F. 2. 2 COLLECTOR REFLECTOR AND HEAT SHIELD For all tubes, this is a molybdenum cone with thickness 0. 002 cm and den- sity , extending back to the collector entrance: base radius 1.5 x collector radius; length = collector length. The actual shield may be more complex (reference 4-4, Addendum E), but this simple design gives a useful weight estimate. F.2.3 BODY RADIATOR This is a circular surface of pyrolytic graphite () backed by heat pipes to insure good conduction and near uniform temperature. The 250°C chosen allows for 50°C temperature rise between the radiator and the heat source. The radiator must ’’see past” the collector, and the view factors and are themselves functions of the area A. But it is assumed here for simplicity that . As before, the radiator weight is taken as one gram per square centimeter, a reasonable figure since the density of pyrolytic graphite is only 2. 2 g/cm . The heat figures of Tables E-l and E-2 (interpolated for 16 kW) then give the following radiator weights:
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