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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Shuttle cryogenic supply system optimization study. Volume 4: Cryogenic cooling in environmental control systems

An analysis of cryogenic fluid cooling in the environmental control system of the space shuttle was conducted. The technique for treating the cryogenic fluid storage and supply tanks and subsystems as integrated systems was developed. It was concluded that a basic incompatibility exists between the heat generated and the cryogen usage rate and cryogens cannot be used to absorb the generated heat. The use of radiators and accumulators to provide additional cooling capability is recommended.

Source record↗
NASA NTRS1979

Cryogenic cooling of instruments in orbit - A standard solid cryogen cooler approach

A study has been conducted to determine the utility and characteristics of a solid cryogen cooler which could meet a variety of instrument and mission requirements. The cooler consists essentially of two stages of solid cryogen and two cooled shields. The inner shield is thermally grounded to the secondary (warmer) cryogen and provides a low temperature boundary around the colder primary stage, while the outer shield reduces the heat loads upon the secondary cryogen. The baseline design provides cooling of approximately 1 watt over the temperature range 60-100 K, 0.5 watts from 15 to 60 K, and 0.2 watts from 8 to 15 K for a one-year lifetime. For low cooling loads (0.1 W) and with use of an optional cooled shield, cooling lifetimes of 8 years are possible.

Nast, T. C.↗
NASA NTRS1986

Advances in cryogenic engineering. Volume 31; Proceedings of the Cryogenic Engineering Conference, MIT, Cambridge, MA, Aug. 12-16, 1985

The present conference on the applications of state-of-the-art cryogenic engineering technologies considers topics associated with the development status of the 'Superconducting SuperCollider', superconducting magnetic energy storage methods, large magnets for fusion and other physics researches, cryogenic hardware improvements, and phenomena and applications of superconducting magnet-employing acoustic emission test equipment. Also discussed are design criteria for superconducting magnet stability, heat exchangers and heat transfer to liquid He and N, heat and mass transfer characteristics of He II, refrigeration techniques for magnetic resonance imaging and other small systems, refrigeration for liquefaction and for superconducting fusion as well as for accelerator and generator systems, magnetic refrigeration, cryocooling and refrigeration for space applications, the storage and transfer of cryogenic fluids, the properties of cryogenic liquids, and air liquefaction equipment.

Fast, R. W.↗
NASA NTRS2006

Cryogenic Pound Circuits for Cryogenic Sapphire Oscillators

Two modern cryogenic variants of the Pound circuit have been devised to increase the frequency stability of microwave oscillators that include cryogenic sapphire-filled cavity resonators. The original Pound circuit is a microwave frequency discriminator that provides feedback to stabilize a voltage-controlled microwave oscillator with respect to an associated cavity resonator. In the present cryogenic Pound circuits, the active microwave devices are implemented by use of state-of-the-art commercially available tunnel diodes that exhibit low flicker noise (required for high frequency stability) and function well at low temperatures and at frequencies up to several tens of gigahertz. While tunnel diodes are inherently operable as amplitude detectors and amplitude modulators, they cannot, by themselves, induce significant phase modulation. Therefore, each of the present cryogenic Pound circuits includes passive circuitry that transforms the AM into the required PM. Each circuit also contains an AM detector that is used to sample the microwave signal at the input terminal of the high-Q resonator for the purpose of verifying the desired AM null at this point. Finally, each circuit contains a Pound signal detector that puts out a signal, at the modulation frequency, having an amplitude proportional to the frequency error in the input signal. High frequency stability is obtained by processing this output signal into feedback to a voltage-controlled oscillator to continuously correct the frequency error in the input signal.

Dick, G. John↗
NASA NTRSDate not supplied

Ground-Based Cryogenic Leak Test of Fittings for Cryogenic Fluid Management

Mechanically connected fluid joints are virtually unavoidable in complex cryogenic system designs. In the case of spacecraft, the performance of these joints is critical to mission success. This is especially true for long-duration space missions where even very low leak rates can eventually lead to significant propellant losses or failure of vital cryogenic cooling systems. NASA has recently undertaken an effort to quantify the leak rate of Vacuum Coupling Radiation (VCR) fittings over the temperature range from ambient to 20 K, both before and after exposure to a launch vibration profile. A test apparatus employing a cryocooler and a calibrated helium mass spectrometer was developed, validated, and used to obtain quantifiable leak rates at a fitting test pressure of 31 bar (450 psig). Three different fitting sizes were tested, 25.4 mm (¼ inch), 12.7 mm (½ inch), and 6.35 mm (1 inch) and two gasket materials, stainless steel, and silver-plated nickel. Each fitting configuration (size/seal material) was subjected to two consecutive cryogenic thermal cycles/measurement tests, followed by a launch vibration test profile at ambient temperature, and then two additional cryogenic thermal cycles/measurement tests. The design and development of the test apparatus, and test data are presented and discussed in detail.

