Environmental effects on surface covers and thermal control of satellites and designing ground-base tests in improving reliability of satellites operations

The out surface of any object that is placed on the outside of the atmosphere is under vacuum,meteorites and the full spectrum of solar radiation (including electromagnetic waves, charged particles,atoms and plasma). These inappropriate conditions can significantly alter the surface properties of thematerial. To determine the changes of properties of the orbit of the Earth, series of experiments based on statistical models are used. In addition, in space with no thermal transfer of air, the only way oftransferring heat is radiation. Therefore in selecting surface material of spacecrafts, satellites and their cover, the way and amount of reflection and absorption of solar radiation and their changes during mission should be determined exactly in order to achieve a proper balanced temperature. In order toverify the thermal design and ensuring successful operation in orbit, a satellite must be considered undera process of comprehensive thermal test. Thermal ground tests act as quality control screens in order to detect weaknesses in the design, failures and human errors during construction, starting downtime and other operational problems which are not easily recognized by conventional inspection techniques. In thispaper, the way of selection and test of surface materials of satellites and spacecrafts and improvement of thermo optics features are reviewed. Also generalities and different types of thermal-environmental tests are introduced and introduction of execution stages and processes of doing these test are performed. Finally, the results of thermal cycle tests are provided for a small satellite.

Keywords:

satellite operation , thermal control , ground tests , reliability , surface covers