An Ultra Low Power Cryo-Refrigerator for Space

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 190 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 and electronics is 3 kg, the size of the cryocooler is 6 liters, the area of the cryo-radiator is 0.5 square meters and the input power is significantly less than current state-of-the-art cryocoolers. 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 will optimize the cryocooler design for a particular mission class and predict the performance of the cryocooler using component-level test data. On the Phase II project, we will build and test a brassboard cryocooler and cryo-radiator. The Phase II testing will be structured to achieve a TRL of 5, and will include testing with a cold-end temperature of 35 K and a heat rejection temperature of 150 K.