REG NASA-LLIS-0968-2001 Lessons Learned Avoid Test Program Reductions on Lower Cost Higher Risk Instrument Projects.pdf

1、Lessons Learned Entry: 0968Lesson Info:a71 Lesson Number: 0968a71 Lesson Date: 2001-05-31a71 Submitting Organization: JPLa71 Submitted by: Robert J. WilsonSubject: Avoid Test Program Reductions on Lower Cost/Higher Risk Instrument Projects Abstract: Project test deficiencies frequently occur in cost

2、/schedule driven flight instrument developments. Cost/schedule driven, high-risk instrument projects should plan for expanded test programs. Should engineering problems arise and reserves become depleted, consideration should be given to reductions in mission scope, instead of reductions in the test

3、 program. Allow time for retest after correcting problems discovered during testing.Description of Driving Event: Project test deficiencies frequently occur in cost/schedule driven flight instrument developments.1. Early cost estimates prepared when a missions science concept is first proposed are f

4、requently overly optimistic due to lack of full understanding of the science scope and instrument complexity. Budget constraints based upon these early cost estimates normally preclude any funding increases. The instrument project may then be forced to cope with unknown, understated, or perhaps unac

5、ceptable risk to comply with the funding cap. Under these conditions, the proposed mission assurance plan/funding is usually inadequate for the actual level of mission risk.2. Problems typical of complex instrument developments quickly deplete the minimal reserves accepted early in the project. Fail

6、ure to perform timely risk trade studies of reductions in mission scope versus early depletion of reserves renders contingency plans inadequate.3. The lack of additional budget, and schedule slips characteristic of complex instrument designs, result in the project having few or no options other than

7、 to shrink the overall test program (both functional and environmental). As a result, problems are frequently not discovered until systems integration - or even worse, after launch.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Additional Key Words:

8、 test planning, mission assurance program, tailoring, integration and test, ATLO, project reserves, risk managementLesson(s) Learned: Cost and schedule constraints affecting the delivery of science instruments may create pressure for a reduced testing program. In fact, the higher level of risk assoc

9、iated with cost-driven development projects may mandate a more rigorous testing program.Recommendation(s): 1. Cost/schedule driven, high-risk instrument projects should plan for expanded test programs.2. Should engineering problems arise and reserves become depleted, reduce the mission scope instead

10、 of the test program.3. Allow time for retest after correcting problems discovered during testing.Evidence of Recurrence Control Effectiveness: A JPL Corrective Action Notice may be assigned and practices modified as appropriate.Documents Related to Lesson: N/AMission Directorate(s): a71 ScienceAddi

11、tional Key Phrase(s): a71 Flight Equipmenta71 Hardwarea71 Payloadsa71 Policy & Planninga71 Risk Management/Assessmenta71 Safety & Mission Assurancea71 Test & VerificationAdditional Info: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 2001-07-23a71 Approval Name: Eric Raynora71 Approval Organization: QSa71 Approval Phone Number: 202-358-4738Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-