Development of space transportation launch and re-entry emission inventories for 2019-2025

The space sector has experienced significant growth in recent years, with rocket launch rates increasing from 102 in 2019 to 329 in 2025. Launch and re-entry operations of space transportation systems are the only source of anthropogenic emissions in the upper atmosphere. This increase in space activities is raising concerns about both ozone and climate effects. In recent years, there has been an increasing number of studies assessing the effects of these emissions using global Earth system models. For accurate assessments of the atmospheric effects, emission inventories that take into account the individual characteristics (trajectory, propellant, engine parameters, materials) of launches and re-entries are required.
This study addresses the general problem of how to model launch and re-entry emissions of space transportation systems under contemporary and near-future operational conditions. Here, we present results using the Launch Emissions Assessment Tool (LEAT) and the Re-entry Emissions Assessment Tool (REAT) to model all orbital space transportation missions conducted between 2019 and 2025. We show that the combined LEAT–REAT framework enables modelling of emission composition, trajectories, and altitude-dependent chemical effects of afterburning for multiple propulsion technologies and vehicle configurations. Compared to previous approaches that relied on generic profiles, the new toolset captures individual flight paths, staging and fragmentation events, and vehicle-specific launch and re-entry combustion modelling, pointing out uncertainties compared to previous emission inventories. The results are compared with natural sources such as meteorites and other anthropogenic sources. An assessment of uncertainties via the implementation of a parameter study concludes the presentation.
In a further step, future measures for modelling the reaction pathways in the upper atmosphere are presented.