This project is aimed at developing a cryocooler for space-borne, infrared astronomical telescopes which require 50 mW or less cooling at 1 to 2 K. It consists of a linear-drive, three-stage, split-Stirling cryocooler which will produce refrigeration at 8 K to cool a niobium-tin, alternating-current, superconducting magnet and a magnetic cold stage. During Phase I, the design of the refrigerator was studied to determine the size, weight and power input. Specific areas of innovation include: warm and cold, flexible, suspension means; a concentric, three-stage expander with clearance seals; a new, cold regenerator geometry; cold heat switches; and a conduction-cooled 8 K ac superconducting magnet.The design studies confirmed the feasibility of the refrigerator concept to achieve the desired goals in a practical design capable of achieving long life in space with low noise and vibration levels. Results of the analysis show the cold end to have a volume of about 6 liters and a weight of 22 kilograms while the compressor volume is about 20 liters and weight is 64 kilograms. Total system power input is about 720 watts. Weights and power include magnetic shielding but not power supply components.Potential Commercial Application:Applications are in cost effective refrigeration systems for cryo-pumps and cryo-electronic devices, including computers. With the magnetic cold stage, the refrigerator will offer a competitive way of liquefying helium (e.g., cooling magnets) and providing low temperatures for basic research.STATUS: Project Proceded to Phase II
