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Primary mission objectives were deployment of the Laser Geodynamic Satellite II ( LAGEOS-II ) and operation of the U. S. Microgravity Payload-1 ( USMP-1 ).

LAGEOS-II, a joint effort between NASA and the Italian Space Agency ( ASI ), was deployed on day 2 and boosted into an initial elliptical orbit by ASI's Italian Research Interim Stage ( IRIS ).

The spacecraft's apogee kick motor later circularized LAGEOS orbit at its operational altitude of 3, 666 miles.

The USMP-1, activated on day one, included three experiments mounted on two connected Mission Peculiar Equipment Support Structures ( MPESS ) mounted in the orbiter's cargo bay.

USMP-1 experiments were: Lambda Point Experiment ; Matériel Pour L ' Etude Des Phénomènes Intéressant La Solidification Sur Et En Orbite ( MEPHISTO ), sponsored by the French agency Centre National d ' Études Spatiales ; and Space Acceleration Measurement System ( SAMS ).