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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 1,369 records · Page 76
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Experimental evaluation of a 600 lbf spacecraft rocket engine.

Experimental results are presented for a long-duration-capability (1000-sec), space-storable, bipropellant liquid rocket motor burning fluorine/hydrazine or FLOX/monomethylhydrazine. The interrelationship between injected mixture ratio and the per cent film cooling on vacuum specific impulse performance and chamber heat transfer is given. Experimental sea level measurements are used to predict space vacuum performance based upon simplified JANNAF reference procedures. Dynamic combustion stability is demonstrated over a wide range of operating conditions. Analytical results of char penetration, erosion, and ablative wall temperature distributions are presented for prototype chamber designs.

Hoehn, F. W.↗
NASA NTRS1972

Geology of the Apollo 14 landing site.

Apollo 14 landed in the Fra Mauro region of the moon, within about 1,100 m of a 90 m high ridge of the Fra Mauro formation, interpreted as being ejecta from the Imbrium Basin. The primary geologic objective of the mission was to sample ejecta from Cone Crater, which is 340 m in diameter and penetrates at least 60 m into the ridge. Data from the mission strongly support the Imbrian ejecta origin for the Fra Mauro formation. Returned samples and photographs show that ejecta from Cone Crater is composed of composite breccias that include multiple clasts of still older, pre-Imbrian, breccias. Cone Crater ejecta displays a wide range of thermal metamorphism effects. Samples from the valley where the Lunar Module landed, which was not on a recognizable ray of ejecta from Cone Crater, are predominantly fines and poorly consolidated breccias formed by the disintegration of Fra Mauro rocks and probably are not volcanic rocks as had been postulated before the mission.

Sutton, R. L.↗
NASA NTRS1972

Some surface characteristics and gas interactions of Apollo 14 fines and rock fragments.

Comprehensive survey of the physical surface characteristics of Apollo 14 fines, two fragments of a breccia (14321), and a crystalline rock (14310). The survey was carried out with optical and both scanning and transmission electron microscopy and by studying the adsorption of a variety of gases including nitrogen, hydrogen, and water vapor. Our objective in the optical microscope study was to relate the visible geological and petrological features to the surface properties. Electron microscopy particularly helped relate surface roughness and particle fusion to gas adsorption and pore structure. The fine sample (14163,111) had a surface area of 0.210 sq m/g and a helium density of 2.9 g/cc. Similar values have been observed with breccia fragments. Other observations include physical adsorption of molecular hydrogen at low temperatures and of water vapor at ambient temperatures. It is concluded that these particular lunar materials, while capable of adsorbing water vapor, do not retain it for any significant time at low pressures, nor, under lunar conditions, is there any indication of absorption or penetration.

Cadenhead, D. A.↗
NASA NTRS1972

Multiple-orifice liquid injection into hypersonic air streams.

Review of oblique water and fluorocarbon injection test results obtained in experimental studies of the effects of multiple-orifice liquid injection into hypersonic air streams. The results include the finding that maximum lateral penetration from such injections increases linearly with the square root of the jet-to-freestream dynamic-pressure ratio and is proportional to an equivalent orifice diameter.

Weaver, W. L.↗
NASA NTRS1973

Space Shuttle response to atmospheric turbulence.

A fully reusable Space Shuttle configuration has been analyzed during ascent flight to determine its response to atmospheric turbulence. Propellant sloshing, gust penetration, and automatic control system effects were included. The steady-state aerodynamic method of Woodward was used to derive the generalized aerodynamic forces, using the standard quasi-steady assumption. Aerodynamic interference effects between adjacent wings and bodies were found to be significant, with symmetric responses generally higher than antisymmetric. The stability augmentation system tended to lower booster response while increasing orbiter response. Loads due to 9 m/s quasi-square-wave gusts were considerably higher than the 3 sigma random turbulence loads. The elastic portion of the response accounted for about 15% of the total wing load in the discrete gust analysis, while in the random case the elastic effect was small.

Huntington, R. G.↗
NASA NTRS1973

Ion cyclotron waves observed in the polar cusp.

During the penetration by Ogo 5 of the low-latitude disturbed polar cusp region on Nov. 1, 1968, while a major magnetic storm was in progress, a variety of plasma wave activity was observed. Observations of waves with amplitudes less than 2% of the background magnetic field intensity and having frequencies between approximately 0.67 and 0.87 times the local proton gyrofrequency are described. The polarization of these waves indicates that they are propagating at an appreciable angle to the local geomagnetic field line direction. The source of these waves has not been determined, but currents and gradient drifts are suggested as possible agents.

