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.

空间2K低温技术是深空探测的关键支撑技术之一。在早期的太空任务中，超流体氦低温恒温器用于获得低于 2 K 的温度。然而，超流氦低温恒温器已逐渐被太空2K机械低温冷却器所取代，以减轻卫星重量并延长探测器的使用寿命。近日，一款太空混合动力车⁴工作温度约为 2 K 的焦耳-汤姆逊 (JT) 低温冷却器是我们实验室开发的，结构紧凑。JT 循环由两级热耦合脉冲管低温冷却器 (PTC) 预冷，由高效的四级 JT 压缩系统驱动。该混合型 JT 低温冷却器中用于驱动 JT 循环和 PTC 的所有压缩机都是为未来的空间应用而设计的。这种混合型 JT 低温冷却器的最低空载温度为 2.17 K，并在 2.39 K 时实现了 4.0 mW 的冷却能力。