Low Cost Space Cryocooler System for Launch and Boost Phase Sensor Applications

The South Bay Science and Technology Corp (SBSTC), teamed with Raytheon, proposes a cryogenic system concept utilizing all low cost space-qualified elements to yield a Low Cost Space Cryocooler System (LCSCS) for space-based launch and boost phase detection and tracking sensor applications.  To satisfy the projected two-stage cryocooling requirement, the LCSCS uses two (2) long-life, low cost single-stage cryocoolers, one at each stage.  Each cryocooler is powered and controlled by its own dedicated electronics module.  The basis for the design is the Low Cost Space Cryocooler (LCSC), developed by SBSTC and Raytheon on a previous SBIR Program. To reduce the exported vibration of the cryocooler, a simple vibration mitigation algorithm and/or a thermal storage unit is used.The objective of the Phase II Program is to develop low-cost cryocooler for LCSCS with high efficiency and modularity for multiple programs support.  At the end of Phase II, we expect to have demonstrated the key cryocooler hardware components of a low-cost and modular LCSCS that will form a basis to support multiple DoD programs and commercial applications. BENEFIT: Most significantly, the LCSCS provides independent temperature control of each stage.  The only coupling is through the thermal interactions between the temperature stages in the sensor; the thermodynamics of the cryocoolers themselves are totally independent.  This provides much greater operational flexibility to optimize the design, adjust to changing heat loads, manage time-variant loads, etc.  From a packaging perspective, the locations of the first and second stage cryogenic interfaces are not coupled, as they would be in a two-stage linear cooler, providing packaging flexibility./The initial commercialization opportunity we are targeting for the LCSCS is the Third Generation Infrared Surveillance (3GIRS) Program.  The high capacity of the cryocooler employed is well suited to meet the 3GIRS need to cool large focal plane arrays and large optical benches.  The vibration mitigation techniques (low cost active control and/or thermal storage units) can be employed in various combinations to provide best value to the user community. Besides 3GIRS the LCSCS is also applicable to wide field of view (WFOV) full-Earth staring infrared sensor.  Each space payload will likely require two of these cryocoolers, one operational and one redundant. We anticipate that low number of cryocooler systems will be deployed starting in 2015 costing several million dollars each. The long life, high reliability, maintenance free, and low cost characteristics of this cryocooler make it ideal also for commercial applications.  Our current assessment is that for LCSCS size cryocooler, the major application is in the medical diagnostic area with Magnetic Resonance Imaging (MRI).  The noisy Gifford-McMahon cryocoolers used to cool the MRI superconductive magnets would ideally be replaced with quieter linear pulse tube cryocoolers, if the cost target can be met.  Based on the MRI market size, our preliminary assessment showed that the estimated global market for the pulse tube, high capacity type of cryocooler is $50 70 millions in 2009.  This includes other applications of using cryocoolers for products such as superconductive equipment for communication.