HE-4 REFRIGERATOR FOR SPACE

A compact, self-contained He-4 refrigerator suitable for use in space has been developed. The refrigerator is recyclable, has no moving parts, and requires only electrical connections for heaters and thermometers to operate from a T less-than-or-equal-to 4.2 K cold stage. It consists of a sorption pump filled with charcoal and an evaporator filled with lightweight silicose sponge to contain the liquid He-4 in zero-gravity. Gas-gap heat switches attached to the pump and to the evaporator allow the refrigerator to be cycled in any orientation and to be operated in zero-gravity. The refrigerator has an operating temperature of 1.10 K and a cooling capacity of 6.5J when operated from a 4.2 K cold stage, and an operating temperature of 0.96K and a cooling capacity of 13J when operated from a 2 K cold stage. The refrigerator has been vibration tested and has been successfully used in a sounding rocket experiment.