Advances in Thermal Control Technologies for Small Satellite Systems

The miniaturization of cryogenic components plays a significant role in the never ending quest for "smaller, better, faster, cheaper" satellite systems. My advisor and I are developing three separate applicable technologies for the thermal control of small satellite systems. The first of these technologies is called FiST (Fiber Support Technology). FiST serves to thermally isolate and mechanically support cryogenically cooled components from their warm surroundings by utilizing high performance fibers in tension. Use of this technique on a preliminary breadboard model for the SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) cooled focal plane assembly reduced conduction parasitic heat loads through the support structure by two orders of magnitude from nearly 90 mW to less than 1 mW. The mechanical stiffness of the system has been dramatically enhanced by increasing the first natural resonant frequency of the system from 50 Hz to 700 Hz. The second of these technologies is the development of a solderless flexible thermal link. Thermal links play a vital role in the thermal management of space based cryogenically cooled instruments by connecting the cold heat sink with a cooled component. Using the "swaging" process, we have developed a fast, simple, and cost effective method for providing a low thermal impedance, highly flexible thermal link. With this process, a link has been developed that has a thermal resistance of 1.8 K/W over a 4.5" length and weighs only 63 grams. The flexibility of this link is such that a 7 mm deflection in any axis will result in no more than a 2 N load on the opposite end. The third area of advancement in thermal control which we are studying is controlling the reject temperature of cryogenic mechanical refrigerators. By maintaining a stable, lower reject temperature the efficiency of these mechanical refrigerators is greatly enhanced which results in lower power consumption and/or greater cooling capacity for the cooled satellite systems. The weight and power savings make this approach an important part of small satellite thermal control. This paper briefly describes the basic concepts behind these thermal control technologies and their potential benefits to small satellite systems.