Reflect Orbital Space Mirror Approved by FCC: What It Means for Astronomy

There are moments when technological progress genuinely feels like progress. We develop cleaner energy, better batteries, more efficient solar panels and smarter electrical grids. Then there are moments when it feels as if we have completely gone off the rails - I feel personally, this is one of those moments.

The FCC has now authorized Reflect Orbital to launch Eärendil-1, an experimental satellite carrying a massive reflective surface designed to redirect sunlight from space onto the Earth after sunset. The company calls its broader vision “sunlight on demand.”

I call it trying to solve the problem of nighttime solar generation in perhaps the most complicated, expensive and environmentally reckless way imaginable.

To be clear, the FCC has not approved a fleet of 50,000 space mirrors - the Heavens! It has only approved one experimental spacecraft. Eärendil-1 is intended to determine whether Reflect Orbital can deploy, control and accurately direct a large, ultrathin reflector in orbit. The authorization is limited to this demonstration satellite, reportedly operating at an altitude of roughly 625 kilometers. 

That distinction matters here people. This is a test, not a functioning commercial power system. It may fail. The reflector may not deploy properly. The pointing may prove too difficult. The light may be too diffuse to produce meaningful electricity. Atmospheric conditions may make the system less reliable than advertised. The economics may collapse the moment anyone attempts to scale it.

Hopefully, this entire idea falls flat before we begin filling low Earth orbit with mirrors designed to interfere with one of the most basic natural conditions on Earth: darkness.

What Has Actually Been Approved?

Reflect Orbital’s demonstration satellite will carry a deployable, highly reflective thin-film surface approximately 18 meters by 18 meters, or about 59 feet across. That gives the experimental mirror a surface area of roughly 324 square meters, assuming the full square reflector deploys as described.

This is not a small mirror attached to an ordinary satellite. It is a reflective sheet about as wide as the wingspan of a commercial airliner, unfolding in low Earth orbit and intentionally aimed at the planet below.

The company says the light can be directed to approved locations, relocated as needed and turned off when the customer is finished. Its website promotes uses including construction, agriculture, military operations, public events and extending the operating hours of solar farms.

The FCC’s decision, however, is fundamentally a satellite communications and operating authorization. The Commission did not certify that the system is economically practical, environmentally responsible or safe for astronomy. It authorized Reflect Orbital to operate a single non-geostationary experimental spacecraft.

That is a much narrower decision than some headlines suggest.

It is also part of the problem. The FCC determined that many of the broader environmental and astronomical objections were outside the immediate scope of this particular authorization. In practical terms, that means a communications regulator has allowed the test to proceed without resolving the full implications of intentionally redirecting sunlight onto the nighttime Earth.

Nearly 2,000 public objections were reportedly submitted, with concerns involving astronomy, wildlife, human health, aviation and the preservation of the natural night sky. 

How Large Will the Patch of Light Be?

The reflected light will not arrive as a tight science-fiction laser beam. Sunlight reflected across hundreds of kilometers spreads because the Sun is not a single, infinitely small point of light. It has an apparent angular diameter of about half a degree in our sky.

Even with a perfectly flat mirror and perfect aiming, that geometry produces a footprint on the Earth measuring several kilometers across.

Current descriptions of the Eärendil-1 mission suggest that its reflected light could cover an area approximately five to six kilometers wide. That is a circle roughly three to four miles across.

A six-kilometer-wide circular footprint would cover about 28 square kilometers, or nearly 11 square miles.

That is not a pinpoint of light neatly landing on a fenced solar farm. It is an enormous illuminated area. Depending on the site, the footprint could include farmland, roads, homes, natural habitats, bodies of water and communities that never requested orbital illumination.

The exact size and intensity will depend upon the satellite’s altitude, reflector shape, surface quality, orientation, atmospheric conditions and how directly the reflected sunlight strikes the target. But the basic geometry cannot be negotiated away. A mirror hundreds of kilometers above Earth does not create a perfectly defined square of sunlight matching the dimensions of a solar array.

There will be a broad footprint. There may also be scattered light and glare extending outside the nominal target area.

