This company’s plans to deploy space mirrors could jeopardize the night sky for many

A US-based company, Reflect Orbital, is planning to deploy a network of large space mirrors designed to reflect sunlight onto Earth, potentially altering the night sky in ways that could harm astronomical observations and disrupt natural darkness. According to a recent study, the deployment of these mirrors could cause widespread illumination, making the night sky significantly brighter than intended. Reflect Orbital aims to launch a test satellite named Eärendil-1 later this year. This satellite will extend an 18-by-18-meter mirror in orbit, serving as a prototype for future satellites that measure 54 by 54 meters. These larger satellites are intended to reflect sunlight to Earth on demand, with applications ranging from extending daylight hours for solar panel charging to aiding emergency responses and military operations. The project has drawn criticism from astronomers and environmental groups. The Federal Communications Commission approved the launch in July, but some experts argue that the plan poses serious risks. Samantha Lawler, an astronomer at the University of Regina in Canada, stated that the initiative is incompatible with astronomy and threatens the preservation of dark skies. A team led by Miroslav Kocifaj, an astronomer at the Slovak Academy of Sciences, conducted research on the potential effects of the reflected light. Their findings, published in a paper accepted for publication in the Astrophysical Journal Letters, indicate that a single Reflect Orbital satellite could appear 40 times brighter than the full moon within its intended target area, a circular patch five kilometers across. Even at distances up to 14 kilometers from the center, the satellite would remain as bright as the full moon. When considering the cumulative effect of 400 satellites, the study suggests that the combined light would be equivalent to 10,000 full moons within the five-kilometer area, or approximately 2.4% as bright as the sun. The brightness would extend up to 80 kilometers away, creating a noticeable glow above the horizon. This means the night sky could be affected by far more people than those directly within the targeted area. Olivier Hainaut, an astronomer at the European Southern Observatory, acknowledged the significance of the findings. He noted that while the results were not entirely unexpected, the detailed modeling provided valuable insights. Hainaut had previously estimated that the reflected light could brighten the sky up to 300% globally, and this new study offers a more comprehensive understanding of the issue. Reflect Orbital CEO Ben Nowack has expressed disagreement with the study's conclusions. He argues that some of the assumptions made by Kocifaj’s team are inaccurate. Nowack emphasized that the company has implemented safeguards, including exclusion zones, to mitigate scattering of light. He claimed that Reflect Orbital has engaged with scientific concerns and incorporated feedback into its technological and operational strategies. However, Kocifaj pointed out that the company has not provided supporting data for its claims. He stated that while Reflect Orbital mentions safeguards and acknowledges scattering, it has not shared specific numerical data, model descriptions, or assumptions. Without such information, Kocifaj asserts that meaningful technical engagement is not possible, as the study’s calculations offer concrete figures. Reflect Orbial plans to position its satellites in highly inclined orbits, spanning nearly from pole to pole. This positioning allows the satellites to reflect sunlight during twilight hours, effectively extending daylight in selected regions. The company’s vision includes using this technology to enhance energy production, support emergency services, and aid military operations through extended visibility.