REG NASA-LLIS-0307--1993 Lessons Learned Anomalous AMPTE CCD Command Counter Readings.pdf

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1、Lessons Learned Entry: 0307Lesson Info:a71 Lesson Number: 0307a71 Lesson Date: 1993-09-20a71 Submitting Organization: JPLa71 Submitted by: R. F. CollinsSubject: Anomalous AMPTE/CCD Command Counter Readings Abstract: Five times during one month the “Unexecuted Command Counter” value was anomalous. Po

2、ssible causes included incorrect incrementing of the counter, incrementing due to noise, or commands that were rejected due to incorrect bit patterns. The telemetry formats should be designed considering all potential analyses that may require time-tagged data.Description of Driving Event: During a

3、one month period, the Active Magnetospheric Particle Tracer Explorer/Charge Composition Explorer Spacecraft experienced five occasions when the “Unexecuted Command Counter“ value was anomalous and no explanation could be found. Real-time and delayed commands had all been executed and correctly accou

4、nted for in the “Executed Command Counter“. These counters are only read out in the memory readout at the beginning and/or end of a pass and not in the normal real-time telemetry.Three possible causes of the anomaly are as follows:1. The counter incremented anomalously.2. The counter was incremented

5、 by noise or other stimuli.3. The system received commands from an unidentified source but rejected them for incorrect bit patterns.Additional Keyword(s): OperationsLesson(s) Learned: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Counter status is

6、more valuable if transmitted in real-time telemetry data which is time-tagged and permits the counter readings to be continuously correlated with command events.Recommendation(s): The telemetry formats should be designed considering all potential analyses that may require time-tagged data.Evidence o

7、f Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Flight Operationsa71 SpacecraftAdditional Info: Approval Info: a71 Approval Date: 1985-12-05a71 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-,-,-