Radiative Forcing and Ozone Depletion of a Decade of Satellite Megaconstellation Missions

[Geoengineering News]

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025EF007229

Authors: Connor R. Barker, Eloise A. Marais, Eric Y. P. Tan, Sebastian D. Eastham, Glenn S. Diskin, Joshua P. DiGangi, Yonghoon Choi, Andrew W. Rollins, Eleanor Waxman, et al.

First published: 14 May 2026

https://doi.org/10.1029/2025EF007229

Abstract

Satellite megaconstellations (SMCs) are driving rapid increases in rocket launch and re-entry rates, emitting pollutants throughout the atmosphere. The environmental impact of SMCs lacks characterization to determine the need for regulation. We utilize a global 3D emission inventory of recent (2020–2022) space activity that distinguishes SMC and non-SMC emissions. We calculate a decade of emissions using trends in propellant consumption and re-entry mass to project growth rates in SMC (28% a−1) and non-SMC (<20% a−1) propellant and re-entry mass. We implement this in the GEOS-Chem chemical transport model coupled to a radiative transfer model to characterize impacts of SMCs and all mission types on atmospheric composition and climate. By 2029, global chemical loss of stratospheric ozone from all missions, dominated by chlorine from solid propellant, is small (0.02%) compared to regulated sources (2%). SMC missions predominantly use kerosene-fueled rockets that do not emit chlorine, so account for only 9% of all-mission ozone depletion. Kerosene is a large source of black carbon (BC) that induces positive instantaneous radiative forcing per mass unit BC emitted that is more than 500 times greater than BC forcing from Earth-bound sources. Unlike surface sources, BC from rockets are released above the tropopause, so behave like potential solar geoengineering strategies: positive instantaneous forcing (6.47 mW m−2), negative stratospherically adjusted forcing (−6.40 mW m−2). SMCs account for over half (56%) the instantaneous forcing and 42% of the stratospherically adjusted forcing. Ambient measurements and laboratory studies are critically needed to constrain and validate our model findings.

Plain Language Summary

Megaconstellations of thousands of satellites are being rapidly launched into low-Earth orbit, increasing rocket launches and re-entry events. These activities release harmful chemicals throughout the atmosphere, impacting climate and the ozone layer. We use a global inventory of launch and re-entry emissions covering the onset of the megaconstellation era (2020–2022), and project these to 2029 based on 2020–2022 growth rates. We implement this inventory into a 3D atmospheric chemistry model to determine the impacts of megaconstellations on the ozone layer and climate. We find that global stratospheric ozone depletion from all mission types is relatively small compared to surface sources and megaconstellation missions only account for about one-tenth of this depletion. This is because rockets launching megaconstellations almost all use kerosene, a large source of black carbon or soot particles, but not of chemicals such as chlorine that directly destroy ozone. Soot from rockets absorbs sunlight, warming the upper layers of the atmosphere and decreasing the amount of sunlight reaching Earth's lower atmosphere, causing it to cool. Megaconstellation missions are responsible for about half of this climate effect. In this regard, rockets launching megaconstellations and other missions are like small-scale stratospheric aerosol injection experiments without forethought for potential unintended consequences.

Source: AGU