1、Lessons Learned Entry: 1300Lesson Info:a71 Lesson Number: 1300a71 Lesson Date: 2002-08-28a71 Submitting Organization: JPLa71 Submitted by: Richard B. BennettSubject: Review Test Procedure for Circuit Voltage Compatibility (2000) Abstract: A 500-volt insulation/isolation resistance test intended for
2、the propellant line heaters and tank heaters was mistakenly applied to all electrical connections in the Space Infrared Telescope Facility (SIRTF) propulsion subsystem, caused the failure of 6 pressure transducers.Test procedures should protect flight hardware by specifying all voltage limitations.
3、Before approving the test procedures, the cognizant subsystem engineer must perform a careful, detailed review both for functionality and to preclude injury to personnel or damage to the hardware. Description of Driving Event: An electrical test, performed at a contractor facility during acceptance
4、test of the Space Infrared Telescope Facility (SIRTF) propulsion subsystem, caused the failure of 6 pressure transducers. These transducers are used to sense the pressure in propellant lines. The incident occurred when a 500-volt insulation/isolation resistance test intended for the propellant line
5、heaters and tank heaters was mistakenly applied to all electrical connections in the subsystem. Applying 500 volts to the entire subsystem caused the transducer damage. The transducer circuitry should have been tested at a maximum of 50 volts. The test failure was traced to an error in the acceptanc
6、e test procedure (ATP). A careful, detailed review of the ATP by the lead propulsion engineer would likely have detected the circuit compatibility error. Additional Key Words: test induced failure, test error, over voltage, excess voltage, voltage ratingLesson(s) Learned: Provided by IHSNot for Resa
7、leNo reproduction or networking permitted without license from IHS-,-,-1. When preparing test procedures, protect flight hardware by specifying all voltage limitations.2. 3. Test procedures must be approved by the cognizant subsystem engineer. This approval indicates completion of a careful, detaile
8、d review both for functionality and to preclude injury to personnel or damage to the hardware.Recommendation(s): See Lesson(s) Learned. Evidence of Recurrence Control Effectiveness: Preventive Action Notice No. Z77630 was closed by JPL on May 7, 2003. The measures taken to implement Laboratory-wide
9、corrective action on the above recommendations were (1) modifying the JPL procedure “Develop Hardware Products, Rev. 5” (JPL DocID 57752) of 8/4/05 to place these recommendations in the JPL Cognizant Design Engineer training outline and (2) verifying the adequacy of a sample of current JPL test plan
10、s/procedures for specification of voltage limitations. Under this second action, the Rocker Deployment Actuator latch procedure (MER Project), the Static Load Testing procedure (MER Project), and the Assembly and Inspection Data Sheet (Planck Project) were found to be adequate.Documents Related to L
11、esson: N/AMission Directorate(s): a71 Aeronautics & Space Transportation Technologya71 Earth Sciencea71 Human Exploration & Development of Spacea71 Space ScienceAdditional Key Phrase(s): a71 Flight Equipmenta71 Ground Equipmenta71 Hardwarea71 Spacecrafta71 Test & Verificationa71 Test Articlea71 Test
12、 FacilityProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Additional Info: Approval Info: a71 Approval Date: 2002-10-10a71 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-,-,-
