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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 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Spacecraft heat transfer by two-phase flow method

A refrigerator/freezer has been designed with an oil-free compressor to provide an economical two-phase flow system for heat transfer. A computer simulation has been done for the condenser and evaporator to determine the design parameters, such as length, diameter, and flow regimes, for different refrigerants and load requirements. A large Reynolds number was considered to ensure annular flow (in order to maximize heat transfer coefficients) and large Froude number. The simulation was correlated with the test data of a vapor compression refrigerator/freezer flown on STS-4 (which provided information on vapor compression in a zero-gravity environment). The two-phase system will be used for the Spacelab mission SLS-1 and can be used in future spacecraft and high-speed aircraft, where weight, volume, and power requirements are critical.

Hye, A.↗
NASA NTRS1985

Safety considerations in the design of Spacelab refrigerator/freezer

A vapor compression refrigerator/freezer has been designed for Spacelab to conduct life sciences experiments. It is equipped with different safety features to eliminate all probable types of failures. The whole Freon loop is enclosed in a second containment so that any leakage of Freon can be contained. The unit is provided with an 'Emergency On' switch to actuate during backup mode which provides the spacecraft power directly to the compressor and the cooling fans while removing the power supply and all normal control elements from the circuit. During this mode, the compressor runs continuously when operating as a freezer (-22 C) and is controlled by a thermostat to cycle when operating as a refrigerator (4 C). It has a push button switch at the front panel to momentarily power the thermometer by a battery to monitor the inside temperature during an emergency. It has a door switch which shuts off the internal cooling fans when the door is opened. All the important critical performance data will be downlinked through a data connector to monitor during mission.

Hye, A.↗
NASA NTRS1985

The Freon loop double containment design for Spacelab refrigerator/freezer to protect environment

General Electric is building a vapor compression refrigerator/freezer for NASA-Johnson Space Center for the Spacelab mission SLS-1 for life sciences experiments. Freon R502 is used as refrigerant. As R502 is considered toxic, the whole Freon loop is enclosed in a second containment to avoid exposure to crewmen. A detailed description of the design and construction of the safety enclosure is presented.

Hye, A.↗
NASA NTRS1987

Inflatable Perimeter Seal

Effective, inexpensive pressure seal between two flat surfaces formed from silicone rubber tubing. Resembling refrigerator seal, pressure seal especially useful where shape of sealed region irregular or subject to change. Unlike gaskets and O-rings, tubing seals require no machined grooves or custom-made parts and not adversely affected by warpage of sealed surfaces.

Shepherd, Clayton C., Jr.↗
NASA NTRS1987

Getter Capsules for Heat-Transport Systems

Metal absorbs hydrogen dissolved in heat-transfer fluids. Blockages by hydrogen gas in refrigerators, heat pipes, and other two-phase heat-transport systems eliminated by use of degassing metals or alloys called getters. Getter contained in getter capsule placed in series or in parallel with heat-transport loop. Gas-removal technique more specific and more reliable in solving problem of gas blockage than older procedures.

Seidenberg, Benjamin↗
NASA NTRS1987

Space station experiment definition: Long term cryogenic fluid storage

A preliminary design of an experiment to demonstrate and evaluate long-term cryogenic fluid storage and transfer technologies has been performed. This Long-Term Cryogenic Fluid Storage (LTCFS) experiment is a Technology Development Mission (TDM) experiment proposed by the NASA Lewis Research Center to be deployed on the Initial Operational Capability (IOC) space station. Technologies required by future orbital cryogenic systems such as Orbital Transfer Vehicles (OTV's) were defined, and critical technologies requiring demonstration were chosen to be included in the experiment. A three-phase test program was defined to test the following types of technologies: (1) Passive Thermal Technologies; (2) Fluid Transfer Technologies; and (3) Active Refrigeration Technologies. The development status of advanced technologies required for the LTCFS experiment is summarized, including current, past and future programs.

