The California-based startup Reflect Orbital is developing mirror satellites to provide sunlight on demand, according to multiple reports. The company plans to launch a 60-foot (18.3-meter) prototype mirror called Earendel-1 into orbit later this year. This mirror satellite will orbit at an altitude of 400 miles (640 km) and illuminate a patch of Earth about 3-5 miles (4.8-5 km) wide.
Reflect Orbital says its space mirrors could allow solar power plants to operate 24 hours a day, provide lighting for disaster-struck regions, replace street lights, assist in search-and-rescue missions, and provide extra sunlight for plantations. The company plans to sell sunlight on demand to people, companies, and governments, potentially costing around $5,000 per hour.
Scientists and scientific societies have warned that orbital illumination systems could disrupt sleep and biological rhythms on a planetary scale, with far-reaching consequences for human health and ecosystems. The presidents of four international scientific societies—the European Biological Rhythms Society, Society for Research on Biological Rhythms, Japanese Society for Chronobiology, and Canadian Society for Chronobiology—wrote to the Federal Communications Commission expressing concerns that the proposed scale of orbital deployment would represent a significant alteration of the natural nighttime light environment at a planetary scale.
The international scientific groups, representing about 2,500 researchers from over 30 countries, urged the FCC and other regulators to conduct a full environmental review and set limits on satellite reflectivity and cumulative night sky brightness. DarkSky International stated that orbital illumination systems represent an unprecedented environmental intervention and, based on current scientific evidence, does not see a viable pathway for such systems to align with responsible lighting principles or with its mission to protect natural darkness.
According to major media, the illuminated area would have a brightness between 0.8 to 2.3 lux. Reflect Orbital has raised more than $28 million (£20.8 million) from investors, according to major media.
This initiative comes amid broader concerns about satellite proliferation, as the US government is considering plans from Elon Musk's SpaceX to put up to one million more satellites in Earth's orbit.