In just five years, the number of satellites in low Earth orbit has surged nearly tenfold. That sounds like great news considering the services they provide. Yet scientists are increasingly worried about the fallout.
Satellites help us explore the universe, return critical Earth data, sharpen weather forecasts, transmit signals, bolster public safety and national defense, support emergencies, and pinpoint our location anywhere on the globe. Their numbers keep climbing—and given all they do, you’d think everyone would be thrilled.
Reflected light from the half a million satellites expected to launch into Earth’s orbit in the coming years could contaminate not just ground-based imaging, but also almost all the readings taken by space telescopes, NASA astronomers warn. 🛰️ 🔭 💫 https://t.co/aby1el0n1H pic.twitter.com/euMrMulAtx
— AFP News Agency (@AFP) December 3, 2025
Yet concerns are mounting. One major issue is light pollution: the glow from thousands of satellites could contaminate almost every image taken by space telescopes. NASA researchers writing in Nature note that since 2019, low-orbit satellites have jumped from 2,000 to 15,000—many of them Starlink. If current plans proceed, the total could hit 560,000 by the late 2030s. Even Hubble, despite its narrow field of view, could see a third of its images degraded.
Did you know
A 100–square meter satellite can appear as bright to the naked eye as the sky’s brightest star. And to meet the growing demands of artificial intelligence, designs are being floated for craft as large as 3,000 square meters.
You still don’t see the problem? Imagine trying to spot a potentially hazardous asteroid when what streaks across the sky looks suspiciously like… a satellite. Lowering satellites beneath space-based instruments might reduce interference—but at the cost of thinning the ozone layer.
#Nature Satellite megaconstellations will threaten space-based astronomy https://t.co/lEw561rirH “if these constellations are completed, one-third of the images of the Hubble Space Telescope will be contaminated, while the SPHEREx, ARRAKIHS and Xuntian space telescopes…” pic.twitter.com/4wIJamevwj
— Francis Villatoro (@emulenews) December 3, 2025
Beyond light pollution, a problem of pollution plain and simple
A second worry involves atmospheric contamination from launch fuels and the pollutants released as satellites and rocket stages burn up on reentry. These byproducts spread through nearly every layer of the atmosphere. Launches used to be too infrequent to matter; now, with activity ramping up in Europe, China, Russia, India, Japan, South Korea, and Israel, 2025 could see close to 300 liftoffs.
Scientists admit they don’t yet know how, or how much, this surge is altering the atmosphere—or what it could mean for weather, climate, and life on Earth. Early research indicates that reentry events can inject black carbon into the stratosphere, threatening the ozone layer, as a 2022 American Geophysical Union study suggested.
As satellite launches ramp up, experts are increasingly concerned about the emissions from rocket fuels and from satellites burning up on reentry.
“We are doing something new to the atmosphere that hasn’t been done before,” says a scientist.
Read more: https://t.co/ZUlDUPlOor pic.twitter.com/lBeSuYsCsT
— Yale Environment 360 (@YaleE360) December 3, 2025
The threat of space debris
Another study in PNAS adds a troubling wrinkle: as hardware burns up on reentry, it releases fine aluminum particles that can linger for decades, forming aluminum oxide that also harms ozone. That’s an unintended side effect of “design for destruction,” the idea that satellites should burn up rather than clutter orbit. The European Space Agency is therefore considering “design for survival” approaches that reduce both space junk and atmospheric harm.
Google’s Project Suncatcher would cluster 81 satellites less than 200 meters apart in one of Earth’s most congested orbits, to create a solar-powered orbiting data center. The hitch? The likelihood of cascading collisions with space debris. https://t.co/QZoiPntOWp
— The Conversation U.S. (@ConversationUS) December 4, 2025
And still, orbital debris remains a major concern. Google’s Suncatcher concept—81 satellites harvesting solar energy to power space-based data centers—illustrates the risk. A University of Michigan researcher points out that the proposed orbit, while ideal for operations, is among the most congested. A single collision could trigger a cascade: one shattered satellite slamming into its neighbors, wiping out the mission and seeding a cloud of debris that threatens every spacecraft nearby.
Nathalie Mayer
Journalist
Born in Lorraine on a freezing winter night, storytelling has always inspired me, first through my grandmother’s tales and later Stephen King’s imagination. A physicist turned science communicator, I’ve collaborated with institutions like CEA, Total, Engie, and Futura. Today, I focus on unraveling Earth’s complex environmental and energy challenges, blending science with storytelling to illuminate solutions.