1、Public Lessons Learned Entry: 2956Lesson Info:a71 Lesson Number: 2956 a71 Lesson Date: 2010-04-25 a71 Submitting Organization: KSC a71 Submitted by: Annette Pitt Subject: Local Design vs. COTS Implementation Abstract: Instead of using commercial off-the-shelf (COTS) equipment to replace the ground i
2、nstrumentation data acquisition system (Permanent Measurement System PMS), NASA and its contractor designed the Ground Measurement System (GMS) in-house. As the result of a technology transfer effort, GMS was manufactured by a commercial vendor. The design of GMS was still undergoing changes during
3、its implementation at the pad. Several components of the system never became fully operational. These complications eventually led the Ground Instrumentation department to replace GMS with a COTS implementation (GMS2/CDAS). Description of Driving Event: After years of use and improvements, to both t
4、he hardware and the related departmental internal processes (testing, repair, and certification), PMS had matured, realizing a high degree of reliability. The main reason to replace PMS with GMS was to eliminate its limited resolution and minor susceptibility to ground-induced noise. The new GMS des
5、ign also opened the potential for a shared technology initiative to work with private industry. Lesson(s) Learned: It would have been beneficial to capture the end-users requirements prior to the design phase. GMS encountered several roadblocks and the need for major design changes during attempts t
6、o implement the system. One component of the system, which required many work hours of troubleshooting, never attained full functionality. In addition, one of the advertised benefits of GMS was the ability to locate the signal conditioning and amplifier circuitry near the transducer or measurement d
7、evice, but this scheme was also fraught with problems and proved extremely hard to implement in the launch environment. Another weakness observed was the lack of continuing support. In this case, designers were involved in several projects and had limited resources available to assist after the syst
8、em had been turned over to the end user. This problem could have been avoided by using a COTS system. Recommendation(s): A COTS implementation would have been a better solution for a data acquisition and instrumentation replacement project. With a mature system in place and operating reliably, there
9、 was plenty of time to evaluate needs and requirements with the user. The need for a new system was not urgent. Data acquisition and instrumentation manufacturers are generally focused on their product, are dedicated to continual improvement, have resources available to support design changes, and p
10、romptly respond to system problems. The use of COTS when possible can lead to a better, more mature design that has been extensively tested and comes with available technical support. Evidence of Recurrence Control Effectiveness: N/A Documents Related to Lesson: N/A Mission Directorate(s): a71 Space
11、 Operations Additional Key Phrase(s): a71 1.Ground Operations a71 1.Acquisition / procurement strategy and planning a71 1.Business processes a71 0.Crew operations and support concepts a71 1.Engineering design and project processes and standards a71 1.Long term sustainability and maintenance planning
12、 a71 0.Entry Systems Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a71 1.Ground Equipment a71 1.Ground support systems a71 1.Test & Verification Additional Info: a71 Project: Shuttle Ground Instrumentation Systems Approval Info: a71 Approval Date: 2010-08-09 a71 Approval Name: mbell a71 Approval Organization: HQ Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