Fredricks, R. W.↗
NASA NTRS1973

Solar flare cosmic rays at and beyond the modulation boundary.

Consideration of the characteristics of solar flare cosmic ray events observed beyond a postulated modulation boundary, should any such boundary exist. It is pointed out that observations of solar flare particles at great distances from the sun provide a sensitive and precise diagnostic for any such boundary. Such considerations are of substantial interest in view of the probable penetration of deep space probes to distances of the order of 10 AU in the near future.

Jokipii, J. R.↗
NASA NTRS1973

High altitude aircraft water vapor measurements.

A hygrometer for water vapor measurements from an aircraft was developed. An aluminum oxide hygrometer mounted in an aircraft Rosemount air temperature scoop was flown on the NASA Convair 990 and on a USAF B-57 aircraft. Water vapor measurements from the Convair 990 were conducted up to 40,000 ft with penetration into the stratosphere. Good agreement was obtained with simultaneously flown remote sounders of water vapor. During transcontinental flights the hygrometer demonstrated adequate response to measure the natural variability of water vapor near the tropopause. Rapid response was demonstrated in pursuit of the jet wake of an F-104 at 35,000 ft.

Hilsenrath, E.↗
NASA NTRS1973

Early results of Pioneer 10 particulate experiments.

On March 2, 1972 the Pioneer 10 spacecraft was launched on an interplanetary trajectory to encounter Jupiter late in 1973. The spacecraft carries four experiments designed to measure interplanetary particulates in a wide range of sizes from submicron to millimeter diameters. One experiment measures individual particulates by reflected sunlight. Two measure the aggregate particulates by scattered sunlight, while the fourth measures penetrations caused by individual particles. All have been collecting data from one to beyond four astronomical units. The data includes the first in situ measurements of small particulates in the Asteroid Belt. The results of the early analyses will be presented with particular emphasis on the distribution in the Asteroid Belt and its comparison to the interplanetary particulate distribution between the orbits of Earth and Mars.

Soberman, R. K.↗
NASA NTRS1973

Equilibrium properties of a one-dimensional kinetic system.

One-dimensional systems of N = 500 and 250 particles in equilibrium are numerically simulated utilizing the method of molecular dynamics. Periodic boundary conditions are imposed. The classical two-body interaction potential is short range, repulsive and has a corresponding finite force. The equations of state are determined for densities both less and greater than one. Corresponding theoretical isochores are determined from models based on nearest-neighbor interactions and on a truncated virial expansion, and a comparison is made with the experimental isochores. Time independent radial distributions are constructed numerically and discussed. A change of state from a solidlike state to a fluid-gas state based on the penetrability of the particles is predicted. The transition temperatures are estimated from the radial distribution functions and the nearest-neighbor model. Self-diffusion is observed and the corresponding constants are determined from the velocity autocorrelation functions.

Williams, J. H.↗
NASA NTRS1973

Magnetic storm inflation in the evening sector.

Analysis of the different behavior of a double magnetic disturbance in November 1971, as observed by Explorer 45, and in December 1971, as shown by ground level magnetic observations. The time sequence of magnetic storm inflation in the evening quadrant of the magnetosphere, as determined by both series of observations, is used as the criterion of the analysis. Particular attention is given to the various phases of proton penetration into the evening quadrant of the magnetosphere during the magnetic disturbance.

Cahill, L. J., Jr.↗
NASA NTRS1973

Nutrition systems for pressure suits.

Nutrition systems were successfully developed in the Apollo Program for astronauts wearing pressure suits during emergency decompression situations and during lunar surface explorations. These nutrition systems consisted of unique dispensers, water, flavored beverages, nutrient-fortified beverages, and intermediate moisture food bars. The emergency decompression system dispensed the nutrition from outside the pressure suit by interfacing with a suit helmet penetration port. The lunar exploration system utilized dispensers stowed within the interior layers of the pressure suit. These systems could be adapted for provision of nutrients in other situations requiring the use of pressure suits.

Huber, C. S.↗
NASA NTRS1973

Reliability of cosmic dust data from Pioneers 8 and 9.

