Astronomers alarmed: US satellites to reflect sunlight back to Earth
A US company wants to launch a satellite in 2026 that acts as a mirror and reflects sunlight back to Earth. Thousands more are planned. Criticism is increasing.
(Image: Reflect Orbital)
Astronomers are criticizing the plans of a US company that wants to use thousands of satellites orbiting the earth to reflect sunlight at night so that solar power plants can continue to generate electricity. The start-up is called Reflect Orbital and, according to Bloomberg, recently applied for a license from the Federal Communications Commission (FCC) in the USA to launch its first satellite next year. By 2030, around 4,000 satellites will be orbiting the Earth, with potentially catastrophic consequences for the already untouched night sky. According to the American Astronomical Society, more than 1,000 researchers have already stated that the realization of the plans would affect their work.
Catastrophic light pollution to be expected
In the spring, Reflect Orbital raised 20 million US dollars from investors for its plan and explained that it was about building a new infrastructure in space. Large mirrors are to reflect sunlight onto existing solar installations in the morning and evening so that they can generate electricity for longer. However, because the satellites move at high speed and can only illuminate narrowly defined areas for a short time, the devices will replace each other. It is doubtful how great the potential is; after all, the satellites can only reflect a fraction of the sunlight that is then available to generate energy. At the same time, the satellites would shine extremely brightly in the sky.
As the US magazine The Conversation summarizes, the satellites would orbit the earth at an altitude of 625 kilometers and illuminate a five-kilometer area on the earth's surface. The aim is to reflect 20 percent of the energy of the midday sun onto the earth, i.e., 200 watts per square meter. The conversation calculates that thousands of satellites would be needed to illuminate the area at the same time to achieve this with satellites that are not oversized. That doesn't sound feasible, but Reflect Orbital has already announced that a total of 250,000 such mirrors are possible in space. This would also limit the potential for solar power plants, but the consequences for the night sky would probably be catastrophic.
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If the satellites work as planned, they would shine much brighter than the full moon over the neighboring region, Bloomberg continues. If the reflections were moved from one solar power plant to the next, the neighboring areas would be illuminated at least briefly by bright flashes of light in the sky. For contemporary optical astronomy from the ground, thousands of such satellites would be potentially devastating, Bloomberg quotes the chief scientist of the Vera C. Rubin Observatory. The light pollution caused by thousands of Reflect Orbital satellites would literally pale in comparison to that caused by Starlink. Resistance is forming in the research community, but it is still unclear whether the FCC will authorize the test planned for 2026.
(mho)
