Metals from space debris found in stratosphere

When space debris reenters the atmosphere, the heat generated from friction causes most of it to vaporize. Scientists have recently found that the vaporized metals condense as they descend, ending up in aerosol particles in the stratosphere ( Proc. Natl. Acad. Sci. U.S.A. 2023, DOI: 10.1073/pnas.2313374120 ). This discovery is part of the Stratospheric Aerosol processes, Budget, and Radiative Effects (SABRE) mission. During a series of flights in February and March, the researchers sampled the stratosphere at altitudes up to 19 km. The researchers detected almost two dozen elements that come from meteors, volcanoes, and vaporized spacecraft. Meteors are considered the main sources of sodium, magnesium, chromium, iron, and nickel, but the researchers also found aluminum, copper, lead, and lithium that could not be accounted for by natural causes. “What we measured is consistent with what we know about what spacecraft are made of,” says Daniel Murphy , an aerosols