How Bright Will It Be?

Reflect Orbital describes its product as adjustable from “noon light to moon light.” Critics and independent reports have discussed illumination levels exceeding three or four times the brightness of a full moon.

That description can be misleading because the brightness experienced on the ground and the apparent brightness of the object in the sky are not the same measurement.

A patch of ground lit to several times full-moon illumination may not resemble broad daylight to the human eye. However, the satellite itself could appear extraordinarily bright from certain locations because observers may be looking toward a highly specular reflector intentionally sending sunlight toward Earth.

This is what makes orbital mirrors so different from ordinary light pollution.

A poorly shielded parking lot light affects a local area. A bright city dome can damage the sky for dozens or even hundreds of miles. But a mirror in orbit moves rapidly across the sky, remains exposed to sunlight long after the ground below has entered darkness and can potentially direct intense reflected light across multiple locations during each orbit.

A tracking failure, pointing error, unexpected deformation of the reflector or incorrect prediction of the beam’s location could place that light somewhere it was never intended to go.

Reflect Orbital says the system can be turned off rapidly by changing the mirror’s orientation. That may reduce risk when everything is operating correctly. It does not eliminate the consequences of hardware failure, software failure, loss of communication or incorrect orbital calculations.

The Economics Make Even Less Sense

I am not going to pretend that a complete cost-per-kilowatt-hour calculation can be made before the demonstration satellite even flies. We do not yet know the launch cost, usable operating life, maintenance requirements, reflector efficiency, number of nightly passes, actual power delivered or final constellation architecture.

But we do know the basic economic challenge.

The average customer buying grid electricity might pay somewhere around 15 cents per kilowatt-hour, depending on location. Utility-scale solar energy can be produced for far less under favorable conditions. Batteries, natural gas, nuclear power, hydroelectricity, wind generation and demand management already exist as ways to supply electricity after sunset.

Reflect Orbital proposes competing with those systems by manufacturing a satellite, qualifying it for spaceflight, launching it into orbit, deploying a delicate mirror tens of meters across, tracking it, controlling its attitude, maintaining communications and accurately directing a rapidly moving patch of reflected sunlight onto solar panels for a short period after sunset or before sunrise.

Every satellite would eventually fail or need to be replaced.

Every satellite would need launch capacity.

Every satellite would have only limited opportunities to illuminate a particular solar facility because it would be moving at orbital velocity, not hovering over the site.

Clouds could block the reflected light.

Atmospheric haze could reduce it.

The footprint would be much larger than many individual solar farms.

The panels would receive substantially less energy than they receive under the direct midday Sun unless an enormous reflective area or a large number of satellites were used.

At some point, someone will have to divide the total lifetime cost of this orbital infrastructure by the actual kilowatt-hours it produces. I suspect that number will make ordinary nighttime electricity look incredibly inexpensive.

This feels less like a sensible energy system and more like venture-capital engineering: take a common problem, attach satellites and an app to it, then describe the result as revolutionary.

The Sun setting is not a defect in solar power. It is a known limitation around which electrical systems can be designed. Batteries can be installed on the ground. Transmission lines can connect different generating regions. Stored energy can be released when it is needed. None of those solutions requires altering the night sky for everyone underneath an orbital path.

Reflective mirrors in space to light up the dark side of Earth

What This Means for Astronomy

Astronomy already faces a growing crisis from satellite constellations.

Ordinary communication satellites reflect enough sunlight to leave bright streaks across astronomical images. Even satellites specifically modified to appear darker can create trails that contaminate sensitive exposures and force observatories to mask or discard portions of their scientific data.

Now imagine replacing an ordinary satellite body with a mirror intentionally designed to reflect sunlight toward Earth.

That is not an accidental side effect. Reflection is the entire purpose of the spacecraft.

The American Astronomical Society urged the FCC to deny the application, arguing that even a single demonstration satellite could negatively affect astronomy and the broader human environment. The AAS warned that Reflect Orbital’s eventual 50,000-satellite concept would be disastrous for professional and amateur astronomy, ecology and human health.

