Innovative Stirling-Cycle Cryocooler for Long Term In-Space Storage of Cryogenic Liquid Propellants

Under this Phase II SBIR project we will build and test a stirling-cycle cryocooler and coolant circulating subsystem for use with broad area cooling (BAC) systems to deliver reduced or zero boil-off propellant storage. We will also refine the design of an innovative linear-reciprocating cold-circulator that resides at the same temperature as the BAC coolant, although we will not have the resources to build this component in Phase II. Compared to conventional reverse turbo-brayton cycle cooling technology our stirling-cycle technology offers higher cooling efficiency and requires no bulky recuperator component. Our double-acting stirling cycle configuration combines a linear motor with a moving piston/regenerator assembly into a self-contained module. A number of such modules can be connected together into several possible cryocooler layouts to scale heat lift capacity, achieve system redundancy and provide flexible integration with the BAC coolant loop. This modular approach provides the system designer with packaging options not available with conventional stirling cryocoolers.