G J Tamasy↗
DOE OSTI2022

A cryogenic torsion balance using a liquid-cryogen free, ultra-low vibration cryostat

We describe a liquid-cryogen free cryostat with ultra-low vibration levels, which allows for continuous operation of a torsion balance at cryogenic temperatures. The apparatus uses a commercially available two-stage pulse-tube cooler and passive vibration isolation. Here, the torsion balance exhibits torque noise levels lower than room temperature thermal noise by a factor of about four in the frequency range of 3–10 mHz, limited by residual seismic motion and by radiative heating of the pendulum body. In addition to lowering thermal noise below room-temperature limits, the low-temperature environment enables novel torsion balance experiments. Currently, the maximum duration of a continuous measurement run is limited by accumulation of cryogenic surface contamination on the optical elements inside the cryostat.

47 OTHER INSTRUMENTATION↗
NASA NTRS2004

The Cryogenic, High-Accuracy, Refraction Measuring System (CHARMS): A New Facility for Cryogenic Infrared through Vacuum Far-Ultraviolet Refractive Index Measurements

The optical designs of future NASA infrared (IR) missions and instruments, such as the James Webb Space Telescope's (JWST) Near-Mixed Camera (NIRCam), will rely on accurate knowledge of the index of refraction of various IR optical materials at cryogenic temperatures. To meet this need, we have developed a Cryogenic, High-Accuracy Refraction Measuring System (CHARMS). In this paper we discuss the completion of the design and construction of CHARMS as well as the engineering details that constrained the final design and hardware implementation. In addition, we will present our first light, cryogenic, IR index of refraction data for LiF, BaF2, and CaF2, and compare our results to previously published data for these materials.

Frey, Bradley J.↗
DOE OSTI2022

Cryogenic tracer irradiation facility at the university of Texas at Austin

We report on a cryogenic gas irradiation facility in the 1.1 MW TRIGA reactor at The University of Texas at Austin. The system was designed to produce radioactive xenon and argon for environmental studies, and it can be applied to produce other gaseous radiotracers. The system design includes modeling accident scenarios to ensure operation does not risk damage to the reactor and minimizes risk of release of radioactive material. In conclusion, the SCALE code was used to model a 30-day irradiation of one liter of Xe-126 and the predicted activity is 0.9 Ci of Xe-127 at irradiation end.

Ar-37↗
DOE OSTI2021

Cryogenic operation of planar ultrananocrystalline diamond field emission source in SRF injector

Here, we report a demonstration of electron beam generation in a superconducting radio frequency (SRF) Teraelectronvolt Energy Superconducting Linear Accelerator 1.3 GHz gun equipped with a field emission cathode and operated at 2 K. The cathode is a submicrometer film of nitrogen-incorporated ultrananocrystalline diamond [(N)UNCD] deposited atop a Nb RRR300 cathode plug that is 4 mm in diameter. Measurements of the output current showed that it increased exponentially as a function of the gun gradient. Our results demonstrate a feasible path toward simplified fully cryogenic SRF injector technology. At a maximal gradient of 0.9 MV/m, a current density of 22 μA/cm2 was obtained [calculated as a 2.75 μA current over the total cathode surface area of π(2 mm)2]. One important finding is that the electron emitter made of (N)UNCD, a material long been known as a highly efficient field emission material, demonstrated a record low turn-on gradient of 0.6 MV/m. A hypothesis explaining this behavior is proposed.

