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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 847 records · Page 47
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

On the possibility of explaining features of the latitude variations of Sq(H) and Sq(Z) in the equatorial region by electrical modelling

Curves of H (the horizontal component) and Z (the vertical component) of the magnetic field from a strip with an assigned current-density distribution compiled from the results of electrical modelling are calculated. The calculated curves are compared qualitatively with latitude curves obtained from ground magnetic observatory data. It is shown that the forms of the theoretical H and Z and the experimental latitude variations are qualitatively similar.

Pogrebnoy, V. N.↗
NASA NTRS1972

Interpretation of geographic patterns in simulated orbital television imagery of earth resources

In order to better determine the effects of the television imagery characteristics upon the interpretation of geographic patterns obtainable from orbital television sensors, and in order to better evaluate the influences of alternative sensor system parameters such as changes in orbital altitudes or scan line rates, a team of three professional interpreters independently mapped thematically the selected geographic phenomena that they could detect in orbital television imagery produced on a fourteen inch monitor and recorded photographically for analysis. Three thematic maps were compiled by each interpreter. The maps were: (1) transportation patterns; (2) other land use; and (3) physical regions. The results from the three interpreters are compared, agreements noted, and differences analyzed for cause such as disagreement on identification of phenomenon, visual acuity, differences in interpretation techniques, and differing professional backgrounds.

Latham, J. P.↗
NASA NTRS1971

Design of optical mirror structures

The structural requirements for large optical telescope mirrors was studied with a particular emphasis placed on the three-meter Large Space Telescope primary mirror. Analysis approaches through finite element methods were evaluated with the testing and verification of a number of element types suitable for particular mirror loadings and configurations. The environmental conditions that a mirror will experience were defined and a candidate list of suitable mirror materials with their properties compiled. The relation of the mirror mechanical behavior to the optical performance is discussed and a number of suitable design criteria are proposed and implemented. A general outline of a systematic method to obtain the best structure for the three-meter diffraction-limited system is outlined. Finite element programs, using the STRUDL 2 analysis system, were written for specific mirror structures encompassing all types of active and passive mirror designs. Parametric studies on support locations, effects of shear deformation, diameter to thickness ratios, lightweight and sandwich mirror configurations, and thin shell active mirror needs were performed.

Soosaar, K.↗
NASA NTRS1972

The geometry and physical properties of exhaust clouds generated during the static firing of S-1C and S-2 rocket engines

An experimental program was conducted during the static firing of the S-1C stage 13, 14, and 15 rocket engines and the S-2 stage 13, 14, and 15 rocket engines. The data compiled during the experimental program consisted of photographic recordings of the time-dependent growth and diffusion of the exhaust clouds, the collection of meteorological data in the ambient atmosphere, and the acquisition of data on the physical structure of the exhaust clouds which were obtained by flying instrumented aircraft through the clouds. A new technique was developed to verify the previous measurements of evaporation and entrainment of blast deflector cooling water into the cloud. The results of the experimental program indicate that at the lower altitudes the rocket exhaust cloud or plume closely resembles a free-jet type of flow. At the upper altitudes, where the cloud is approaching an equilibrium condition, structure is very similar to a natural cumulus cloud.

Forbes, R. E.↗
NASA NTRS1972

Material Compatibility with Space Storable Propellants. Design Guidebook

An important consideration in the design of spacecraft for interplanetary missions is the compatibility of storage materials with the propellants. Serious problems can arise because many propellants are either extremely reactive or subject to catalytic decomposition, making the selection of proper materials of construction for propellant containment and control a critical requirement for the long-life applications. To aid in selecting materials and designing and evaluating various propulsion subsystems, available information on the compatibility of spacecraft materials with propellants of interest was compiled from literature searches and personal contacts. The compatibility of both metals and nonmetals with hydrazine, monomethyl hydrazine, nitrated hydrazine, and diborance fuels and nitrogen tetroxide, fluorine, oxygen difluoride, and Flox oxidizers was surveyed. These fuels and oxidizers encompass the wide variety of problems encountered in propellant storage. As such, they present worst case situations of the propellant affecting the material and the material affecting the propellant. This includes material attack, propellant decomposition, and the formation of clogging materials.

Uney, P. E.↗
NASA NTRS1972

Summary of design considerations for airplane spin-recovery parachute systems

A compilation of design considerations applicable to spin-recovery parachute systems for military airplanes has been made so that the information will be readily available to persons responsible for the design of such systems. This information was obtained from a study of available documents and from discussions with persons in both government and industry experienced in parachute technology, full-scale and model spin testing, and related systems.

Burk, S. M., Jr.↗
NASA NTRS1972

A study of system requirements for Phobos/Deimos missions. Volume 4: Phase 3 results, combined missions to Mars and its satellites

Combined missions to Mars and Phobos/Deimos were considered in relation to large scientific returns at a low total cost. A matrix of all feasible major combined mission concepts was compiled. The most promising approach was selected from which a nominal mission profile was developed. A systems analysis was performed to trade off performance, configuration, and cost characteristics of candidate mission concepts. Configuration and subsystem optimization analysis were then conducted from which a baseline and an alternate program were selected. Program schedules and cost estimates were prepared for the recommended and alternate program.

