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Thermal Barrier/Seal for Extreme Temperature ApplicationsLarge solid rocket motors, as found on the Space Shuttle, are fabricated in segments for manufacturing considerations, bolted together, and sealed using conventional Viton O-ring seals. Similarly the nine large solid rocket motor nozzles are assembled from several different segments, bolted together, and sealed at six joint locations using conventional O-ring seals. The 5500 F combustion gases are generally kept a safe distance away from the seals by thick layers of phenolic or rubber insulation. Joint-fill compounds, including RTV (room temperature vulcanized compound) and polysulfide filler, are used to fill the joints in the insulation to prevent a direct flow-path to the O-rings. Normally these two stages of protection are enough to prevent a direct flow-path of the 900-psi hot gases from reaching the temperature-sensitive O-ring seals. However, in the current design 1 out of 15 Space Shuttle solid rocket motors experience hot gas effects on the Joint 6 wiper (sacrificial) O-rings. Also worrisome is the fact that joints have experienced heat effects on materials between the RTV and the O-rings, and in two cases O-rings have experienced heat effects. These conditions lead to extensive reviews of the post-flight conditions as part of the effort to monitor flight safety. We have developed a braided carbon fiber thermal barrier to replace the joint fill compounds in the Space Shuttle solid rocket motor nozzles to reduce the incoming 5500 F combustion gas temperature and permit only cool (approximately 100 F) gas to reach the temperature-sensitive O-ring seals. Implementation of this thermal barrier provides more robust, consistent operation with shorter turn around times between Shuttle launches.
Document ID
20020046979
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Steinetz, Bruce M.
(NASA Glenn Research Center Cleveland, OH United States)
Dunlap, Patrick H., Jr.
(NASA Glenn Research Center Cleveland, OH United States)
Phelps, Jack
(NASA Marshall Space Flight Center Huntsville, AL United States)
Bauer, Paul
(Alliant Techsystems, Inc. Brigham City, UT United States)
Bond, Bruce
(Techniweave, Inc. Rochester, NH United States)
McCool, Alex
Date Acquired
September 7, 2013
Publication Date
January 1, 2002
Subject Category
Nonmetallic Materials
Funding Number(s)
CONTRACT_GRANT: NAS8-97238
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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