A California-based start-up is moving ahead with an ambitious plan to reflect sunlight from space onto Earth at night, promising cleaner energy and improved disaster response. However, the proposal has also raised serious concerns among astronomers, who warn that the technology could threaten ground-based observations of the night sky.
Reflect Orbital, based in Hawthorne, California, recently received approval from the US Federal Communications Commission to launch its first demonstration satellite, Eärendil-1, later this year. The company ultimately aims to deploy 50,000 mirror-equipped satellites by 2035, creating controlled patches of daylight in selected locations.
The first spacecraft, roughly the size of a mini refrigerator, will carry an ultra-thin mirror about the size of a tennis court. Orbiting approximately 625 kilometres above Earth, the satellite will direct sunlight onto a test area of around 24 square kilometres. According to the company, the reflected light can be switched on or off as needed.
Reflect Orbital says the technology could enable solar panels to generate electricity after sunset, extend daylight for agriculture, and provide emergency lighting during natural disasters. Company CEO Ben Nowack describes the first mission as a technology demonstration designed to evaluate the mirror’s deployment and precision while studying its environmental impact.
Despite these potential benefits, astronomers have expressed concern that large numbers of reflective satellites could significantly increase light pollution and interfere with sensitive telescopes. Researchers warn that even a single reflected beam could saturate images captured by advanced observatories, making them unsuitable for scientific analysis. They argue that a constellation of tens of thousands of mirrors could severely disrupt optical astronomy.
The project also faces engineering challenges. Experts note that the delicate mirrors must withstand collisions with space debris and continuous exposure to atomic oxygen, a highly reactive substance that can gradually erode spacecraft surfaces. Any malfunction in deployment or navigation could also compromise the mission.
Reflect Orbital says it has incorporated safeguards to minimise unintended light exposure and is working with the scientific community to address concerns. The company plans to establish exclusion zones around major observatories and use data from the first mission before expanding its satellite network.
As space-based technologies continue to evolve, the project highlights the growing challenge of balancing innovation in clean energy with the protection of scientific research and the night sky.
Author
