Pertinent NASA projects include missions to the outer planets and their moons, such as Europa, Titan, Neptune, and Triton. All of these missions need to carry considerable propellants for many years to be used in braking and/or orbital insertion maneuvers at the target location(s). High thrust propulsion (acceleration comparable to planetary surface gravitational acceleration) is required for these near planetary maneuvers. Significant benefit can be gained from improved mission performance, which is greatly impacted by propulsion system mass. Propellant is usually the predominant contributor to the mass of such chemical systems. Therefore, the largest potential system and mission performance gains are likely from improved specific impulse (ISP) by using cryogenic propellants. The challenges associated with cryogenic propellant use include the reduction of propellant boil-off so that the system is not penalized by the additional propellant mass required to accommodate typical boil-off. The availability of a low input power, low mass cryocooler will make this option more attractive and attainable. Madison CryoGroup's intent is to design the cryocooler for a low reject temperature, which makes it highly applicable to missions to remote locations and orbits that have a low level of solar input. Depending on the extent of radiation shielding applied, even earth orbiting systems may benefit from the innovation.
The design and construction process is targeted to produce a space-born cryocooler that will have a host of qualities in-demand for space missions. However, its small system size, efficient performance, long-life reliability, low input power and low vibration all make this cryocooler a high-value product that meets the demand of businesses aiming to deliver truly high-quality products for systems that require low failure rates. The proposed cooler is operable over a wide range of loads and temperatures. Several government agencies outside NASA (MDA, Air Force) and various commercial entities have interest in integrating small and efficient high-frequency cryocoolers into their equipment. For the proposed technology there are many potential business and civilian applications that require compact, reliable and efficient cryogenic cooling, such as: Cryopumps for semiconductor manufacturing, Superconducting magnets for MRI systems, SQUID magnetometers for heart and brain studies, HTS filters for the communication industry, Superconducting electronics and Liquefaction of industrial gases. Even for large system, in which one might apply distributed cooling loop schemes, our small cryocooler may be advantageous by installing multiple such discrete active coolers at strategic locations, when high reliability is the more pertinent feature.