1、Lessons Learned Entry: 0157Lesson Info:a71 Lesson Number: 0157a71 Lesson Date: 1992-10-08a71 Submitting Organization: KSCa71 Submitted by: David PenningtonSubject: External Tank (ET) Vent Deceleration Unit. Description of Driving Event: The external tanks gaseous hydrogen vent arm provides for venti
2、ng of the LH2 tank, pneumatics, and electrical services to the ground umilical carrier. The deceleration unit has failed twice. These failures were caused by a low fluid level in the shock absorber. During one launch failure the QD was damaged and broke in half. Several hours after launch, the detan
3、king of the LH2 dewer tank was started and gaseous hydrogen vented out of the broken QD/pipe, instead of venting to the Pad-A burn pond as designated.Lesson(s) Learned: Low fluid level in the shock absorber could cause failure of the deceleration unit damaging the QD and result in a hydrogen fire.Re
4、commendation(s): Design a mechanism that will prevent the ET GH2 vent arm from rebounding back into an SRM.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AMission Direct
5、orate(s): a71 Space Operationsa71 Exploration SystemsAdditional Key Phrase(s): a71 Energetic Materials - Explosive/Propellant/Pyrotechnica71 Facilitiesa71 Ground Operationsa71 Ground EquipmentAdditional Info: Approval Info: a71 Approval Date: 1994-06-06a71 Approval Name: James G. Klinea71 Approval Organization: KSC/HEIa71 Approval Phone Number: 407-867-7614Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
