A California startup plans to launch an experimental satellite as early as this summer. The spacecraft would beam sunlight back to Earth using a large reflective surface. Reflect Orbital has applied to the U.S. Federal Communications Commission for approval, according to Gizmodo. Scientists and astronomers are pushing back over potential impacts on the night sky and the environment.
The prototype, Earendil-1, would fly in a 400-mile (640 km) orbit. It would carry an approximately 60-foot (18.3-metre) mirror. The mirror is designed to illuminate a ground patch about three miles (4.8 km) wide. The light would be comparable in brightness to a full moon, measured at roughly 0.8 to 2.3 lux.
Boosting solar generation after sunset
Reflect Orbital says the mission will show that redirected sunlight can boost solar generation after sunset. The goal is to help solar power plants operate around the clock. The company envisions “sunlight on demand” for energy, disaster relief, extended industrial work hours, agriculture, defense operations, and even replacing streetlights in some settings. The CEO says the project is meant to develop technology that could ultimately displace fossil energy as a primary power source.
As conceived, the orbital reflectors would redirect sunlight to solar farms after sunset and before sunrise. Targeted illumination could provide temporary lighting for rescue teams and other time-sensitive operations. The company has floated a pricing model of approximately $5,000 per hour to rent light from a single space mirror. It has also proposed revenue-sharing with solar farms and a long-term plan to build a customer base that purchases targeted sunlight on demand.
Changing the night experience
The scale of the proposal, which contemplates a constellation after the prototype, has raised alarms. Astronomers and dark-sky advocates warn a field of orbiting mirrors could interfere with ground-based observations. They say it could worsen light pollution, distract pilots, and change the public’s experience of the night sky. Scientists cite the risk of collisions and debris in already crowded orbital lanes if thousands of reflective satellites are deployed.
Environmental and wildlife specialists warn that artificial nighttime light can disrupt animal behavior, migratory patterns, and plant reproduction. They note that nocturnal ecosystems are particularly sensitive to even low-level illumination at night. Critics argue there is no clear regulatory process tailored to govern large-scale orbital illumination systems. Dark-sky advocates call the concept an unprecedented environmental intervention that conflicts with established principles for responsible lighting.
The company has moved to show feasibility and attract investors. In March 2024, Reflect Orbital tested a robotic mirror on a hot-air balloon. The device redirected sunlight toward ground-based solar panels during twilight. The experiment aligns with an early concept to use low-orbit Mylar mirrors to send light to solar installations roughly 90 minutes before sunrise and after sunset.
Reflect Orbital says the orbital mirror would target a defined footprint of approximately three miles (4.8 km) across at an altitude of 400 miles (640 km). The geometry is meant to deliver full-moon-like illumination to a specific area while the satellite passes overhead. The concept has historical precedents. A 1977 proposal explored large-scale orbiting reflectors, and in 1993 a Russian experiment known as Znamya, or Banner, unfurled a 19.812-metre mirror that briefly reflected a beam reported to be as bright as two or three full moons.
Reflect Orbital has reported raising more than US$28 million from investors. It says Sequoia is backing the venture in what it describes as the firm’s first space investment since SpaceX. The company has also indicated that it previously raised US$6.5 million and fielded more than 10,000 inquiries. It emphasizes possible benefits across energy, emergency response, agriculture, defense, and municipal lighting. It also asserts that precisely targeted overhead light could, in some circumstances, reduce the need for traditional ground-based fixtures and lessen certain sources of light pollution, according to Vice News.