Measurement of a lithium plume from the uncontrolled re-entry of a Falcon 9 rocket

Abstract 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. The upper-atmospheric extension of the ICON general circulation model, nudged to ECMWF, was used to calculate winds. Backwards trajectories, including wind variability as measured by radar, traced air masses to the Falcon 9 re-entry path at 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 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.