The sky above us is not as pristine as it once was. A new study reveals a hidden pollutant: soot from rocket launches. These launches, an ever-increasing phenomenon, are injecting harmful chemicals into the upper atmosphere, a delicate and previously untouched environment. This revelation comes from researchers at University College London (UCL), who have found that the soot created by deploying 'megaconstellations' of satellites could have significant and poorly understood consequences for Earth's climate.
The study's lead author, Connor Barker, an atmospheric chemist at UCL, warns that rocket launches are akin to an unregulated geoengineering experiment. The burning of kerosene in rocket fuel releases soot particles that absorb sunlight, causing a minimal cooling effect. While this might seem beneficial in the face of global warming, Barker emphasizes that the particles could have numerous other serious unintended consequences. The impact is already significant, with soot particles lingering in the upper atmosphere 540 times more effectively than ground-based emissions from cars and power plants.
The trend of rocket launches is alarming. Since 2019, the number of launches has skyrocketed, with 2025 seeing a record 329 launches, and 2026 already surpassing that number. This surge is primarily driven by SpaceX's Falcon 9 rockets and China's record 92 launch attempts. The space industry's pollution is a growing concern, and the predictions are dire.
By 2029, the space industry is projected to release approximately 870 tonnes of soot annually, a figure that dwarfs the annual emissions of the UK's entire passenger car fleet (728 tonnes). Barker warns that these predictions are likely underestimates, making the problem even more urgent. The environmental impacts of satellite megaconstellations must be understood now, before any unforeseen consequences become irreversible.
The study highlights the need for regulation and further research. The team is developing an emissions tracker to visualize space industry emissions and using satellite imagery to detect and quantify rocket launch emissions. However, the current lack of regulation and understanding of these emissions is a cause for concern. As Barker states, 'Space industry pollution is like an unregulated geoengineering experiment,' and it's time we take it seriously.
