One of the most important characteristics of a cryocooler is its useful operating life. Cryocoolers intended for
space environments require cryocoolers with very long lifetimes, as the opportunity for servicing a failed unit
is minimal. Tactical cryocooler requirements have increasing followed the trend of the space cryocooler, with
required lifetimes reaching tens of thousands of hours.
Three tactical one watt linear (OWL) cryocoolers at Carleton Life Support Systems, Inc. (CLSS) of Davenport,
IA, recently surpassed 20,000 hours of operation. Acceptance tests show that the performance of the
cryocoolers has not significantly degraded over this timeframe. This paper reports the performance of the cryocoolers
over the span of the test. Steady-state and cooldown performance at various ambient temperatures are