1、Lessons Learned Entry: 1521Lesson Info:a71 Lesson Number: 1521a71 Lesson Date: 2005-03-03a71 Submitting Organization: JPLa71 Submitted by: Grant Faris / David OberhettingerSubject: Uplink Command Errors (A Cornerstone Lesson), 2002 Abstract: A history of commanding anomalies experienced by the Mars
2、Global Surveyor, Stardust, Mars Odyssey, and Genesis missions prompted JPL to perform a comprehensive review of the command uplink process. Implementation of 9 recommendations has resulted in a decrease in the rate of command errors on subsequent JPL missions. The two most important recommendations
3、are to ensure that each command has a unique and clear identifier and to schedule periodic Flight Team training in command processes.Description of Driving Event: In-flight commanding errors- even when detected early- may trigger events that cannot be halted before a mission is irreversibly compromi
4、sed. A history of commanding anomalies experienced by the Mars Global Surveyor (10 command errors within 1009 command files radiated), Stardust (4 within 665), Mars Odyssey (22 within 2379), and Genesis (5 within 975) missions prompted JPL to perform a comprehensive review of the command uplink proc
5、ess. Although no anomalies proved critical to the success of these missions, the review found three distinct types of errors: 1. Directly related to real-time, on-console, processing of a command file for radiation via the Deep Space Network (Reference (1).2. Traceable to an uplink process that wasn
6、t followed correctly, or an error that should have been detected by the process (Reference (2).3. Where the uplink process was adhered to, but the command produced unexpected spacecraft or instrument behavior (Reference (3).The proximate causes of these command errors may be attributed to: Provided
7、by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1. Each newly assembled flight teams initial inexperience with the flight system.2. Inadequate review of command products to assure that all checks were performed.3. An incomplete command uplink process (e.g., m
8、issing procedural steps).The root causes of in-flight commanding errors include the erosion of Flight Team technical expertise upon the transition from completed projects to new missions, limitations in testbed capability and fidelity, and the tendency to short-cut established processes under schedu
9、le pressure. Following this 2002 review, a number of command uplink process improvements were implemented by the flight projects to prevent commanding errors. This resulted in a decrease in the rate of command errors on JPL missions. References:1. JPL Incident Surprise Anomaly (ISA) Nos. Z71855 (07/
10、09/01), Z72385 (10/15/01), Z71679 (05/31/01), Z71804 (06/20/01), Z72699 (11/08/01).2. JPL ISA Nos. Z71476 (04/26/01), Z71900 (07/20/01), Z72363 (10/08/01), Z72421 (10/19/01), Z71269 (03/27/01), Z72235 (09/13/01), Z71810 (06/20/01), Z72053 (08/16/01), Z72354 (10/05/01), Z72525 (10/28/01), Z73216 (12/
11、21/01), Z73247 (12/29/01), Z72062 (08/16/01).3. JPL ISA Nos. Z70999 (02/16/01), Z71572 (03/23/01), Z71817 (06/26/01), Z72046 (08/06/01), Z71947 (07/31/01), Z72166 (08/29/01), Z71323 (04/09/01), Z71529 (05/08/01), Z72587 (10/15/01), Z73207 (12/21/01), Z71543 (05/10/01), Z71547 (05/10/01), Z71690 (05/
12、30/01), Z71750 (06/12/01), Z71934 (07/26/01), Z71981 (08/08/01), Z72043 (08/13/01), Z72063 (08/16/01), Z72194 (08/31/01), Z72455 (10/25/01), Z72072 (08/20/01), Z72073 (08/17/01), Z73021 (12/06/01).4. Grant Faris, “MMO Command Anomaly Working Group Status Report (Draft),” February 15, 2002.5. “Operat
13、ion of Uplink Process,” Rev. 2, JPL Doc ID 27232, July 19, 2002.6. “Duplicate Transmission of Operational Command,” JPL Lessons Learned No. 7-122, January 26, 2004.7. “Take CM Measures to Control the Renaming and Reuse of Old Command Files,” JPL Lessons Learned No. 1481, July 13, 2004.8. “Early Invo
14、lvement of Mission Ops is a Key Success Factor,” JPL Lessons Learned No. 1415, November 1, 2004.Additional Key Words: mission operations, operations procedures, erroneous commanding, operations training, operations assurance, flight team anomalies, command failures Lesson(s) Learned: Should an uplin
15、k command error occur during a critical mission phase, it may cause the loss of an instrument or the spacecraft.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Recommendation(s): Reference (4) provides two major recommendations for preventing in-flig
16、ht spacecraft and instrument commanding errors: 1. Ensure that each command has a unique and clear identifier, and verify the indicated creation date and time. For example, the characters in the file name should all be the same case (upper or lower), and of a length that can easily be read over the
17、voice-net phonetically.2. Schedule periodic Flight Team training in command processes, including an overview of the uplink process, discussion of lessons learned, and identification of needed center-wide changes.It also recommends that the Mission Manager and staff: 3. Encourage deliberation in the
18、processing of commands, even if it slows the command uplink process.4. Minimize the use of real-time commanding in favor of incorporating the commands into sequences, where feasible.5. Verify, validate, and make maximum use of tools for uplink product generation and product review processing that au
19、tomate the command uplink process and help to reduce the likelihood of operator error.6. Tap experienced flight team personnel for critical events, activities new to the Flight Team, recovery from anomalies, and transitioning to a new mission phase.7. Utilize the full capabilities of the flight syst
20、em testbed; when in doubt, err on the side of too much testing of commands.8. Use the standard JPL command uplink process (Reference 5), and share command uplink lessons learned with other projects.9. Conduct monthly project-level reviews of command anomaliesEvidence of Recurrence Control Effectiven
21、ess: Preventive Action Notice No. Z87143 was opened by JPL on August 2, 2005 to initiate and document appropriate Laboratory-wide action on the above recommendations.Documents Related to Lesson: a71 Operation of Uplink Process, Rev. 2, JPL Doc ID 27232, July 19, 2002.a71 Provide Operation Services,
22、Rev. 0, JPL Doc ID 58013, July 11, 2002.Mission Directorate(s): Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a71 ScienceAdditional Key Phrase(s): a71 Communication Systemsa71 Flight Operationsa71 Ground Operationsa71 Information Technology/Systems
23、a71 Safety & Mission Assurancea71 Softwarea71 Spacecrafta71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 2005-04-14a71 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-,-,-
