A 10-20 K Cryocooler for Cooling Electro-Optical Payloads

ABSTRACT: Advanced space-borne infrared detectors require cooling in the 10 to 20 K temperature range. Cooling loads will be approximately 0.25 W to 1.0 W for the detectors, with additional loads at higher temperatures for other subsystems. A multistage cooler, capable of providing refrigeration at more than one temperature simultaneously, can provide the greatest system efficiency and lowest mass. Turbomachine-based Brayton cryocoolers are ideal candidates for these applications because they are highly efficient, lightweight, vibration-free, multistage compatible, and have long maintenance-free lifetimes. Creare has developed state-of-the-art components needed to create turbo-Brayton cryocoolers for these missions. During the current program, we propose to integrate these components to form a two-stage cryocooler that provides refrigeration in the 10 to 20 K temperature range. During the Phase I project, we obtained key operational and performance data for the cold-stage turboalternator. During the Phase II project, we plan to assemble a brassboard cryocooler, measure its performance at cold load temperatures as low as 10 K, and use the results to develop a preliminary design for a fully optimized cryocooler. BENEFIT: The successful completion of this program will demonstrate a two-stage turbo-Brayton cryocooler that operates in the 10-20 K temperature range. 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).