The number of rockets and satellites launched into space has rapidly increased since the late 2010’s as a response to the expanding interest in both the commercial and government opportunties available in Low Earth Orbit (LEO). The year 2021 saw the number of rockets launched into space break the record set in 1967 during the height of the space race, while a GAO report on satellite megaconstellations released in 2023 estimated that the number of satellites present in LEO will balloon from present day numbers of roughly 6,000 to over 60,000 individual units by 2040. With this new near Earth activity, a new emission source into the middle and upper atmosphere has emerged. Emissions of black carbon from rocket engines and exotic metals produced via the vaporization of reentering satellites are expected to increase to unprecedented concentrations relative to natural sources. Here we present modeling work which looks at hypothetical future emission scenarios of black carbon and aluminum oxide (Al2O3), and estimate how these emerging anthropogenic emissions may impact the stratosphere. We find that aerosols from both sources are transported throughout the stratosphere with the most mass residing at high latitudes. Stratospheric heating via the absorption of shortwave and longwave radiation from these aerosols was found to exceed 1.5 K depending on the scenario. This heating has the potential to alter the dynamics of the middle atmosphere, as well as high latitude ozone concentrations. We also discuss the numerous sources of uncertainty regarding the satellite ablation process and the aerosol chemical and physical properties produced during reentry, as well as the significant need for future observations of launch and reentry events.
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