1、Lessons Learned Entry: 1385Lesson Info:a71 Lesson Number: 1385a71 Lesson Date: 2003-12-05a71 Submitting Organization: MSFCa71 Submitted by: Lisa BonineSubject: Comet Nucleus Tour (CONTOUR) Mishap Investigation Abstract: The Comet Nucleus Tour, CONTOUR, was designed and built by Johns Hopkins Univers
2、ity with specialized support from NASA as a part of NASAs Discovery series of solar system exploration satellites. Launched on July 3, 2002, it was intended to encounter at least two comets to perform a variety of analyses on comet material. However, sometime after the solid rocket motor (SRM) inten
3、ded to move the satellite out of eccentric earth orbit was fired, the satellite was lost. Mission design did not allow for observation or telemetry coverage during SRM burn, so the mishap investigation board was unable to determine with certainty the cause of the failure. However, a major finding of
4、 the investigation was that telemetry or visual coverage of the satellite during SRM burn was, in fact, possible and may help prevent similar mishaps in the future.Description of Driving Event: The Comet Nucleus Tour, CONTOUR, was designed and built by Johns Hopkins University with specialized suppo
5、rt from NASA as a part of NASAs Discovery series of solar system exploration satellites. Launched on July 3, 2002, CONTOUR was intended to encounter at least two comets to perform a variety of analyses on comet material. However, sometime after the solid rocket motor (SRM) intended to move the satel
6、lite out of eccentric earth orbit was fired, the satellite was lost. Mission design did not allow for observation or telemetry coverage during SRM burn, so the mishap investigation board was unable to determine with certainty the cause of the failure. However, a number of possible root causes were d
7、ocumented, along with recommendations for corrective actions. The following probable proximate cause was identified: a71 Overheating of the spacecraft by SRM exhaust plumeProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-The following alternate proxima
8、te causes were identified: a71 Catastrophic failure of SRMa71 Collision of spacecraft with debris or meteoroidsa71 Loss of dynamic control of spacecraftLesson(s) Learned: I. A major lesson learned was that all spacecraft should retain telemetry or visual contact during critical phases of the mission
9、. II. The team felt the mishap may have been driven by certain practices that the team described as more typical of small projects managed by contractor Principal Investigators. These practices include: II-1. Reliance of CONTOUR project on analysis by similarity Although flight history of a selected
10、 component is one aspect of acceptance by similarity, it is important to consider whether the application is consistent and within the bounds of previous qualification. II-2. Inadequate systems engineering process and specification of requirements The board cited the fact that few requirements were
11、imposed by NASA regarding the way contractors document or performed work on CONTOUR, creating opportunities for contractors to adopt nonstandard engineering practices. II-3. Inadequate review functions The board felt that inadequate oversight was especially dangerous in combination with nonstandard
12、engineering practices. Other observations noted by the team were the lack of telemetry/observation of spacecraft during a critical mission event, a tendency to rely on subcontractors without appropriate insight/oversight, the use of analytic models that were not specific to CONTOUR, a limited unders
13、tanding of SRM plume heating environments in space, the lack of an orbital debris conjunction plan, and a limited understanding of SRM operating conditions. These are covered in detail in the “CONTOUR Mishap Investigation Board Report.” Recommendation(s): I. Always maintain telemetry or visual conta
14、ct with spacecraft during critical phases of the mission. II-1. Projects should conduct inheritance reviews (i.e. analyses by similarity) early in the project life cycle and should assure that the analysis properly evaluates the inherited items capabilities and prior use against all mission critical
15、 requirements. II-2. Projects should establish clear and appropriate requirements for performing and documenting engineering work. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-III-3. Projects should establish mechanisms for increased NASA oversigh
16、t for projects led by principal investigators. Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: NPG 7120.5Mission Directorate(s): a71 Exploration Systemsa71 Sciencea71 Space Operationsa71 Aeronautics ResearchAdditional Key Phrase(s): a71 Accident Investigationa71 Adminis
17、tration/Organizationa71 Configuration Managementa71 Flight Operationsa71 Hardwarea71 Independent Verification and Validationa71 Mishap Reportinga71 NASA Standardsa71 Policy & Planninga71 Program and Project Managementa71 Research & Developmenta71 Risk Management/Assessmenta71 Safety & Mission Assura
18、ncea71 Spacecrafta71 Standarda71 Test & VerificationAdditional Info: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 2004-02-09a71 Approval Name: Lisa Boninea71 Approval Organization: MSFCa71 Approval Phone Number: 256-544-2544Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
