Future NASA Space Science Missions will incorporate detectors, sensors, shields, and telescopes that must be cooled to cryogenic temperatures. An enabling technology for these missions is advanced cryocoolers that can provide continuous and distributed cooling with minimal input power. On this program, Creare proposes to develop and demonstrate an innovative cryocooler that produces refrigeration at temperatures of 30 to 70 K and rejects heat at a temperature of 150 to 210 K with extremely high efficiency. The heat rejected can be absorbed by an upper stage cryocooler or rejected to space through a small cryo-radiator. The overall mass of the cryocooler, cryo-radiator and electronics is nominally 6 kg, the area of the cryo-radiator is 0.8 m2 and the input power is significantly less than current state-of-the-art cryocoolers. The electronics utilize parts that are tolerant to 300 kRad total ionizing dose. In addition, the cryocooler technology is extremely reliable and scalable, and produces no perceptible vibration. The key innovation is a cryogenic compressor which has heritage to the cryogenic circulator developed by Creare and operated on the Hubble Space Telescope for 6.5 years. On the Phase I project, we optimized the cryocooler design for a particular mission class and predicted the performance of the cryocooler using a combination of analyses and component-level test data. On the Phase II project, we will build and test a demonstration cryocooler and cryo-radiator. The Phase II testing will be structured to achieve a TRL of at least 5, and will include cryogenic performance and launch vibration testing.

The successful completion of this program will provide mission planners with an extremely high performance, lightweight, and compact cryocooler that can meet requirements for a variety of missions. The cryocooler is reliable, emits no vibration, and can be used for remote and distributed cooling. The latter feature is expected to reduce size, mass and costs of the overall payload. The primary application will be for cooling detectors, sensors, shields, and telescopes for space science missions. NASA applications include future satellites, probes and astronomical observatories utilizing superconducting bolometers, and infrared, far infrared, submillimeter and X-ray detectors. Missions include the Jupiter-Europa Orbiter (JEO), Wide Field Infrared Survey telescope (WFIRST), Single Aperture Far-IR (SAFIR) telescope, Space Infrared Interferometric Telescope (SPIRIT), Submillimeter Probe of the Evolution of Cosmic Structure (SPECS), and the International X-Ray Observatory (IXO).

The proposed cryocooler requires minimal input power and is extremely compact making it ideal for small satellites. Military space applications for this cooling system include space-based surveillance for Operationally Responsive Space missions. Terrestrial applications for the military and intelligence community include high speed conventional and quantum supercomputing, RF signal sensing for communications, electronic warfare, and signal intelligence. For these terrestrial applications the cryo-radiator would be replaced with either a stored cryogen or a tactical Stirling cryocooler. The small size and low input power are ideal for mobile applications. Commercial applications include cooling for communication satellites, superconducting circuits, and cryogenic computers.