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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 1,675 records · Page 93
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Comparison of thermal analytic model with experimental test results for 30-sentimeter-diameter engineering model mercury ion thruster

A thermal analytic model for a 30-cm engineering model mercury-ion thruster was developed and calibrated using the experimental test results of tests of a pre-engineering model 30-cm thruster. A series of tests, performed later, simulated a wide range of thermal environments on an operating 30-cm engineering model thruster, which was instrumented to measure the temperature distribution within it. The modified analytic model is described and analytic and experimental results compared for various operating conditions. Based on the comparisons, it is concluded that the analytic model can be used as a preliminary design tool to predict thruster steady-state temperature distributions for stage and mission studies and to define the thermal interface bewteen the thruster and other elements of a spacecraft.

Oglebay, J. C.↗
NASA NTRS1976

Comparison of layer thickness as observed by Nimbus E microwave spectrometer and by radiosonde

Atmospheric layer thicknesses observed by the microwave spectrometer of the Nimbus E satellite are compared with radiosonde-derived thicknesses for selected short periods. An average 45 m rms discrepancy is found for the 100-50 kPa layer, and several sources of this discrepancy are quantified in the following way. Correlation coefficients between pairs of spectrometer observations and between pairs of radiosonde observations are each extrapolated to zero separation distance to provide measures of instrument noise. Microwave spectrometer noise is found to be 16 m rms and radiosonde noise 23 m rms. Estimates are also made of those portions of the total discrepancy which are due to different resolution of the sensors (about 15 m rms) and real spatial and temporal variation of the atmosphere between observations (about 17 m rms).

Wilcox, R. W.↗
NASA NTRS1977

Pontlyfni - A differentiated meteorite related to the group IAB irons

The abundances of 23 major and trace elements in the Pontlyfni meteorite have been measured by instrumental neutron activation analysis. The compositions of the metal and silicate fractions suggest a genetic relationship between Pontlyfni and the group IAB irons.

Davis, A. M.↗
NASA NTRS1975

JANNAF Rocket Engine Performance Test Data Acquisition and Interpretation Manual

Procedures recommended by the JANNAF Performance Standardization Working Group for acquisition and Interpretation of performance test data are presented. Included with the description of these procedures are recommended procedures covering the required measurements, associated instrumentation, calibration methods, and data uncertainties. In addition, criteria for the applicability of existing test data, the selection of test models, and analytical performance prediction improvement based on test results are outlined. Three sample cases using the recommended procedures are presented as an addendum under separate cover. Author

Evans, S. A.↗
NASA NTRS1977

LANDSAT menhaden and thread herring resources investigation

The author has identified the following significant results. The relationship between the distribution of menhaden and selected oceanographic parameters (water color, turbidity, and possibly chlorophyll concentrations) was established. Similar relationships for thread herring were not established nor were relationships relating to the abundance of either species. Use of aircraft and LANDSAT remote sensing instruments to measure or infer a set of basic oceanographic parameters was evaluated. Parameters which could be accurately inferred included surface water temperature, salinity, and color. Water turbidity (Secchi disk) was evaluated as marginally inferrable from the LANDSAT MSS data and chlorophyll-a concentrations as less than marginal. These evaluations considered the parameters only as experienced in the two test areas using available sensors and statistical techniques.

Kemmerer, A. J.↗
NASA NTRS1977

Microwave radiometry for soil moisture sensing

Investigations have been conducted with truck-mounted radiometers to study the variation of microwave emissivity from a soil. It was found that the longer wavelength radiometers, (21 cm), are preferable for the remote sensing of soil moisture. Aircraft observations indicated a nonlinear dependence of microwave brightness temperature on soil moisture. The dielectric constants of soils are considered along with the radiative transfer in soils, and soil water characteristics. A description is presented of test flights conducted with a NASA aircraft, taking into account soil moisture measurements and instrumentation. The obtained results show that the surface emissivity of a soil is determined by the dielectric properties of the surface soil layer a few tenths of a wavelength thick while the thermal sampling depths are much greater. The capability of the 21-cm radiometer to sense soil-moisture variations through a moderate vegetation canopy, and the promising Skylab results encourage consideration of a radiometer operating at this wavelength for routine soil moisture observations.

