Update on development of the Space Shuttle main engine /as of 5 May 1977/

The development and testing of the Space Shuttle main engine are described. The preburners, main injector, main combustion chamber, and 35:1 expansion ratio test nozzle were successfully run at full power level (109 percent of rated power level). Integral combustion stability aids damped induced instability oscillations within 6 milliseconds. Three significant turbomachinery problems were identified and solved during the past year. These problems involved high-pressure fuel turbopump subsynchronous whirl, severe overheating of the turbine bearing and components and, in the high-pressure oxidizer turbopump, burning that first occurred in the drain cavity downstream of the primary oxidizer seal.