The European Southern Observatory has been even more direct. Discussing orbital mirrors and other proposed mega-constellations, ESO Director General Xavier Barcons said:

“For optical astronomy, this is an existential threat.”

That is not an amateur astrophotographer complaining about a streak across one picture. ESO operates some of the most advanced observatories on the planet and studies objects so faint that individual photons matter. Its warning is grounded in the possibility that sufficiently large numbers of bright satellites could increase the overall brightness of the sky, contaminate wide-field surveys and make certain observations fundamentally more difficult or impossible.

Reflect Orbital may argue that it can avoid major observatories and coordinate illumination schedules. That does not solve the problem.

Astronomy is not limited to a handful of famous mountaintops. There are research telescopes, university observatories, asteroid surveys, all-sky cameras and amateur observatories distributed across the world. Transient astronomical events cannot always be rescheduled. A supernova, asteroid occultation, gamma-ray burst or newly discovered near-Earth object does not wait until a company finishes renting sunlight to a solar farm.

Astronomers also photograph large portions of the sky at once. The Vera C. Rubin Observatory, for example, is designed to repeatedly survey the entire visible sky and detect objects that change or move. A bright orbital mirror could saturate detectors, create internal reflections, produce electronic artifacts and contaminate far more than the narrow line directly crossed by the object.

Scheduling around thousands of satellites is not a realistic mitigation strategy.

One Mirror Is a Test. Fifty Thousand Would Be a Transformation.

Eärendil-1 is one satellite. By itself, it will not permanently eliminate darkness.

The real concern is what happens if the demonstration succeeds.

Reflect Orbital has discussed a future constellation potentially numbering tens of thousands of satellites. Recent reporting places its long-term vision at as many as 50,000 orbital reflectors by 2035.

At that scale, this stops being a test of an unusual lighting technology. It becomes an attempt to alter the nighttime environment across the planet.

The company speaks of delivering sunlight without the limitations of geography or time. But geography and time are not simply obstacles that technology should automatically erase.

Night is part of the Earth’s natural environment.

Darkness regulates migration, feeding, reproduction and predator-prey behavior. Insects use natural light for navigation. Birds migrate under the stars. Sea turtles orient themselves using the relative brightness of the natural horizon. Plants respond to the length of darkness as well as the length of daylight.

Humans are also biological organisms. Our sleep cycles and hormonal systems evolved around repeating patterns of light and darkness. Artificial light at night has already expanded far beyond cities and highways. Orbital illumination would add a source that could not be blocked through local lighting ordinances, better fixtures or responsible community planning.

DarkSky International opposes orbital illumination systems as currently conceived and has called for comprehensive environmental review before launches proceed. It argues that these systems violate the basic principles of responsible lighting because the light may be broader than necessary, brighter than necessary and imposed from above upon people and ecosystems outside the intended target.

Those objections are entirely reasonable.

A community can vote to replace an overly bright streetlight. A homeowner can install curtains. An observatory can work with a nearby city to improve shielding. But no town council can reach 625 kilometers into space and turn a commercial mirror away.

The Environmental Review Gap

This project exposes a troubling weakness in how space activities are regulated.

The FCC licenses communications and satellite operations. It is not primarily an environmental, wildlife, public-health or astronomical agency. Yet satellite authorization can have consequences in every one of those areas.

Once a spacecraft is in orbit, its effects do not respect state lines or national borders.

The light could cross multiple jurisdictions during a single pass. A satellite launched by an American company could affect observers in other countries. A failed mirror could remain bright or uncontrolled. A larger constellation could alter the sky for people who had no representation in the decision that allowed it.

Twenty-eight scientific and professional organizations joined comments expressing serious concerns about Reflect Orbital’s proposal. Those organizations represented astronomers, physicists, biologists, meteorologists, ecologists, wildlife specialists and dark-sky advocates.

That breadth should tell us something. This is not merely a disagreement between people who like technology and people who like telescopes.

It is a question about who owns the night.

