Oct 20 1981

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NASA declared the mission of the stratospheric aerosol and gas experiment (SAGE) launched February 18, 1979, successful. SAGE, designed for a 1-year life in orbit, was the second of two small applications-explorer missions built to provide a global data base on ozone and aerosols in the atmosphere.

Like its predecessor, the heat-capacity mapping mission (HCMM), the SAGE spacecraft was built by Boeing. It carried an instrument designed by LaRC that met or exceeded all design specifications, despite power-subsystem problems. Before battery capacity dropped in June 1979, SAGE had acquired 96% of all possible events; since then, about 82%.

SAGE obtained the first global measurements accurate within 1%, more than 12,000 between 78 °S and 78°N, to define mass aerosol loading of the stratosphere and its seasonal variations. Worldwide ground-truth measurements validated the accuracy of its measurements from space of vertical profiles of aerosol extinction and of ozone and nitrogen dioxide concentration.

SAGE also detected and tracked at least five volcanic-eruption plumes that had penetrated the stratosphere, one every six months: La Soufriere in May 1979, Sierra Negra in November 1979, Mt. St. Helens in May 1980, Ulawun in October 1980, and Aloid in May 1981. The volcanic data were the first clear instance of gas-to-particle conversion in the stratosphere and of using volcanic aerosols to track global circulation. (NASA MOR E-659-79-01 [postlaunch] Oct 20/81)

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