The research team was able to measure the pollution left behind by the Falcon 9's uncontrolled re-entry, demonstrating for the first time that the atmospheric impact of rocket breakups can be quantified. The lithium contamination — a byproduct of the rocket's battery systems burning up during re-entry — spread across a wide area of European airspace.

While the immediate health risks from a single event are considered minimal, the scientists warn that the finding has significant implications as the number of rocket launches continues to climb. SpaceX alone conducts dozens of launches per year, and the broader commercial space industry is scaling rapidly.

The study adds to a growing body of research on the environmental impact of the space industry, which has until recently received relatively little scrutiny compared to aviation or other transport sectors. Previous studies have raised concerns about the aluminium oxide particles deposited by re-entering satellites and rocket stages.