REG NASA-LLIS-0355--1994 Lessons Learned - Galileo Photopolarimeter Radiometer (PPR) Cover Damage During Assembly and Test.pdf

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1、Lessons Learned Entry: 0355Lesson Info:a71 Lesson Number: 0355a71 Lesson Date: 1994-12-12a71 Submitting Organization: JPLa71 Submitted by: R.F. CollinsSubject: Galileo Photopolarimeter Radiometer (PPR) Cover Damage During Assembly and Test Abstract: The Galileo Photopolarimeter Radiometer subsystem

2、cover was damaged on three separate occasions during assembly and test operations. Design all external areas of spacecraft flight hardware with consideration for assembly and handling operations: avoid sharp or pointed corners. Conduct physical surveys to identify hardware that is susceptible to han

3、dling damage.Description of Driving Event: The Galileo Photopolarimeter Radiometer (PPR) subsystem cover was damaged on three separate occasions during assembly and test operations. The PPR cover is very delicate and has sharp corners that make it vulnerable to snagging.The damage occurred during th

4、ermal blanket operations which required access to areas behind the PPR location and was caused by a technicians protective clothing snagging on the sharp edges of the PPR cover. After the first incident, when damage was relatively minor and easily repaired, the workers were cautioned to avoid this p

5、roblem. In the second incident, damage was serious and required rework. A protective guard was then built to protect the cover. The third incident happened after this protective guard had been removed to permit further thermal blanket fitting activity. All of the incidents occurred even though the w

6、ork was being performed by well trained, experienced and highly qualified technicians under the watchful eye of QA personnel. After the third incident, the mechanical assembly procedures were revised to require a second technician (buddy system) to continuously monitor and provide a shielding arm or

7、 hand to protect sensitive areas not observable by the technician doing the work.Additional Keyword(s): Hardware IntegrationProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Reference(s): PFRS # 45429, 45463, and 45482Lesson(s) Learned: When external a

8、reas of spacecraft flight hardware are not designed with regard for assembly and test operations, protective guards and other procedural safeguards can be inadequate to prevent damage to delicate hardware.Recommendation(s): 1. All external areas of spacecraft flight hardware should be designed with

9、consideration for assembly and handling operations. In particular, sharp or pointed corners, which could easily snag protective clothing should be avoided. This should be a topic for preliminary and critical design reviews at subsystem, instrument and system levels.2. Physical surveys should be cond

10、ucted early in the assembly operations to identify hardware that is susceptible to handling damage. Protective guards and other procedural safeguards should be developed early before damage occurs. In situations where these safeguards are not possible or adequate, a second technician (buddy system)

11、should be assigned to monitor and assist in the operation to provide another level of protection.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Industrial Operationsa71 Packaging Handling Storagea71 Spacecraft

12、Additional Info: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 1989-03-02a71 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-,-,-