonstration satellite is similar to the illumination of a full moon, but it’s still “blindingly bright” for sensitive astronomy cameras, Tyson says.
“Like other large ground-based telescopes, Rubin relies on dark skies,” he adds.
The American Astronomical Society began its investigation in August. We asked its members to weigh the impact of Orbital’s proposed satellite reflections. Of the more than 1,400 astronomers who have submitted responses so far, the majority said their work would be affected.
“We understand that our system continually raises important questions as we introduce new scales to redirect natural light,” Orbital wrote in a statement emailed to Bloomberg Green. The startup says it is working with the astronomical community to mitigate any potential negative impacts.
There may be other pitfalls when reflecting sunlight off the dark side of the Earth. Scientists have documented how artificial light at night disrupts the behavior of nocturnal species such as moths, frogs, and bats, disrupting some of the benefits the ecosystem provides. Light pollution can also have negative effects on human health, but may be less of a concern in many large solar power plants located far from population centers. Reflection Orbital has pledged to assess environmental impacts and potential impacts on local communities everywhere the company serves.
The “cost, rapid deployment, and proven implementation” of solar and battery technologies likely make them a more viable route to producing clean energy compared to selling sunlight to solar power plants, says Grant Hauber, a researcher at the Institute for Energy Economics and Financial Analysis. He added that the environmental impact of satellite launches may also dampen climate benefits.
Reflection Orbit declined to specify an estimated cost for the service. Although the startup has not yet conducted a full lifecycle emissions assessment, its initial calculations indicate that emissions from the satellite’s launch could be “offset within weeks” by the additional clean solar power the system will enable.
A growing number of satellites have been launched by private companies, including SpaceX’s Starlink, Amazon.com Inc.’s Project Kuiper, and Eutelsat Oneweb. Almost 2,700 satellites will enter space in 2024 alone, according to a May report by the satellite industry ASSN.
Meredith Rawls, a research scientist and astronomer at the University of Washington, said the growing swarm of satellites has a negative impact on astronomical imaging, and the potential effects of reflective orbits are especially worrisome. That’s because unlike most existing satellites, which are illuminated by the sun shining on their antennas and other reflective components, the climate tech startup’s satellite intentionally places a giant mirror in space to reflect the sun.
“Astronomers are certainly concerned about this,” she says.
Orbital says it redirects sunlight in a “concise, predictable and targeted” way. It also pledges to avoid systematically reflecting light near observatories and says it will share satellite positions with scientists to help plan their work. Next year’s demo will inform the company as the design has also been refined. However, Rawls questions the effectiveness of the proposed measures, some of which he says have been deployed by other satellite operators.
It remains unclear whether or when the FCC will grant a license to reflect the orbit. The agency did not respond to requests for comment.
“The astronomy community can point to the impact on basic research like this,” Tyson says. “But it’s someone else’s responsibility to set the policy.”
Liu writes in Bloomberg.
