Endeavor launched from Kennedy Space Center on September 7, 1995 at 11:09 AM EDT and landed at Kennedy on September 18 at 7:37 AM EDT. The shuttle orbited 171 times at an altitude of 190 nautical miles at an inclination of 28.4 degrees and travelled 4.5 million miles. The mission lasted 10 days, 20 hours, 28 minutes and 56 seconds.
STS-69 marked the first time two different payloads were retrieved and deployed during the same mission. Also featured was a spacewalk to practice for International Space Station activities and to evaluate space suit design modifications.
Spartan 201-03 deployed on flight day two. This was the third Spartan 201 mission in planned series of four. The primary objective was to study the outer atmosphere of the sun and its transition into solar wind that constantly flows past Earth. The timing of the Spartan 201-03 flight was intended to coincide with the passage of the Ulysses spacecraft over the sun’s polar region to expand the range of data being collected about the origins of solar wind. The Spartan 201-03 configuration featured two scientific instruments, the Ultraviolet Coronal Spectrometer (UVCS) and the White Light Coronagraph (WLC). UVCS measured characteristics of light emitted by neutral hydrogen atoms in the solar corona, the outermost portion of the sun’s atmosphere from which the solar wind evolves. The WLC imaged the changing shape and form of the corona.
Concerns arose about performance of the two instruments when Spartan was retrieved after about two days of data-gathering. As the shuttle approached the free-flying spacecraft it was rotating slowly and located in a different attitude than expected for retrieval. However, later analysis confirmed UVCS and WLC operated smoothly, with WLC obtaining good data.
The second primary payload, the Wake Shield Facility-2 (WSF-2) deployed on flight day five and became first spacecraft to maneuver itself away from orbiter rather than other way around, by firing a small cold gas nitrogen thruster to maneuver away from Endeavour. WSF-2 was the second in planned series of four flights. WSF was a 12-foot- (3.7-meter) diameter stainless steel disk designed to generate an ultravacuum environment in space within which to grow thin films for the next generation advanced electronics.
The WSF-2 hung over side of Endeavour’s cargo bay one final time for the Charging Hazards and Wake Studies (CHAWS) experiment, an Air Force-sponsored experiment to collect data on the buildup of electrical fields around an orbiting space vehicle.
On flight day ten, Voss and Gernhardt conducted a six-hour, 46-minute spacewalk, completing the final primary objective of STS-69. They evaluated thermal improvements made to their extravehicular activity suits and reported they remained comfortable, and also tested a variety of tools and techniques were later used in the assembly of the International Space Station.
Additional payloads: International Extreme Ultraviolet Hitchhiker (IEH-1), to measure and monitor long-term variations in magnitude of absolute extreme ultraviolet flux coming from sun; Solar Extreme Ultraviolet Hitchhiker (SEH), to accurately measure solar flux in the extreme ultraviolet region of solar spectrum; and Consortium for Materials Development in Space Complex Autonomous Payload (CONCAP IV-3), third flight of an experiment that studied the growth of organic nonlinear optical crystals and thin films.
In-cabin payloads included Space Tissue Loss/National Institutes of Health-Cells (STL-NIH-C); Commercial Generic Bioprocessing Apparatus-7 (CGBA); Biological Research in Canister (BRIC); Electrolysis Performance Improvement Concept Study (EPICS) and Commercial MDA ITA Experiments (CMIX-4).
Endeavor was crewed by Commander David M. Walker, Pilot Kenneth D. Cockrell, Payload Commander James S. Voss, and Mission Specialists James H. Newman and Michael L. Gernhardt.