REG NASA-LLIS-0989-2001 Lessons Learned ETU Laser Diode Pump Array Failure - Indium gasket short between contacts caused electrical failure.pdf

1、Lessons Learned Entry: 0989Lesson Info:a71 Lesson Number: 0989a71 Lesson Date: 2001-10-02a71 Submitting Organization: GSFCa71 Submitted by: Ron KoleckiSubject: ETU Laser Diode Pump Array Failure - Indium gasket short between contacts caused electrical failure Description of Driving Event: The ETU La

2、ser for GLAS started showing signs of failing to lase. Initial failure investigations pointed to the laser Oscillator Diode. A detailed investigation disclosed that the cause of the short was an indium bridge within a screw hole in the pump array. In the diode pump array, the manufacturer uses a thi

3、n indium gasket to assure good thermal conductivity from the diode bar to the diode bar mount. The assembly torque used on the screws of this diode and the repeated assembly and disassembly of this particular diode stack caused the indium gasket to bridge/creep (smear across) the insulator. Basicall

4、y, there were insufficient clearances around the holes in the indium gasket to allow proper alignment of the gasket to hole interface given that the indium will flow under pressure. Lesson(s) Learned: N/ARecommendation(s): N/AEvidence of Recurrence Control Effectiveness: As this was an ETU, controls

5、 were put into place to prevent recurrence. To date, no flight hardware has been affected by this issue.Documents Related to Lesson: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AMission Directorate(s): a71 Exploration Systemsa71 Aeronautics Res

6、earchAdditional Key Phrase(s): a71 Configuration Managementa71 Flight Equipmenta71 Hardwarea71 Parts Materials & Processesa71 Risk Management/Assessmenta71 Safety & Mission Assurancea71 Spacecrafta71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 2001-10-15a71 Approval Name: Jay Liebowitza71 Approval Organization: GSFCa71 Approval Phone Number: 301-286-4467Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-