1、Lessons Learned Entry: 0225Lesson Info:a71 Lesson Number: 0225a71 Lesson Date: 1992-11-23a71 Submitting Organization: KSCa71 Submitted by: Lisa L. MusgraveSubject: Solid Rocket Motor (SRM) Processing Operations Description of Driving Event: Solid Rocket Motor segments are shipped from the facility i
2、n Utah to KSC horizontally on railroad cars. During the assembly process at KSC, it has become necessary to reshape case segments to make them concentric with mating segments. This has resulted in assembly difficulties and eccentric loads on the joint o-rings. Assembly difficulties resulting from th
3、e lack of concentricity include the generation of case metal slivers produced by having to force pins into the joint pin holes. The pin-to-pin hole tolerances are such that the pin is difficult to install if the tang and clevis pin holes are not precisely aligned. Case segment ovality (which apparen
4、tly results from the horizontal shipment on railcars) can cause tight tolerances in the area of the o-ring sealing surface. This can cause assembly difficulties and result in undesirable o-ring squeeze.Lesson(s) Learned: Case segment ovality and inadequate assembly tooling/procedures may have result
5、ed in field joint o-ring damage during mating operations.Recommendation(s): Develop shipping/handling aids to maintain circularity of case segments and mating aids to control entry of tang into clevis during joint mating.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: P
6、rovided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Launch Vehiclea71 Packaging Handling Storagea71 TransportationAdditional 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-,-,-
