A California startup called Reflect Orbital has applied to the U.S. Federal Communications Commission (FCC) for approval to launch a constellation of steerable mirror satellites.

The goal: redirect sunlight from space onto specific spots on Earth’s night side, creating “sunlight on demand.”

These beams could range from full-moon brightness up to near-daylight levels, illuminating areas roughly 5–6 km wide for short periods (a few minutes per satellite pass).

Potential uses include extending solar power generation after sunset, lighting disaster zones or construction sites, or supporting agriculture/industry.

The company has discussed scaling to thousands—or even tens of thousands—of such satellites.

In early April 2026, the presidents of four major international scientific societies—the European Biological Rhythms Society (EBRS), the Society for Research on Biological Rhythms (SRBR), the Japanese Society for Chronobiology, and the Canadian Society for Chronobiology—sent formal letters to the FCC.

Representing ~2,500 researchers from over 30 countries, they warn that deploying these mirrors (combined with broader low-Earth-orbit satellite growth, including SpaceX proposals for up to 1 million additional satellites) would cause “a significant alteration of the natural night-time light environment at a planetary scale.”

Human (and animal/plant) biology is tuned to the natural 24-hour light-dark cycle. Even modest artificial light at night is known to:

• Suppress melatonin production.
• Shift sleep timing and quality.
• Affect hormone balance (e.g., cortisol), metabolism, and long-term health risks like insomnia, cardiovascular issues, and metabolic disorders.

Orbital mirrors would introduce controllable, intense nighttime illumination that could:

• Reach pristine dark-sky or remote areas currently unaffected by ground-based light pollution.
• Create brief but powerful “daylight bursts” as satellites overhead pass by.
• Compound existing skyglow from megaconstellations like Starlink.

The experts highlight risks not just to human sleep but to wildlife (nocturnal migration, foraging, breeding), plants (seasonal flowering/fruiting cycles), and ocean ecosystems (phytoplankton rhythms that support marine food webs).

The story has been widely covered in the past few days by outlets including The Guardian, New York Post, Daily Mail, Telegraph, and Yahoo News.

It underscores a growing debate: space technology offers huge upsides (cleaner energy, better disaster response), but it can have unintended “down-to-Earth” biological consequences if natural darkness is altered at planetary scale.

Whether the FCC requires full environmental reviews, brightness limits, or mitigation (e.g., dimming tech, orbital restrictions) will shape how this plays out.

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Satellite mirror plans could disrupt sleep and ecosystems worldwide, scientists say

Letters to US agency raise concerns over tech firms’ plans to use reflective satellites and expand numbers in low Earth orbit

Proposals to deploy reflective mirrors and up to 1m more satellites in low Earth orbit could have far-reaching consequences for human health and ecosystems, leading sleep and circadian rhythm researchers have said. The Guardian has the story.

Presidents of four international scientific societies representing about 2,500 researchers from more than 30 countries are among those who have raised concerns in letters to the US Federal Communications Commission (FCC).

The regulator is considering plans by the start-up Reflect Orbital to illuminate parts of the Earth at night using reflective satellites, as well as applications from SpaceX that could dramatically expand satellite numbers in low Earth orbit.

“The proposed scale of orbital deployment would represent a significant alteration of the natural night-time light environment at a planetary scale,” said the presidents of the European Biological Rhythms Society (EBRS), the Society for Research on Biological Rhythms, the Japanese Society for Chronobiology and the Canadian Society for Chronobiology.

They said altering the light-dark cycle could disrupt biological clocks that regulate sleep and hormone secretion in humans and animals, migration in nocturnal species, seasonal cycles in plants and the rhythms of marine phytoplankton that underpin ocean food webs.

They urged regulators to conduct a full environmental review and set limits on satellite reflectivity and cumulative night sky brightness. Prof Charalambos Kyriacou, a geneticist at the University of Leicester and president of the EBRS, said: “We’re saying, please think before you go through with this, because this could have global implications for things like food security. Plants need the night. You can’t just get rid of it.”

Reflect Orbital hopes to use satellites equipped with large reflective mirrors to redirect sunlight on to areas roughly 5km to 6km wide “on demand”, with brightness adjustable “from full moon to full noon”. The company says the system could extend solar energy production into the evening and provide lighting for construction projects, disaster response and agriculture, with illumination delivered only to locations approved by local authorities.

Meanwhile, SpaceX has proposed launching up to 1m satellites to create a giant solar-powered computing network in orbit designed to run artificial-intelligence workloads. The company says the system could reduce the energy and cooling demands of terrestrial datacentres.

Read the full story here.

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Mirrors in space could disrupt human sleep, scientists warn

Deploying mirrors in space to create on-demand daylight could affect humans’ sleep, researchers say.

Officials in the US are considering plans by Reflect Orbital, an aerospace start-up, to illuminate parts of the Earth at night using reflective satellites, as well as from Elon Musk’s SpaceX to put up to one million more satellites in Earth’s low orbit. Yahoo News UK has the story.

However, the presidents of four international scientific groups, representing about 2,500 researchers from more than 30 countries, are among those to write to the US government with concerns.

The letter, written by the presidents of the European Biological Rhythms Society (EBRS), the Society for Research on Biological Rhythms, the Japanese Society for Chronobiology and the Canadian Society for Chronobiology, said: “The proposed scale of orbital deployment would represent a significant alteration of the natural night-time light environment at a planetary scale.”

The experts warned the Federal Communications Commission (FCC), which regulates satellites and space policy, that altering the natural rhythm of light and dark could have untold consequences on biological clocks that regulate sleep, and hormone secretion in humans and animals.

They also warned that it could impact migration of nocturnal species, seasonal cycles in plants and the rhythms of marine phytoplankton that underpin ocean food webs.

They urged the FCC and other regulators to conduct a full environmental review and set limits on satellite reflectivity and cumulative night sky brightness.

Read the full story here.