ESO study proposes cap of 100,000 satellites to safeguard astronomy

The European Southern Observatory released a study recommending that the total number of Earth-orbiting satellites be limited to 100,000 to protect ground-based astronomy. Led by astronomer Olivier Hainaut, the researchers ran simulations of upcoming megaconstellations and concluded that exceeding that threshold would markedly degrade observations from facilities such as the Very Large Telescope and the Vera C. Rubin Observatory.

They noted that planned constellations by SpaceX and Reflect Orbital could push the total into the millions unless regulatory limits are imposed. ESO spokesperson Betty Kioko said the recommendation is intended to give policymakers a practical benchmark. The study urges the Federal Communications Commission to consider the cap when reviewing future satellite licensing applications.