REG NASA-LLIS-0951-1995 Lessons Learned Solid Rocket Motor Case-to-Nozzle Joint O Ring Compression Increase.pdf

1、Lessons Learned Entry: 0951Lesson Info:a71 Lesson Number: 0951a71 Lesson Date: 1995-03-27a71 Submitting Organization: MSFCa71 Submitted by: Billy Cole / RetiredSubject: Solid Rocket Motor Case-to-Nozzle Joint: “O“ Ring Compression Increase Description of Driving Event: The Challenger (Space Shuttle

2、Flight #51L) accident triggered a detailed review of all of the joints in the Solid Rocket Motor. Analyses showed a potential weakness and potential flow paths for hot gasses through he case-to-nozzle joint that could cause a catastrophic event similar to that encountered in Challenger.Lesson(s) Lea

3、rned: Greater compression of the primary “O“ ring is required to achieve reliable operation of a case-to-nozzle joint.Recommendation(s): Increase the diameter of the “O“ ring and redimension the “O“ ring groove to provide optimum “O“ ring squeeze while preventing “O“ ring entrapment. (In the Solid R

4、ocket Motor (SRM), the primary “O“ ring diameter was increased to 0.290 in and the groove was decreased in width from 0.378 inch to 0.345 inch.)Evidence of Recurrence Control Effectiveness: As of this date, eight-six (86) Revised Solid Rocket Motors (RSRM) have flown successfully and ten (10) full-s

5、cale RSRM test motors have been tested successfully since Challenger with no failures and no evidence of joint deterioration or burn-through. This successful record indicates that recurrence control has been successful.Documents Related to Lesson: Provided by IHSNot for ResaleNo reproduction or netw

6、orking permitted without license from IHS-,-,-N/AMission Directorate(s): a71 Space Operationsa71 Exploration SystemsAdditional Key Phrase(s): a71 Energetic Materials - Explosive/Propellant/Pyrotechnica71 Launch VehicleAdditional Info: Approval Info: a71 Approval Date: 2001-07-23a71 Approval Name: Eric Raynora71 Approval Organization: QSa71 Approval Phone Number: 202-358-4738Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-