Riemer, David H.↗
NASA NTRS1987

Use of a 2.3-GHz traveling-wave maser on the Usuda 64-meter antenna

A 2.3 GHz traveling-wave maser/closed-cycle refrigeration system was installed on the 64 m antenna at Usuda, Japan. This was done to evaluate the beam-waveguide antenna noise performance, and to support the International Cometary Explorer's (ICE's) comet flyby mission. System noise temperature at 2270 MHz was measured to be 15 K, including the maser noise contribution of 2.5 K. Maser installation and noise performance are described. The Usuda 64 m antenna is of high quality with a system operating noise temperature better than the DSN 64 m antennas.

Neff, D.↗
NASA NTRS1987

Space station experiment definition: Long-term cryogenic fluid storage

The conceptual design of a space station Technology Development Mission (TDM) experiment to demonstrate and evaluate cryogenic fluid storage and transfer technologies is presented. The experiment will be deployed on the initial operational capability (IOC) space station for a four-year duration. It is modular in design, consisting of three phases to test the following technologies: passive thermal technologies (phase 1), fluid transfer (phase 2), and active refrigeration (phase 3). Use of existing hardware was a primary consideration throughout the design effort. A conceptual design of the experiment was completed, including configuration sketches, system schematics, equipment specifications, and space station resources and interface requirements. These requirements were entered into the NASA Space Station Mission Data Base. A program plan was developed defining a twelve-year development and flight plan. Program cost estimates are given.

Jetley, R. L.↗
NASA NTRS1987

An analysis of bipropellant neutralization for spacecraft refueling operations

Refueling of satellites on orbit with storable propellants will involve venting part or all of the pressurant gas from the propellant tanks. This gas will be saturated with propellant vapor, and it may also have significant amounts of entrained fine droplets of propellant. The two most commonly used bipropellants, monomethyl hydrazine (MMH) and nitrogen tetroxide (N2O4), are highly reactive and toxic. Various possible ways of neutralizing the vented propellants are examined. The amount of propellant vented in a typical refueling operation is shown to be in the range of 0.2 to 5% of the tank capacity. Four potential neutralization schemes are examined: chemical decomposition, chemical reaction, condensation and adsorption. Chemical decomposition to essentially inert materials is thermodynamically feasible for both MMH and N2O4. It would be the simplest and easiest neutralization method to implement. Chemical decomposition would require more complex control. Condensation would require a refrigeration system and a very efficent phase separator. Adsorption is likely to be much heavier. A preliminary assessment of the four neutralization shemes is presented, along with suggested research and development plans.

Kauffman, David↗
NASA NTRS1987

The Telecommunications and Data Acquisition Report

Developments in programs managed by the Jet Propulsion Laboratory's Office of Telecommunications and Data Acquisition are discussed. Topics discussed include sorption compression/mechanical expanded hybrid refrigeration, calculated 70-meter antenna performance for offset L-band, systolic arrays and stack decoding, and calibrations of Deep Space Network antennas.

Posner, E. C.↗
NASA NTRS1986

The C3H2 2(20)-2(11) transition - Absorption in cold dark clouds

The first observations of the 2(20)-2(11) transition of cyclopropenylidene (C3H2) at 21.6 GHz are described. The most significant finding is that the 2(20)-2(11) transition line is always seen in absorption, in contrast to the 18.3-GHz 1(10)-1(01) resonance line of the ortho species which always appears in emission in cold dust clouds. Thus the former must have an excitation temperature less than the brightness temperature of the universal microwave background and becomes only the second molecule to exhibit such 'refrigeration' below this temperature in cold, dark dust clouds.

Matthews, H. E.↗
NASA NTRS1985

Design and testing of a coaxial linear magnetic spring with integral linear motor

The design of a coaxial linear magnetic spring which incorporates a linear motor to control axial motion and overcome system damping is presented, and the results of static and dynamic tests are reported. The system has nominal stiffness 25,000 N/m and is designed to oscillate a 900-g component over a 4.6-mm stroke in a Stirling-cycle cryogenic refrigerator being developed for long-service (5-10-yr) space applications (Stolfi et al., 1983). Mosaics of 10 radially magnetized high-coercivity SmCO5 segments enclosed in Ti cans are employed, and the device is found to have quality factor 70-100, corresponding to energy-storage efficiency 91-94 percent. Drawings, diagrams, and graphs are provided.

