For the first time, a group of scientists managed to measure the pollution left by a rocket upon re-entering the atmosphere. The data is not minor: they detected a sudden increase in lithium in very high layers of the air after the uncontrolled entry of the upper stage of a rocket Falcon 9a type of launcher commonly used to put satellites into orbit.
The discovery marks a before and after in the study of the environmental impact of space activity. Until now, these phenomena were very difficult to detect and quantify.
The study was led by the Leibniz Institute of Atmospheric Physics in Germany and focused on a “column” of pollution observed in February 2025. The researchers detected that the concentration of lithium atoms in the upper atmosphere was up to ten times higher than the usual reference value.
The rocket’s upper stage re-entered the atmosphere off the west coast of Ireland and disintegrated over Central Europe, generating a shocking fireball. About 20 hours after that event, the increase in lithium was recorded in Germany.
By analyzing the trajectories of the air and the variability of the wind – measured by radar – the scientists were able to reconstruct the path of these masses and link them to the exact point of re-entry, about 100 kilometers high, west of Ireland. The lithium cloud It extended between 97 and 94 kilometers above sea level and was observed for 27 minutes, until the data recording ended.
Lithium is an element widely used in spacecraft components. However, in those layers of the atmosphere – the mesosphere (between 50 and 85 kilometers) and the lower thermosphere (between 85 and 120 kilometers) – it only appears naturally in minimal quantities. Therefore, such a marked increase raised alarm bells.
To confirm that it was not a natural phenomenon, the team also analyzed geomagnetic conditions, atmospheric dynamics and ionospheric measurements. According to the work, published in the journal Communications Earth & Environment, all the data supports that the origin of the lithium was the disintegration of the rocket.
Decommissioned satellites and rocket upper stages are designed to be destroyed upon re-entry into the atmosphere. In the case of the Falcon 9, the first stage is reusable, but the upper stage burns up during reentry. That process, known as ablation, releases metals and metal oxides.
The study warns that, beyond this specific case, recurrent reentries could maintain an increasing flow of metals of human origin in the middle atmosphere. And that could have cumulative climate-relevant effects.
To carry out the measurements, the scientists used an atmospheric lidar radar, a technology that makes it possible to accurately detect the distribution and properties of suspended particles.
Although not all of the material released can be measured due to the chemical changes that occur during descent, researchers maintain that it is now possible to identify these contaminants and trace their origin. With the sharp increase in orbital launches in the last decade, they warn that pollution in the upper atmosphere will likely continue to grow.
With information from EFE
