Overview
- The European Southern Observatory led paper, accepted for publication in Astronomy & Astrophysics on July 1, 2026, models planned constellations and finds very large fleets would sharply increase sky brightness and create image-streaking that can destroy observations.
- Researchers led by Olivier Hainaut calculate that keeping satellites fainter than roughly magnitude 7 and limiting the total to about 100,000 is necessary to avoid substantial data loss at major sites such as the Vera C. Rubin Observatory and ESO’s Paranal telescopes.
- The study shows proposals for up to 1.7 million satellites and specific plans like Reflect Orbital’s 50,000 mirror satellites could make the night sky several times brighter and render many exposures unusable, with single bright mirrors capable of spoiling whole camera images.
- Authors and astronomy bodies have submitted the findings to regulators and the work is being cited in responses to pending Federal Communications Commission licensing decisions for SpaceX and Reflect Orbital.
- Beyond lost science, the paper warns of wider harms including more launches and emissions, disruption to ecosystems and human sleep cycles from added night light, and a greater collision and debris risk that could cascade into long-term orbital hazards.