1、Lessons Learned Entry: 1415Lesson Info:a71 Lesson Number: 1415a71 Lesson Date: 2004-01-26a71 Submitting Organization: JPLa71 Submitted by: Carol DumainSubject: Duplicate Transmission of Operational Command (2002) Abstract: On two occasions during the ULYSSES mission, a mission controller erroneously
2、 performed a duplicate transmission of an operational command. The problem was traced to imprecise execution of existing command procedures. Four recommendations reinforce the mission operators charge to ensure that the correct command has been “loaded“ when it is “fired off“ to the spacecraft.Descr
3、iption of Driving Event: On two occasions during the ULYSSES mission, a mission controller erroneously performed a duplicate transmission of an operational command. Each incident resulted in storage of the duplicate commands aboard the spacecraft, overflow of a data buffer, and rejection of subseque
4、nt spacecraft operational instructions. Erasing the onboard instruction set and reloading the original instruction set restored operational commanding. The problem was determined to be imprecise execution of existing command procedures. Had it occurred during a more critical phase, this error could
5、have resulted in the loss of an instrument or the spacecraft.References:1. Jet Propulsion Laboratory Incident Surprise Anomaly (ISA) No. Z78791, “Mission Controller Procedural Command Error,” December 17, 2002.2. 3. Jet Propulsion Laboratory Incident Surprise Anomaly (ISA) No. Z80269, “Procedural Re
6、Transmission of Command,” April 17, 2003.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Additional Key Words: mission operations, operations procedures, erroneous commanding, operations training, operations assurance Lesson(s) Learned: It is the re
7、sponsibility of the mission operator to ensure that the correct command has been “loaded” when it is “fired off” to the spacecraft.Recommendation(s): 1. Assure that the projects established spacecraft operational commanding procedures are followed and that the correct command file is selected.2. 3.
8、To avoid procedural errors in transmitting commands to a spacecraft, review command sequences to ensure that the appropriate command is prepared for transmission prior to radiation.4. Periodic participation by command operators in review of spacecraft uplink procedures, command errors, and other spa
9、cecraft uplink issues is necessary.5. During commanding activities for key events, projects should review and mitigate the risk of command errors, which could lead to loss of mission.Evidence of Recurrence Control Effectiveness: Corrective Action Notice No. Z83896 was opened by JPL on May 11, 2004 t
10、o initiate and document appropriate Laboratory-wide corrective action on the above recommendations.Documents Related to Lesson: N/AMission Directorate(s): a71 Exploration Systemsa71 Aeronautics ResearchAdditional Key Phrase(s): a71 Communication Systemsa71 Configuration Managementa71 Flight Operatio
11、nsa71 Ground OperationsProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a71 Spacecrafta71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 2004-05-20a71 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-,-,-
