A start-up company wants to light up the night with 50,000 big mirrors orbiting Earth, bouncing sunlight to the night side of the planet to power solar farms after sunset, provide lighting for rescue workers and illuminate city streets, among other things.
Scientists have questions about that.
It is an idea seemingly out of a sci-fi movie, but the company, Reflect Orbital of Hawthorne, Calif., could soon receive permission to launch its first prototype satellite with a 60-foot-wide mirror. The company has applied to the Federal Communications Commission, which issues the licenses needed to deploy satellites.
If the F.C.C. approves, the test satellite could get a ride into orbit as soon as this summer. The F.C.C.’s public comment period on the application closes on Monday.
“We’re trying to build something that could replace fossil fuels and really power everything,” Ben Nowack, Reflect Orbital’s chief executive, said in an interview. The company has raised more than $28 million from investors.
It’s not the first time someone has thought of doing this.
In 1977, a German‐born rocket engineer, Krafft A. Ehricke, proposed space mirrors to prevent crop freezes and to illuminate disaster-struck areas. And in 1993 a Russian satellite carrying a mirror about 80 feet across briefly reflected a narrow beam of sunlight across the planet as part of an experiment to extend daylight hours in Arctic Siberia.
And the idea is controversial. “We just don’t have a regulatory process for these types of novel space activities yet,” said Roohi Dalal, an astronomer and director of public policy at the American Astronomical Society.
Opponents say the mirrors could distract airplane pilots, mess up astronomical observations and interfere with circadian rhythms — the light-and-dark cycles that help people, creatures and plants know when to wake and sleep, when to bloom, when to migrate and so forth.
If animals were to get confused by the extra light, they might breed at the wrong time, when food is scarce, said Martha Hotz Vitaterna, a research professor of neurobiology at Northwestern University and co-director of the Center for Sleep and Circadian Biology.
Hibernating insects and migrating birds might also become confused. Light at the wrong times of day could also lead to flowers blooming when pollinators are not active, Dr. Vitaterna said. “The implications for wildlife, for all life, are enormous,” she said.
But those are generally not concerns for the F.C.C. when it reviews satellite applications. Rather, the agency checks to ensure that a spacecraft’s radio communications do not create interference problems for others and that the spacecraft will be safely disposed of at the end of its operational lifetime.
The agency’s stance is that activities in space — which, by definition, are not on Earth — are not subject to environmental review. The agency did not respond to a request for comment about the Reflect Orbital application.
Reflect Orbital’s first prototype, which will be roughly the size of a dorm fridge, is almost complete.
Once in space, about 400 miles up, the test satellite would unfurl a square mirror nearly 60 feet wide. That would bounce sunlight to illuminate a circular patch about three miles wide on the Earth’s surface. Someone looking up would see a dot in the sky about as bright as a full moon.
Two more prototypes could follow within a year. By the end of 2028, Reflect Orbital hopes to launch 1,000 larger satellites, and 5,000 of them by 2030. The largest mirrors are planned to be nearly 180 feet wide, reflecting as much light as 100 full moons.
The company said its goal was to deploy the full constellation of 50,000 satellites by 2035.
How much does it cost to order sunlight at night?
Mr. Nowack said the company would charge about $5,000 an hour for the light of one mirror if a customer signed an annual contract for 1,000 hours or more. Lighting for one-time events and emergencies, which might require numerous satellites and more effort to coordinate, would be more expensive. For solar farms, he envisions splitting revenue from the electricity generated by the additional hours of light.
Mr. Nowack says that Reflect Orbital’s satellites could be a tool to reduce the burning of fossil fuels and thus slow climate change. One of the biggest weaknesses of solar power is that electric generation stops when the sun goes down.
Astronomers have raised alarms about the toll taken on their observatories by the rapidly rising number of satellites crisscrossing the night sky. The constellation of nearly 10,000 Starlink satellites operated by Elon Musk’s SpaceX now routinely produces bright streaks across photographs of the universe taken by ground-based telescopes.
Some companies, including SpaceX, have voluntarily worked to minimize light pollution in the night sky by making their satellites less reflective.
For critics, even one Reflect Orbital satellite is worrying, because the whole point is to be as bright as possible.
Michael Brown, an astronomer at Australia’s Monash University, calculated that the reflected sunlight from one satellite would be spread over about 18 square miles. That would mean that the number of photons hitting a solar panel would be about 1/140,000th of the rate during midday.
Even with the 180-foot-wide mirrors, “over 3,000 satellites would be required to produce the equivalent of just 20 percent of the midday sun at a single site,” Dr. Brown wrote in his comment to the F.C.C. about Reflect Orbital’s application.
With 87,000 satellites, the company could provide, at best, 20 percent of midday illumination to 27 sites, Dr. Brown said. He said that a network of mirror satellites was not an efficient means to augment energy production.
“I think his idea keeps coming up because it has a certain simplicity and elegance,” Dr. Brown said in an interview. “But when you start crunching the numbers, and the numbers are pretty easy to crunch, then you find there’s a lot of serious issues with it.”
Gaspar Bakos, an astronomer at Princeton University, questioned the company’s claim that the reflected light would be visible only in the targeted area. Light is inevitably scattered by particles of air, and glow from the beam could brighten the night sky miles farther away, an effect that is evident with the street lighting of even small towns, he said.
Mr. Nowack of Reflect Orbital said that the company had studied the scattering issue in simulations, and that the effects were not as dire as critics portrayed. The test satellite will try to validate that, he said.
“We plan to show exactly what’s happening with real measurements in the real world from our actual satellite,” he said. “That’s going to help a ton. You can’t fake that.”
So, do space mirrors have a role to play in helping humanity see in the dark? Dr. Bakos is actually enthusiastic about the concept. Not on Earth, but on the moon.
With NASA and other space agencies planning to build lunar outposts in the coming years, reflected sunlight could provide a workable energy source and brighten the two-week-long nights. The moon also lacks an atmosphere, eliminating the problems of scattering.
“This thing is basically designed for the moon,” Dr. Bakos said. “They found the wrong celestial body.”
Kenneth Chang, a science reporter at The Times, covers NASA and the solar system, and research closer to Earth.
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