Launch from Cape Canaveral (KSC); landing on Cape Canaveral (KSC).

In September 1996 Jeffrey Ashby was assigned to serve as a pilot on STS-85. He trained with the crew until March 1997 when he was named as an assistant to the Director, Flight Crew Operations. At that time Jeffrey Ashby withdrew from STS-85 to take care of his wife, who was dying of cancer.

A few hours after the launch the German built satellite CRISTA-SPAS-02 (Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere) was deployed. CRISTA-SPAS consists of three telescopes and four spectrometers that measured trace gases and dynamics of the Earth's middle atmosphere. Later the crew retrieved the satellite with the help of the shuttle robot arm.

Two other instruments mounted on the SPAS also studied the Earth's atmosphere. The Middle Atmosphere High Resolution Spectrograph Instrument (MAHRSI) measured hydroxyl and nitric oxide by sensing UV radiation emitted and scattered by the atmosphere, while the Surface Effects Sample Monitor (SESAM) was a passive carrier for state-of-the-art optical surfaces to study the impact of the atomic oxygen and the space environment on materials and services.

The crew also supported the Manipulator Flight Demonstration (MFD) experiment being sponsored by NASDA, the Japanese Space Agency. MFD consists of three separate experiments located on a support truss in the payload bay. The primary objective was to demonstrate the newly designed dexterous robot arm in the space environment, before installing on the Japanese Experiment Module (JEM) of the International Space Station.

Several scientific experiments like tests with Utraviolet Spectrograph Telescope and Camera were performed. Several Hitchhiker payloads, including the Technology Applications and Science Payload (TAS-01), the International Extreme Ultraviolet Hitchhiker (SEH), and the Ultraviolet Spectrograph Telescope for Astronomical Research (UVSTAR) were housed in Discovery's payload bay, operating independently of crew support during the flight. Another experiment onboard STS-85 was the Southwest Ultraviolet Imaging System (SWUIS-01) from the Southwest Research Institute (SwRI) along with scientific collaborators from JPL, APL, and the University of Maryland. Finally the crew tested tools for the ISS (e.g. Japanese built robotarm).

The mission lasted a day longer than originally planned due to a threat of ground fog at Kennedy Space Center.