1、Lessons Learned Entry: 1520Lesson Info:a71 Lesson Number: 1520a71 Lesson Date: 2005-01-28a71 Submitting Organization: JPLa71 Submitted by: Philip KwanSubject: Check Testbed Health Before Beginning or Resuming Flight System Test (2003) Abstract: In a scenario that is most likely to occur on severely
2、time-constrained flight projects, system-level testing is interrupted and test time is lost because of unreported changes to the testbed configuration. Use walkthroughs, briefings, startup procedures, and reporting tools to ensure at the beginning of each work shift that test operators are apprised
3、of all changes to the system testbed configuration.Description of Driving Event: In a scenario that is most likely to occur on severely time-constrained flight projects, testing is interrupted and test time is lost because of unreported changes to the testbed configuration. During subsystem integrat
4、ion and test (I&T) of Mars Exploration Rover (MER), for example, a software test operator spent two hours at a keyboard preparing for a special MER flight software (FSW) test case. When the test began, the system crashed, and extensive troubleshooting disclosed that the test operator had been unawar
5、e that the previous shift had removed the Rover camera from the testbed. Other similar incidents might stem from a loose cable caused by an equipment swap. This problem is exacerbated for projects like MER where system development continues even while testing is underway in dual work shifts.JPL flig
6、ht system I&T programs typically implement the following steps to minimize lost test time: 1. A meeting is held at the beginning of each I&T shift to brief the incoming team on changes to the testbed configuration.2. A startup procedure, maintained for each testbed, is continually updated to reflect
7、 the current testbed configuration.3. An on-line reporting tool is used to capture the activities of each test shift, document hand-over instructions to the next shift, report changes to the testbed configuration, and provide Provided by IHSNot for ResaleNo reproduction or networking permitted witho
8、ut license from IHS-,-,-links to problem/failure reports generated during the shift.4. A spreadsheet reports the status of connectors and cables that have been mated or demated.A walkthrough of the testbed configuration prior to each work shift would likely have prevented the MER test errors. They w
9、ere not feasible for MER, though, because there were several hundred connectors in each testbed, and not all of them were visible to the operator.References: 1. System Test and Launch Operations (STLO) Guide Executive Summary, Rev. 2, JPL Doc ID 31335, September 18, 2000, Para. II E.2. Subsystem Int
10、egration and Test for PPS, C&DH, and GN&C Subsystems, Rev. 0, JPL Doc ID 65633, December 12, 2003, Paras. 5.11, 6.8. Additional Key Words: subsystem test, test configuration, test bed, test procedure, test plan, ATLO, assemble, test, and launch operations Lesson(s) Learned: When flight system testin
11、g is begun or resumed on projects under great time pressure, the test operator may be unaware of changes to the testbed configuration, resulting in delays to the test schedule and an increased risk of flight hardware damage.Recommendation(s): 1. Ensure that the four steps listed above in the “Descri
12、ption of Driving Event” are performed on all flight system I&T programs.2. On system testbeds where it is feasible, perform a walkthrough of the testbed configuration at the beginning of each I&T work shift. Evidence of Recurrence Control Effectiveness: Preventive Action Notice No. Z87144 was opened
13、 by JPL on August 2, 2005+C26.Documents Related to Lesson: JPL Flight Project Practices (Doc ID 58032), Paragraph 5.7.6: Spares, Testbeds, and Models, Feb 27, 2003.1Mission Directorate(s): Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a71 Explorati
14、on Systemsa71 Sciencea71 Space Operationsa71 Aeronautics ResearchAdditional Key Phrase(s): a71 Configuration Managementa71 Flight Equipmenta71 Ground Equipmenta71 Ground Operationsa71 Spacecrafta71 Test & Verificationa71 Test Articlea71 Test FacilityAdditional 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-,-,-
