DLR Global Launch Emission Inventory 2024: Overview and Initial Results

Kurzfassung

The year 2024 marks the fourth consecutive year with record-breaking launch activity. The total number of launches more than doubled since 2019. The propellant mass burnt during these launches has grown even faster, underscoring the need to quantify their environmental impact. Understanding the direct launch emissions into all atmospheric layers is essential for assessing their effects on atmospheric chemistry, ozone depletion, and climate change. This paper introduces the DLR Global Launch Emission Inventory 2024, a comprehensive, three-dimensional dataset documenting emissions from all orbital launches conducted throughout 2024. The focus here is on an overview of the inventory and initial findings, while a subsequent publication will provide a detailed account of the underlying methodology. A core aspect of the inventory is the precise remodeling of individual launch systems, incorporating detailed representations of their trajectories, propulsion technologies, and engine performance. To ensure accurate modeling, all launch systems that contributed at least 0.5% of the total propellant burned in 2024 are individually simulated and validated. This includes major operational vehicles such as the Ariane 62, multiple variants of the Chinese Long March family, the Falcon 9, the Starship, the Soyuz, and several additional systems. For these rockets, we apply our proven preliminary design tools to construct detailed aerodynamic, mass, and propulsion models. These models enable precise estimates of exhaust for key species, such as CO2, H2O, chlorine compounds, and soot. To capture the geographic and altitudedistribution of the exhaust, each ascent trajectory and the booster return trajectory of reusable systems is optimized based on the specific launcher, target orbit and launch site. For smaller launch systems, using less than 0.5% of the yearly propellant consumption, surrogate models that represent the propellant mass and propellant type are employed. At the time of IAC 2025, the inventory will include only direct rocket nozzle exhaust, without post-combustion effects. However, developing a model to incorporate plume-atmosphere interactions and post-combustion is a key research goal, and an outlook on planned modeling approaches will be presented. The DLR Global Launch Emission Inventory 2024 is designed for seamless integration into global chemistry-climate models and will be freely available, making it a valuable resource for researchers studying at- mospheric composition, stratospheric dynamics, and spaceflight-related climate effects. By providing a comprehensive and openly available dataset, this work establishes a foundational resource for assessing the increasing role of space activity in Earth’s atmosphere and climate system.