Key Points

We present the first atomic-scale molecular dynamics simulation of high-temperature aluminum ablation during reentry from low-Earth orbit

The amount of aluminum oxide nanoparticles generated is quantified and the accumulation in the atmosphere is estimated

The long-term accumulation of aluminum oxides from reentering satellites can cause significant ozone depletion

With ongoing plans for many constellations of small satellites, the number of objects orbiting the Earth is expected to continue increasing in the foreseeable future. At the end of service life, satellites are disposed into the atmosphere, burning up during the process and generating aluminum oxides, which are known to accelerate ozone depletion.

The environmental impacts from the reentry of satellites are currently poorly understood. This paper investigates the oxidation process of the satellite’s aluminum content during atmospheric reentry utilizing atomic-scale molecular dynamics simulations.

We find that the population of reentering satellites in 2022 caused a 29.5% increase of aluminum in the atmosphere above the natural level, resulting in around 17 metric tons of aluminum oxides injected into the mesosphere.

The byproducts generated by the reentry of satellites in a future scenario where mega-constellations come to fruition can reach over 360 metric tons per year. As aluminum oxide nanoparticles may remain in the atmosphere for decades, they can cause significant ozone depletion.