A new report offers ways both astronomers and satellite developers can reduce the effect mega constellations have on ground-based astronomy, but warned that no combination of measures can entirely eliminate the problem. The report released Aug. 25 by the American Astronomical Society and the National Science Foundation’s National Optical-Infrared Astronomy Research Laboratory, or NOIRLab, is the outcome of a four-day workshop called Satellite Constellations 1 (SATCON1) held nearly two months ago. That workshop brought together more than 250 people, including both astronomers and satellite operators, to evaluate how to minimize the effect satellite constellations would have on astronomy.
For more than a year, astronomers have expressed concern that constellations of thousands of satellites could interfere with their observations. The satellites, visible through reflected sunlight, can leave bright streaks as they pass through the fields of view of telescopes. The workshop concluded that while there are a number of ways to reduce the problem, there is no panacea. “No combination of mitigations will eliminate the impact of satellite constellations on optical astronomy,” said Connie Walker of NOIRLab, one of the co-chairs of the workshop, in an Aug. 25 press conference. The exception, she said, was not to launch such systems at all, but acknowledged “it’s not viable for industry.” Instead, the report offered a set of recommendations to mitigate the effects of mega constellations on astronomy, including ways for companies to reduce the brightness of their satellites and the amount of time they are visible in the night sky. Those steps include placing satellites in orbits no higher than 600 kilometres, as well as darkening them and controlling their attitude to reduce their reflectivity.