1、Lessons Learned Entry: 0609Lesson Info:a71 Lesson Number: 0609a71 Lesson Date: 1999-01-14a71 Submitting Organization: JPLa71 Submitted by: W. Moore/D. OberhettingerSubject: Develop and Test the Launch Procedure Early (1997) Abstract: During the terminal countdown for the first attempted launch of Ca
2、ssini, spacecraft telemetry channels indicated a false alarm condition that delayed verification of spacecraft readiness for launch, and contributed to a delay on the first launch day. The anomaly was traced to erroneous telemetry documentation.Develop and release the launch procedure early enough f
3、or comprehensive testing prior to launch. Rigorously test and verify all telemetry channels and their alarms, and ensure documentation such as telemetry definitions is kept up to-date. Description of Driving Event: During the terminal countdown for the first attempted launch of Cassini, spacecraft t
4、elemetry channels indicated a false alarm condition that delayed verification of spacecraft readiness for launch, and contributed to a delay on the first launch day.In planning for Cassini launch activities, the RED-ALARM strategy was to set critical measurement alarms for telemetry values differing
5、 from those expected at liftoff. As expected, pre-launch conditioning generated a number of red alarms, most of which cleared as the spacecraft was brought to the final liftoff state. However, two red alarms did not clear, resulting in the false alarm conditions. This anomaly was traced to erroneous
6、 telemetry documentation: the SAFE/ARM logic states for the two channels whose alarms did not clear were found to be reversed in the data dictionary.The Cassini launch procedure was developed late in the Assemble, Test, and Launch Operations (ATLO) process, and alarm testing with correct parameters
7、was not done. Also, testing of these Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-particular alarms prior to actual launch was not possible at KSC due to safety considerations.The Mars Pathfinder (MPF) project developed their launch procedure earl
8、y, and subjected it to rigorous, multiple tests during their 18-month ATLO. In this case, additional testing had negligible cost and schedule impact since it was conducted in conjunction with other testing to gain operating hours.Additional Keyword(s): Launch Readiness Review, Operations Readiness R
9、eview, Configuration Management, Interface ControlReference(s):1. Cassini Spacecraft Assembly, Test, and Launch Operations (ATLO) Final Report, Volume I, JPL Document D-15701, May 15, 1998, page 151.2. JPL Problem/Failure Report No. Z44319, October 13, 1997.Lesson(s) Learned: All spacecraft related
10、launch operation procedures should be demonstrated multiple times prior to shipment.Recommendation(s): 1. Develop and release the launch procedure early enough for comprehensive testing prior to launch.2. Rigorously test and verify all telemetry channels, and their alarms, that will be used during l
11、aunch and flight.3. Ensure documentation such as telemetry definitions is kept up-to-date.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Addi
12、tional Key Phrase(s): a71 Configuration Managementa71 Launch Processa71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 1999-01-27a71 Approval Name: Carol Dumaina71 Approval Organization: 125-204a71 Approval Phone Number: 818-354-8242Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
