Cryostat-100

Cryostat-100 combines the best features of previous cryostats developed by NASA, while offering new features and conveniences. This unit can readily handle the full range of cryogenic-vacuum conditions over several orders of magnitude of heat flux. Guide rings, handling tools, and other design items make insulation change-out and test measurement verification highly reliable and efficient to operate. The new apparatus requires less ancillary equipment (it is not connected to storage tank, phase separator, subcooler, etc.) to operate properly. It is top-loading, which makes disassembly, change-out, and instrumentation hook-up much faster. The thermal stability is improved because of internal vapor plates, a single-tube system of filling and venting, bellows feed-throughs, Kevlar thread suspensions, and heavy-wall stainless-steel construction. The cold mass of Cryostat-100 is 1m long, with a diameter of 168 mm. The test articles can therefore be of a corresponding length and diameter, with a nominal thickness of 25.4 mm. Shorter lengths are acceptable, and thicknesses may be from 0 mm to 50 mm. Tests are conducted from ambient pressure (760 torr) to high vacuum (below 110-4 torr) and at any vacuum pressure increment between these two extremes. The residual gas (and purge gas) is typically nitrogen but can be any purge gas, such as helium, argon, or carbon dioxide. Typically, eight cold vacuum pressures are performed for each test series. The warm boundary temperature is approximately 293 K, and the cold boundary temperature is approximately 78 K. The delta temperature for the cryogenic testing is therefore approximately 215 K. A unique lift mechanism provides for change-out of the insulation test specimens. It also provides for maintenance and other operations in the most effective and time-efficient ways. The lift mechanism is also a key to the modularity of the overall system.

The Cryostat-500 provides laboratory measurement of the steady-state thermal transmission properties of thermal insulation systems under conditions below ambient temperature. Liquid nitrogen is used as a direct measure of the energy going through the test specimen. Thermal insulation systems may be composed of one or more materials that may be homogeneous or non-homogeneous at boundary conditions from 77 K to 373 K and in environments from high vacuum (10E-7 torr) to ambient pressure (10E+3 torr). The Cryostat-500 provides a much wider range of thermal performance and covers the full range of environmental conditions for applications below ambient temperature. The instrument has been proven through extensive testing of foams, composite panels, multilayer insulation (MLI) systems, aerogel blankets, fiberglass, and many other types of materials. Both the quality and quantity of the thermal performance data for insulation materials and systems have increased even as the process and method has become more time efficient and cost effective. Further guidelines on the test method and equipment for the Cryostat-500 are given in ASTM C1774, Annex A3.

The Cryostat-600 provides steady state thermal performance data, including the effective thermal conductivity and heat load, through insulation systems with or without structural elements. The cold boundary temperature can be varied at discrete points between 4 K and 80 K with warm boundary temperatures between approximately 250 K and 400 K. The vacuum level can be changed between 10E-7 torr and 10E3 torr, covering the full vacuum range and environments using different background gasses. Of greatest interest in this configuration is the high performance, high vacuum insulation systems that are not covered by existing ASTM test methods. The instrument has been proven through extensive testing of different multilayer insulation (MLI) systems, foams, and composites, including testing the effects of various structural elements.

Traditional cryogenic cooling methods, such as pulse-tube and reverse Brayton cryocoolers, are constrained by moving parts, high mass, and limited cooling capacity. Their mechanical complexity increases maintenance needs and reduces reliability, while their bulk adds significant weight penalties to mobile platforms. Although these systems can achieve kilowatt-scale cooling, they struggle to maintain stable, efficient performance under the continuous, high thermal loads required for megawatt-scale superconducting propulsion. The CryoQuad was developed specifically to address these shortcomings, delivering a lighter, more reliable, and higher-capacity solution tailored for superconducting electric propulsion systems. The novel design utilizes four thermoacoustic Stirling heat engines arranged a quarter wavelength apart in a quad loop configuration. This configuration – wherein each engine has high-power acoustic energy pulled off via power pulse-tube coolers – allows for rapid acoustic wave amplification without moving parts (e.g., pistons, turbines, pumps) or electricity. Importantly, the innovative design eliminates the need for large linear piston generators and large recuperator heat exchangers – two features common in megawatt-scale cryocooling pressure systems today – significantly reducing the overall system mass and complexity. While designed for use with liquid Helium, CryoQuad can utilize a variety of fluids depending on the required cryogenic temperatures. CryoQuad has the potential to be used in superconducting electric aircraft, other advanced propulsion systems, in-space cryogenic fluid management, cryosurgical cancer treatment probes, MRI systems, cryogenic cooling and packaging systems for superconducting electronics, space fuel depots, and other power applications. CryoQuad is available for patent licensing.

NASA's TVS Augmented Injector includes an internal heat exchanger, a fluid injector spray head, and an external surface condensation heat exchanger - all combined with multiple intertwined flow paths containing liquid, two-phase, and gaseous working fluid. The TVS provides a source of coolant to the injector, which chills the incoming fluid flow. This cooled flow promotes condensation of the tank ullage dropping pressure and maintains incoming fluid flow. The system eliminates the potential for a stalled fill condition and reduces tank pressure during cryogenic fluid transfer. During fill operations, the tank vent can be closed early in the process before fluid is introduced, and, in some cases, the tank vent may not even need to be opened. Furthermore, the TVS Augmented Injector can remove sufficient thermal energy to reach a 100% liquid level in the receiver tank. A cryo-cooler can be used in place the TVS flow circuit for a zero-loss system. The TVS Augmented Injector couples internal fluid flow cooling and external surface ullage gas condensation into a single, compact package that can be mounted to small tank flanges for minimal impact insertion into any vessel. The injector is printed as one part using additive manufacturing, resulting in part count reduction, improved reproducibility, shorter lead times, and reduced cost compared to conventional approaches. The injector may be of particular interest in applications where cryogenic fluid is expensive, fluid loss through vents is problematic, and/or achieving high filling levels would be helpful. The injector can benefit typical cryogenic fluid transfer between containers or, alternatively, can serve as a tank pressure control device for long-term storage using a fluid recirculation system that pumps fluid through the injector and sprays cooled liquid back into the tank. Additionally, where ISRU processes are employed, the injector can be used to liquefy incoming propellant streams.