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The Solar Mesosphere Explorer (SME) spacecraft was launched into orbit from Vandenburg Air Force Base on October 6, 1981, at 11:27 UT. The spacecraft is in a near-circular orbit at 540-km altitude and has the proper inclination of 97.4° to assure a 3 A.M.–3 P.M. sun-synchronous orbit. All orbit parameters appear nominal.

The SME spacecraft is designed to study the influence of changing solar ultraviolet radiation on the density of ozone in the earth's upper stratosphere and mesosphere. The satellite carries five scientific instruments, three to measure the distribution of ozone: an ultraviolet spectrometer measuring the back-scattered radiation between 255 and 310 nm, an infrared radiometer measuring thermal emission from ozone at 9.6 μm, and an infrared spectrometer measuring the 1.27 μm airglow emission resulting from ozone photolysis. In addition, the infrared radiometer measures the temperature of the atmosphere as a function of pressure and altitude by measuring the thermal emission in two portions of the 15-μm CO2 band and the water vapor density by measuring the emission in the 6.3-μm band. A visible light spectrometer measures the density of nitrogen dioxide in the atmosphere by measuring the differential absorption of scattered sunlight at two wavelengths near 443 nm. The four atmospheric instruments will view the earth's limb once every 12 s in the plane of the orbit as the spacecraft spins at a rate of 5 rpm.