Impact of Rocket Engine Exhaust Product Uncertainties on the DLR Inventory of Global Emissions by Launchers

Abstract

Global launch emission inventories, which aggregate rocket flight trajectories and engine exhaust data, are essential for analysing the atmospheric and climate impacts of the space transportation sector. However, because these databases rely heavily on publicly available data, they contain inherent uncertainties. This study quantifies these uncertainties for the DLR Inventory of Global Emissions by Launchers to evaluate their impact on the global exhaust species distribution. The analysis involves the detailed reconstruction of 32 individual rocket engines, accounting for main combustion chamber flows as well as secondary streams such as gas generator exhaust, expander bleed flows, and steering units. Using Monte Carlo simulations, engine-level uncertainties are propagated to the global inventory scale. Results indicate that for a nominal global exhaust mass of approximately 110 million kg, the distributions of major exhaust species can vary by a couple million kilograms, highlighting the critical need for uncertainty boundaries in climate modelling inputs.