Measurement of a Lithium Plume from the Uncontrolled Re-entry of a Falcon 9 Rocket

A 10-fold enhancement of lithium atoms was detected at 96 km altitude by a resonance lidar at Kühlungsborn, Germany, approximately 20 hours after the uncontrolled re-entry of a Falcon 9 upper stage on 19 February 2025. The upper atmospheric extension of the ICON general circulation model nudged to the ECMWF operational analysis was used to calculate winds. Backwards trajectories, including wind variability as measured by a radar network, traced air masses to the Falcon 9 re-entry path at approximately 100 km altitude, west of Ireland. This study presents the first measurement of upper atmospheric pollution resulting from space debris re-entry and the first observational evidence that the ablation of space debris can be detected by ground-based lidar. The analysis of geomagnetic conditions, atmospheric dynamics, and ionospheric measurements strongly supports the claim that the enhancement was not of natural origin. Our findings demonstrate that identifying pollutants and tracing them to their sources is achievable, with significant implications for monitoring and mitigating space emissions in the atmosphere.