A California startup plans to launch 4,000 giant mirrors into orbit to reflect sunlight onto Earth after dark, promising on-demand lighting for cities and solar farms while raising alarms among astronomers and space safety experts.
Reflect Orbital, backed by Sequoia Capital and Lux Capital, filed an FCC license request for its first satellite, Earendil-1, targeting an early April 2026 launch to demonstrate the concept. Each mirror would span up to 180 feet wide, redirecting sunlight to specific locations on Earth during nighttime hours.
The company envisions users triggering light delivery via an app — entering coordinates to illuminate construction sites, remote solar arrays, or disaster zones long after sunset. Ben Nowack, co-founder and CEO, said the idea came to him in 2021 while watching a YouTube video about African solar farms exporting energy to Europe, sparking his quest to bypass costly transmission infrastructure.
Nowack’s engineering background includes operate on SpaceX’s Dragon spacecraft and autonomous drone systems at Zipline, which he says gave him the technical foundation to pursue what he calls an “audacious” use of orbital mirrors to distribute clean solar energy on demand.
But the plan places bright, moving objects in low-Earth orbit during twilight hours — precisely when many ground-based observatories conduct sensitive observations. Alejandro S. Borlaff of NASA’s Ames Research Center warned that even compact increases in sky brightness can interfere with faint object detection and time-sensitive astronomical measurements.
Reflect Orbital’s own models indicate the reflected beam could appear up to four times brighter than the full moon and remain visible up to 60 miles from the target site. Atmospheric scattering would spread the light beyond the intended area, brightening nearby skies and potentially sweeping across telescope fields of view as the mirrors pass overhead.
The proposed constellation would operate in a sun-synchronous orbit, staying near the day-night line to capture sunlight while Earth below is in darkness. This geometry also positions the mirrors prominently in the sky during dawn and dusk — peak activity times for both astronomers and nocturnal wildlife.
Adding to concerns, low-Earth orbit is already crowded with active satellites and debris, where collisions occur at several miles per second. NASA continuously tracks this traffic, noting that even small fragments can cause catastrophic damage to functioning spacecraft.
While the technology builds on earlier concepts studied by NASA, ESA, and the University of Glasgow, Reflect Orbital argues falling launch costs and advanced materials now make the constellation economically feasible — a claim that hinges on unproven scalability and regulatory approval.
Astronomers counter that the cumulative effect of thousands of reflective objects could fundamentally alter the natural night sky, undermining a shared environmental resource used for science, culture, and ecological balance for millennia.
How bright would the reflected light appear from Earth?
According to the company’s own modeling cited in the sources, the direct beam from a sky mirror could appear up to four times brighter than the full moon and remain noticeable up to 60 miles away due to atmospheric scattering.
What happens to the mirror after it reflects sunlight?
After completing a pass over its target, the sky mirror tilts away from Earth to shorten exposure time and reduce stray brightness, as stated in the FCC license request for the Earendil-1 demonstration satellite.
