Amazon's Project Kuiper satellites are too bright for astronomy—and we have the measurements to prove it.
A new study analyzed 1,938 observations of Amazon's low-Earth-orbit satellites and found their mean apparent magnitude is 6.28—right at the edge of naked-eye visibility. More concerning: 92% of operational satellites exceeded the International Astronomical Union's recommended brightness threshold for preventing interference with scientific research.
One-quarter of the satellites are bright enough to interfere with simply enjoying the night sky.
The research, published on arXiv and reviewed by two referees appointed by the IAU Centre for the Protection of the Dark and Quiet Sky, reveals that Amazon's satellites exhibit reflective properties comparable to early versions of SpaceX's Starlink constellation.
That's not a compliment. Early Starlink satellites prompted widespread complaints from astronomers before SpaceX implemented partial mitigation measures like visors and dark coatings. Those measures helped—somewhat—but didn't eliminate the problem.
Now we're facing another mega-constellation with the same issues, launching thousands more satellites into an already crowded orbital environment.
For ground-based telescopes, these bright streaks create headaches. Long-exposure astronomical images get contaminated by satellite trails. Surveys searching for near-Earth asteroids, transient events, or faint distant galaxies have to work around an increasing number of bright moving objects.
The fundamental problem is simple physics: these satellites are large, reflective, and in low orbits where sunlight illuminates them during twilight hours—precisely when many astronomical observations occur.
Amazon has stated its commitment to dark sky protection, but this study suggests current measures aren't sufficient. The astronomical community isn't asking these companies to stop—just to engineer satellites that don't interfere with humanity's ability to study the universe.
The universe doesn't care what we believe. But we should care about preserving our ability to observe it.
