Overview
- Researchers detected a lithium plume roughly 20 hours after a Falcon 9 upper stage reentered on February 19, 2025, observing the signal between 94.5 and 96.8 kilometers for about 27 minutes.
- The study, published in Communications Earth & Environment, attributes the lithium to spacecraft materials, chiefly lithium‑ion batteries and lithium–aluminum alloys.
- The finding demonstrates that reentering hardware leaves identifiable, traceable pollution in the upper atmosphere and that lidar can tie such plumes to specific events.
- Scientists warn that cumulative effects on ozone chemistry, aerosol microphysics and radiation transport remain uncertain, citing prior evidence of aluminum and other metals in stratospheric particles.
- With satellite deployments accelerating and a single Falcon 9 carrying about 30 kilograms of lithium, research groups and agencies plan expanded observations, though SpaceX did not respond to the authors' outreach.