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Effects of Free Molecular Heating on the Space Shuttle Active Thermal Control SystemDuring Space Transportation System (STS) flight 121, higher than predicted radiator outlet temperatures were experienced from post insertion and up until nominal correction (NC) burn two. Effects from the higher than predicted heat loads on the radiator panels led to an additional 50 lbm of supply water consumed by the Flash Evaporator System (FES). Post-flight analysis and research revealed that the additional heat loads were due to Free Molecular Heating (FMH) on the radiator panels, which previously had not been considered as a significant environmental factor for the Space Shuttle radiators. The current Orbiter radiator heat flux models were adapted to incorporate the effects of FMH in addition to solar, earth infrared and albedo sources. Previous STS flights were also examined to find additional flight data on the FMH environment. Results of the model were compared to flight data and verified against results generated by the National Aeronautics and Space Administration (NASA), Johnson Space Center (JSC) Aero-sciences group to verify the accuracy of the model.
Document ID
Document Type
Conference Paper
McCloud, Peter L.
(Boeing Co. Houston, TX, United States)
Wobick, Craig A.
(Boeing Co. Houston, TX, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2007
Subject Category
Spacecraft Design, Testing And Performance
Meeting Information
46th AIAA Aerospace Sciences Meeting and Exhibit(Reno, NV)
Distribution Limits
Work of the US Gov. Public Use Permitted.
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