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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Optical properties of thermal control coatings contaminated by MMH/N2O4 5-pound thruster in a vacuum environment with solar simulation.

Cat-a-lac Black and S13G thermal control coatings were exposed to the exhaust of a thrustor in a simulated space environment. Vacuum was maintained at less than 10 microtorr during thrustor firing in the liquid helium cooled facility. The thrustor was fired in a 50-millisecond pulse mode, and the accumulated firing time was 224 seconds. Solar absorptance and thermal emittance of the coatings were measured in-situ at intervals of 300 pulses, using a calorimetric technique. The Cat-a-lac Black coatings showed no change in solar absorptance or thermal emittance. The S13G showed up to 25% increase in solar absorptance but no change in thermal emittance.

Sommers, R. D.↗
NASA NTRS1971

Solar radio emission at 1.2 mm wavelength.

A 36-ft radio telescope was used in the investigations. The 1.2 mm wavelength receiver connected to the telescope is a helium-cooled germanium bolometer. The 1.2 mm solar maps were obtained by scanning the sun in right ascension at the rate of 1 deg per minute. A temperature of 6000 K was assumed for the 1.2 mm quiet sun temperature for all solar maps. Eight maps at 1.2 mm were obtained on six different days. The 1.2 mm regions are rather large and without much structure; they are closely associated with Ca-plage regions.

Kundu, M. R.↗
NASA NTRS1973

Exhaust plume and contamination characteristics of a bipropellant (MMH/N2O4) RCS thruster

Results are presented for three recent tests in a series of thruster contamination experiments made in liquid helium-cooled environmental facility. The contaminating effects encountered on various materials, surfaces, and components, due to the exhaust products from a 5-pound thrust, bipropellant (MMH/N2O4) thruster are investigated. The angular distribution of plume effects around the periphery of the thruster established by transmittance changes of quartz samples over the wavelength range from 0.2 to 2.0 micrometer is studied, along with mass deposition rates at a specific location measured with a quartz crystal microbalance for three different experiments. Quadrupole mass spectrometer measurements of the exhaust products over the mass number range from 12 to 75; infrared transmittance measurements of contaminated samples for the wavelength range from 2.5 to 15 microns; and infrared transmittance measurements of residue from the thruster nozzle are also considered.

Spisz, E. W.↗
NASA NTRS1973

Far infrared astronomy

The research to develop a spectrometer to be used with a ground based telescope is described. Two liquid helium cooled infrared spectrometers were designed and built. The first, has a Cassegrain optical system and a variable focal length between 51.4 cm and 92.6 cm. It is capable of a resolution of 500. The second, has a focal length of 19.1 cm and has a resolution of 100. Both spectrometers have been operated at 10-30 microns. Sample spectra are included.

Houck, J. R.↗
NASA NTRS1973

Irradiation of TZM: Uranium dioxide fuel pin at 1700 K

A fuel pin clad with TZM and containing solid pellets of uranium dioxide was fission heated in a static helium-cooled capsule at a maximum surface temperature of 1700 K for approximately 1000 hr and to a total burnup of 2.0 percent of the uranium-235. The results of the postirradiation examination indicated: (1) A transverse, intergranular failure of the fuel pin occurred when the fuel pin reached 2.0-percent burnup. This corresponds to 1330 kW-hr/cu cm, where the volume is the sum of the fuel, clad, and void volumes in the fuel region. (2) The maximum swelling of the fuel pin was less than 1.5 percent on the fuel-pin diameter. (3) There was no visible interaction between the TZM clad and the UO2. (4) Irradiation at 1700 K produced a course-grained structure, with an average grain diameter of 0.02 centimeter and with some of the grains extending one-half of the thickness of the clad. (5) Below approximately 1500 K, the irradiation of the clad produced a moderately fine-grained structure, with an average grain diameter of 0.004 centimeter.

Mcdonald, G. E.↗
NASA NTRS1973

Balloon measurements of the far-infrared background radiation.

