A startup that aims to keep solar farms running at night by reflecting sunlight from space has sparked controversy among astronomers whose work relies on dark skies.

California-based Reflect Orbital recently requested a license from the Federal Communications Commission to launch a demonstration satellite in 2026, as its first step to creating a constellation that will redirect sunlight to precise locations on demand. 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.

Reflect Orbital’s plan has won the backing of investors that include Sequoia Capital and tech billionaire Baiju Bhatt. But while its mission is to extend the operating hours of solar farms, astronomers say doing so will come at the expense of their research.

“Illuminating the ground at night with 4,000 bright satellites of this kind is potentially ruinous to state-of-the-art, ground-based optical astronomy,” says Anthony Tyson, the chief scientist of the Rubin Observatory, which will begin its sky survey next year.

While Reflect Orbital says the redirected light from its first demonstration satellite will be similar to the illumination of a full moon, that would still be “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 launched a survey in August asking its members to weigh in on the effects of Reflect Orbital’s proposed satellite. Of more than 1,400 astronomers who submitted their responses so far, the majority said that their work would be impacted.

“We understand that because our system introduces a new scale to redirect natural light, it will continuously raise important questions,” Reflect Orbital wrote in an emailed statement to Bloomberg Green. The startup says it is working with the astronomical community to mitigate potential negative effects.

Reflecting sunlight to the dark side of Earth may have other pitfalls. Scientists have documented how artificial light at night can disrupt the behavior of nocturnal species such as moths, frogs and bats, and degrade some of the benefits ecosystems provide. Light pollution can also have adverse effects on human health, though with many large solar farms located far from population centers, that may be less of a concern. Reflect Orbital has pledged that it will assess the environmental impact and potential effects on local communities at every location the company serves.

“The cost, rapid deployability, and proven implementability” of solar and battery technology is also likely to make it a more viable pathway to generate clean energy compared with selling sunlight to solar farms, says Grant Hauber, a researcher at the Institute for Energy Economics and Financial Analysis. He adds that the environmental impact of satellite launches may also blunt the climate benefit.

Reflect Orbital declined to specify the estimated cost of its service. The startup has yet to conduct a full life cycle emission assessment, but said its initial calculation shows that the emissions from its satellite launch can be “offset within weeks” by the additional clean solar power its system enables.

The sky has become increasingly clogged with satellites launched by private companies, including SpaceX’s Starlink, Amazon.com Inc.’s Project Kuiper and Eutelsat OneWeb. Almost 2,700 satellites entered space in 2024 alone, according to a May report by the Satellite Industry Assn.

The expanding swarms of satellites have negatively affected astronomical imaging and the potential impact of Reflect Orbital is particularly worrisome, says Meredith Rawls, a research scientist and astronomer at the University of Washington. That’s because unlike most existing satellites that are illuminated because the sun happens to shine on antennas or other reflective components, the climate tech startup’s satellites will intentionally put giant mirrors in space to reflect the sun.

“Astronomers are certainly concerned about this,” she says.

Reflect Orbital says it will redirect sunlight in ways that are “brief, predictable and targeted.” It has also pledged to systematically avoid reflecting light near observatories and says it will share satellite positions with scientists to help plan their work. Next year’s demo will also inform the company as it refines its design as well. But Rawls questions the effectiveness of the proposed countermeasures, some of which she says have been deployed by other satellite operators with limited success.

It remains unknown if or when the FCC will grant a license to Reflect Orbital. The government agency didn’t respond to a request for comment.

“The astronomy community can point out such impacts on basic research,” says Tyson. “It is, however, the responsibility of others to set policy.”

Quelle: Los Angeles Times