The space industry is undergoing rapid growth, but unlike many other industries remains unregulated in terms of emissions. As the number of space missions is set to increase even faster, understanding the environmental impact of different aspects of spaceflight becomes increasing
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The space industry is undergoing rapid growth, but unlike many other industries remains unregulated in terms of emissions. As the number of space missions is set to increase even faster, understanding the environmental impact of different aspects of spaceflight becomes increasingly important. We develop a four-dimensional emission inventory for spaceflight activities in 2022, incorporating the effects of re-entry and afterburning, and simulate their effects on stratospheric composition, radiative forcing and air quality using the GEOS-Chem chemical transport model. We show that spaceflight emissions lead to a global column ozone loss of 0.086 DU and a net radiative forcing of 6.3 mW/m$^{2}$. Our results suggest that the global air quality impacts are limited, with a population-weighted \ch{PM_{2.5}} concentration increase of 2.082 \cdot 10$^{-8}$ $\mu$g/m$^{3}$ per Tg of propellant burned. We find that \ch{NO_{x}} emissions from re-entry account for 83.9\% of the column ozone depletion and we are the first to show that the inclusion of afterburning reduces the ozone depletion by 12.2\% and the net radiative forcing by 30.5\%. Among individual propellant types, solid propellant has the greatest impact on ozone depletion, causing a reduction of 0.015 DU, while RP1-fueled rockets contribute the most to radiative forcing, with a value of 5.56 mW/m$^{2}$. If the number of launches and re-entries increases sixfold, the radiative forcing would become \textasciitilde 38 mW/m$^{2}$ and the column ozone depletion would reach 0.45 DU, negating the current recovery of the ozone layer. Our results highlight the need to consider and accurately model re-entry emissions and show that the impact from afterburning is non-negligible.
