Astronomers warn that space mirrors proposed by startup Reflect Orbital could appear forty times brighter than the full moon, turning starry night skies into glaring twilight zones. The warning follows a U.S. Federal Communications Commission license granted to launch a test satellite called EARENDIL-1 into orbit 373 miles above Earth.
A U.S.-based startup named Reflect Orbital has received a license from the U.S. Federal Communications Commission to launch a demonstration satellite into orbit. The spacecraft, called EARENDIL-1, will test how sunlight can be reflected toward Earth to extend solar power plant operations into nighttime hours or illuminate disaster zones after dark. But the plan has triggered sharp warnings from researchers and scientists regarding extreme light pollution.
Calculated Night Sky Impact and Atmospheric Scattering
Researchers calculated that operational mirrors measuring 174 by 174 feet would produce intense illumination for observers on the ground. A study found that to an observer standing at the center of a mirror’s 3.4-mile-wide beam, the satellite would appear 40 times as bright as the full moon, making the sky as luminous as an after-sunset twilight zone.
Atmospheric light scattering would expand the affected zone significantly. Even at a distance of nearly 9 miles from the beam, the sky would remain brighter than a full moon, while at 21 miles away, the horizon in the direction of the beam would still outshine a normal lunar night. Reflect Orbital plans to eventually fly 40,000 such satellites to deliver sunlight on demand for agriculture, solar farms, and emergency operations.
“It will be worse than big cities like London,”
Gaspar Bakos, professor of astrophysics at the University of Princeton
“You would not see any stars if you were in the beam.”
Gaspar Bakos, professor of astrophysics at the University of Princeton
Bakos noted that generating energy even in highly efficient modern solar panels would require the combined reflection of at least 400 mirrors simultaneously. Together, those beams would create a sky glow 10,000 times brighter than the full moon, visible from 50 miles away.
Broader Risks for Astronomy, Aviation, and Ecosystems
The regulatory approval has alarmed multiple industries and scientific communities. Astronomers filing objections with the Federal Communications Commission noted that viewing the satellites through a 12-inch telescope could cause serious eye damage. Commercial pilot associations warned that moving light beams might induce flash blindness in the air, while nighttime drivers could face hazardous glare on roadways.
Biologists also raised concerns that artificial nighttime illumination could disrupt circadian rhythms in humans and animals, interfering with sleep patterns, plant growth, migration routes, and ocean phytoplankton. Critics expressed frustration over unresolved questions regarding safety, public notice, and coordination with observatories.
“There has been some disbelief from Reflect Orbital about our original estimates, so we have taken data on light scattering in Earth’s atmosphere which is based on papers that go back for decades to calculate the light pollution.”
Gaspar Bakos, professor of astrophysics at the University of Princeton
Company Response and Ongoing Oversight Debates
Reflect Orbital dismissed the study’s conclusions as relying on inaccurate assumptions.
Scientists and environmental advocates continue to press for strict safeguards and formal coordination procedures before any expanded fleet launches. Questions remain over how communities will be alerted to active mirror operations as the technology moves past its initial demonstration phase.
