The requirement for a reliable long-life refrigerator to cool spacecraft payloads to cryogenic temperatures dates to the very beginning of the era of space flight. The development of spacecraft cryocooler technology has been funded on a more or less continuous basis for over 30 years. A number of cryocoolers have flown on spacecraft during this period. However, this technology has been slow to achieve full maturity and operational status for spacecraft use.This paper describes the efforts to advance spacecraft cryogenic refrigerators beyond the technology development demonstration level. The early hardware programs and flight experiments are described. The evolution of both system level payload requirements and technology bases is discussed. Current US efforts are described and some prediction of future trends attempted.