Solar Radiation on a Catenary Collector M. CRUTCHIK? AND J. APPELBAUM^ Summary A tent-shaped structure with a flexible photovoltaic blanket acting as a catenary collector is presented. The shadow cast by one side of the collector on the other side producing a self shading effect is analyzed. The direct beam, the diffuse and the albedo radiation on the collector are determined. An example is given for the insolation on the collector operating on the martian surface for the location of Viking Lander 1 (VL1). Introduction Missions to the lunar or martian surface will require electric power. A power supply that requires little installation time, being light weight and stowable in a small volume can be accomplished by a photovoltaic (PV) array. A tent-shaped structure with a flexible PV blanket for solar power generation is proposed in [1], Fig.l. The array is designed with a self-deploying mechanism using pressurized gas expansion. The structural design for the array uses a combination of cables, beams and columns to support and deploy the PV blanket. The shape of the PV blanket is determined by an optimization between reduction in the cable tension and increase in blanket area. Under the force of gravity a cable carrying a uniformly distributed load will take the shape of a catenary curve, fc(y), with respect to the y- z plane, Fig. 2. The catenary constant k can be determined using the condition fc(O) = H and solving iteratively. However, when the blanket is fairly taut, the load may be assumed uniformly distributed along the y-axis and the catenary curve may be approximated by a parabola [2], i.e., 1 t Faculity of Engineering, Tel-Aviv University 69978, Israel 2tt National Aeronautics and Space Administration, Lewis Research Center, Cleveland, OH 44135. Current address: Tel-Aviv University, Faculty of Engineering, Tel-Aviv 69978, Israel. This work was done while the author was a National Research Council — NASA Research Associate at NASA Lewis Reseaech Center. Work funded under NASA Grant NAGW — 2022.
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