One of the brightest objects in the night sky is a man-made satellite

A prototype satellite has become one of the brightest objects in the night sky and could soon be accompanied by dozens more. A Monitoring of the BlueWalker 3 satellite, launched in September 2022 by AST SpaceMobile, found that it is at times brighter than all but a handful of stars and planets that can be seen from Earth. The findings published in the journal. Nature They highlight a rapidly escalating concern among astronomers, who have warned that the influx of private space companies into low-Earth orbit could alter our view of the night sky and interfere with research.

Researchers from the International Astronomical Union’s Center for the Protection of Dark and Quiet Skies from Satellite Constellation Interference (CPS) observed BlueWalker 3 for 130 days. BlueWalker 3’s antenna array measures just under 700 square feet, making it the largest yet for a commercial low-Earth orbit satellite. That huge array reflects sunlight and, after unfolding, its brightness increased. The effect is not constant, but fluctuates depending on factors such as the position of the satellite relative to the sun and the viewing angle. The CPS team observed it from sites in Chile, the United States, Mexico, New Zealand, the Netherlands and Morocco.

“These results demonstrate a continuing trend toward larger, brighter commercial satellites, which is especially concerning given plans to launch many more in the coming years,” he said. Siegfried Eggl, one of the co-authors of the study. “While these satellites can play a role in improving communications, it is imperative that their disruption to scientific observations be minimized.” AST SpaceMobile eventually plans to deploy a fleet of approximately 100 cellular broadband satellites based on the BlueWalker 3 design.

spacex, whose thousands of Starlink satellites has repeatedly come under scrutiny for its potential impact on the night sky, it has experimented with dark coatings to reduce the amount of reflected light, with limited success. For astronomers, for whom it is a growing headache, is not sufficient. Stations observing from the ground will need to develop satellite avoidance strategies to avoid these artificial constellations, the researchers note in the paper.

And visibility is not the only problem. Commercial satellites, including BlueWalker 3, flooding low-Earth orbit also threaten to interfere with radio astronomy. A seperation and published earlier this year found that Starlink satellites are leaking “unintentional electromagnetic radiation” that could disrupt radio telescope observations.