The Federal Communications Commission approved Reflect Orbital's application on July 9 to launch Eärendil-1, a satellite with an 18-by-18-meter glossy mylar mirror that will orbit 625 kilometers above Earth and reflect sunlight onto the planet's nightside, casting a moving 5-kilometer-wide spotlight as bright as a full moon.
The company plans to launch later this year aboard a SpaceX Falcon 9. No US agency regulates how bright a satellite may shine.
The business case is real. Reflect Orbital CEO Ben Nowack envisions selling reflected sunlight to solar farms that want to generate electricity after dark, construction projects that want to work overnight, search-and-rescue operations, and disaster relief efforts.
The company has received more than 260,000 inquiries for service and raised $35.2 million in venture funding backed by Sequoia Capital.
The scientific objection is equally real. The FCC received nearly 2,000 public comments against the approval, most from astronomers.
The American Astronomical Society warned the commission that Eärendil-1 poses a risk of retinal damage to amateur astronomers who accidentally view the satellite through a telescope larger than 12 inches, a risk of temporarily blinding pilots and drivers, and a threat to astronomical research as scattered light brightens the sky even at remote observatories.
The European Southern Observatory concluded that the eventual full constellation of Reflect Orbital satellites, the company wants 50,000 of them by 2035, would increase sky brightness by a factor of two to three and could effectively invalidate the Vera Rubin Observatory's science program.
Betty Kioko of the ESO called it an "existential threat" for optical astronomy.
The FCC acknowledged the concerns but said optical astronomy and the environment lie outside its jurisdiction. It can only regulate radio spectrum use. The launch is approved. The mirror is coming.