Radiation Hard Cryocooler Electronics for HMWIR Sensors

Development is well underway on a compact cryocooler control electronics (CCCE) module optimized for low power (<20 WAC input) cryocoolers. These electronics are radiation hard to support a wide range of space-borne applications with the expectation that the greatest interest will be for hot mid-wave infrared (HMWIR) space sensors operating around 150K. By focusing on low power coolers and their associated low drive voltages as compared to larger coolers, component selection options open up to include much smaller parts than are typically required for radiation hard cryocooler electronics. The result is a 75% size reduction as compared to the current art in radiation hard cooler electronics. An initial brassboard of the motor drive and telemetry circuits has been successfully built and tested with five different cryocoolers from three different manufacturers, including both Stirling and pulse tube type cryocoolers. An element of the ongoing test program is to better characterize the temperature control firmware to gain understanding, which will lead to more rapid optimization for different cryocoolers and operating points. This paper describes some of the early test results obtained with two small Stirling cryocoolers, an AIM SX035 and a FLIR FL-100.