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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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NASA NTRS1973

New radiometric techniques and solar constant measurements.

A series of absolute cavity radiometers, designed to measure solar irradiance, has been developed at the Jet Propulsion Laboratory. Analysis indicates the absolute uncertainty of irradiance measurements made by the most recent devices to be less than plus or minus 0.5 mW/sq cm. In a series of experiments the radiometric scale defined by the JPL instruments has been compared with the International Pyrheliometric Scale (IPS). A systematic 2.2% difference has been observed with the IPS producing consistently lower measurements. The solar constant and spectral distribution have been derived from high-altitude balloon flight measurements made by two types of JPL cavity radiometers. Measurements at 25 km in 1968 produced a solar constant value of 137.0 mW/sq cm. From 1969 measurements at 36 km, a value of 136.6 mW/sq cm was derived, with an estimated absolute uncertainty of plus or minus 0.5%. The solar spectrum information from these experiments agrees most closely with the solar spectrum model of Labs and Neckel (1968).

Willson, R. C.↗

NASA NTRS1973

EOS image data processing system definition study

The Image Processing System (IPS) requirements and configuration are defined for NASA-sponsored advanced technology Earth Observatory System (EOS). The scope included investigation and definition of IPS operational, functional, and product requirements considering overall system constraints and interfaces (sensor, etc.) The scope also included investigation of the technical feasibility and definition of a point design reflecting system requirements. The design phase required a survey of present and projected technology related to general and special-purpose processors, high-density digital tape recorders, and image recorders.

Gilbert, J.↗

NASA NTRS1976

Shuttle infrared telescope facility (SIRTF) preliminary design study

An overall picture of the SIRTF system is first presented, including the telescope, focal plane instruments, cryogen supply, shuttle and spacelab support subsystems, mechanical and data interfaces with the vehicles, ground support equipment, and system requirements. The optical, mechanical, and thermal characteristics of the telescope are then evaluated, followed by a description of the SIRTF internal stabilization subsystem and its interface with the IPS. Expected performance in the shuttle environment is considered. Tradeoff studies are described, including the Gregorian versus the Cassegrain telescope, aperture diameter tradeoff, a CCD versus an image dissector for the star tracker, the large ambient telescope versus the SIRTF, and a dedicated gimbal versus the IPS. Operations from integration through launch and recovery are also discussed and cost estimates for the program are presented.

Source record↗

NASA NTRS1976

Interplanetary scintillation observations with the Cocoa Cross radio telescope

Physical and electrical parameters for the 34.3-MHz Cocoa Cross radio telescope are given. The telescope is dedicated to the determination of solar-wind characteristics in and out of the ecliptic plane through measurement of electron-density irregularity structure as determined from IPS (interplanetary scintillation) of natural radio sources. The collecting area (72,000 sq m), angular resolution (0.4 deg EW by 0.6 deg NS), and spatial extent (1.3 km EW by 0.8 km NS) make the telescope well suited for measurements of IPS index and frequency scale for hundreds of weak radio sources without serious confusion effects.

Cronyn, W. M.↗

NASA NTRS1977

Structure-property relationships in oxide-dispersed iron-beryllia alloys

Two BeO dispersed iron alloys containing about 2.5 and 5.5 v/o dispersoid were produced by attritting, internally oxidizing, and extruding dilute, prealloyed Fe-Be powders. As-extruded alloys were given various thermomechanical treatments involving room temperature swaging and annealing above and below the allotropic transformation temperature. The elevated temperature rupture strengths were measured and correlated with changes in structure; strengthening trends were examined in the light of proposed models for such strengthening. The results obtained showed that the elevated temperature strength was determined by the oxide interparticle spacing (IPS) in recrystallized material and IPS as well as prior deformation in swaged specimens. In fact, a parametric correlation was found between rupture strength values in the longitudinal direction with prestrain during swaging. The overall pattern in strength and microstructural observations were more consistent with a strength-stored energy (substructure) dependence than a strength-grain shape (grain aspect ratio) relation.

Wolf, S.↗

NASA NTRS1977

Instrument pointing system applicability and orbiter stabilization for EVAL missions. Application studies

Related aspect of the Earth Viewing Applications Laboratory (EVAL) shuttle missions were investigated. The applicability of the gimballed Instrument Pointing System (IPS) to EVAL missions by comparing the IPS capabilities with the EVAL requirements was evaluated, and a means of stabilizing the shuttle orbiter attitude in earth viewing orientations for prolonged periods without use of the orbiter gas reaction control system was assessed.

