microwave components. Components were made of graphite/epoxy and in all cases were found to meet criteria of temperature stability, reproducibility and reasonable cost. These components were tested for mechanical and electrical properties in a temperature range between 117 to 394° K (-250 to 250°F). Application to the MPTS would require cost-effective manufacture of composite components in significantly larger lengths, and tested in a much harsher environment: 50 to 600°K (-370 to 620° F). Manufacturing techniques for interfacing microwave conversion devices such as amplitrons and klystrons are required. Materials other than graphite could lead to a more cost-effective total system. One such material is Kevlar. This material has a tendency to degrade in the presence of UV radiation and coating methods to preclude this degradation would be required. 4.2.7.2 Desired Output • Manufacturing methods for long length composite material • Material tests at the temperature extremes • Radiation characteristic testing • Manufacture costs • Extent of UV degradation • Suitable protective coatings. 4.3 THERMAL SYSTEM 4.31 Maximum Temperature For a given microwave converter efficiency and antenna diameter, the power transmission capability of the MPTS is limited by the maximum permissible structural temperature. Potential payoffs for greater power transmission and wider selection of structural materials to choose from warrant studies for reducing the maximum temperature experienced by the structure. 4.3.1.1 Background The Gaussian waste heat distribution of the MPTS causes peak temperatures in the center of the antenna support structure that are 200''K hotter than the temperatures at the edges. If one material is to be used efficiently throughout the structure, all of the structure should be near the maximum working temperature of the material. This will maximize the transmission capability of the MPTS. Studies are required to evaluate
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