Development of the Thermal Control System for the RadMap Telescope Experiment on the International Space Station

The RadMap Telescope (RMT) is a radiation-measuring device to operate inside the International Space Station (ISS) to provide data about the radiation environment in low Earth orbit (LEO). Due to crew safety considerations, a maximum touch temperature of 45°C is required for all experiments on board the ISS. This paper presents the development of the thermal control concept of the RMT. The thermal design is based on a convective model evaluated without CFD methods. The convective heat transfer is calculated using simple geometries and analytical equations for calculating the airflow. A forced-convection model is used to calculate the local convection heat-transfer coefficients. Lacking CFD analyses, the development process of the thermal control design was supported with a one-channel bread board analysis to verify the simplified methods. The bread board was thermally analyzed and tested allowing for a validation of the applied methods. Based on the generated results the complete thermal control design of the RMT was developed, including the convective channel layout and the selection of the installed fans. The resulting thermal control system is based on five flow channels that are integrated into the design of the experiment and are operated with two or four separately controlled fans. The heat dissipating components are mounted directly onto the walls of the flow channels. Using ESATAN, a thermal simulation of the developed design was set up to simulate the complete RMT model. The simulation was correlated after a full thermal test using a structural thermal model (STM) to reduce the deviations of the analytical calculations and verify the ESATAN model. This paper shall demonstrate the bread board and final thermal design analyses, test results and model correlations, providing a verified thermal design for the RadMap Telescope.