Astronomers and the operators of new, thousands-strong constellations of low-orbiting satellites will have to work together to prevent them from having a devastating impact on ground-based observations of planets, stars, and other celestial objects, says a report released today. Even then, there is no escaping some harm from the fleets of commercial orbiters. “All optical and infrared observatories will be affected to some degree,” astronomer Anthony Tyson of the University of California, Davis, said at a briefing on the report. “No combination of mitigation will eliminate their impact,” added astronomer Connie Walker of the U.S. National Optical-Infrared Astronomy Research Laboratory (NOIRLab).