MANILA, Philippines – Bright satellites orbiting close to Earth are increasingly threatening astronomical research, as a new study on Amazon’s internet satellites underscores a wider problem facing scientists worldwide.
Low Earth orbit (LEO) satellites are designed to sit just a few hundred kilometers above the planet to deliver faster internet coverage. But their proximity to Earth also makes them reflect sunlight more intensely, creating bright streaks that can contaminate images captured by telescopes.
A study posted on the preprint platform arXiv on January 12 analyzed nearly 2,000 observations of Amazon’s LEO satellites, formerly known as Project Kuiper. The researchers found that the satellites exceed brightness limits recommended by the International Astronomical Union (IAU), thresholds meant to protect astronomical observations from artificial light pollution.
Although Amazon’s satellites have an average apparent magnitude of 6.28—generally too faint to be seen by the naked eye—they remain bright enough to disrupt scientific data. In about one out of four observations, the satellites were visible without telescopes, increasing the likelihood that they would appear in astronomical images.
Why brightness matters
Modern astronomy relies on long-exposure images that collect faint light from distant stars, galaxies, and cosmic events. Even a brief pass by a bright satellite can leave a glowing trail across an image, forcing astronomers to discard or heavily process affected data.
“Bright satellites are particularly troublesome for large-scale astronomical surveys conducted at ground-based observatories like the Vera C. Rubin Observatory,” said study lead author Anthony Mallama of the IAU Center for Protection of the Dark and Quiet Sky. Such surveys are designed to repeatedly scan wide portions of the sky, making them especially vulnerable to satellite interference.
Space-based observatories are not immune either. Mallama warned that bright satellites can also interfere with instruments like the Hubble Space Telescope, which observes faint objects beyond Earth’s atmosphere.
LEO satellites: A growing sky traffic problem
Amazon’s satellites orbit at about 391 miles (630 kilometers) above Earth. Future spacecraft are expected to fly even lower, around 366 miles (590 kilometers), which could make them appear brighter from the ground.
The issue extends far beyond Amazon. Mallama and his colleagues have previously studied other satellite networks, including SpaceX’s Starlink constellation, which currently dominates low Earth orbit with roughly 9,500 satellites. They have also examined AST SpaceMobile’s BlueBird satellites, whose massive antennas make them the brightest artificial objects in the night sky.
While Amazon’s satellites are dimmer than the BlueBirds and slightly fainter than most Starlink satellites, their sheer numbers—and the continued growth of satellite megaconstellations—compound the problem. More satellites mean more frequent streaks across telescope images, increasing the loss of usable data.
Mitigation helps, but limits remain
Satellite operators say they are working with astronomers to reduce brightness by redesigning spacecraft surfaces and adjusting satellite orientation to reflect sunlight away from Earth. According to astronomer John Barentine, Amazon has made progress since launching its first test satellites in 2023 by reducing how much light they reflect.
Still, astronomers caution that mitigation alone may not be enough. A November 2025 study by Mallama and colleagues found that nearly all operational internet satellite constellations—except OneWeb, which orbits much higher—exceed IAU-recommended brightness limits.
As more companies race to fill low Earth orbit, scientists warn that without stricter standards, bright satellites could permanently alter how humanity studies the universe—turning once-dark skies into a crowded, luminous obstacle for discovery.
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