Does a private company have the right to place a mirror in orbit and shine sunlight onto the Earth because one customer purchased a few minutes of illumination? What rights do the people living outside the target have? What happens when the beam crosses protected habitat? Who is responsible if the light distracts a pilot, disrupts an astronomical observation or affects an animal migration route?

These are not questions we should answer after thousands of satellites have been launched.

The Emergency-Response Argument

Reflect Orbital also promotes search-and-rescue operations, disaster response and remote construction as possible uses.

It is easy to build an emotionally powerful argument around disaster relief. Imagine a hurricane, earthquake or wildfire. Emergency responders need light. Roads are blocked. Power lines are down. A satellite directs sunlight onto the area and helps save lives.

That sounds compelling until we compare it with the alternatives.

Portable LED lighting systems already exist. So do generators, battery trailers, emergency microgrids, helicopters, drones, mobile solar systems and rapidly deployable power equipment. Those tools can remain at the site continuously. An orbital mirror would provide temporary illumination during the brief period when its orbit and sunlight geometry allowed it to reach the target.

Emergency lighting is also required precisely where smoke, clouds, dust and severe weather may be present. Those are the same conditions that could weaken or block reflected sunlight.

There may be rare situations in which orbital illumination could help. That does not justify building a global commercial constellation whose normal operation would be lighting construction projects, agricultural sites, events or solar farms.

The most emotionally appealing edge case should not be used to avoid examining the ordinary commercial use of the system.

We Are Losing the Ability to Leave Nature Alone

Modern society seems to treat darkness as an engineering failure.

We illuminate empty parking lots all night. We flood office buildings with light when no one is inside. We install digital billboards bright enough to dominate entire neighborhoods. We place decorative lighting on buildings, bridges, landscapes and trees. We launch thousands of reflective machines into orbit and then search for coatings that might make them slightly less destructive to astronomy.

Now the proposal is to reflect the Sun itself back onto the planet because we cannot tolerate the fact that solar panels stop producing energy at night.

Daylight is natural. Darkness is natural.

They belong together.

The alternating rhythm of light and darkness existed long before humanity and shaped nearly every living system on Earth. Night is not empty space waiting to be monetized. It is an environment.

We should be developing better energy storage, more resilient electrical grids and more efficient terrestrial infrastructure. We should not be spending vast amounts of money launching delicate sheets of reflective material into orbit so that solar panels can operate for a few additional minutes after sunset.

There is a certain arrogance in believing that every natural limit exists merely as an invitation for a startup to overcome it.

Hopefully the Test Proves the Obvious

Eärendil-1 has not yet demonstrated that Reflect Orbital can economically deliver useful solar energy from orbit.

The reflector still has to survive launch.

It has to deploy correctly.

It has to remain stable.

It has to point accurately.

It has to produce a predictable footprint.

It has to deliver enough usable energy through the atmosphere to justify its existence.

It has to do all of this without creating unacceptable risks for astronomy, aviation, wildlife and surrounding communities.

That is a tremendous list of unanswered questions for a technology being promoted with the simplicity of ordering sunlight through an app.

Perhaps this single experiment will demonstrate that an orbital mirror can briefly illuminate a patch of ground. That would be an interesting technical achievement.

It would not demonstrate that the system is economical.

It would not demonstrate that thousands of mirrors are environmentally acceptable.

It would not demonstrate that the night sky can absorb yet another massive commercial intrusion.

And it certainly would not demonstrate that beaming sunlight from space onto terrestrial solar panels is a more intelligent solution than simply storing electricity on the ground.

The FCC has allowed Reflect Orbital to conduct a test. It has not declared the project wise, necessary or safe at commercial scale.

There is still time for the economics, physics and public opposition to stop this idea before one experimental mirror becomes thousands.

I sincerely hope they do.

The natural night sky has already been pushed aside by city lights, advertising, expanding development and satellite mega-constellations. The answer is not to finish the job by installing a switch for the Sun in low Earth orbit.

Some technological boundaries are worth crossing.

Others exist because crossing them would be profoundly stupid.

Sign DarkSky's open letter opposing Reflect Orbitals proposal