The trade-offs that must be considered when selecting a cryocooler for infrared detector cooling are complex. When split-
Stirling cryocoolers are used, the designer can select the expander separately from the compressor. However, there will be performance implications. Larger systems provide benefits in terms of performance margin and operating lifetime, but may not meet size and mass goals. Larger cryocoolers tend to generate more heat, albeit over a larger surface area, and generate higher vibration forces. The expander coldfinger must be stiff enough to achieve image plane motion requirements. The transfer tube should be as short and with as few bends as possible, while the path available for the transfer tube may be affected by the geometry of the expander and compressor. Several characteristics of tactical cryocoolers are considered in this paper in such a way that trends can be identified and design choices can be clarified. A step-by-step approach is recommended that will lead to a design solution in the most direct manner. This is accomplished by starting with "show-stopper" choices, then progressing to choices where concessions can be more easily made. The implications of the interfaces to the cryocooler will also be briefly discussed. Cryocooler developments at RVS that will expand the available design space are described. This enabling technology provides more options in terms of cryocooler size and performance, and continues the trend toward longer operating lifetime and higher reliability.