(07/23/1997) -- STS-85 Payload Commander N. Jan Davis (left) and Mission Specialist Robert L. Curbeam, Jr., go through countdown procedures aboard the Space Shuttle orbiter Discovery during Terminal Countdown Demonstration Test (TCDT) activities for that mission. The TCDT includes a simulation of the final launch countdown. The primary payload aboard the Space Shuttle orbiter Discovery is the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere-2 (CRISTA-SPAS-2). Other STS-85 payloads include the Manipulator Flight Demonstration (MFD), and Technology Applications and Science-1 (TAS-1) and International Extreme Ultraviolet Hitchhiker-2 (IEH-2) experiments