Cryostat-500

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.

Advances in new polymers and composites along with growing industrial needs in below-ambient temperature applications have brought about the Macroflash development. Accurate thermal performance information, including effective thermal conductivity data, are needed under relevant end-use conditions. The Macroflash is a practical tool for basic testing of common materials or research evaluation of advanced materials/systems. The Macroflash can test solids, foams, or powders that are homogeneous or layered in composition. Test specimens are typically 75mm in diameter and 6mm in thickness. The cold side is maintained by liquid nitrogen at 77 K while a heater disk maintains a steady warm-side temperature from ambient up to 373 K. The steady boiloff of the liquid nitrogen provides a direct measure of the heat energy transferred through the thickness of the test specimen. Nitrogen or other gas is supplied to the instrument to establish a stable, moisture-free, ambient pressure environment. Different compression loading levels can also be conveniently applied to the test specimen as needed for accurate, field-representative thermal performance data. The Macroflash is calibrated from approximately 10 mW/m-K to 800 mW/m-K using well-characterized materials.

Li-ion batteries are an integral part of energy storage systems used in NASA's Exploration program, as well as many modern terrestrial industries. Innovators at the NASA Johnson Space Center wanted a better way to measure total and fractional heat response of specific types of Li-ion cells when driven into a thermal runaway condition. They developed a calorimeter with at least two chambers, one for the battery cell under test and at least one other chamber for receiving the thermal runaway ejecta debris. Both are designed to be structurally strong and thermally insulated. When the test cell is intentionally driven into thermal runaway, ejecta explodes into the ejecta chamber and is decelerated and collected. Thermal sensors are strategically placed throughout the chambers to collect thermal data during the test. Customized software analyzes the thermal data and determines key calorimeter parameters with a high degree of accuracy.

The Multilayered Fire Protection system uses technology from the space craft flexible heat shield for future planetary missions. By optimizing this material for the fire environment, utilizing heat shield test methods, and experimenting with different materials, the NASA team developed a multilayered fire protection system. This system includes an outer textile layer which reflects over 90 percent of the radiant heat, an insulated layer which protects against convective heat and hot gases, and a non-porous film layer which is a gas barrier layer.

Space and ground launch support related hardware often operate under extreme pressure, temperature, and corrosive conditions. When dealing with this type of equipment, it is frequently necessary to run wiring, tubes, or fibers through a barrier separating one process from another with one or both operating in extreme environments. Feedthroughs used to route the wiring, tubes, or fibers through these barriers must meet stringent sealing and leak tightness requirements. This affordable NASA feedthrough meets or exceeds all sealing and leak requirements utilizing easy-to-assemble commercial-off-the-shelf hardware with no special tooling. The feedthrough is a fully reconfigurable design; however, it can also be produced as a permanent device. Thermal cycling and helium mass spectrometer leak testing under extreme conditions of full cryogenic temperatures and high vacuum have proven the sealing capability of this feedthrough with or without potting (epoxy fill) on the ends. Packing material disks used in the construction of the device can be replaced as needed for rebuilding a given feedthrough for another job or a different set of feeds if potting is not used for the original feedthrough build. (Potting on one or both sides of the sleeve provides double or triple leak sealing protection). Variable Compression Ratio (VCR) connectors were adapted for the pressure seal on the feedthrough; however, any commercial connector can be similarly adapted. The design can easily be scaled up to larger (2" diameter) and even very large (12" or more) sizes.