Overview
- A peer-reviewed study led by ESO operations director Olivier Hainaut, published in early July 2026, models proposed fleets and concludes that numbers and brightness now planned would seriously degrade or destroy ground-based optical and near‑IR observations.
- The paper sets a practical guideline of roughly 100,000 satellites that must remain faint (about visual magnitude 7 or dimmer) to avoid major losses of data from streaks, detector saturation and a rising diffuse sky glow.
- The study singles out SpaceX’s proposal for up to one million additional ‘orbital data center’ satellites and Reflect Orbital’s plan for 50,000 mirror-like satellites as the most damaging, with simulations showing field‑of‑view losses of up to 28% for the VLT and near‑total image loss for wide‑field cameras like the Rubin Observatory.
- ESO, the Royal Astronomical Society and the IAU have filed formal objections using the study in responses to Federal Communications Commission applications, and the FCC has received thousands of public comments while decisions remain pending.
- Beyond lost astronomy, the paper warns of wider harms including disruption to ecosystems and human circadian rhythms from brighter nights, added launch and re‑entry pollution, and increased collision and debris risk, making regulatory rulings in the coming weeks consequential for science and the night sky.