REG NASA-LLIS-0328-1993 Lessons Learned - Solid Propellant Electro-Static Discharge Ignition.pdf

1、Lessons Learned Entry: 0328Lesson Info:a71 Lesson Number: 0328a71 Lesson Date: 1993-11-10a71 Submitting Organization: MSFCa71 Submitted by: Fisher, MarkSubject: Solid Propellant, Electro-Static Discharge Ignition Description of Driving Event: The accident investigation into the fire and destruction

2、of a Pershing II stage I missile motor in Germany revealed that it was accepted that the propellant (QBJ-29) was insensitive to ESD. The cause of the accident was attributed to ESD. Older ESD sensitivity tests based upon the determination of spark energy, such as the layer test, the dust test, and t

3、he human spark test, were found to be inaccurate when U.S. hazard technologists began determining the ESD sensitivity of QBJ-29. It was found that the spark gap tests did not accurately reflect the actual energy delivered to a propellant sample. U.S. technologists, in addition, did not consider how

4、changes in humidity or temperature affected the electrical properties of the propellant samples. Therefore, U.S. investigators borrowed the test techniques, which SNPE has been developing since 1976. The SNPE employed a three-part test methodology based on the RC discharge test, volume resistivity m

5、easurements as a function of temperature, and percolation coefficient calculations. While the SNPE test is more discriminating than the older tests, it is itself unreliable.Lesson(s) Learned: Presently available technology (as of 1988) for determining sensitivity of solid propellant to electro-stati

6、c discharge is unreliable.Recommendation(s): Until such time as a reliable method for determining sensitivity to ESD is developed and proven, solid propellants should be treated as sensitive to ESD and appropriate measures taken to avoid exposure to ESD.Evidence of Recurrence Control Effectiveness:

7、Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Guarding against the possibility of ignition by ESD is evidently more effective than not doing so because an unreliable test indicated insensitivity.Documents Related to Lesson: N/AMission Directorate(s

8、): N/AAdditional Key Phrase(s): a71 Energetic Materials - Explosive/Propellant/Pyrotechnica71 Energya71 Hazardous/Toxic Waste/Materialsa71 Industrial OperationsAdditional Info: Approval Info: a71 Approval Date: 1994-08-17a71 Approval Name: Fisher, Marka71 Approval Organization: EP22a71 Approval Phone Number: 205-544-9503Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-