An update of space waste matter injection into the atmosphere

In the last 5 years, the mass of human-made objects like satellites or rocket stages launched into orbit has strongly risen due to the implementation of satellite mega-constellations and generally increased space activity. Besides the well-known problems of on-orbit space debris and ground impacts, this means a strong increase of the human-made mass re-entering Earth’s atmosphere. Upon reentry, this space waste ablates in the atmosphere, injecting matter in form of aerosols and vapor. Murphy et al. (PNAS, 2023, Vol. 120, No. 43, e2313374120) detected remnants of such material in stratospheric aerosol particles. Thus, there is the concrete possibility of environmental effects due to space waste matter injection like ozone depletion or increased cloud nucleation (Mitchell et al., Understanding the Atmospheric Effects from Spacecraft Re-entry, Whitepaper, 2024). In order to understand what the exact effects on the atmosphere are, first, the amount and element-wise composition of the injected material has to be known. In this context, we present updated annual injection estimates compared to the first comprehensive estimation in Schulz and Glassmeier, 2021 (Advances in Space Research, 2021, 67 (3), 1002-1025) taking into account launch and re-entry databases, used spacecraft materials, as well as the observational data from the stratosphere. We present estimates of the overall injected mass as well as of specific elements. This data can serve as a baseline for modelling efforts and help steer towards the most promising future research.