Solar Powered Thermoacoustic Stirling Heat Engine Pulse Tube Cryocooler

A highly efficient and reliable solar powered Thermoacoustic Stirling Heat Engine (TASHE) driven pulse tube cryocooler for the active cooling and long-term on-orbit storage of cryogenic propellants is proposed to be developed. The Solar Thermal Cryocooler(STC), which consists of a solar concentrator, Thermoacoustic Stirling Heat Engine driver, and a pulse tube cryocooler, efficiently uses solar energy for refrigeration. The STC directly converts thermal energy into acoustic energy, which is then used bythe pulse tube cryocooler for active cooling of cryogenic propellants and boil-off elimination. The STC has no moving parts or rotational machinery and is truly a long-life cryocooler suitable for space applications. The STC has the unique advantage ofusing a solar orbit transfer vehicle's concentrator to maintain the cryogenic propellant for long periods of time while in a parking orbit. In addition, the STC is fully compatible with Sierra Lobo's in-space densified cryogenic propellant storage systemtechnologies already under development for the Missile Defense Agency and NASA. Sierra Lobo therefore proposes to develop the STC and create a system simulation model that will be integrated with Sierra Lobo's Cryogenic System Design Tool (CSDT). TheCSDT will be used to determine the feasibility of the STC technology for orbit transfer vehicles. The research and development of the proposed technology will have the greatest impact on the design of future space transportation systems. The ability tostore cryogenic fluids for long periods of time on orbit, in deep space, or on planetary bodies in an efficient and reliable manner has a direct effect on the mission design, operation, and cost. Space systems that can use the STC include orbit transfervehicles, storage depots, Mars and Lunar transfer vehicles, space stations, deep space probes, and Mars in-situ propellant liquefaction. Terrestrial applications of the STC include refrigeration in remote locations where power is not available, freezersfor the storage of medicine and perishable food stables, cryogenic compressed gas liquefiers, and pollution free refrigeration.