Determining mass fluxes of space debris upon demise in the atmosphere

The number of anthropogenic objects orbiting the Earth is expected to increase significantly with ongoing plans for large constellations of small satellites. As most space debris burns up during reentry, the long-term impacts of this demise process on the atmosphere are currently unknown. This paper presents a method for determining the high-altitude atmospheric injection of anthropogenic objects that reenter from Earth’s orbit and estimating the chemical species generated during reentry. Empirical reentry data is used to analyze annual trends, showing a record-breaking launch and reentry mass in 2024 of over 2200 tonnes and 490 tonnes, respectively. The accumulation of chemical compounds of anthropogenic origin in the mesosphere is compared against natural levels. We find that the amount of aluminum that reentered the atmosphere originated from satellites and upper stages of launch vehicles surpassed, for the first time in 2024, that of meteoroids. We show that the methodology presented can be applied to estimate the atmospheric burden of individual chemical species originated during reentry.