A study on emission characteristics of rocket launches (2020—2024)

The rapid development of spaceflight has significantly advanced science and technology, but it also poses non-negligible environmental challenges. This study focuses on major emissions from rocket launches, including CO₂, black carbon (BC), H₂O, Al₂O₃, and chlorine species (Cl_y). To assess the atmospheric influence of space activities, their horizontal and vertical spatial distributions are examined using worldwide launch data from 2020 to 2024. The results indicate that gaseous emissions are dominated by CO₂ and H₂O, with total quantities of approximately 2.71×10⁸ kg and 1.44×10⁸ kg, respectively. In contrast, particulate emissions consist mainly of BC and Al₂O₃, with estimated releases of 6.70×10⁶ kg and 7.80×10⁶ kg, respectively. Horizontally, the emissions exhibit strong regional concentration, with the United States and China accounting for the majority of CO₂, H₂O, and BC emissions. Al₂O₃ and Cl_y emissions are mainly concentrated in China, France, the United States, and India. Vertically, CO₂ emissions are concentrated in the troposphere, while BC emissions peak in the stratosphere and mesosphere. Due to the persistence of BC in the upper atmosphere, a near twofold increase in net radiative forcing can be observed in these regions. This suggests that because of their high-altitude BC emissions, space launch operations are more dangerous to the climate than aircraft and conventional industrial sources that are limited to the troposphere.