REG NASA-LLIS-3056-2010 Lessons Learned - RMS Shoulder Brace Anomaly.pdf

1、Public Lessons Learned Entry: 3056Lesson Info:a71 Lesson Number: 3056 a71 Lesson Date: 2010-05-12 a71 Submitting Organization: KSC a71 Submitted by: Annette Pitt Subject: RMS Shoulder Brace Anomaly Abstract: During STS-119 ground processing, a functional test of the Remote Manipulator System (RMS) w

2、as performed in accordance with OMI V1175, RMS Turnaround Verification, to ensure that all RMS hardware was ready for flight. The RMS shoulder brace was cycled and left in the latched position for flight. The required visual inspection for quality verification was reported as nominal. During the on-

3、orbit checkout, the shoulder brace was released for operation. It was during this release that the crew reported a quicker than expected release (2 seconds instead of 5 to 8 seconds). Troubleshooting revealed that the requirements used to verify the shoulder brace latch prior to flight were not as a

4、ccurate as thought. Historically, console program VAB40 was used to provide the data for the shoulder pitch angle prior to latching the shoulder brace. The requirement for shoulder pitch angle was 0.0 0.1 degrees in order to latch. Troubleshooting revealed that the pitch angle must be 0.0 0.07 degre

5、es in order for the shoulder brace collet to engage. VAB40 only provided a resolution of one decimal place. Orbiter Display Page SPEC 169 provides a higher resolution of two decimal places and will be used for all future shoulder brace latch verifications. Lesson Learned: Ensure that the requirement

6、s can be supported by the actual testing and that the required resolution can be obtained from the specified data points. Description of Driving Event: During STS-119, MER-04 was initiated when the RMS shoulder brace release time was less than expected (2 seconds instead of 5 to 8 seconds for nomina

7、l release). An Interim Problem Report (IPR) was initiated to document the anomaly (128V-0003). STS-119 closeout photos were reviewed and verified that the plunger was not fully engaged in the collet. The collet is released after launch as specified by RMS checkout operations and is not reengaged unt

8、il the next turnaround flow. The shoulder brace is not required for on-orbit operations or landing. Lesson(s) Learned: A shoulder pitch angle of 0.0 0.1 degrees is necessary for the shoulder brace to latch. Historically, VAB40 console display has been used to verify this requirement. Troubleshooting

9、 revealed that if the shoulder pitch angle is more than 0.07 degrees, the collet will not engage the plate. Therefore, the RMS recommended action is to verify the shoulder pitch angle prior to latching the shoulder brace. The shoulder pitch angle must be 0.0 0.07 degrees, instead of the previously u

10、sed angle requirement of 0.1 degrees. Because of the lower resolution (one decimal place), VAB40 will no longer be used for this verification. Instead, RMS will use Orbiter Display Page SPEC 169 to verify joint angles because of the two-decimal-place resolution. Recommendation(s): In verification te

11、sting, ensure that the fidelity of the data points meets the requirements. Evidence of Recurrence Control Effectiveness: No problems have occurred with shoulder brace latching since implementation of new controls. Documents Related to Lesson: IPR 128V-0003 RMS Shoulder Brace Summary presentationClic

12、k here to download communication document. Mission Directorate(s): a71 Space Operations Additional Key Phrase(s): a71 1.Ground processing and manifesting a71 1.Engineering design and project processes and standards Additional Info: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a71 Project: Shuttle Program Approval Info: a71 Approval Date: 2010-08-25 a71 Approval Name: mbell a71 Approval Organization: HQ Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-