1、Lessons Learned Entry: 0964Lesson Info:a71 Lesson Number: 0964a71 Lesson Date: 1995-05-15a71 Submitting Organization: MSFCa71 Submitted by: Billy Cole / RetiredSubject: Space Shuttle Main Engine (SSME): Dry Gaseous Purges Description of Driving Event: Prior to starting the engine, there is a period
2、of time referred to as the start preparation phase. At the beginning of this time period, the oxidizer side of the engine is purged with dry nitrogen to eliminate moisture and the fuel side is purged with dry helium to eliminate air as well as moisture. This prevents the formation of ice particles i
3、n the LOX system or air frozen by the hydrogen.Lesson(s) Learned: Dry gaseous purges in a start preparation phase will aid in obtaining a reliable start sequence.Recommendation(s): Use dry gaseous purges in a start preparation phase to aid in obtaining a reliable start sequence for high performance
4、liquid propellant rocket engines.Evidence of Recurrence Control Effectiveness: The 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 su
5、stain reliable performance in over 200 flight performances of individual engines.Documents Related to Lesson: N/AProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Mission Directorate(s): a71 Space Operationsa71 Exploration SystemsAdditional Key Phrase(
6、s): a71 Configuration Managementa71 Cryogenic Systemsa71 Ground Equipmenta71 Hardwarea71 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-,-,-
