1、Lessons Learned Entry: 0215Lesson Info:a71 Lesson Number: 0215a71 Lesson Date: 1992-11-18a71 Submitting Organization: KSCa71 Submitted by: Lisa L. MusgraveSubject: Solid Rocket Motor (SRM) Processing and Inspection Description of Driving Event: All inventory SRM case o-rings were reinspected during
2、the STS 51-L investigation. When reinspected using original inspection equipment (mechanical micrometer), very few out-of-tolerance conditions were identified. However, when reinspected with a laser micrometer with a 0.007-inch measuring beam, numerous small localized out-of-tolerance conditions wer
3、e detected. All inventory o-rings were also x-rayed, indicating numerous o-ring inclusions. Although tests proved that these conditions did not affect the sealing capability, this does indicate a potential problem and a need for processing and inspection improvements. It was also learned during this
4、 investigation that the o-ring material manufacturer had changed material formulations and processing numerous times since starting to produce srm o-ring material. While all these formulations resulted in o-ring material that was in compliance with MIL-R-83248, this lack of standardization could pos
5、sibly result in application problems and is unacceptable for such a critical item.Lesson(s) Learned: 1. Inadequacies in the processing and inspection of o-rings for the SRM may affect sealing capabilities.2. A lack of standardization in the SRM o-ring material formulations and processing may result
6、in application problems.Recommendation(s): 1. Review o-ring processing and inspection requirements to assure they are compatible with the criticality 1 criteria.2. Maintain a current/updated inventory of all critical flight hardware and check records prior to use for any manufacturing changes.Provid
7、ed by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): a71 Space Operationsa71 Exploration SystemsAdditional Key Phrase(s): a71 Launch Vehiclea71 Parts Materials & ProcessesAdditional 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-,-,-
