Primary mission objectives were deployment of the Laser Geodynamics 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).