Overview
- The European Southern Observatory ran simulations for observatories at Paranal that modeled constellations up to one million satellites and concluded existing proposals for more than 1.7 million devices would substantially degrade astronomical observations.
- The study identifies concrete thresholds where harm grows steeply: about 100,000 satellites produces a tolerable level of interference while roughly 300,000 would cause severe data loss for some telescopes.
- Interference comes from reflected sunlight: each satellite crossing a telescope’s field leaves a bright streak that removes part of an image and can raise the overall sky brightness, making faint objects harder to detect.
- There are roughly 15,000 satellites in orbit today and commercial internet projects such as SpaceX’s Starlink and Amazon’s Leo are driving rapid launches, but the coverage reports no coordinated regulatory or industry-wide mitigation has been adopted.
- The findings increase pressure for technical and policy fixes—darker satellite surfaces, altered operations, or limits on constellation size—because some observations lost to streaks may be impossible to repeat and could hamper studies of faint galaxies, transient events, and hazardous asteroids.