The US Approves the Launch of a Mirror Satellite That Can Reflect Sunlight and Illuminate the Earth at Night

On July 9, the US Federal Communications Commission (FCC) authorized Reflect Orbital to build, launch, and operate a mirror satellite in low Earth orbit. The experimental satellite, named Eärendil-1, would be capable of reflecting sunlight onto specific locations on Earth during the night. The project has long drawn criticism from astronomers and environmental advocates.

WIRED wrote about Reflect Orbital's giant mirror in September 2024, when the project was still in its early stages: “The ambitious goal of the Santa Monica, California–based startup is to ensure a continuous supply of light for large solar panel installations, allowing them to generate electricity even at night and thereby overcoming one of the main limitations of this renewable energy source.” Two years later, the Trump administration has given the green light to this provider of “on-demand” sunlight.

Equipped with an 18-meter reflector, Eärendil-1 could illuminate areas 5 to 6 kilometers in diameter for brief periods (the mirror satellite's name is a reference to a character from J.R.R. Tolkien's Lord of the Rings series). The authorization allows the company to deploy the test satellite at an altitude of about 625 kilometers. Its primary objective is to evaluate the technical feasibility of its ultrathin, highly reflective, film-based reflector.

“We're grateful to the FCC for granting our application to fly our test mission,” the company said on social media. “This ruling is hugely validating for our company and reflects America's leadership in testing innovative space technology.”

The US startup argues that this highly controversial technology could have a variety of civilian, commercial, and government applications. These include providing illumination for search-and-rescue operations, supporting critical infrastructure during emergencies, extending productive hours for solar energy facilities, and temporarily lighting remote construction sites without relying on conventional generators.

Beyond “Let Us Sleep”

Eärendil-1 would be only the beginning. Reflect Orbital envisions operating 50,000 satellites by 2035. And that's just one company. If the initiative succeeds, it could give rise to an entirely new global industry—something that is already keeping many people awake, for now at least figuratively. “Imagine the sky filled with moons,” says Tony Tyson, a researcher at the University of California, Davis and chief scientist for the Vera C. Rubin Observatory. Tyson remains skeptical that these satellites will be able to direct reflected light with the precision the startup claims.

During the regulatory review process, the FCC received nearly 2,000 public comments questioning the proposal. Among its leading critics were the American Astronomical Society, DarkSky International, and the Royal Astronomical Society. These organizations warn about the potential effects such satellites could have on astronomy, nocturnal ecosystems, and aviation safety.

Opponents argue that ground-based observatories already have to contend with thousands of satellites in low Earth orbit that interfere with astronomical observations. Even a small number of space-based mirrors could increase light pollution and make observations more difficult, while a future large-scale satellite constellation would radically transform the appearance of the night sky. “For optical astronomy, this is an existential threat, and we hope that the regulators will share that view,” said Betty Kioko, institutional affairs officer for the European Southern Observatory (ESO), in a statement ahead of the FCC decision.

Some researchers have also raised concerns about possible flashes of reflected light that could affect aircraft pilots, drivers, or wildlife that depends on natural cycles of light and darkness.

Despite those objections, the FCC concluded that the application covers only a single experimental satellite, not a commercial constellation. In its decision, the agency states that Eärendil-1 is a limited-duration technology demonstration whose results will help determine whether the concept is technically viable and identify the challenges associated with any future developments. Any future deployment of multiple satellites would require new regulatory approvals.

The agency also declined to address concerns related to astronomy. “We find that concerns regarding Eärendil-1's impact on optical astronomy fall outside the scope of our review and authorization of this space station and therefore do not provide a basis for denying Reflect Orbital's application or imposing additional operating conditions,” the FCC said.

On its website, the company pledged to engage with affected stakeholders and the scientific community. “Reflect Orbital is earning the right to operate and expand. That means demonstrating that reflected sunlight can be precisely controlled, used only where appropriate, limited in brightness and duration, and coordinated with affected communities and scientific institutions. It means measuring real-world impacts rather than relying on assumptions. And it means being willing to change course if the evidence does not support deployment.”

This story originally appeared on WIRED en Español and has been translated from Spanish.