A heat switch for space cryocooler applications

A new passive cryogenic heat switch which is capable of thermally disconnecting a nonoperating cryocooler is considered. The design uses the principle of an amplified differential contraction between two dissimilar materials with metal-metal contact and a flexible coupling. An on resistance of 3.64 K/W and an off resistance of greater than 2000 K/W was measured. The switching temperature can be easily adjusted but was set up to be approximately 150 K for the 80 K coolers used in this study. Thermal vacuum and shaker vibration tests are presented.