REG NASA-LLIS-3760-2011 Lessons Learned - Space Shuttle Orbiter Interconnecting Hardware Test Configuration Verification and Status.pdf

1、Public Lessons Learned Entry: 3760 Lesson Info: Lesson Number: 3760 Lesson Date: 2010-09-13 Submitting Organization: KSC Submitted by: Annette Pitt Subject: Space Shuttle Orbiter Interconnecting Hardware Test Configuration Verification and Status Abstract: When processing a space vehicle for launch,

2、 the test team needs to know how the vehicles interconnecting hardware is configured just before a test begins. A cable disconnected in one system for troubleshooting can inadvertently affect another system one under test. This has happened multiple times over the life of the Shuttle Program. An onb

3、oard system that can rapidly and accurately determine the configuration of interconnecting hardware and is capable of including all electrical interconnections would provide the pretest visibility required by the test team. Description of Driving Event: For hazardous or critical operations, it is vi

4、tal to know if a systems electrical configuration is operational. For example, an actuator must have at least one channel of control when hydraulic power is applied. If no channels are connected, there is no control of the actuator. In one incident, the rudder/speedbrake (RSB) was powered up hydraul

5、ically when the command path connections were demated for troubleshooting not associated with actuator control itself. As a result, the power driver unit was damaged. Fortunately, the drive shafts for the RSB were disconnected, so no surface movement resulted. Unexpected engine or surface movement c

6、an damage critical flight hardware or injure workers. Lesson(s) Learned: When Orbiters were first being processed, the test team used the Connector Integrity Group (CIG) system to manually track the electrical wiring configuration. This CIG system also manually tracked the retest status of each pin

7、on every connector that was demated and remated. However, this manual tracking was labor-intensive, the resulting data contained errors, and the information was not available in real time. Over time, the CIG system evolved into the Shuttle Connector Analysis Network (SCAN), an electronic wire list d

8、atabase. With SCAN, the test engineer can determine the retest requirements before a connector is demated and verify the final connector configuration required for flight. However, SCAN cannot verify the configuration just before a hazardous test begins. Recommendation(s): Provide an onboard system

9、that can rapidly and accurately determine the configuration of interconnecting hardware before any hazardous test is begun. The Saturn V launch vehicle had the Remote Automatic Calibration System (RACS), which verified the operational path of all measurements on the Saturn V. RACS verified measureme

10、nt circuit operation and continuity by stimulating the transducer directly or by inserting a simulated transducer signal in the signal conditioner circuit. Measurement operation was verified at 80 percent of the maximum transducer range (high level), at 20 percent of the maximum range (low level), a

11、nd at the normal run level. A system similar to RACS but capable of including all electrical interconnections would provide the pretest visibility required by the test team. Evidence of Recurrence Control Effectiveness: N/A Documents Related to Lesson: N/A Mission Directorate(s): Space Operations Pr

12、ovided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Additional Key Phrase(s): Ground processing and manifesting Configuration Management Long term sustainability and maintenance planning Launch Systems Engineering design and project processes and standards

13、 Level II/III requirements definition Ground support systems Launch support systems Additional Info: Project: Space Shuttle Program Approval Info: Approval Date: 2011-03-04 Approval Name: mbell Approval Organization: HQ Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-