Description of a balloon-borne radiometer designed to make direct measurements of the background radiation in the spectral range from 1 to 20 cm, and evaluation of the results of two balloon flights performed with the aid of this radiometer. Measurements in five different passbands in the spectral region below 20 per cm were made with a liquid-helium-cooled radiometer in two flights at approximately 40-km altitude. The results obtained are found to be consistent with a 2.7 K thermal radiation background. In addition, an atmospheric radiation of certain magnitude is found to dominate the region above 11 per cm.

Muehlner, D.↗
NASA NTRS1973

Observation of the J = 2 to J = 1 transition of interstellar CO at 1.3 millimeters

The NRAO 36-foot antenna at Kitt Peak with a novel type of millimeter-wave superheterodyne receiver was used in observations of 1.3-mm line interstellar radiation due to J ? 2-1 transitions of C(12)0(16) and C(13)0(16). The liquid-helium-cooled hot-electron bolometer mixer of the superheterodyne receiver was used as the detecting element. The Orion Nebula CO system was found to be thermalized, showing a peak excitation temperature of about 76 K.

Phillips, T. G.↗
NASA NTRS1975

Far infrared spectroscopy of the Orion Nebula

A coarse resolution spectrum of the Orion Nebula between 65 and 125 microns is presented which closely fits the color dependence of a 75 K blackbody. A high resolution search for O III at 88.16 microns yields an upper limit below theoretical predictions. Observations were carried out in November, 1974, using the 31 cm gyrostabilized telescope mounted in the NASA Lear jet. The instrument employed was a fully liquid helium cooled grating spectrometer with a 3 mm entrance slit that gave a square beam on the sky, 5 arc minutes in diameter. The results are presented.

Ward, D. B.↗
NASA NTRS1974

Balloon-based measurements of the cosmic background radiation

A balloon-borne liquid-helium-cooled spectrometer was developed and flown to measure the cosmic background radiation in the 3- to 18-per-cm region. It features a cooled horn antenna, a polarizing Michelson interferometer, and a germanium bolometer. These design features and the performance of the instrument are discussed.

Mather, J. C.↗
NASA NTRS1975

Measurement of the spectrum of the submillimeter cosmic background

The spectrum of the night sky has been measured in the wave number range from 3 to 40 per cm using a fully calibrated liquid-helium-cooled balloon-borne spectrophotometer at an elevation of 39 km. A model based on the known molecular parameters was used to subtract the atmospheric emission. In the range from 4 to 17 per cm, the spectrum of the background radiation is that of a blackbody with a temperature of about 2.99 K.

Woody, D. P.↗
NASA NTRS1975

Far Infrared Spectroscopy of H II Regions

The far infrared spectra of H II regions are investigated. A liquid helium cooled grating spectrometer designed to make observations from the NASA Lear Jet is described along with tests of the instrument. The observing procedure on the Lear Jet telescope is described and the method of data analysis is discussed. Results are presented from a search for the (O III) 88.16 micron line. An upper limit on the emission in this line is obtained and line detection is described. Results are compared to theoretical predictions, and future applications of fine structure line observations are discussed. Coarse resolution results are given along with calibration problems. The spectra obtained are compared to models for dust emission.

Ward, D. B.↗
NASA NTRS1975

Ispra Mark-10 water splitting process

A thermochemical water splitting process, the Ispra Mark-10 chemical reaction cycle, was chosen for examining the possibility of using water to produce hydrogen on a large scale for fuel and major industrial chemical uses. The assumed energy source for the process is an HTGR (helium cooled). A process flow diagram, a material balance, and an energy balance were developed for the thermochemical reaction cycle. Principal reactions which constitute the cycle are included.

Source record↗
NASA NTRS1975

Space shuttle orbital maneuvering engine platelet injector program

A platelet-face injector for the fully reusable orbit maneuvering system OMS on the space shuttle was evaluated as a means of obtaining additional design margin and low cost. Performance, heat transfer, and combustion stability were evaluated over the anticipated range of OMS operating conditions. The effects of acoustic cavity configuration on combustion stability, including cavity depth, open area, inlet contour, and other parameters, were investigated using sea level bomb tests. Prototype injector and chamber behavior was evaluated for a variety of conditions; these tests examined the effects of film cooling, helium saturated propellants, chamber length, inlet conditions, and operating point, on performance, heat transfer and engine transient behavior. Helium bubble ingestion into both propellant circuits was investigated, as was chugging at low pressure operation, and hot and cold engine restart with and without a purge.

