LAUSR

Abstract The space 2 K cryogenic technology is one of the key supporting technologies for deep-space exploration. Superfluid helium cryostats were used to obtain the temperature below 2 K in early space missions. However, superfluid helium cryostats have been gradually replaced by space 2 K mechanical cryocoolers to reduce the weight of satellites and extend the lifetime of detectors. Recently, a space hybrid 4He Joule-Thomson (JT) cryocooler operating at about 2 K is developed by our laboratory, which has a compact structure. The JT cycle, precooled by a two-stage thermally coupled pulse tube cryocooler (PTC), is driven by an efficient four-stage JT compression system. All the compressors used to drive the JT cycle and PTC in this hybrid JT cryocooler are designed for future space applications. This hybrid JT cryocooler reaches a minimum no-load temperature of 2.17 K and achieves the cooling capacity of 4.0 mW at 2.39 K.