REG NASA-LLIS-0386-1995 Lessons Learned - Magellan Battery Fire.pdf

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1、Lessons Learned Entry: 0386Lesson Info:a71 Lesson Number: 0386a71 Lesson Date: 1995-02-23a71 Submitting Organization: JPLa71 Submitted by: J.C. MarrSubject: Magellan Battery Fire Abstract: A technician inadvertently shorted a connector on the test battery to a wrong harness connector. The resultant

2、battery short circuit destroyed the test battery, the battery wiring harness, and the flight harness connector, and ignited the thermal blanket. Batteries should be mated to flight spacecraft only in a fully discharged state, and several cable and connector design suggestions are made.Description of

3、 Driving Event: During Magellan prelaunch activity at Kennedy Space Center, a technician, attempting to connect a test battery to the spacecraft, inadvertently shorted the battery connector to a wrong harness connector. The resultant battery short circuit destroyed the test battery, the battery wiri

4、ng harness, the flight harness connector and ignited the thermal blanket. The use of Kapton insulated wire in the battery wiring harness was a significant contributor to the cause of the fire and resultant destruction of the harness. As a result of the event, the spacecraft was impounded until a NAS

5、A review board conducted an investigation. Fortunately all spacecraft damage was repairable; however, this resulted in over a weeks impact on an already tight schedule.The event was caused by:1. The connector connection had to be made with no direct visual access because of the location and thermal

6、blanket obstruction.2. The connectors were thought to be designed to prevent pin contact until the alignment keys of the connectors were sufficiently engaged to ensure a correct connection. This was not the case and sufficient contact was made between at least two pins of the mismated connectors to

7、cause the short and resultant damage.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Reference(s): Magellan Investigation Board Report, 3/24/89Lesson(s) Learned: 1. Inadvertent shorting of a battery when connecting it to the spacecraft can damage fli

8、ght hardware.2. Design of spacecraft connector locations with no direct visual access can result in mismating of connectors during spacecraft assembly operations.3. Connector designs which allow pin contact prior to full engagement of the alignment keys can result in direct shorts if connectors are

9、inadvertently mismated.4. Design of spacecraft connector locations with no direct visual access can result in mismating of connectors during spacecraft assembly activity.5. Connector designs which allow pin contact prior to full engagement of the alignment keys can result in direct shorts if connect

10、ors are inadvertently mismated.6. Kapton wire insulation can be a significant contributor to the cause of fire in wiring harnesses and cables.Recommendation(s): 1. Batteries should be mated to flight spacecraft only in a fully discharged state.2. Cables should be dressed and tied such that connectio

11、ns to wrong connectors are physically impossible.3. Connector designs should be selected such that pins can only make contact after full engagement of all alignment keys. This is particularly important when power connections are involved.4. Spacecraft design should avoid, whenever possible, connecto

12、r locations that require blind mating of connectors.5. Design umbilical and direct access circuitry with protection to withstand direct shorts at the external connector interface without damage to the spacecraft.6. Use of Kapton insulation should be critically examined, particularly in spacecraft po

13、wer circuit applications.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AAdditional Key Phrase(s): a71 Energya71 Human FactorsAdditional Info: Approval Info: a71 Approval Date: 1989-06-29a71 Approval Name: Carol Dumaina71 Approval Organization: 125-204a71 Approval Phone Number: 818-354-8242Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-