Evaluation of the resiliency characteristics of several candidate Solid Rocket Booster O-ring materials

Resiliency tests have been conducted in order to evaluate O-ring sealing response in the revised Space Shuttle SRBs, giving attention to the effects of temperature and gap-opening rates. Additional testing was conducted to ascertain O-ring responses to simulated SRB field-joint deflections. All tests employed a face-seal fixture mounted on a servohydraulic apparatus. The Viton candidate O-ring material tracked the gap-opening rate better at higher temperatures and lower gap-opening rates; it was also the only material inert to the calcium grease employed. Heaters must be used to maintain the 70 F minimum temperature at which the Viton O-ring will track the required gap opening rate.