1、Lessons Learned Entry: 0375Lesson Info:a71 Lesson Number: 0375a71 Lesson Date: 1995-01-25a71 Submitting Organization: JPLa71 Submitted by: Jim TaylorSubject: Telemetry Data Return and Telecom Link Margin Strategy Abstract: Viking adopted a simple single-number criterion for managing the risk in sele
2、cting “optimum” downlink science data rates, and used it consistently in sequence planning. Formal adoption by the project of a clear and consistent set of telecom link criteria is an effective strategy for risk management of varying telecom performance.Description of Driving Event: After several mo
3、nths of flight experience, the Viking project adopted a simple single-number criterion for managing the risk in selecting “optimum“ downlink science data rates in the face of varying telecom performance. The rule, developed with inputs from the Deep Space Network and the Telecommunications Systems S
4、ection, is to pick from the available set the highest rate that the downlink can support at that time, assuming the downlink is 32% (1 dB) less capable than the best estimate of performance. After a further period of validation, the project widely disseminated this rule and used it consistently in s
5、equence planning. The conclusions at the end of the project were (a) the chosen rule was right for an S-band downlink and the Viking science data, and (b) this approach provided a good balance between the total data received and the total data lost.Additional Keyword(s): Operations PlanningLesson(s)
6、 Learned: Formal adoption by the project of a clear and consistent set of telecom link criteria is an effective strategy for risk management of varying telecom performance.Recommendation(s): Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Each projec
7、t must thoughtfully establish its own criteria for using the project resource of telecom link performance, based on sufficient pre-launch and in-flight telecom link characterization. Desirable characteristics of a set of criteria include (a) being clear and without ambiguity, (b) having balance betw
8、een risk, complexity and consequence, and (c) providing a means to measure (compare) the predictions against actual performance. The project must formally authorize the selected criteria, ensure their consistent use among all elements of the project and formally communicate any changes required from
9、 further experience.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Communication Systemsa71 Policy & Planninga71 Risk Management/AssessmentAdditional Info: Approval Info: a71 Approval Date: 1986-11-20a71 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-,-,-