A comprehensive study of the characteristics and capabilities of the Pioneer cosmic dust mission is presented to facilitate accurate astronomical adaptations of the data by independent researchers. The characteristics of the sensor and associated electronics as they relate to dynamic range, field of view, and penetration effects in the film are discussed, comparisons are made between flight and simulation data, and statistical analyses are made of the reliability of the flight data. It is shown that the measurements from the Pioneer experiment are highly reliable and provide a valuable contribution to man's knowledge of the meteoroid environment of the solar system.

Gruen, E.↗
NASA NTRS1974

Detection of cracks in surface insulation

Volatile organic liquid surface penetrants used with appropriate detector paper leave tested surfaces uncontaminated. Method can be used to detect minute cracks in materials such as metal, glass, plastics, ceramics, etc.

Leger, L. J.↗
NASA NTRS1973

A buoyant tornado-probe concept incorporating an inverted lifting device

Addition of an inverted lifting device to a simple balloon probe is shown to make possible low-altitude entry to tornado cores with easier launch conditions than for the simple balloon probe. Balloon-lifter combinations are particularly suitable for penetration of tornadoes with average to strong circulation, but tornadoes of less than average circulation which are inaccessible to simple balloon probes become accessible. The increased launch radius which is needed for access to tornadoes over a wide range of circulation results in entry times of about 3 minutes. For a simple balloon probe the uninflated balloon must be first dropped on, or near, the track of the tornado from a safe distance. The increase in typical launch radius from about 0.75 kilometer to slightly over 1.0 kilometer with a balloon-lifter combination suggests that a direct air launch may be feasible.

Grant, F. C.↗
NASA NTRS1973

Processing of thermionic power on an electrically propelled spacecraft

A study to define the power processing equipment required between a thermionic reactor and an array of mercury-ion thrusters for a nuclear electric propulsion system is reported. Observations and recommendations that resulted from this study were: (1) the preferred thermionic-fuel-element source voltages are 23 V or higher; (2) transistor characteristics exert a strong effect on power processor mass; (3) the power processor mass could be considerably reduced should the magnetic materials that exhibit low losses at high frequencies, that have a high Curie point, and that can operate at 15 to 20 kG become avaliable; (4) electrical component packaging on the radiator could reduce the area that is sensitive to meteoroid penetration, thereby reducing the meteoroid shielding mass requirement; (5) an experimental model of the power processor design should be built and tested to verify the efficiencies, masses, and all the automatic operational aspects of the design.

Macie, T. W.↗
NASA NTRS1972

Some new results on electron transport in the atmosphere

The penetration, diffusion and slowing down of electrons in a semi-infinite air medium has been studied by the Monte Carlo method. The results are applicable to the atmosphere at altitudes up to 300 km. Most of the results pertain to monoenergetic electron beams injected into the atmosphere at a height of 300 km, either vertically downwards or with a pitch-angle distribution isotropic over the downward hemisphere. Some results were also obtained for various initial pitch angles between 0 deg and 90 deg. Information has been generated concerning the following topics: (1) the backscattering of electrons from the atmosphere, expressed in terms of backscattering coefficients, angular distributions and energy spectra of reflected electrons, for incident energies T(o) between 2 keV and 2 MeV; (2) energy deposition by electrons as a function of the altitude, down to 80 km, for T(o) between 2 keV and 2 MeV; (3) the corresponding energy depostion by electron-produced bremsstrahlung, down to 30 km; (4) the evolution of the electron flux spectrum as function of the atmospheric depth, for T(o) between 2 keV and 20 keV. Energy deposition results are given for incident electron beams with exponential and power-exponential spectra.

Berger, M. J.↗
NASA NTRS1973

High gas velocity burner tests on silicon carbide and silicon nitride at 1200 C

Specimens of silicon carbide and silicon nitride were exposed to a Mach one gas velocity burner simulating a turbine engine environment. Cyclic tests up to 100 hour duration were conducted at specimen temperatures of 1200 C. A specimen geometry was used that develops thermal stresses during thermal cycling in a manner similar to blades and vanes of a gas turbine engine. Materials were compared on a basis of weight change, dimensional reductions, metallography, fluorescent penetrant inspection, X-ray diffraction analyses, failure mode, and general appearance. One hot pressed SiC, one reaction sintered SiC, and three hot pressed Si3N4 specimens survived the program goal of 100 one-hour cycle exposures. Of the materials that failed to meet the program goal, thermal fatigue was identified as the exclusive failure mode.

Sanders, W. A.↗