Spector, V. A.↗

NASA NTRS1978

Optical detection of local interstellar particles during an out-of-ecliptic mission

A proposed NASA/ESA 'out of ecliptic' mission for placing limits on the brightness of the interstellar (IS) relative to the interplanetary (IP) component of zodiacal light is discussed. The brightness integral used to estimate the monochromatic is introduced, and it is explained that, although the interstellar contribution is below the limit of detectability for earth-based measurements, sunwards viewing from a spacecraft located at a distance of 1 AU would be able to detect the IS component. The color difference between the IS and IP components is considered in an analysis of the upper limit of IS component detectability.

Greenberg, J. M.↗

NASA NTRS1979

Interstellar scattering, the North Polar Spur, and a possible new class of compact galactic radio sources

Claims for a galactic-latitude dependence of interstellar angular broadening based on interplanetary-scintillation (IPS) observations are investigated. Analysis of the statistics of the angular sizes in an IPS survey shows that there is no evidence for increased angular broadening in the galactic plane. A region of sky about 500 sq deg of arc in area is considered in which significant angular broadening is thought to exist. An association between this region and the nearby North Polar Spur is proposed on the basis of the former's extension off the galactic plane to high latitudes. An evaluation of two-frequency angular-broadening measurements suggests that the data used to support the conclusion about a galactic-latitude dependence are not statistically significant. A study of pulsar data and implications for the angular broadening expected in the interstellar medium for sources at galactic latitudes below + or - 10 deg indicates the possible existence of a previously unsuspected class of compact galactic nonthermal radio sources, designated 'scintars'.

Rickard, J. J.↗

NASA NTRS1978

Preliminary study of head-up assessment techniques. 1: Viewing duration of instrument panel and HUD symbology using a recall methodology

Eight commercial pilots were shown 50 colored, high fidelity slides of a standard instrument panel (IP) with the needle positions of each instrument varying from slide to slide and then 50 slides of a head-up display (HUD) symbology format which contained an equivalent amount of flight-related information as the instrument panel slides. All stimuli were presented under controlled, static viewing conditions that allowed the measurement of the speed and accuracy with which one randomly selected flight parameter on each slide could be read. The subject did not know which parameter would be requested and, therefore, had to remember the total set of information in order to answer the question correctly. The results showed that from 6.6 - 8.7 sec total viewing time was required to correctly extract altitude, airspeed, heading, VSI, or ADI from the IP slides and from 6.1 to 7.4 sec for the HUD slides.

Haines, R. F.↗

NASA NTRS1981

Solar wind motion within 30 R solar masses - Spacecraft radio scintillation observations

New remote-sensing observations are reported of the solar wind motion within about 30 earth radii. Use is made of the interplanetary scintillation (IPS) spaced receiver technique with the radio source being a spacecraft signal (rather than a natural radio source as in previous spaced receiver studies). The spacecraft used are Helios A and B and the Viking orbiters. The purposes of the study are (1) to augment the scarce estimates of solar wind bulk flow speed near the sun and in the ecliptic with measurements made using spacecraft signals, and (2) to estimate random velocity components and identify the region where the random velocity is a significant fraction of the mean velocity. In addition, the radial evolution of speed and random velocity is compared with that of the plasma density fluctuation spectrum. Also reported are the first accurately normalized IPS scintillation index measurements using a monochromatic point source.

Armstrong, J. W.↗

NASA NTRS1983

Image motion compensation for the OSS-3/7 telescopes

The three telescope for the NASA Office of Space Science (OSS) Missions 3/7 will be clustered on the Instrument Point System (IPS). The IPS is to be mounted on a Spacelab pallet in the space shuttle orbiter. The three telescopes include the Ultraviolet Imaging Telescope (UIT), the Hopkins Ultraviolet Telescope (HUT), and the Wisconsin Ultraviolet Photopolarimetry Experiment (WUPPE). All three instruments have the ability to view from earth orbit stellar objects which are fainter than those which can be seen with ground-based telescopes. An Image Motion Compensation (IMC) system will be required for the appropriate conduct of the observations. The OSS-3/7 pointing problem is discussed, and a cost effective IMC system is proposed.

Shelton, H.L.↗

NASA NTRS1982

Interplanetary radio storms. 2: Emission levels and solar wind speed in the range 0.05-0.8 AU

Storms of interplanetary type III radio bursts (IP storms) are commonly observed in the interplanetry medium by the ISEE-3 radio instrument. This instrument has the capability of accurately determining the arrival direction of the radio emission. At each observing frequency, the storm radio sources are tracked as they cross the line-of-sight to the Sun. Usng a simple model, the emission levels are determined at a number of radio frequencies for four separate storms. The IP storm radiation is found to occur in regions of enhanced density at levels of 0.05 to 0.8 AU. The density in these enhancements falls off faster than R(-2). The solar wind speed in the storm region is also measured. The analysis is consistent with steady conditions in the storm region during a few days around the central meridian passage of the storm. The comparison with average in situ density measurements compiled from the HELIOS 1-2 observations favors type III storm burst radio emission at the harmonic of the local plasma frequency.

