WEAPON SYSTEM 107A-1. MARK 3 ADVANCED REENTRY VEHICLE PROGRAM. SOLAR THERMAL ENERGY

The following results and conclusions were obtained from this study Vacuum thermionic converters were developed that yielded 1.15 watts per square centimeter for an electrode spacing of 0.0002 inch at 1100C. Operating life of 30 hours was obtained at an output of 0.35 watt per square centimeter. Thus, the program accomplished a large part of the objective to improve thermionic converter performance. Further improvements are still needed in operating life and here the major problem is one of materials. An analytical investigation of a solar thermionic power system resulted in a preliminary conceptual design. Optical and thermal analyses were made, and these provided design optimization data for a solar power system. A preliminary solar thermionic test system was operated during the study. The maximum power level obtained was 0.56 watt at 1.4 amperes. Maximum open-circuit voltage was 0.983 volt. A control network in this experimental system was improved to provide a capability for maintaining an accuracy of 0.1 degree after the collecter had been locked on the sun. Temperatures taken in an artificial blackbody absorber operating in air during this test indicate good agreement with the analytical study. Author