REG NASA-LLIS-0287--1993 Lessons Learned Magellan Power Control Unit Failure During Test.pdf

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1、Lessons Learned Entry: 0287Lesson Info:a71 Lesson Number: 0287a71 Lesson Date: 1993-07-13a71 Submitting Organization: JPLa71 Submitted by: J. O. BlosiuSubject: Magellan Power Control Unit Failure During Test Abstract: Following rework of the Magellan Power Control Unit (PCU), an engineer performed a

2、n after-hours test of the unit without quality assurance assistance or adequate test procedures. Reverse polarity voltage was applied to electronic circuitry within the unit, causing blown fuses and potential damage to electronic parts. Test or retest of flight hardware should always be performed wi

3、th adequate personnel in attendance, with QA surveillance, and with approved test procedures. Prior to tests, review the use of test instrumentation to verify the proper configuration and precautions.Description of Driving Event: While the Magellan Power Control Unit (PCU) underwent test following r

4、ework, an engineer was performing a test of the unit at a contractor facility after hours and without quality assurance (QA) assistance and adequate test procedures. During this continuity and resistance testing, test instrumentation applied reverse polarity voltage to electronic circuitry within th

5、e unit. This resulted in three blown fuses and potential damage to other electronic parts.After analysis, repair, and testing the PCU was reinstalled in the Magellan spacecraft at Kennedy Space Center, fortunately with no delay in launch operations.Additional Keyword(s): Subsystem TestReference(s):

6、Mars #B 16003Lesson(s) Learned: 1. Testing of flight critical hardware without approved test procedures, and without the presence Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-of quality assurance, can lead to serious problems.2. Test instrumentati

7、on, used improperly, can induce voltages and currents in components, resulting in degradation or failures.Recommendation(s): 1. Test or retest of flight hardware should always be performed with adequate personnel in attendance, with QA surveillance and with approved test procedures. Clarification of

8、 this requirement in the flight project practices document should be considered.2. Prior to the use of test instrumentation, reviews should be conducted to verify that proper configuration and adequate precautions have been taken to prevent damage to flight hardware.Evidence of Recurrence Control Ef

9、fectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Safety & Mission Assurancea71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 1991-01-31a71 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-,-,-