1、Lessons Learned Entry: 0965Lesson Info:a71 Lesson Number: 0965a71 Lesson Date: 1995-05-15a71 Submitting Organization: MSFCa71 Submitted by: Billy Cole / RetiredSubject: Space Shuttle Main Engine (SSME): Turbopump Bearing Lubrication Description of Driving Event: In the SSME, a small recirculation fl
2、ow is maintained by flowing the propellant through a bleed valve located at the main fuel valve to an overboard dump line or pumped back into the LH2 inlet. Recirculation flow of LOX is maintained by flowing LOX through a bleed valve located a the fuel preburner oxidizer valve to an overboard dump s
3、ystem. These recirculation flows have successfully eliminated gas pockets in the LH2 and LOX systems.Lesson(s) Learned: Recirculation flows of propellants can be used to pre-chill turbopumps to cryogenic temperatures and to eliminate gas pockets in the propellant feed system.Recommendation(s): Use r
4、ecirculation flows of propellants in liquid rocket engines to pre-chill turbopumps to cryogenic temperatures, which will eliminate gas pockets in the propellant feed system. Maintain these flows for an hour or more prior to attempting an engine start.Evidence of Recurrence Control Effectiveness: The
5、 Space Shuttle Main Engines have operated successfully in over 68 flights. Although many minor changes have been made to improve performance and reliability, this lesson learned or feature described has continued to sustain reliable performance in over 200 flight performances of individual engines.D
6、ocuments Related to Lesson: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AMission Directorate(s): a71 Space Operationsa71 Exploration SystemsAdditional Key Phrase(s): a71 Configuration Managementa71 Cryogenic Systemsa71 Ground Equipmenta71 Hardw
7、area71 Launch Vehiclea71 Parts Materials & Processesa71 Safety & Mission Assurancea71 Spacecrafta71 Test Articlea71 Test FacilityAdditional Info: Approval Info: a71 Approval Date: 2001-07-23a71 Approval Name: Eric Raynora71 Approval Organization: QSa71 Approval Phone Number: 202-358-4738Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