Source record↗
NASA NTRS1975

Detection of the O III 88.16-micron forbidden line in M17

This paper reports the detection of the fine-structure forbidden line of O III at 88.16 microns in emission from M 17 (the Omega Nebula), which is an optically bright galactic H II region and a strong thermal radio source. The observations were made using an airborne 30-cm telescope and a liquid helium-cooled grating spectrometer with Ge:Ga photoconductive detectors. The line intensity is found to be 2.2 (+1.0, -0.7) by 10 to the -15th power W/sq cm. The results are compared with those of a search for the present line in M 42 as well as with theoretical predictions of the line intensity.

Ward, D. B.↗
NASA NTRS1976

Far-infrared photometry of NGC 1068

The detection of far-IR emission from the galaxy NGC 1068 in four passbands spanning the spectral range from 28 to 320 microns is reported. The observations were made with a 61-cm airborne IR telescope and a liquid-helium-cooled multifilter radiometer. It is found that the flux density between 38 and 100 microns increases with increasing wavelength to a maximum value of 454 (plus or minus 94) Jy, but decreases rapidly for wavelengths greater than 100 microns. The total flux is estimated to be about 3 by 10 to the -11th power W/sq m, which corresponds to a bolometric luminosity of 3.7 by 10 to 11th power times the solar luminosity at a distance of 20 Mpc. The nuclear M/L ratio is shown to be no greater than about 0.003, indicating that the scale, optical depth, or both, of a thermal far-IR source in NGC 1068 would have to be larger than those of the extended IR sources around the nuclei of our Galaxy, NGC 253, or M82.

Telesco, C. M.↗
NASA NTRS1976

16-25 micron spectroscopy of the Trapezium and BN-KL source in Orion

Spectrophotometric observations from 16 to 25 microns of the Trapezium and the Becklin-Neugebauer-Kleinmann-Low (BN-KL) object in Orion are reported. These observations were obtained with a liquid-helium-cooled grating spectrometer. The observations of the Trapezium show a relatively flat spectrum between 16 and 25 microns, which is consistent with a 20-micron emission peak similar to that previously found at 10 microns. The BN-KL source has a smooth spectrum over the same range, showing little absorption such as characterizes the 10-micron spectrum of this source. This lack of a deep 20-micron absorption is attributed to complex radiative-transfer processes within the molecular cloud.

Forrest, W. J.↗
NASA NTRS1976

Nuclear driven water decomposition plant for hydrogen production

The conceptual design of a hydrogen production plant using a very-high-temperature nuclear reactor (VHTR) to energize a hybrid electrolytic-thermochemical system for water decomposition has been prepared. A graphite-moderated helium-cooled VHTR is used to produce 1850 F gas for electric power generation and 1600 F process heat for the water-decomposition process which uses sulfur compounds and promises performance superior to normal water electrolysis or other published thermochemical processes. The combined cycle operates at an overall thermal efficiency in excess of 45%, and the overall economics of hydrogen production by this plant have been evaluated predicated on a consistent set of economic ground rules. The conceptual design and evaluation efforts have indicated that development of this type of nuclear-driven water-decomposition plant will permit large-scale economic generation of hydrogen in the 1990s.

Parker, G. H.↗
NASA NTRS1976

Hydrogen production by water decomposition using a combined electrolytic-thermochemical cycle

A proposed dual-purpose power plant generating nuclear power to provide energy for driving a water decomposition system is described. The entire system, dubbed Sulfur Cycle Water Decomposition System, works on sulfur compounds (sulfuric acid feedstock, sulfur oxides) in a hybrid electrolytic-thermochemical cycle; performance superior to either all-electrolysis systems or presently known all-thermochemical systems is claimed. The 3345 MW(th) graphite-moderated helium-cooled reactor (VHTR - Very High Temperature Reactor) generates both high-temperature heat and electric power for the process; the gas stream at core exit is heated to 1850 F. Reactor operation is described and reactor innards are illustrated. A cost assessment for on-stream performance in the 1990's is optimistic.

Farbman, G. H.↗