1、Lessons Learned Entry: 1335Lesson Info:a71 Lesson Number: 1335a71 Lesson Date: 2003-03-31a71 Submitting Organization: JPLa71 Submitted by: P. Narvaez / D. OberhettingerSubject: Ensure Test Facilities Can Accommodate “Test-as-You-Fly“ (2002) Abstract: The Mars Exploration Rover UHF Transceiver failed
2、 to attain carrier lock in duplex mode during flight qualification testing. The cause was finally traced to RF reflections into the UHF receiver from the non-anechoic walls of the test chamber.Ensure that primary test facilities are capable of the full range of tests that the facility may reasonably
3、 be expected to support. Ensure that test facilities for duplex RF testing are equipped with appropriate ferrite anechoic cones. Description of Driving Event: Flight qualification testing of the Mars Exploration Rover 2 (MER 2) Ultra High Frequency (UHF) Transceiver in duplex mode, utilizing an air
4、link, failed to attain carrier lock in a JPL screen room. The duplex mode for MER 2 had been successfully tested earlier for EMI/EMC in the same screen room via a hardline link. This extra air link test was added as an afterthought in accordance with the test principle of “test-as-you-fly.“ Many sta
5、ff hours were spent trying to isolate the failure cause, which was finally traced to RF reflections into the UHF receiver from the non-anechoic walls of the test chamber. This failure mode was not seen during the 1990s test of the Pathfinder Rover because (1) Pathfinder used less output power than M
6、ER and (2) the Pathfinder Rover was small enough to fit into an existing test chamber lined with RF energy absorbing material. This problem of RF reflections would not occur during operations on Mars, but the incident illustrated the need for JPL to utilize an appropriate test chamber lined with fer
7、rite anechoic absorbing material. The incident was a test facility failure - not a system failure - and it did not damage flight hardware. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-References: Problem/Failure Report No. Z78182, Jet Propulsion L
8、aboratory, November 4, 2002. Additional Key Words: test-induced failure, radio frequency test, Radio Frequency Subsystem, communications, RF leakageLesson(s) Learned: N/ARecommendation(s): N/AEvidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/A
9、Additional Key Phrase(s): a71 Communication Systemsa71 Facilitiesa71 Ground Equipmenta71 Hardwarea71 Industrial Operationsa71 Payloadsa71 Policy & Planninga71 Test & Verificationa71 Test Articlea71 Test FacilityAdditional Info: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 2003-05-14a71 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-,-,-
