The Navy requires affordable and robust cryogenic cooling solutions for use in High Temperature Superconducting (HTS) cable technology. Currently, gaseous helium is cooled by a cryocooler through a cryogenic heat exchanger and circulated using a helium circulation fan through a superconducting cable. While Stirling refrigerators are commonly used in the cryogenics industry, they do not scale well to large capacities and inherently exhibit significant vibration due to their piston-based operation. Therefore, Concepts NREC (CN) proposes to develop a reverse-Brayton cryocooler. Reverse-Brayton cryocoolers offer several unique advantages, such as high-capacity cooling at high efficiency, and long life without maintenance due to wear-free and vibration-free components. Indeed, reverse-Brayton cryocoolers are inherently high-capacity systems, and rely on turbomachinery with noncontact bearings, resulting in wear-free and vibration-free operation. During Phase I, CN will complete the design of the cryocooler system, including its key components: the compressor, the turbine and the recuperator. During the Phase I Option, CN will perform risk reduction activities in preparation for Phase II. During Phase II, CN will build and test the cryocooler.