Researchers identify metals released into the atmosphere by satellite reentry

Stratospheric aerosols contain significant amounts of metals released as satellites burn-up during re-entry, mass spectrometry high above Alaska has shown. While this fraction is expected to increase dramatically in the coming decades, the impact of these additional metals on atmospheric chemistry is unknown.

Aerosols in the upper atmosphere primarily comprise sulfuric acid from the condensation of oxidized carbonyl sulfide or sulfur dioxide with water vapour. These aerosols sometimes nucleate on metallic nanoparticles, which can naturally form by meteor ablation. ‘The meteors burn up very high in the atmosphere – like 100km,’ explains atmospheric scientist Daniel Murphy of the National Oceanic and Atmospheric Administration in Boulder, Colorado. Metals like iron and magnesium are vaporised from the meteors, and as the atoms undergo Brownian motion and cool, they condense into nanoparticles less than 100nm in size.