Bougeret, J. L.↗

NASA NTRS1984

Interplanetary radio storms. II - Emission levels and solar wind speed in the range 0.05-0.8 AU

Storms of interplanetary type III radio bursts (IP storms) are commonly observed in the interplanetary medium by the ISEE-3 radio instrument. This instrument has the capability of accurately determining the arrival direction of the radio emission. At each observing frequency, the storm radio sources are tracked as they cross the line-of-sight to the sun. Using a simple model, the emission levels are determined at a number of radio frequencies for four separate storms. The IP storm radiation is found to occur in regions of enhanced density at levels of 0.05 to 0.8 AU. The density in these enhancements falls off faster than R(-2). The solar wind speed in the storm region is also measured. The analysis is consistent with steady conditions in the storm region during a few days around the III storm burst radio emission at the harmonic of the local plasma frequency.

Bougeret, J.-L.↗

NASA NTRS1985

Effect of angular inflow on the vibratory response of a counter-rotating propeller

This report presents the results of a propeller vibratory stress survey on the Fairey Gannet aircraft aimed at giving an assessment of the difference in vibratory response between single and counter-rotating propeller operation in angular inflow. The survey showed that counter-rotating operation of the propeller had the effect of increasing the IP response of the rear propeller by approximately 25 percent over comparable single-rotation operation while counter-rotating operation did not significantly influence the IP response of the front propeller.

Turnberg, J. E.↗

NASA NTRS1986

Observational study of ion-electron equilibration and of cloud evaporation in supernova remnants under the HEAO-2 guest investigator program

Observations of three selected supernovae remnants (Cygnus Loop, IC 443, and Puppis A) were made in the forbidden coronal iron lines (Fe X) lambda 6374 and (Fe XIV) lambda 5303. The resulting data was compared quantitatively with Einstein images of the same objects, and an attempt was made to determine (a) the process by which ion and electron energies are equilibrated behind the shock front in the ISM and (b) whether cloud evaporation occurs within the hot remnant interiors. Spatially-resolved X ray emission were modeled for Sedov-Taylor blast wave models of supernovae remnants (SNR) under conditions of non-equlibrium ionization. The computations are intended to provide results that can be directly compared with Einstein high resolution image (HRI) and imaging proportional counter (IPS) data. The computer program for predicting the spatial distribution of HRI and IPS counting rates was completed, and final testing of it had begun.

Teske, R. G.↗

NASA NTRS1985

Analysis and test evaluation of the dynamic response and stability of three advanced turboprop models

Results of dynamic response and stability wind tunnel tests of three 62.2 cm (24.5 in) diameter models of the Prop-Fan, advanced turboprop, are presented. Measurements of dynamic response were made with the rotors mounted on an isolated nacelle, with varying tilt for nonuniform inflow. One model was also tested using a semi-span wing and fuselage configuration for response to realistic aircraft inflow. Stability tests were performed using tunnel turbulence or a nitrogen jet for excitation. Measurements are compared with predictions made using beam analysis methods for the model with straight blades, and finite element analysis methods for the models with swept blades. Correlations between measured and predicted rotating blade natural frequencies for all the models are very good. The IP dynamic response of the straight blade model is reasonably well predicted. The IP response of the swept blades is underpredicted and the wing induced response of the straight blade is overpredicted. Two models did not flutter, as predicted. One swept blade model encountered an instability at a higher RPM than predicted, showing predictions to be conservative.

Bansal, P. N.↗

NASA NTRS1987

Coronal and interplanetary Type 2 radio emission

Several observations suggest that the disturbances which generate coronal (meter wavelength) type II radio bursts are not driven by coronal mass ejections (CMEs). A new analysis using a large sample of metric radio bursts and associated soft X-ray events provides further support for the original hypothesis that type II-producing disturbances are blast waves generated at the time of impulsive energy release in flares. Interplanetary (IP) shocks, however, are closely associated with CMEs. The shocks responsible for IP type II events (observed at kilometer wavelengths) are associated with the most energetic CMEs.

Cane, H. V.↗

NASA NTRS1987

Radio emission from coronal and interplanetary shocks

Observational data on coronal and interplanetary (IP) type II burst events associated with shock-wave propagation are reviewed, with a focus on the past and potential future contributions of space-based observatories. The evidence presented by Cane (1983 and 1984) in support of the hypothesis that the coronal (metric) and IP (kilometric) bursts are due to different shocks is summarized, and the fast-drift kilometric events seen at the same time as metric type II bursts (and designated shock-accelerated or shock-associated events) are characterized. The need for further observations at 0.5-20 MHz is indicated.

Cane, H. V.↗