43 PARTICLE ACCELERATORS↗
NASA NTRS1991

Predicted thermal response of a cryogenic fuel tank exposed to simulated aerodynamic heating profiles with different cryogens and fill levels

A two dimensional finite difference thermal model was developed to predict the effects of heating profile, fill level, and cryogen type prior to experimental testing the Generic Research Cryogenic Tank (GRCT). These numerical predictions will assist in defining test scenarios, sensor locations, and venting requirements for the GRCT experimental tests. Boiloff rates, tank-wall and fluid temperatures, and wall heat fluxes were determined for 20 computational test cases. The test cases spanned three discrete fill levels and three heating profiles for hydrogen and nitrogen.

Hanna, Gregory J.↗
NASA NTRS1991

The cryogenic on-orbit liquid analytical tool (COOLANT) - A computer program for evaluating the thermodynamic performance of orbital cryogen storage facilities

The United States plans to establish a permanent manned presence at the Space Station Freedom in low earth orbit (LEO) and then carry out exploration of the solar system from this base. These plans may require orbital cryogenic propellant storage depots. The COOLANT program has been developed to analyze the thermodynamic performance of these depots to support design tradeoff studies. It was developed as part of the Long Term Cryogenic Storage Facility Systems Study for NASA/MSFC. This paper discusses the program structure and capabilities of the COOLANT program. In addition, the results of an analysis of a 200,000 lbm hydrogen/oxygen storage depot tankset using COOLANT are presented.

Taylor, W. J.↗
NASA NTRS1995

Effect of entry of subcooled cryogen on thermal stratification in a cryogenic storage tank

The purpose of this study was to predict if subcooled cryogenic liquid entering the bottom of a storage tank will destroy the thermal stratification of the tank. After an extensive literature search, a formula for maximum critical Reynolds Number which used to predict the destratification of a cryogenic tank was found. Example of calculations and graphics to determine the mixing of fluid in the tank were presented.

Wang, Pao-lien↗
NASA NTRS2000

Cryogenic Optical Systems and Instrumentation IX (AM 116) Newly Modified Cryogenic Optical Test Facility at the Marshall Space Flight Center

Marshall Space Flight Center (MSFC) has maintained and operated a world-class x-ray optics and detector testing facility known as the X-ray Calibration Facility (XRCF) since the mid 1970's. The ground test and calibration of the Chandra X-ray Observatory optics and detectors were successfully completed at the XRCF in 1997. The beginning of the Next Generation Space Telescope (NGST) development programs (NMSD, SBMD, AMSD, etc.) and the establishment of the Space Optics Manufacturing Technology Center at MSFC have led to an XRCF modification. In 1999 the facility was upgraded to perform cryogenic testing of lightweight visible optics (without compromising the existing x-ray testing capability). A thermal enclosure capable of 20 degrees Kelvin and vibration isolated instrumentation mount were added. A vacuum-compatible five-axis motion table was modified to operate under cryogenic conditions. Optics up to two meters in diameter with radii of curvature of up to twenty meters can be accommodated. Facility characterization tests and one NGST program mirror test have been completed to date. By July 2000, two other mirrors will be tested. Optical wavefront measurements were made at < 35 degrees Kelvin with several instruments located at the test mirror's radius of curvature. The current wavefront measuring instruments include a Shack-Hartman wavefront sensor, a point diffraction interferometer, a point spread function-measuring device, and a radius of curvature measuring instrument. A vibration insensitive phase shifting interferometer is planned for future optical testing. This paper will present a brief history of the facility, a discussion of its current x-ray optic testing capabilities, and a complete description of the new capabilities in the visible optical testing regime.

Eng, Ronnie↗
NASA NTRS2005

Improved Cryogenic Optical Test Capability at Marshall Space Flight Center's X-ray Cryogenic Test Facility

Marshall Space Flight Center's X-ray & Cryogenic Test Facility (XRCF) has been performing optical wavefront testing and thermal structural deformation testing at subliquid nitrogen cryogenic temperatures since 1999. Recent modifications have been made to the facility in support of the James Webb Space Telescope (JWST) program. The test article envelope and the chamber's refrigeration capacity have both been increased. A new larger helium-cooled enclosure has been added to the existing enclosure increasing both the cross-sectional area and the length. This new enclosure is capable of supporting six JWST Primary Mirror Segment Assemblies. A second helium refrigeration system has been installed essentially doubling the cooling capacity available at the facility. Modifications have also been made to the optical instrumentation area. Improved access is now available for both the installation and operation of optical instrumentation outside the vacuum chamber. Chamber configuration, specifications, and performance data will be presented.

Kegley, Jeffrey↗