Overview
- A Falcon 9 upper stage from the Starlink Group 11-4 mission reentered uncontrolled over the Atlantic in February 2025, after which a lithium-rich plume was observed.
- Roughly 20 hours later, a lidar in Kühlungsborn, Germany, detected lithium at about 96–97 kilometers altitude with concentrations up to ten times typical levels after the plume traveled around 1,600 kilometers.
- The team combined laser and radar measurements with 8,000 UA-ICON trajectory simulations and European Space Agency reentry data to tie the plume to the stage breakup and rule out natural causes.
- The study estimates a single event like this can inject roughly 400 times the lithium that naturally reaches the upper atmosphere in one day.
- With about 1,000 satellite reentries in 2024 and projections of 25–50 per day by 2035, scientists highlight uncertain impacts on ozone chemistry, aerosols, cloud formation, and climate.