FCC clears first sun-reflecting satellite test amid astronomers' concerns
The U.S. regulator has approved Reflect Orbital's Eärendil-1 satellite, which will use an 18-meter mirror to redirect sunlight onto night-time areas, sparking opposition from astronomers over potential light-pollution and observational interference.
The Federal Communications Commission granted Reflect Orbital permission to launch its Eärendil-1 satellite, a 142-kilogram spacecraft equipped with an 18-meter square mirror designed to reflect sunlight onto regions of Earth that are in darkness. The satellite is slated for a SpaceX Falcon 9 launch in late 2026 and aims to illuminate a three-mile-wide area, a capability the company says could help power solar panels after sunset and reduce reliance on fossil-fuel-based peaking plants.
Reflect Orbital envisions a future constellation of up to 50,000 similar satellites, which would total more than 16 million square meters of reflective surface in low-Earth orbit. The firm acknowledges the lack of a regulatory framework for space-based lighting and says it will work with scientists to mitigate impacts.
Astronomers and lighting-environment groups have voiced strong objections. The American Astronomical Society and DarkSky International warned that even a single mirror could increase sky brightness and interfere with observations, noting that the satellite’s expected optical brightness would be two to four times that of the full moon.
"The concept of illuminating Earth from orbit represents a new category of artificial light at night with global ecological, cultural and regulatory consequences," DarkSky said in an open letter.
European Southern Observatory astronomer Olivier Hainaut, who has studied satellite constellations’ effects on astronomy, said the reflected light would scatter in the atmosphere, raising overall sky brightness much like the natural scattering that makes the sky appear blue. While he expressed personal opposition to a full constellation, he said the prototype could provide valuable data on its actual brightness and impact.
"While I am professionally opposed to the deployment of the full constellation, I'm actually OK with the prototype," Hainaut said.
The approval marks the first step in a test that will allow regulators and the scientific community to assess the feasibility and environmental implications of space-based solar illumination.