The Space Age is leaving fingerprints on one of the most remote parts of the planet — the stratosphere — which has potential implications for climate, the ozone layer and the continued habitability of Earth.
Using tools hitched to the nose cone of their research planes and sampling more than 11 miles above the planet’s surface, researchers have discovered significant amounts of metals in aerosols in the atmosphere, likely from increasingly frequent launches and returns of spacecraft and satellites. That mass of metal is changing atmospheric chemistry in ways that may impact Earth’s atmosphere and ozone layer.
“We are finding this human-made material in what we consider a pristine area of the atmosphere,” said Dan Cziczo, one of a team of scientists who published a study on these results in the Proceedings of the National Academy of Sciences. “And if something is changing in the stratosphere — this stable region of the atmosphere — that deserves a closer look.” Cziczo, professor and head of the Department of Earth, Atmospheric, and Planetary Sciences in Purdue’s College of Science, is an expert in atmospheric science who has spent decades studying this rarefied region.
Led by Dan Murphy, an adjunct professor in the Department of Earth, Atmospheric, and Planetary Sciences and a researcher at the National Oceanic and Atmospheric Administration, the team detected more than 20 elements in ratios that mirror those used in spacecraft alloys. They found that the mass of lithium, aluminum, copper and lead from spacecraft reentry far exceeded those metals found in natural cosmic dust. Nearly 10% of large sulfuric acid particles — the particles that help protect and buffer the ozone layer — contained aluminum and other spacecraft metals.
Scientists estimate that as many as 50,000 more satellites may reach orbit by 2030. The team calculates that means that, in the next few decades, up to half of stratospheric sulfuric acid particles would contain metals from reentry….