1、Lessons Learned Entry: 1372Lesson Info:a71 Lesson Number: 1372a71 Lesson Date: 2003-08-25a71 Submitting Organization: JPLa71 Submitted by: David Oberhettinger / Ronald WelchSubject: Prevent Ground Straps from Contacting Power Sources (2002) Abstract: Two safety incidents occurred during Mars Explora
2、tion Rover integration and test, caused by uninsulated, braided traveling ground straps that came into contact with exposed facility power terminals during movement of connected flight hardware. Electrical shorts resulted, causing visible sparks and partial melting of the ground straps and power con
3、nectors. All traveling ground straps should be insulated to prevent harm to personnel or critical equipment. Description of Driving Event: During Mars Exploration Rover (MER) integration and test, there were two safety incidents where un-insulated, braided traveling ground straps came into contact w
4、ith exposed facility power terminals during movement of connected flight hardware. The two traveling ground straps each exceeded 25 feet in length. The resulting electrical shorts caused visible sparks and partial melting of the ground straps and power connectors.Provided by IHSNot for ResaleNo repr
5、oduction or networking permitted without license from IHS-,-,-refer to D descriptionDSubsequent circuit analysis showed that neither the star scanner (Reference (1) nor the Rover Equipment Deck (Reference (2) was damaged. References 1. JPL Problem/Failure Report No. Z77937, June 26, 20022. JPL Probl
6、em/Failure Report No. Z78131, October 31, 2002.3. JPL Corrective Action Notice No. Z78250, November 7, 2002.4. JPL Standard for Systems Safety, D-560 (Rev. C), March 9, 1999.Additional Key Words: short circuit, electrical grounding, ground wire, test-induced damage, test error, bare wire Lesson(s) L
7、earned: Long, un-insulated, copper cables used as traveling ground straps may inadvertently come into contact with facility power sources and harm personnel or critical equipment.Recommendation(s): All traveling ground straps should be insulated. Evidence of Recurrence Control Effectiveness: Provide
8、d by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Corrective Action Notice No. Z78250 was opened by JPL on November 7, 2002. The measure taken to implement Laboratory-wide corrective action on the above recommendations was amending the JPL system safety stand
9、ard (JPL D-560) to include a restriction on the use of non-insulated braided ground straps. This corrective action is presently under independent assessment.Documents Related to Lesson: NPG 8715.3 “NASA Safety Manual“Mission Directorate(s): a71 Exploration Systemsa71 Sciencea71 Space Operationsa71 A
10、eronautics ResearchAdditional Key Phrase(s): a71 Facilitiesa71 Flight Equipmenta71 Ground Equipmenta71 Ground Operationsa71 Hardwarea71 Industrial Operationsa71 Occupational Healtha71 Packaging Handling Storagea71 Payloadsa71 Safety & Mission Assurancea71 Test & Verificationa71 Test Articlea71 Test
11、FacilityAdditional Info: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 2003-10-15a71 Approval Name: Carol Dumaina71 Approval Organization: JPLa71 Approval Phone Number: 818-354-8242Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
