A key element of the mission's objectives was EASE/ACCESS, an experiment in assembling large structures in space. EASE/ACCESS was a joint venture between the Langley Research Center and the Marshall Space Flight Center. ACCESS was a "high-rise" tower composed of many small struts and nodes. EASE was a geometric structure shaped like an inverted pyramid, composed of a few large beams and nodes. Together, they demonstrated the feasibility of assembling large pre-formed structures in space. Astronauts Jerry Ross and Sherwood Spring performed the two spacewalks of the mission which marked the 50th and 51st U.S. (12th and the 13th for the Shuttle) EVAs. An IMAX camera mounted in the cargo bay filmed the activities of the astronauts engaged in the EASE/ACCESS work, as well as other scenes of interest.

The Onyx (formerly known as Lacrosse) satellites are terrestrial radar imaging reconnaissance satellite operated by the National Reconnaissance Office (NRO).

Martin Marietta (later Lockheed Martin) was the main contractor of these satellites. Onyx uses synthetic aperture radar (SAR) to perform mapping. Resolution is probably around 1 meter.