Thermal design and verification of the large-temperature-difference space optical system

Abstract

The Wide-field Aurora Imaging Camera (WAIC) with a large-temperature-difference (LTD) optical system is to provide an opportunity to obtain the light intensity map of the aurora. And thus an appropriate thermal design for the compact LTD space optical system is necessary. Depending on the character of the optics, several optical components temperature indexes were achieved. The temperature level of the BaF2 filter should be high at 107–140 degree Celsius, but the best temperature of the mirrors is just at 20–40 degree Celsius. These present a challenging thermal control problem. We introduced thermal design for all optical components in details. Especially, the thermal design for the high temperature BaF2 filter took the great thermal resistance design approach to maintain the BaF2 filter within allowable temperature limits and minimize the influence on the temperature of the other optics. Subsequently, the camera finite element thermal model was established and the thermal test was also carried on. The results indicated that under the cold and hot extreme cases the filter average temperature could reach 106.5 degree Celsius and 139.0 degree Celsius, the control temperature precision was less than 2.5 degree Celsius and the temperature stability was less than 1.5 degree Celsius/2min. The temperature index of the mirrors and detector window also could be satisfied. Thermal design of the LTD space optical system with a large temperature difference is feasible and reasonable.