The satellite industry's rapid growth is raising concerns about its environmental impact, particularly as it relates to climate change. The industry's biggest players, such as SpaceX, are launching more satellites than ever before, with SpaceX recently applying for permission to launch 1 million Starlinks, on top of the 10,000 already in orbit. This rapid expansion has led scientists to scrutinize the potential consequences of satellite deployment, including its impact on air pollution and the climate.
A new study published in the journal Earth's Future suggests that air pollution associated with megaconstellation deployment will account for nearly half of the climate impact from space sector pollution by the end of the decade. The study's lead author, Eloise Marais, a professor of atmospheric chemistry and air quality at University College London, likened space-industry pollution to an "untested geoengineering experiment with many unintended consequences."
The study found that black carbon, or soot, released during rocket launches has a significant cooling effect on the lower layers of the atmosphere, blocking incoming sunlight. While the amount of black carbon released currently by rocket launches is far less than the geoengineering ideas, this may change with unregulated growth. The study also revealed that megaconstellations contributed about 35% to the total climate impact of the space sector in 2020, but that figure is expected to climb to 42% by 2029.
The satellite industry's growth is driven by commercial satellite deployment, with revenue accounting for 71% of the world's space business in 2025. The 29th annual State of the Satellite Industry report found that 296 launches deployed a record number of 4,434 satellites into Earth orbit, a 65% increase from 2024. As the industry explodes, there is a critical need to better assess its growing environmental impact.
Marais and her colleagues used data from a global inventory of air pollution from megaconstellation deployment to project emissions out through 2029. They found that black carbon from kerosene-fueled rocket launches had the biggest environmental impact, lingering in the atmosphere for much longer than soot emitted by ground-based sources. The cooling effect of launch-generated black carbon is about 500 times greater, but it's still minimal compared to global temperature rise driven by greenhouse gas pollution.
The study also investigated whether megaconstellation pollution could deplete the ozone layer, which protects Earth's surface from UV radiation. The impact they estimated was small because most rockets launching megaconstellations do not emit strong ozone-depleting chlorine compounds, but this may change as some satellite companies plan to use chlorine-emitting propellants.
Marais and her team are building an online tracker for launch and re-entry emissions and designing techniques to observe rocket launch pollution using satellite instruments that observe land rather than the air. They hope policymakers will see the warning signs offered by their study and other related studies to design regulation that prevents harm to the environment, so that future generations aren't left with the burden to repair the damage.
