On-Orbit Longevity of Cryogenic Cooling Systems

This proposal addresses cryocooler regenerators, a critical component in all regenerative cryocoolers. Should Exothermics be successful in the materials development efforts during this Phase 1 effort, team member Northrop Grumman Space Technology (NGST)is prepared to use the material in their space pulse tube cryocoolers. The magnetron sputtering-based processing and substrate material approaches that we will examine in Phase 1 directly address the geometry, producibility and reliability challengesassociated with spaceborne VLWIR and LWIR cryocooler component. To assure that our approach meets the needs of real systems such as STSS (Space Tracking and Surveillance System) Exothermics will work closely with NGST, the only US supplier with long lifepulse tube or Stirling space cryocoolers in orbit. Two coating materials (such as Er or Er3Ni) will be investigated as coatings for regenerator mesh substrates via the use of low-temperature, cost-effective and flexible DC or medium frequency AC magnetronsputtering methods.If successful, the development could impact such nearer term programs such as STSS Cycle 2 by improving the efficiency and reliability of the cryocooler required to cool HgCdTe LWIR focal planes to temperatures of 35K. The materials and related cryocooler technology described in this proposal have a potential market for use in commercial low temperature cryocoolers. These machines are widely used in semiconductor manufacturing where cryopumps are the vacuum pumptechnology of choice. Similar cryocoolers are used in the medical field where the superconducting magnets in high performance MRI (Magnetic Resonance Imaging) machines. Improved regenerator materials would result in more efficient and cost-effectivemachines.