LONDON, July 7 — The vaporisation of 260 Starlink satellites over six months has released metal particles, including aluminium, into the upper atmosphere, raising questions about the long-term environmental effects of the expanding commercial satellite industry. A 2023 study by researchers at the University of California, San Diego, found that the reentry of satellites could deposit significant quantities of aluminium oxide, a known ozone-depleting substance, into the atmosphere. The study estimated that by 2030, satellite reentries could add over 360 metric tons of aluminium oxide to the atmosphere annually.
The technical reality of satellite disposal is that when a spacecraft burns up on reentry, it does not simply vanish. The metals and other materials that make up the satellite are vaporised, and the resulting particles can persist in the upper atmosphere for years.
Under the hood, this is a chemistry problem: those particles can interact with atmospheric compounds in ways that may influence ozone depletion or alter cloud formation processes. The detail that matters here is the sheer scale of the planned expansion. The issue is compounded by the forthcoming satellite constellations from companies such as Amazon’s Project Kuiper and OneWeb, which could increase the total number of deorbited satellites to tens of thousands over the coming decade.
Each of those spacecraft will eventually need to be disposed of, and each disposal will contribute to the atmospheric metal load. The Federal Communications Commission has proposed a rule that would exempt satellites from review under the National Environmental Policy Act.
That change would remove the requirement for environmental impact assessments for satellite disposals, effectively allowing the current practice to continue without formal scrutiny. Environmental groups, including the Sierra Club and the Union of Concerned Scientists, have urged the FCC to conduct a full environmental review before finalising any exemption. As ever, the tension is between the pace of commercial deployment and the slower, more deliberate process of environmental regulation.
The 260 Starlink satellites that have already been vaporised represent a relatively small fraction of the total constellation, which numbers in the thousands. But the rate of disposal is set to accelerate as older satellites are replaced and as new constellations come online. The cumulative effect of tens of thousands of satellite reentries over the next decade is what has researchers and advocacy groups concerned.
The chemistry of reentry
The aluminium oxide produced during satellite reentry is particularly concerning because it is a known catalyst for ozone-depleting reactions. Unlike some other atmospheric pollutants, which may be washed out by rain or broken down by sunlight, aluminium oxide particles can remain in the upper atmosphere for extended periods, continuing to catalyse reactions that destroy ozone molecules. The University of California, San Diego study provided the first detailed estimates of the potential scale of the problem.
The researchers calculated that the annual deposition of aluminium oxide from satellite reentries could reach over 360 metric tons by 2030, a figure that would grow further as constellation sizes increase. That estimate was based on the current design and material composition of satellites, as well as projected launch and disposal rates.
As satellite designs evolve and as more companies enter the market, the actual figure could be higher or lower, but the direction of travel is clear: more satellites mean more reentries, and more reentries mean more material deposited in the upper atmosphere.
Regulatory gaps
The FCC’s proposed exemption from NEPA review would remove one of the few existing mechanisms for assessing the environmental impact of satellite disposal. Under current rules, companies seeking licences for satellite constellations must demonstrate that their operations will not cause significant environmental harm. The proposed change would effectively eliminate that requirement for disposal-related impacts.
Environmental groups argue that this creates a regulatory blind spot. The Sierra Club and the Union of Concerned Scientists have both called on the FCC to conduct a full environmental review before proceeding with the exemption.
They contend that the cumulative effect of tens of thousands of satellite reentries warrants a thorough assessment, not a blanket exemption. The FCC has not yet finalised the rule, and the debate is ongoing. The outcome will have significant implications for the future of the satellite industry and for the environmental management of the upper atmosphere.
What to watch next
The next few months will be critical. The FCC is expected to rule on the proposed NEPA exemption, and the outcome will determine whether satellite operators face new environmental review requirements or are allowed to continue current disposal practices without additional scrutiny. Meanwhile, the expansion of satellite constellations continues.
Amazon’s Project Kuiper and OneWeb are both planning to launch thousands of satellites in the coming years, adding to the already large Starlink constellation. Each of those satellites will eventually need to be deorbited, and each deorbit will add to the atmospheric metal load.
The question is whether the regulatory framework will adapt to keep pace with the commercial activity, or whether the environmental consequences of satellite disposal will only become apparent after the fact. For now, the particles from those 260 vaporised Starlink satellites are already in the upper atmosphere, and they will remain there for years to come.
