Evaluation of Thermal Characteristics of Thermal Expansion Actuator in a Vacuum

In the development of the recent scientific satellites, requirements of increases in size and improvements in shape accuracy of observation instruments have become more stringent. In order to satisfy those requirements, our research group has examined a pointing control mechanism utilizing artificial thermal expansion as a linear actuator. Our previous research indicated that the pointing control mechanism could satisfy a design requirement of the next generation scientific satellites under a certain orbital environment. It is desirable to conduct performance evaluation under various orbital environments to design a flight model. In order to do that, a detailed thermal mathematical model needs to be built. In this paper, estimated parameters in a thermal mathematical model were estimated by correlating numerical simulation with experiments obtained by thermal vacuum experiments. As a result, the temperature errors between the numerical simulation and the experiments were minimized when the thermal conductance of elastic hinges of the pointing control mechanism was lower than expected. This implies that the estimation of the thermal conductance of the elastic hinge needs to be carefully done.