The Northrop Grumman Aerospace Systems (NGAS)`s MicroCooler is a split configuration pulse tube cooler incorporating a coaxial cold head connected via a transfer line to a vibrationally balanced back to back linear flexure bearing compressor. Designed for > 10 year operation with no degradation in performance, this 900 gram cryocooler incorporates a very efficient pulse tube cold head for operation over a range of temperatures above 40K. This paper presents the results of a series of tests designed to qualify the NGAS MicroCooler to the Technology Readiness Level (TRL) 6. The MicroCooler was subjected to launch vibration and thermal cycling conditions appropriate to space applications. The measured load lines and unchanged refrigeration performance of the cooler throughout the qualification program demonstrated the robustness of the design. The performance of the MicroCooler was also characterized over a range of rejection temperatures and input powers to demonstrate its suitability for a wide range of missions and applications. The successful completion of series of tests has demonstrated that this very small, low vibration, high frequency cooler is qualified to be integrated into space payloads or an integrated detector cooler assembly (IDCA) for tactical applications, similar to those used with shorter lived tactical coolers.
The Northrop Grumman Aerospace Systems (NGAS) has expanded the cryocooler product line to include a single stage High Efficiency Cryocooler (HEC) cooler with a coaxial pulse tube cold head that operates at temperatures down to 45K. The HEC coaxial pulse tube cooler has been adopted by several customers, and has completed acceptance testing to meet program flight requirements. The NGAS TRL 9 HEC is a pulse tube cryocooler with a flexure bearing compressor which has been delivered for a number of flight payloads that are currently operating in space. To date, NGAS has delivered space cryocoolers in several configurations including single stage with a linear cold head and two stage with both linear and coaxial cold heads. The new HEC coaxial cooler uses the same TRL9 HEC compressor with a passive pulse tube cold head, to maintain the flight heritage of the HEC linear cooler. In this paper, we present the flight acceptance test data of the HEC coaxial cryocooler, which includes thermal performance, launch vibration and thermal cycling. The HEC coaxial cooler has demonstrated excellent performance in family with the flight qualified HEC linear cooler. The HEC coaxial cooler provides users with additional flexibility in selecting the cold head configuration to meet their particular applications.