Satellite Megaconstellations Significantly Impact Upper Atmosphere Pollution

The rapid deployment of satellite megaconstellations since 2019 has led to a significant accumulation of pollution in the upper atmosphere, according to a study published in Earth's Future on May 14, 2026. Researchers from University College London (UCL) found that by 2029, emissions from these satellite systems are projected to account for 42% of the space sector's total climate impact.

The study highlights that black carbon, or soot, produced during rocket launches and satellite re-entries, remains in the upper atmosphere much longer than ground-level emissions, resulting in a climate impact 500 times greater. Professor Eloise Marais of UCL described this phenomenon as an "untested geoengineering experiment with many unintended consequences."

Using data from 2020 to 2022, the researchers projected emissions through 2029, noting that in 2020, megaconstellations contributed about 35% to the space sector's climate impact, a figure expected to rise to 42% by 2029. The study also examined the potential effects on the ozone layer, finding the current impact to be minimal. However, the use of chlorine-emitting propellants in future satellite launches could change this assessment.

Professor Marais emphasized the need for proactive measures, stating, "We still have the chance to act early before it becomes a more serious issue that is harder to reverse or repair." The study underscores the importance of regulating pollution from rocket launches and satellite re-entries to mitigate potential environmental consequences.