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Grease-Resistant O Rings for Joints in Solid Rocket MotorsThere is a continuing effort to develop improved O rings for sealing joints in solid-fuel rocket motors. Following an approach based on the lessons learned in the explosion of the space shuttle Challenger, investigators have been seeking O-ring materials that exhibit adequate resilience for effective sealing over a broad temperature range: What are desired are O rings that expand far and fast enough to maintain seals, even when metal sealing surfaces at a joint move slightly away from each other shortly after ignition and the motor was exposed to cold weather before ignition. Other qualities desired of the improved O rings include adequate resistance to ablation by hot rocket gases and resistance to swelling when exposed to hydrocarbon-based greases used to protect some motor components against corrosion. Five rubber formulations two based on a fluorosilicone polymer and three based on copolymers of epichlorohydrin with ethylene oxide were tested as candidate O-ring materials. Of these, one of the epichlorohydrin/ethylene oxide formulations was found to offer the closest to the desired combination of properties and was selected for further evaluation.
Document ID
Acquisition Source
Marshall Space Flight Center
Document Type
Other - NASA Tech Brief
Harvey, Albert R.
(Thiokol Propulsion Huntsville, AL, United States)
Feldman, Harold
(Thiokol Propulsion Huntsville, AL, United States)
Date Acquired
August 25, 2013
Publication Date
February 1, 2003
Publication Information
Publication: NASA Tech Briefs, February 2003
Subject Category
Man/System Technology And Life Support
Report/Patent Number
Distribution Limits
Public Use Permitted.
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