A Hybrid Thermal Management System for Space Electro-Optical Payloads

ABSTRACT: Advanced space-borne electro-optical payloads require cooling at temperatures of 10 to 20 K. Cooling loads for these detectors will range from 0.25 W to 1.0 W at the primary load site, with additional loads at higher temperatures. During this program, we propose to build and test a multi-stage hybrid cryocooler that is optimized for cooling at a primary load temperature of 10 to 20 K. The hybrid cryocooler will optimally combine the strengths of multiple cryocooler technologies. Performance predictions indicate that our hybrid cryocooler concept will result in a 200% improvement in efficiency over the current state of-the-practice unit which will allow landmark reductions in payload mass. In addition to high efficiency, the system will be lightweight and extremely reliable, and will produce negligible vibration at the coldheads, provide remote and distributed cooling at each stage, and be broadly applicable to cooling temperatures from 10 K to 100 K. During Phase I, we optimized the cryocooler design for a particular mission class. We used existing test data and analytical models to predict the performance of both a flight cryocooler and a brassboard unit which will be tested during the Phase II project. On the Phase II project, we will test the hybrid cryocooler at cold end temperatures as low as 10 K. BENEFIT: The successful completion of this program will result in the demonstration of an extremely efficient low temperature cryocooler. This type of cryocooler is ideal for cooling applications in space-based surveillance and missile defense systems. Government-funded scientific applications include space-based infrared telescopes. Commercial applications include communication satellites, superconducting instruments, hypercomputers, and Superconducting Quantum Interference Devices (SQUIDs).