A US startup, Reflect Orbital, is planning to deploy 50,000 mirror-equipped satellites in space to beam sunlight to parts of Earth at night, raising concerns among astronomers over light pollution and its impact on wildlife and human health.
The company, which describes its service as “sunlight-as-a-service,” says the technology could provide on-demand illumination for solar farms and nighttime search-and-rescue operations.
However, the proposed service, reportedly priced at $5,000 per hour, has sparked concerns that its commercial and military applications could come at the expense of the natural night sky.
Astronomers warn that reflected sunlight could interfere with ground-based observations, worsening the disruption already caused by satellite constellations such as SpaceX’s Starlink.
A study published in The Astrophysical Journal Letters found that a satellite fitted with a 54-metre mirror could produce light brighter than the Moon.
Within the illuminated area, the sky could become as bright as twilight after sunset.
The European Southern Observatory has warned that a constellation of 50,000 such satellites could make the night sky three to four times brighter overall.
Beyond astronomy, scientists fear artificial illumination could disrupt the natural day-night cycle, affecting humans, plants and animals.
Reflect Orbital tested its technology near Independence, California, on October 10, using large floodlights to simulate sunlight reflected from space.
The company has also received approval from the US Federal Communications Commission to develop a demonstration satellite, Earendil-1, and plans to launch its first satellites in partnership with India’s Skyroot Aerospace.
The proposed launches would require authorisation from India’s space regulator, raising concerns that the company could pursue deployment outside the US regulatory system.
Astronomers are calling for greater scrutiny of the project, arguing that the night sky is a shared resource that should not be altered without public consultation.
