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Launches have become an almost daily occurrence as companies and governments from around the world continue to build out satellite mega-constellations in the sky. As a result, we\u2019re rapidly filling up the orbit around our planet with active spacecraft \u2014 and plenty of dangerous detritus<\/a> as well.<\/p>\n And beyond the chance of collisions<\/a>, all of that activity could have potentially grave environmental consequences as well. The Earth\u2019s atmosphere is being littered with new metal aerosols<\/a> from burning spacecraft and rockets, as University of Southampton environmental science professor Ian Williams explained in a new essay for The Conversation<\/a>.<\/p>\n Many satellites are designed to deorbit upon their retirement and burn up in the Earth\u2019s atmosphere, which at the incredible scale of today\u2019s spacetech industry could already by fundamentally altering the chemistry of our planet\u2019s natural defense mechanism.<\/p>\n Not all is lost yet. It\u2019s still possible that scientists, including Williams and his colleagues, will come up with new ways to recover materials or advocate for longer-lasting satellites, efforts that could protect our atmosphere from feeling the hurt in the long run.<\/p>\n Still, it\u2019s cause for concern. Williams pointed to several studies<\/a> warning of metal oxides depleting the ozone layer, or heating up the stratosphere, among other potentially harmful environmental effects.<\/p>\n Aluminum oxides from reentering satellites can \u201ccatalyze the chemistry that destroys the ozone layer,\u201d Williams argued. \u201cMeanwhile, rocket exhaust \u2014 especially black carbon (soot) from rocket engines powered by hydrocarbon propellants \u2014 warms the stratosphere and alters winds.\u201d<\/p>\n In one 2025 study<\/a>, researchers simulated the \u201cpotential yearly emission of 10,000 metric tons of alumina from reentering space debris\u201d and found major accumulations of the stuff in the atmosphere between latitudes of 6.2 and 18.6 miles. The aluminum oxides triggered changes in the \u201cmesospheric heating rates,\u201d temperature anomalies that were \u201caccompanied by changes in wind speed in the polar vortex.\u201d<\/p>\n Researchers have also found that rocket launches could effectively negate a global, decades-long effort<\/a> to reduce our reliance on chlorofluorocarbons (CFCs), which are synthetic organic compounds used in refrigerants and aerosols that have long been known to deplete the ozone layer. One study published in June<\/a> found that the \u201cozone layer is slowly healing from the effects of CFCs, yet global-mean ozone abundances are still two percent lower than measured prior to the onset of CFC-induced ozone depletion.\u201d<\/p>\n That\u2019s not to mention the ever-present danger of space junk falling onto people or property<\/a> \u2014 the odds of which may be small, but not zero. While instances of people getting hurt remain extremely rare, we\u2019ve already seen large pieces of rocket stages crashing down in rural areas<\/a>, including farms<\/a>. Growing satellite constellations have also caused major disruptions for ground-based telescopes<\/a>, appearing as bright streaks in observations.<\/p>\n But there may be a better option than having satellites reenter the atmosphere after they\u2019re deemed no longer useful. For one, as Williams explained, we could make a dent by recovering some of the orbital debris. The professor and his colleagues calculated that the amount of scrap value of all orbital debris combined amounts to around $1.2 trillion, which could make recovery financially attractive \u2014 if we can figure out how to capture it<\/a>, that is.<\/p>\n We could also greatly extend the lives of satellites by servicing them<\/a> in orbit and designing them from the ground up for repair and refueling<\/a>.<\/p>\n Williams argued it\u2019s important to act now, especially considering the \u201cscience in this area is still maturing.\u201d<\/p>\n \u201cWe need coordinated measurements and modelling of soot, alumina and metals in the middle atmosphere,\u201d he argued. \u201cThe direction of travel is clear: under high growth scenarios, space launches and routine burn-ups of satellites can slow ozone healing and reshape the stratosphere.\u201d<\/p>\n \u201cUnder smarter, circular economy scenarios, we can have a clean sky,\u201d Williams concluded.<\/p>\n