1、Lessons Learned Entry: 0224Lesson Info:a71 Lesson Number: 0224a71 Lesson Date: 1992-11-20a71 Submitting Organization: KSCa71 Submitted by: Lisa L. MusgraveSubject: Flight Hardware Performance Evaluation Description of Driving Event: During a hardware performance evaluation, Solid Rocket Motor (SRM)
2、clevis and tang sealing surface diameters were assumed to be stable and were not remeasured during refurbishment. Subsequent testing revealed growth in the diameters after hydroproof (and possibly flight) which introduced an unrecognized variable into o-ring squeeze calculations. The static o-ring c
3、ompression after mating is influenced by these actual hardware dimensions and the degree of segment concentricity, and are critical to hardware performance. During the STS 51-L Investigation, measurements were made on refurbished and reused segments, and the data indicated that segment circumference
4、s at the sealing surfaces change with repeated use.Lesson(s) Learned: Testing sealing surface diameters revealed diameter growth after hydroproof, which introduced unrecognized error in o-ring squeeze calculations.Recommendation(s): Remeasure all case segments in inventory to determine reuse accepta
5、bility and require measurements to be retaken during refurbishment procedures.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AMission Directorate(s): N/AAdditional Key P
6、hrase(s): a71 Parts Materials & Processesa71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 1994-06-08a71 Approval Name: James G. Klinea71 Approval Organization: KSC/HEIa71 Approval Phone Number: 407-867-7614Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