Schmugge, T.↗
NASA NTRS1979

Controlling a wide range of flow rates

Servo-operated valve and two flowmeters allow accurate control over 1,900:1 flow-rate range. It was developed as part of laboratory instrument for measuring properties of confined fluids under conditions analogous to those encountered in deep drilling operations.

Perkins, G. S.↗
NASA NTRS1980

High-temperature high-pressure magnetic pickup

Magnetic-pickup transducers operate at temperature as high as 1,100 C and pressures in excess of 2.5 kilobars. Transducers obtain simulated seismic data in laboratory experiments at high temperatures and pressure. They also have potential applications in industrial instrumentation for measurements under similarly difficult conditions. Transducers use high-temperature cement to bond parts together and high-temperature-insulated copper or aluminum wire for windings.

Ahlberg, L. A.↗
NASA NTRS1978

Rocket observations of electron-density irregularities in the equatorial ionosphere below 200 km

Nike Apache rockets carring instrumentation to measure electron density and its fine structure in the equatorial ionosphere were launched from Chilca, Peru in May and June 1975. The fine structure experiment and the data reduction system are described. Results obtained from this system are presented and compared with those obtained by VHF radar and from other rocket studies. A description of the equatorial ionosphere and its features is also presented.

Klaus, D. E.↗
NASA NTRS1979

Large-scale pool fire test recommendations

The important aspects of external pool fires are outlined. The research objectives are: (1) determine heat flux to surfaces as a function of pool size (convective and radiative heat flux); (2) obtain information that can be compared with theoretical models for radiative flux in the near field; and (3) predict radiative heat flux for arbitrary pool size. The measurements and instrumentation (calorimeters and thermocouples) used for pool fires are outlined.

Bankston, C. P.↗
NASA NTRS1979

Structure of the atmosphere of Venus up to 110 kilometers - Preliminary results from the four Pioneer Venus entry probes

Each of the four Pioneer Venus probes carried instruments to measure the structure of the atmosphere, both below the cloud deck and above it to an altitude of at least 120 km. Preliminary results are presented on lower-atmosphere structure, thermal contrasts, and atmospheric stability. Altitudes derived from the data are given along with the temperature profile from 67 to 105 km, derived from the first analysis of the entry data from the north probe. All four probes lost temperature data at the 640 K level, which is at an altitude of about 12 to 14 km. Values of temperature and pressure at touchdown are presented in a table. The pressure differences imply terrain elevation differences at the landing sites. Above 40 km, the measured profile moves from near-adiabatic toward the theoretical profile for radiative equilibrium.

Seiff, A.↗
NASA NTRS1979

Intense electrostatic waves near the upper hybrid resonance frequency

Plasma wave measurements using instruments on the Imp 6 and Hawkeye satellites are utilized in a study of very intense electrostatic waves near the upper hybrid resonance frequency in the region just outside the plasmapause. Studies of these electrostatic disturbances show that the events occur at local times and at magnetic latitudes varying from the equator to 50 deg, and the polarization of these waves is such that the wave electric field vector is oriented perpendicular to the geomagnetic field. In most cases the center frequency of the intense waves corresponds to an (n + 1/2) fg(-) harmonic near the upper hybrid resonance frequency. The hot distribution on function is described for a few events showing temperature anisotropy and a loss cone distribution. A possible mechanism for producing intense waves near the upper hybrid resonance frequency is suggested, and evidence which indicates that the intense electrostatic waves may be a source of nonthermal continuum radiation is given.

