1、Lessons Learned Entry: 0978Lesson Info:a71 Lesson Number: 0978a71 Lesson Date: 2000-03-25a71 Submitting Organization: GSFCa71 Submitted by: Kevin GradySubject: End-to-End Testing Description of Driving Event: The successful early mission on-orbit space-to-ground communications between the Terra spac
2、ecraft and the EOS Control Center is a reaffirmation of the value of rigorous pre-launch end-to-end testing. The Terra mission has experienced virtually trouble-free space-to-ground communications from launch and ascent, through the present completion of instrument activation. This success is a dire
3、ct product of the mandate to perform rigorous end-to-end testing prior to launch.Lesson(s) Learned: The Terra development schedule had always planned to perform end-to-end testing between the spacecraft and the EOS control center as soon as the ground system was capable of such testing. The initial
4、test between the satellite and the ground system was in fact conducted while the spacecraft was in spacecraft-level thermal/vacuum test. The Terra housekeeping command and control links were exercised, just prior to completion of the Terra thermal/vacuum test. Due to unforeseen problems in the launc
5、h vehicle and the ground system, this initial test would prove to be almost two years before the launch of Terra.When the decision was made to change the implementation of the Terra ground system, due to the fact that a number of technical problems were not reaching resolution, the resolve to execut
6、e rigorous end-to-end testing became even more critical. A decision was made in the fall of 1998 to incorporate a new control center software package. The software was planned for completion in the spring, with the launch of Terra scheduled for the summer.Schedule pressures could have forced a lesse
7、r amount of allocated time for end-to-end testing, however the Project adopted the philosophy that no rigor be compromised, and a comprehensive test flow was adopted. Where early testing was possible with preliminary deliveries of the ground Provided by IHSNot for ResaleNo reproduction or networking
8、 permitted without license from IHS-,-,-software, the philosophy was to always regression test when a subsequent software delivery became available.The spacecraft and ground teams performed tremendously in spite of difficult and challenging circumstances. Both S-band and Ku-band tests were executed,
9、 using the NASA Compatibility Test Van (CTV) which had been shipped to the launch site for this very purpose. The early orbit mission activities were tested and retested, validating the hardware, software, and perhaps most importantly the people.The lesson learned from the success of Terras early co
10、mmunications success, is that there is no substitute for real life end-to-end testing. In Terras unique circumstances, it placed a tremendous demand on the spacecraft and ground systems personnel who had to complete the software development, launch preparations and end-to-end testing on a compressed
11、 schedule. All who were involved with Terra will agree that there should be no compromise when it comes to such critical tests between the flight and ground segments.Recommendation(s): The lesson learned from the success of Terras early communications success, is that there is no substitute for real
12、 life end-to-end testing. In Terras unique circumstances, it placed a tremendous demand on the spacecraft and ground systems personnel who had to complete the software development, launch preparations and end-to-end testing on a compressed schedule. All who were involved with Terra will agree that t
13、here should be no compromise when it comes to such critical tests between the flight and ground segments. No compromises should be made when it comes to pre-launch end-to-end testing.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): a71 ScienceA
14、dditional Key Phrase(s): a71 Test ArticleProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a71 Test Facilitya71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 2001-08-06a71 Approval Name: Eric Raynora71 Approval Organization: QSa71 Approval Phone Number: 202-358-4738Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
