LONG LIFETIME, SPACEBORNE, CLOSED-CYCLE CRYOCOOLER

THIS PROJECT INVESTIGATES A CONCEPT FOR A CONTINUOUS REFRIGERATOR FOR OPERATION IN ZERO-GRAVITY WHILE COOLING SENSORS TO A TEMPERATURE DOWN TO 0.3 KELVIN. NO CAPABILITY SUCH AS THIS CURRENTLY EXISTS. THE CONCEPT ASSUMES A SUPERFLUID HELIUM DEWAR (1.5 KELVIN) AS THE HIGH-TEMPERATUREHEAT SINK. A SUPERFLUID HELIUM-4 STAGE, CALLED A "VORTEX" REFRIGERATOR, SERVES AS AN INTERMEDIATE COOLING SYSTEM TO INCREASE THE EFFICIENCY OF THE FINAL HELIUM-3 STAGE. THE DESIGN OF THE DEVICE WILL BE COMPATIBLE WITH EXISTING SUPER FLUID HELIUM SPACE DEWARS TO ALLOW FLIGHT TESTING TO BE DONEAT MINIMUM COST. THE UNIT WILL MEET ALL SHUTTLE SAFETY REQUIREMENTS, HAVE LOW POWER DISSIPATION, AND BE VIBRATION FREE.