Patt, P. J.↗
NASA NTRS1986

Measurement of the speed of sound in ice

The data presented demonstrate the gathering of sound speed measurements in refrigerated ice, using both compressional and shear waves, on the basis of ice thickness and sound wave time-of-travel parameters. Clear and sharp echo reflections were obtained for both compressional and shear waves at the aluminum/ice and ice/aluminum interfaces for ice at -26 C; ice formed at various conditions can have different sound speeds, depending on the density and elastic constants.

Smith, A. C.↗
NASA NTRS1986

MIPS - The Multiband Imaging Photometer for SIRTF

The Multiband Imaging Photometer for SIRTF (MIPS) is to be designed to reach as closely as possible the fundamental sensitivity and angular resolution limits for SIRTF over the 3 to 700 micron spectral region. It will use high performance photoconductive detectors from 3 to 200 micron with integrating JFET amplifiers. From 200 to 700 microns, the MIPS will use a bolometer cooled by an adiabatic demagnetization refrigerator. Over much of its operating range, the MIPS will make possible observations at and beyond the conventional Rayleigh diffraction limit of angular resolution.

Rieke, G. H.↗
NASA NTRS1986

MIPS - The Multiband Imaging Photometer for SIRTF

The Multiband Imaging Photometer System (MIPS) for SIRTF is to be designed to reach as closely as possible the fundamental sensitivity and angular resolution limits for SIRTF over the 3 to 700 microns spectral region. It will use high performance photoconductive detectors from 3 to 200 microns with integrating JFET amplifiers. From 200 to 700 microns, the MIPS will use a bolometer cooled by an adiabatic demagnetization refrigerator. Over much of its operating range, the MIPS will make possible observations at and beyond the conventional Rayleigh diffraction limit of angular resolution.

Rieke, G. H.↗
NASA NTRS1986

Evaluation of on-orbit cryogenic propellant depot options for the orbital transfer vehicle

An orbital cryogenic propellant storage facility will be required for a space-based Orbital Transfer Vehicle. The facility tanks will have features to permit fluid acquisition and transfer in low gravity and to limit cryogen boiloff caused by environmental heating. Boiloff management features will include thick multilayer insulation, vapor-cooled shields, low conductance structural supports and penetrations, and possibly refrigeration systems.

Schuster, J. R.↗
NASA NTRS1986

Improving adsorption cryocoolers by multi-stage compression and reducing void volume

It is shown that the performance of gas adsorption cryocoolers is greatly improved by using adsorbents with low void volume within and between individual adsorbent particles (reducing void volumes in plumbing lines), and by compressing the working fluid in more than one stage. Refrigerator specific power requirements and compressor volumetric efficiencies are obtained in terms of adsorbent and plumbing line void volumes and operating pressures for various charcoal adsorbents using an analytical model. Performance optimization curves for 117.5 and 80 K charcoal/nitrogen adsorption cryocoolers are given for both single stage and multistage compressor systems, and compressing the nitrogen in two stages is shown to lower the specific power requirements by 18 percent for the 117.5 K system.

Bard, S.↗
NASA NTRS1987

A 2.3-GHz cryogenically cooled HEMT amplifier for DSS 13

A prototype 2.3 GHz (S band) high electron mobility transistor (HEMT) amplifier/closed cycle refrigerator (CCR) system was installed in the DDS-13 feedcone, replacing the 2.3 GHz maser. The amplifier is cryogenically cooled to a physical temperature of 12 K and provides 31.5 K antenna system noise temperature and 29 dB of gain. The HEMT device used in the amplifier is a prototype.

Tanida, L.↗