Multistage Cryocooler With Novel Expanders

"Long life cryocoolers are needed to cool doped silicon focal plane arrays to 10 Kelvin. Simultaneous cooling at several higher temperatures is also needed for optical and thermal components that support these focal planes. Development of a multi-stage10K cryocooler would greatly enhance the total cooling system's reliability and reduce its size, weight, and power consumption. The proposed cryocooler is based on the reverse-Brayton cycle with a major innovation.Redstone has discovered that there is an operating pressure range or a "sweet spot" that leads to an easier and quicker development path. This pressure range eases the requirements for the recuperative heat exchangers, making these smaller and lighter.The required compression ratio is modest, making compressor development easier also.The innovation enabling this cryocooler is a new cryogenic expander that works in the "sweet spot". This expander incorporates many features for long life and robustness against contamination. Redstone's preliminary mechanical and thermodynamic analysisshows that this expander is worthy of further development.This proposal focuses on the development of the 10K multistage cooler and the new expander. Redstone will do this development with assistance from our team member, Swales Aerospace. Supports Air Force, DOD and NASA efforts to develop 10K space cryocoolers. Supports long-wave infrared and hyper spectral imaging sensors. Multistage low