Iterative two-layer thermal design strategy for step sandwich antenna of space solar power satellite using modified constrained multi-objective optimization

To utilize space solar energy efficiently, a concentrating-type space solar power satellite (SSPS) that can collect solar energy in space and transmit it to Earth through energy conversion and transmission is proposed. Given that the thermal subsystem is affected by high temperatures, which directly restricts its development, an iterative two-layer thermal design is proposed herein to optimize the step sandwich antenna (SSA) in the SSPS using a novel modified multi-objective optimization algorithm. To improve the feasibility of the SSPS, the thermal control coating requirements and structural configurations of the SSA are examined. The optimization of the SSA entails thermal analyses involving the conduction and radiation modes using thermophysical and structural parameters. The iterative two-layer thermal design of the SSA includes top-layer conceptual and bottom-layer precise designs. The coating requirement and structural configuration of the top-layer and the precise configuration and temperature uniformity of the bottom layer are improved iteratively to ensure global optimal solutions. Thus, the theoretical critical values of the optical properties of coatings are revealed using the proposed thermal design strategy. Furthermore, the solution set at the Pareto front is appraised, and the constrained multi-objective optimization algorithm is modified to obtain a more dispersed solution set. Finally, an actual SSA with the optimal design variables of the coatings and configurations is constructed using the two-layer strategy to achieve better heat dissipation with a mean temperature gradient of 7.22 °C/m and mass of approximately 2729 t; the effectiveness and feasibility of the design were also verified.