REG NASA-LLIS-0946-1995 Lessons Learned Solid Rocket Motor Case-to-Nozzle Joint Add a Pressurizing Slot in Case Insulation.pdf

1、Lessons Learned Entry: 0946Lesson Info:a71 Lesson Number: 0946a71 Lesson Date: 1995-03-27a71 Submitting Organization: MSFCa71 Submitted by: Billy Cole / RetiredSubject: Solid Rocket Motor Case-to-Nozzle Joint: Add a Pressurizing Slot in Case Insulation Description of Driving Event: The Challenger (S

2、pace Shuttle 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 the case-to-nozzle joint that could cause a catastrophic event similar to that encountered in Challenger

3、.Lesson(s) Learned: A pressurizing slot was designed and implemented in the case-to-nozzle joints in large solid propellant rocket motors between nozzle and case insulation joints.Recommendation(s): Provide a circumferential slot in case insulation near the interface between case and nozzle insulati

4、on. A circumferential flow baffle was installed in this slot to prevent insulation erosion, and a stress-relieving radius former is placed at the base of this slot to prevent potential insulation cracking.Evidence of Recurrence Control Effectiveness: As of this date, eight-six (86) Solid Rocket Moto

5、rs (RSRM) have flown successfully and ten (10) full-scale 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:

6、 Provided by IHSNot for ResaleNo reproduction or networking 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-,-,-