Development of a High Capacity 35 K Multistage Turbo-Brayton Cryocooler

We propose to develop an innovative high-capacity multistage cryocooler for dual cooling loads at temperatures of 85 K and 35 K. The cooler is based on proven turbo-Brayton technology that has been flight demonstrated and qualified for use on the Hubble Space Telescope. This technology will be adapted to the unique requirements of DOD infrared sensor applications at lower temperatures and at significantly increased cooling capacities. The proposed system will be capable of simultaneously providing 2 W of refrigeration at 35 K and 20 W at 85 K within a single integrated assembly. The unique characteristics of the turbo-Brayton cycle permit distributed cooling at multiple sites with a single, multistage configuration with very high thermodynamic efficiency, resulting in low input power and reduced mass. In Phase I, we developed a preliminary design of the cryocooler and its components, developed load curves and assessed the benefits of advanced developments. During Phase II, we propose to develop and demonstrate an advanced recuperator that will provide milestone reductions in cryocooler mass and power consumption. During Phase III, we will demonstrate a multistage 35 K/85 K turbo-Brayton cryocooler.