Low-Cost Space Based Cryocoolers

years, and high reliability as the ability to maintain or repair the cooler once the payload is launched into orbit is cost prohibitive. Therefore, it is imperative that space coolers are rigorously designed and screened to eliminate failure modes caused by friction from moving components and contamination in the cooler helium volume, for example. Nearly all state-of-the-art cryocoolers operating in space are equipped with Stirling based pulse tube cold-fingers to reduce the number of moving components inside the expander and meet vibration specifications. And yet, the overall complexity of current pulse tube Stirling coolers, including those based on some derivative of the Oxford design, amount to very expensive cryocoolers because of the number of components that the failures modes can be stemmed from, and the number of piece parts that need to be screened and yielded in the manufacturing and assembly processes. Rigorous testing, sometimes necessitating X-ray inspection, is performed on critical components to ensure that high reliability can be met, adding to touch time labor needed for verification and analysis. It is clear that a pulse tube Stirling cryocooler designed with even fewer components, without compromising the MTTF and reliability needed for space, would result in cost reduction because of the reduced touch time and the improved end-to-end manufacturing yield, which is the product of the individual processes and component yields to build the final cooler. Additionally, materials and manufacturing processes have significantly improved over the past decade to include advancements and discoveries in high durability films and coatings, as well as methods in additive manufacturing that support 3D printing of metals with better tolerances than before. These manufacturing processes provide an opportunity to revamp and reconsider how pulse tube Stirling cryocoolers can be made using today’s manufacturing technologies to increase component reliability and reduce production costs. In Phase I, Attollo proposes to conduct a feasibility trade study on a novel pulse tube Stirling cryocooler concept that 1) reduces the estimated components needed close to a half, 2) incorporates a new class of Diamond-like Carbon (DLCs) in the contact bearings of the cryocooler, and 3) employs 3D printing for the relatively feature rich heat exchanger and regenerator structures. Additionally, the parts count reduction is primarily achieved in our novel cooler concept by 4) removing high parts count elements in the traditional Oxford design, and replacing them with multi-functional components made possible by the simplified cryocooler architecture. Approved for Public Release | 20-MDA-10643 (3 Dec 20)