A California start up called Reflect Orbital wants to light up parts of the Earth at night using giant space mirrors, and the idea has astronomers on edge. The company has applied for approval to launch its first demo satellite next year, the first step toward a constellation of more than 4,000 reflectors, as reported by Space.com.
The demo craft, EARENDIL 1, is aiming for an April launch. Once in orbit, it will unfold a 60 by 60 foot mirror designed to redirect sunlight onto selected regions after sunset and before sunrise. Reflect Orbital says a full constellation could help extend solar energy production into twilight hours, brighten disaster zones, improve crop growth, and even offset urban lighting.
Astronomers and biodiversity experts, though, see serious risks. They fear the project will intensify light pollution, affecting wildlife and washing out the night sky. John Berentine, an astronomer in Arizona, said the reflected beam could be several times brighter than the full moon and would continue shining past its target. Scattering in the atmosphere would spread that brightness far beyond the illuminated area.
The Royal Astronomical Society has also warned that brightening the sky on purpose could harm observations and set a precedent that makes future research even harder. Light pollution is already rising globally at about 10 percent per year. Where people once saw hundreds of stars, many now see only a fraction. Researchers also link excess nighttime lighting to insect decline, disrupted migration patterns, and sleep issues in humans.
Reflect Orbital says it understands the concerns. The company claims each reflection will cover only a localized five kilometer zone for a limited time. After a pass, the mirror would tilt away from Earth. During the 2026 test, observers would see a bright moving point in the sky and a soft, moonlike glow on the ground. The company also says it plans an environmental impact assessment before building out the full constellation.
Still, astronomers note that even relatively dim satellites like Starlink have already complicated observations. A project built specifically to reflect intense sunlight toward Earth raises new questions, and many scientists say a deeper review is needed before thousands of mirrors launch.