Development Of A Small-Scale Collins-Type 10 K Cryocooler For Space Applications

Future spacecraft cooling and sensing systems will require advanced multi-stage cryocoolers capable of providing continuous cooling at multiple temperature levels ranging from 10K to 95K. A multi-stage 10K cryocooler is under development that applies microelectronic sophistication to achieve high efficiency in a reliable, compact design. The cryocooler is based upon a novel modification of the Collins cycle, a cycle commonly used in many high-efficiency terrestrial cryogenic machines. Innovations of the design include floating piston expanders and electromagnetic smart valves, which eliminate the need for mechanical linkages and thereby reduce the input power, size, and weight of the cryocooler in an affordable modular design. The floating piston expander and smart valves have been successfully developed in room temperature experiments using a series of proof-of-concept component prototypes. These experiments enabled the development of a sophisticated LabView based control algorithm. In parallel to this effort, a manufacturing method was developed to enable production of very long continuous lengths of small bore finned tubing. This tubing is used in the highly effective recuperative heat exchanger associated with each stage of the cryocooler. A three stage engineering prototype has been designed that integrates the floating piston expander and recuperative heat exchanger as a functional cryocooler. The engineering prototype has been assembled and is currently undergoing development testing. This paper will present the results of the room temperature component development testing, the design of the engineering prototype, the results of initial engineering prototype development testing, and the direction of future development.