Space mirrors could ruin astronomy — and your eyes
The dream of space mirrors has captivated futurists for over a century, with the idea of reflecting sunlight onto Earth for solar energy and illumination. While the potential benefits of clean, renewable energy and crisis support are undeniable, the consequences for astronomy and public safety are a cause for serious concern.
The California-based company Reflect Orbital aims to launch a test satellite, Eärendil-1, as a precursor to a fleet of up to 50,000 space mirrors. The satellite's 18-square-meter mirror will create a 5-kilometer-wide beam of light, potentially used for solar energy, agricultural boosts, and search and rescue operations. However, the implications for astronomy and public safety are alarming.
Astronomers warn that the satellite's brightness, estimated to be as bright as Venus from outside the beam and four times as bright as the Moon within the beam, could disrupt scientific observations and cause permanent eye damage to anyone using telescopes in the wrong place at the wrong time. The potential harm to amateur astronomers, who often use backyard telescopes, is particularly concerning.
Light pollution, already a threat to human well-being and local ecosystems, would be exacerbated by space mirrors. The overall brightness of the night sky from tens of thousands of reflective objects in orbit would make it impossible to observe distant objects like galaxies or spot Earth-threatening asteroids. This could spell the end of ground-based optical astronomy.
The lack of regulation around satellite technologies that could harm humans, the environment, and astronomical observations is a significant issue. The FCC's decision to declare astronomical concerns beyond its purview has left a regulatory void, with no government body overseeing satellite brightness. Reflect Orbital's lack of transparency and plans to warn the public further compound the problem.
The company's argument for incremental development and testing is met with skepticism by astronomers and advocacy groups like DarkSky International. The potential for the satellite to cause flash blindness to drivers or pilots during slewing and the uncertainty around the size of the light beam add to the concerns.
The need for renewable energy is clear, but astronomers question the tradeoff of tens of thousands of extremely bright satellites in the night sky. Alternative avenues for solar power generation on Earth exist, and these options don't require damaging the night sky or harming nearby people and ecosystems.
The IAU and Slovakia have proposed a ban on space mirrors if strong oversight measures to protect eye safety and astronomical research cannot be implemented. The consequences of space mirrors on astronomy and public safety are too great to ignore, and the need for regulation and responsible innovation is urgent.
