The Solar Mesosphere Explorer satellite was developed to investigate the processes that create and destroy ozone in the Earth's upper atmosphere. It operated for seven years in the 1980's before power problems led to it being shut down.

The mission's specific goals were to examine the effects of changes in the solar ultraviolet flux on mesospheric ozone densities, the relationship between solar flux, ozone, and the temperature of the upper stratosphere and mesosphere, the relationship between ozone and water vapor, and the relationship between nitrogen dioxide and ozone. All instruments were turned off in December 1988 due to power constraints. Contact was lost on 14 April 1989 after a battery failure, and the vehicle re-entered on 5 March 1991.

The mission was managed for NASA by JPL, and was operated by the Laboratory for Atmospheric and Space Physics of the University of Colorado.

The spacecraft was spin stabilized (~5 rpm) with a fixed solar array recharging NiCd batteries. A tape recorder was used for data storage.

The payload included an ultraviolet ozone spectrometer, 1.27 micron spectrometer, nitrogen dioxide spectrometer, a four-channel infrared radiometer, a solar ultraviolet monitor, and a solar proton alarm detector.

Design Life: 1 year. Typical orbit: 538 x 542 km, incl. = 97 deg, 3 a.m. - 3 p.m. sun. Length: 1.70 m (5.50 ft). Maximum Diameter: 1.25 m (4.10 ft). Mass: 437 kg (963 lb).

• 1981 October 6 - SME - Launch Site: Vandenberg. Launch Complex: SLC2W. Launch Vehicle: Delta. Mass: 437 kg (963 lb). Perigee: 335 km (208 mi). Apogee: 337 km (209 mi). Inclination: 97.60 deg. Period: 91.30 min.
  Solar Mesosphere Explorer. Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C).

• 1989 April 14 - Contact lost with SME. -
  SME was developed to investigate the processes that create and destroy ozone in the Earth's upper atmosphere. All instruments were turned off in December 1988 due to power constraints. Contact was lost on April 14, 1989 after a battery failure, and the vehicle re-entered on March 5, 1991.