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Development of Thermal Barriers For Solid Rocket Motor Nozzle JointsJoints in the Space Shuttle solid rocket motors are sealed by O-rings to contain combustion gases inside the rocket that reach pressures of up to 900 psi and temperatures of up to 5500 F. To provide protection for the O-rings, the motors are insulated with either phenolic or rubber insulation. Gaps in the joints leading up to the O-rings are filled with polysulfide joint-fill compounds as an additional level of protection. The current RSRM nozzle-to-case joint design incorporating primary, secondary, and wiper O-rings experiences gas paths through the joint-fill compound to the innermost wiper O-ring in about one out of every seven motors. Although this does not pose a safety hazard to the motor, it is an undesirable condition that NASA and rocket manufacturer Thiokol want to eliminate. Each nozzle-to-case joint gas path results in extensive reviews and evaluation before flights can be resumed. Thiokol and NASA Marshall are currently working to improve the nozzle-to-case joint design by implementing a more reliable J-leg design that has been used successfully in the field and igniter joint. They are also planning to incorporate the NASA Glenn braided carbon fiber thermal barrier into the joint. The thermal barrier would act as an additional level of protection for the O-rings and allow the elimination of the joint-fill compound from the joint.
Document ID
20010000017
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Steinetz, Bruce M.
(NASA Glenn Research Center Cleveland, OH United States)
Dunlap, Patrick H., Jr.
(NASA Glenn Research Center Cleveland, OH United States)
Date Acquired
August 20, 2013
Publication Date
October 1, 2000
Publication Information
Publication: 1999 NASA Seal/Secondary Air System Workshop
Volume: 1
Subject Category
Spacecraft Propulsion And Power
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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