Amazon is racing to catch up to Starlink in the battle for satellite internet dominance, and it’s creating problems for everyone else. Only 180 of the proposed 3,236 Amazon Leo satellites are currently in low Earth orbit, but they’re already routinely bright enough to disrupt astronomical research, according to a forthcoming study. And of the nearly 2,000 observations conducted during the assessment, 25 percent were determined to “distract from aesthetic appreciation of the night sky.”
Amazon announced its satellite broadband internet company, originally called Project Kuiper, in 2019, but struggled for years to get the endeavor up and running. Meanwhile, Elon Musk’s Starlink has made huge strides in its own satellite internet constellation—while also garnering many of its own criticisms. Amazon finally launched its first equipment into orbit in April 2025 before swapping the Project Kuiper name for Leo last November. Service is expected to begin after 578 satellites reach orbit, and Leo’s current licensing agreement stipulates it must have half of its constellation deployed by July 30, 2026.
Representatives of the International Astronomical Union (IAU) don’t sound very pleased by the progress so far, however. As the leading global consortium of astronomy experts, the IAU helps shape public space policy while also serving as the organization officially responsible for naming and classifying all celestial objects. Its Center for the Protection of a Dark and Quiet Sky also has long maintained two clearly established brightness limits for orbiting objects—one to ensure astronomical research isn’t impeded, and another to conserve the “natural beauty of the stars.”
“The International Astronomical Union recommended an acceptable brightness limit which states that satellites in operational orbits should not be visible to the unaided eye,” the IAU authors explained in their study. “The IAU statement also defined a brightness limit for interference with professional astronomy which we call the research limit.”
The IAU has repeatedly voiced its concerns about night sky light pollution, especially as multiple companies vow to send thousands of additional satellites into an already crowded low Earth orbit. So it’s particularly concerning when only 180 of Leo’s deployments are raising red flags for both the acceptable brightness and research limits. After conducting 1,938 observations of Leo satellites currently deployed, the IAU determined the equipment exhibits an average brightness magnitude of 6.28. For reference, the faintest stars seen in a perfectly dark evening sky register a 6.0 magnitude. Although that makes them faint enough to often miss with the naked eye, the satellites still frequently reflect flaring light that’s discernible without a telescope. The IAU also previously stated all satellites should be below a 7.15 magnitude, but some of Leo’s satellites were “consistently brighter.” The overall findings weren’t any better, either.
“For spacecraft in their operational mode, 92 percent exceeded the brightness limit recommended by the IAU for interference with research, while 25 percent distract from aesthetic appreciation of the night sky,” they concluded.
The IAU notes that “based on private communication, Amazon is working on reducing satellite brightness,” including the development of a specialized dark exterior coating. At the same time, the study authors cautioned these remedies may not be enough. Leo’s current satellites all orbit at an average altitude of 391 miles, but Amazon possesses a Federal Communications Commission approval to operate at heights as low as 366 miles. That could make for an even brighter constellation—one that may drown out the constellations humans have gazed at for hundreds of thousands of years.
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