1、Lessons Learned Entry: 0622Lesson Info:a71 Lesson Number: 0622a71 Lesson Date: 1999-05-21a71 Submitting Organization: JPLa71 Submitted by: A. Acord/W. Moore/D. OberhettingerSubject: Use of Obsolescent Test Facilities Pose Risk to Hardware (1997) Abstract: Cassini: At the beginning of Assembly, Test,
2、 and Launch Operations (ATLO), vibration testing of the massive Cassini spacecraft was performed using facility test equipment that was barely up to the task. Powering an aged power amplifier for a shaker resulted in multiple failures of the test equipment, including board fires. Proactively perform
3、 periodic test facility maintenance and upgrade, and validate the current performance of the environmental test facility prior to use.Description of Driving Event: At the beginning of Cassini Assembly, Test, and Launch Operations (ATLO), the readiness and condition of the JPL Environmental Test Labo
4、ratory equipment was poorly understood.Vibration testing of the massive Cassini spacecraft was performed using facility test equipment that was barely up to the task.a71 Proof mass vibration tests had to be aborted due to instrumentation problems. Since not all elements of the standard instrumentati
5、on suite were needed, various test instruments were uncoupled until the configuration provided a workable subset.a71 a71 The amplifier used to drive the shaker was approaching the end of its useful life during the Cassini proof mass vibration tests. The power amplifier includes 3000 power transistor
6、s on 10 circuit boards. Several days were spent getting the amplifier operational. Powering the amplifier resulted in multiple failures of the test equipment, including board fires. The resultant uncontrolled shutdown of the shaker would have posed a significant risk had the test been conducted on f
7、light hardware.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-The Cassini project had to devote resources for repairing and upgrading the test facility so that the flight spacecraft could be tested.Additional Keyword(s): system safety, test instrume
8、ntation, dynamics test, acoustic test, test planning, test-induced failure, Management and Planning, System Integration and Test, Hardware Fabrication and TestReference(s): Cassini Spacecraft Assembly, Test, and Launch Operations (ATLO) Final Report, Volume I, JPL Document D-15701, May 15, 1998, pag
9、e 151.Lesson(s) Learned: 1. Test facilities may deteriorate between periods of use and may not be fully ready for the next major test program.2. Lack of full readiness may be especially risky when testing near the limit of the environmental equipment capability, or with resource-constrained projects
10、 that may lack the time and funding to correct deficiencies.Recommendation(s): 1. If NASA Centers are to maintain the capability to support environmental testing of multiple small missions, it is important that they proactively perform periodic test facility maintenance and upgrade. Moreover, provid
11、e procedures for validating and documenting current performance of the environmental test facility prior to use.2. It is always a good practice to verify environmental test equipment readiness and set-up with appropriate simulated hardware prior to flight hardware testing. This should be done early
12、enough to avoid impacting project schedules.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a71 Policy & Planninga71
13、 Test & Verificationa71 Test FacilityAdditional Info: Approval Info: a71 Approval Date: 1999-05-24a71 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-,-,-
