More recent studies have indicated trend reversals that are equally alarming. These worrying trends include the introduction of transition and transuranic metals into Earth’s atmosphere, largely through anthropogenic channels. The increasing ubiquity of such materials may have wide-reaching consequences for atmospheric chemistry and environmental health.
Earth’s upper atmosphere is essentially already filled with material that enters through meteorites ablating upon atmospheric entry. One of the main takeaways of a 2015 study might surprise you. It made clear that human activities were by far the top drivers of 18 threatening pollutants in the atmosphere. By 2024, this figure had increased to 24 elements. Satellite mega-constellations such as Starlink and Kuiper have played a substantial role in this increase. To meet this demand, they have accelerated the release of “space junk” into the environment.
Their analysis shows that the injections of these elements have more than doubled in the last ten years. One big factor spurring this surge is how satellites in mega-constellations are designed. These satellites are specifically designed to “demise” themselves after five years of service by burning up when they re-enter the atmosphere. As these satellites break up, they release a complex mixture of metals, including most transition metals, to the stratosphere.
Meteors released by rockets and satellites ultimately contributes a tiny fraction around 7% of the total mass of meteoroids impacting Earth annually. Despite this being a natural phenomenon, the composition of this material is very different to the meteors themselves. Meteors are mostly silicates but rockets and satellites are mostly metals. As a result, the total metal that we are releasing into the atmosphere accounts for about one-sixth of what is released via natural processes.
CastAway 2 authors, Leonard Schulz and co-authors, point out three primary ways this “space waste” can impact the environment. The first biggest risk is that catalysts can facilitate different chemical reactions. This would cause significant damage to the ozone layer, as those chlorofluorocarbons (CFCs) did in the 1970s and 80s. Another issue is the radical effects of particles injected into the atmosphere, which would further aggravate climate change.
Further complicating matters, even the most active debris removal operations would still see these elements spread out across the surface of the atmosphere. This is why understanding these impacts is so important to any future long-range plans that include satellite mega-constellations.
The lifespan of the individual components that make up these newer satellite systems is only an average of five years. Projections indicate that anthropogenic activity will continue to increase concentrations of up to 30 different elements in the atmosphere. This trend is set to continue over the next several decades.
“We’re putting lots of transition metals into the stratosphere. That’s not good.” – Leonard Schulz et al, Space waste: An update of the anthropogenic matter injection into Earth atmosphere, arXiv (2025).