Solar Maximum Mission

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SMM redirects here. For other uses, see SMM (disambiguation)

SMM satellite

Capturing the Solar Maximum Mission satellite from STS-41-C

The Solar Maximum Mission satellite (or SolarMax) was designed to investigate solar phenomenon, particularly solar flares. It was launched on Valentine's Day (February 14) 1980.

Whilst not unique in this endeavour, the SMM was notable in that its useful life compared with similar spacecraft was significantly increased by the direct intervention of a manned space mission. In 1984 the Space Shuttle Challenger intercepted it, maneuvering the SMM into the shuttle's payload bay for maintenance and repairs. SMM has been fitted with a shuttle "grapple fixture" so that the shuttle's robot arm could grab it in anticipation of possible repairs.

Significantly, the SMM's ACRIM instrument package showed that, contrary to common sense, the Sun is actually brighter during the sunspot cycle maximum (when the greatest number of dark 'sunspots' appear). This is because sunspots are surrounded by bright features called faculae, which more than cancel the darkening effect of the sunspot.

The Solar Maximum Mission ended on December 2, 1989 when the spacecraft re-entered the atmosphere and burned up.