The Hidden Pollution of Space Travel: Toxic Metals Litter the Stratosphere

Researchers have discovered significant amounts of metals in aerosols in the stratosphere, likely from spacecraft launches and returns. The presence of these metals is changing atmospheric chemistry and may have implications for climate, the ozone layer, and the habitability of Earth. The mass of metals from spacecraft reentry far exceeds those found in natural cosmic dust, and as more satellites are launched, the amount of metals in the stratosphere is expected to increase. The impact of human spaceflight on the planet may be more significant than previously imagined, highlighting the need for further research.