Detection of Uranium from Cosmos-1402 in the Stratosphere

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Science  23 Oct 1987:
Vol. 238, Issue 4826, pp. 512-514
DOI: 10.1126/science.238.4826.512


The nuclear reactor from the Soviet radar reconnaissance satellite, Cosmos-1402, reentered the earth's atmosphere on 7 February 1983 and disintegrated over the South Atlantic Ocean. The reactor was powered by approximately 50 kilograms of uranium-235 (235U). In an effort to determine the fate of the reactor core, a series of aerosol samples were collected at altitudes between 27 and 36 kilometers in the Northern Hemisphere approximately 1.1 years later by high-altitude balloons. At an altitude of 36 kilometers a 53 ± 20 percent excess in the 235U concentration was measured. The total excess of 235U in the stratosphere was calculated to be 44 ± 15 kilograms.