ABSTRACT Optimization is now an established tool for obtaining better solutions in engineering design. Nevertheless, the multiplicity of possible applications and the continuing search for better computational performance has motivated researchers in continuing to propose new methods, as well as improvements on existing ones. Not only optimization has allowed a better exploration of the design space, it also can significantly reduce the time of the design process. In this paper the advantages of using a fully multiobjective and multicase approach for the design of space radiators is presented. The optimization of Amazonia-1 satellite batteries panel thermal design is investigated. Instead of conventional space radiators, in this work an innovative solution considering the fin as heat absorber is analyzed. The results have shown that there are several viable configurations regarding to fin coating material, heater power consumption and additional mass, and the choice of the appropriate radiator configuration shall be evaluated based on system impact. The possibility of testing automatically different coatings and sizes for the fin, allowed by the optimization approach, increased significantly the probability of finding viable solutions on the design space.

ABSTRACT: The optical solar reflector is basically a mirror of second surface with low absorptivity/emissivity ratio and negligible degradation in the space environment, which makes it an excellent coating for thermal control of satellites. It works as a radiator and is used in particular parts of the external surfaces of the satellites in order to reject the undesirable heat to the deep space. In the Brazilian Space Programs, the radiators of the satellites are generally painted with special white paints in order to reject heat instead of the use of optical solar reflector. The problem of white-ink radiators is the high degradation of the thermo-optical properties that happen over the useful lives. Thus, a process of manufacturing and assembly of optical solar reflector was developed in Brazil. To validate this process in terms of mechanical and thermal properties, 3 types of optical solar reflector radiators were manufactured, and their absorptivity and emissivity properties at the temperature of 23 ºC were measured. Optical solar reflector coupons were mounted on aluminum plates to perform vibration, thermal vacuum and thermal-shock tests. A study was also done to optimize the thickness of the glue to fix the structure of the satellite on the optical solar reflector. It showed an excellent environmental stability and maintained its thermo-optical characteristics after the tests.

ABSTRACT: Amazonia-1 is a Brazilian remote sensing satellite providing mainly images, in order to observe and monitor deforestation, especially in the Amazon region. This paper describes the thermal control design, which uses passive and active concepts. The active thermal control is based on heaters regulated by software via thermistors. The passive thermal control consists of multi-layer insulation blankets and radiators, paints, surface finishes to maintain temperature level of the overall carrier components within an acceptable value. The thermal control design is supported by thermal analysis using thermal mathematical model. The temperatures and heater power are predicted for critical cases.