Kurth, W. S.↗
NASA NTRS1979

High temperature UF6 RF plasma experiments applicable to uranium plasma core reactors

An investigation was conducted using a 1.2 MW RF induction heater facility to aid in developing the technology necessary for designing a self critical fissioning uranium plasma core reactor. Pure, high temperature uranium hexafluoride (UF6) was injected into an argon fluid mechanically confined, steady state, RF heated plasma while employing different exhaust systems and diagnostic techniques to simulate and investigate some potential characteristics of uranium plasma core nuclear reactors. The development of techniques and equipment for fluid mechanical confinement of RF heated uranium plasmas with a high density of uranium vapor within the plasma, while simultaneously minimizing deposition of uranium and uranium compounds on the test chamber peripheral wall, endwall surfaces, and primary exhaust ducts, is discussed. The material tests and handling techniques suitable for use with high temperature, high pressure, gaseous UF6 are described and the development of complementary diagnostic instrumentation and measurement techniques to characterize the uranium plasma, effluent exhaust gases, and residue deposited on the test chamber and exhaust system components is reported.

Roman, W. C.↗
NASA NTRS1980

Argon/UF6 plasma experiments: UF6 regeneration and product analysis

An experimental and analytical investigation was conducted to aid in developing some of the technology necessary for designing a self-critical fissioning uranium plasma core reactors (PCR). This technology is applicable to gaseous uranium hexafluoride nuclear-pumped laser systems. The principal equipment used included 1.2 MW RF induction heater, a d.c. plasma torch, a uranium tetrafluoride feeder system, and batch-type fluorine/UF6 regeneration systems. Overall objectives were to continue to develop and test materials and handling techniques suitable for use with high-temperature, high-pressure, gaseous UF6; and to continue development of complementary diagnostic instrumentation and measurement techniques to characterize the effluent exhaust gases and residue deposited on the test chamber and exhaust system components. Specific objectives include: a development of a batch-type UF6 regeneration system employing pure high-temperature fluorine; development of a ruggedized time-of-flight mass spectrometer and associated data acquisition system capable of making on-line concentration measurements of the volatile effluent exhaust gas species in a high RF environment and corrosive environment of UF6 and related halide compounds.

Roman, W. C.↗
NASA NTRS1980

The stratcom 8 effort

The ozone-nitrogen oxides ultraviolent flux interactions were investigated to obtain data on stratospheric photochemistry. The balloon, rocket, and aircraft operations are described along with the instruments, parameter measurements, and payloads.

Reed, E. I.↗
NASA NTRS1971

Earth orbital experiment program and requirements study

A compilation of Earth orbital experiments and their required support technological developments is given. Six disciplines including manned spaceflight capability, space biology, spce astronomy, space physics, communications and navigation, and Earth observations were subjected to an overview analysis that resulted in the identifiying of 3,800 critical issues. Of these critical issues, 1,983 that were deemed suitable for near-term manned space research were grouped into 136 research clusters in accordance with commonality of instrumentation and measurements. These clusters are described at a level of detail that identifies the important aspects of the research and establishes the principal requirements that will be placed on the missions in accomplishing the research and on the space research facilities for these missions. Summaries of the space facility requirements and guidelines for mission planning are given. The supporting technology developments required to pursue the research are identified and grouped into 233 work packages.

Source record↗
NASA NTRS1980

The mechanisms of the SAMS experiment flown on Nimbus 7 with particular reference to the 2 axis scanning mirror

The stratospheric and mesospheric sounder (SAMS) experiment on Nimbus 7 includes a 2 axis scanning mirror and 7 pressure modulator cells. The SAMS experiment is a limb sounding instrument to measure the temperature profile and minor constituents of the atmosphere. The limb scan requires small mirror steps over a 3 deg range, while the scan in azimuth is in larger steps over a 15 deg range. The mirror is plane, 20 cm in diameter, and of zero expansion glass-ceramic. It is supported on two tilt tables, fitted one on the other, with the axes at right angles. The angle of tilt is adjusted by means of recirculating ball screws which are ion plated with lead for lubrication and driven by stepper motors. The seven gas filled cells are each pressure modulated by a 3 cm diameter, 0.3 cm stroke piston which is supported by diaphragm springs and driven electromagnetically at the system's mechanical resonant frequency. The mean pressure of the filling gas, which is the atmospheric constituent being measured, is changed by varying the temperature of a suitable molecular sieve.

Hadley, H.↗