Source record↗
NASA NTRS1972

Documentation and environment of the Apollo 16 samples: A preliminary report

A catalog which is a working document that shows the locations from which samples were collected during the Apollo 16 mission, and that provides a descriptive geologic context for each sample is presented. It is a compilation of notes from work in progress, and supersedes an earlier report prepared by the Apollo Lunar Geology Investigation Team. The information was obtained from the Air-to-Ground transcript from the astronaut crew, from lunar surface television, from 60 mm Hasselblad camera photographs, and from available LRL mugshot photographs of the samples. The sample descriptions are based on these sources of data.

Source record↗
NASA NTRS1972

Study of a comet rendezvous mission. Volume 2: Appendices

Appendices to the comet Encke rendezvous mission consider relative positions of comet, earth and sun; viewing condition for Encke; detection of Taurid meteor streams; ephemeris of comet Encke; microwave and optical techniques in rendezvous mission; approach instruments; electrostatic equilibrium of ion engine spacecraft; comet flyby data for rendezvous spacecraft assembly; observations of P/Encke extracted from a compilation; and summary of technical innovations.

Source record↗
NASA NTRS1972

Lightning summary report through 1971

An updated summary is presented of the lightning activity recorded at the John F. Kennedy Space Center and the Cape Kennedy Air Force Station. Data was compiled during the periods 1903 through 1924, 1957 through 1962, and 1964 through 1971.

Source record↗
NASA NTRS1972

Fatigue Tests with Random Flight Simulation Loading

Crack propagation was studied in a full-scale wing structure under different simulated flight conditions. Omission of low-amplitude gust cycles had a small effect on the crack rate. Truncation of the infrequently occurring high-amplitude gust cycles to a lower level had a noticeably accelerating effect on crack growth. The application of fail-safe load (100 percent limit load) effectively stopped subsequent crack growth under resumed flight-simulation loading. In another flight-simulation test series on sheet specimens, the variables studied are the design stress level and the cyclic frequency of the random gust loading. Inflight mean stresses vary from 5.5 to 10.0 kg/sq mm. The effect of the stress level is larger for the 2024 alloy than for the 7075 alloy. Three frequencies were employed: namely, 10 cps, 1 cps, and 0.1 cps. The frequency effect was small. The advantages and limitations of flight-simulation tests are compared with those of alternative test procedures such as constant-amplitude tests, program tests, and random-load tests. Various testing purposes are considered. The variables of flight-simulation tests are listed and their effects are discussed. A proposal is made for performing systematic flight-simulation tests in such a way that the compiled data may be used as a source of reference.

Schijve, J.↗
NASA NTRS1972

The Celescope catalog of ultraviolet observations

Data obtained from approximately 7500 ultraviolet television pictures are used to compile a celescope catalog of ultraviolet observations. This catalog lists the magnitude as observed in each of celescope's four ultraviolet color bands, the standard deviations of the observed ultraviolet magnitudes, positions, identifications, and ground based magnitudes, colors, and spectral types for approximately 5000 stars.

Davis, R. J.↗
NASA NTRS1972

VISCEL: A general-purpose computer program for analysis of linear viscoelastic structures (user's manual), volume 1

This program, an extension of the linear equilibrium problem solver ELAS, is an updated and extended version of its earlier form (written in FORTRAN 2 for the IBM 7094 computer). A synchronized material property concept utilizing incremental time steps and the finite element matrix displacement approach has been adopted for the current analysis. A special option enables employment of constant time steps in the logarithmic scale, thereby reducing computational efforts resulting from accumulative material memory effects. A wide variety of structures with elastic or viscoelastic material properties can be analyzed by VISCEL. The program is written in FORTRAN 5 language for the Univac 1108 computer operating under the EXEC 8 system. Dynamic storage allocation is automatically effected by the program, and the user may request up to 195K core memory in a 260K Univac 1108/EXEC 8 machine. The physical program VISCEL, consisting of about 7200 instructions, has four distinct links (segments), and the compiled program occupies a maximum of about 11700 words decimal of core storage.

Gupta, K. K.↗
NASA NTRS1972

A cognitive operating system (COGNOSYS) for JPL's robot, phase 1 report

The most important software requirement for any robot development is the COGNitive Operating SYStem (COGNOSYS). This report describes the Stanford University Artificial Intelligence Laboratory's hand eye software system from the point of view of developing a cognitive operating system for JPL's robot. In this, the Phase 1 of the JPL robot COGNOSYS task the installation of a SAIL compiler and a FAIL assembler on Caltech's PDP-10 have been accomplished and guidelines have been prepared for the implementation of a Stanford University type hand eye software system on JPL-Caltech's computing facility. The alternatives offered by using RAND-USC's PDP-10 Tenex operating sytem are also considered.

Mathur, F. P.↗
NASA NTRS1971

Tranquillity Base map.

A comparison of the qualities of photographs taken by astronauts Armstrong and Aldrin from Tranquillity Base and of photographs taken from the Lunar Module window, in terms of valuable information. The latter, found to be more reliable than the former, are used as the primary source in compiling the Tranquillity Base Surface and Experiment Locations Map. The former are rated as excellent for identification purposes and are used in locating supplemental details. However, the geometry obtained on most of these latter frames is believed to be less reliable because of large changes in vertical angles.

Arant, W. H.↗
NASA NTRS1972

Traveling ionospheric disturbance as a diagnostic tool for thermospheric dynamics.

Evaluation of observational results of traveling ionospheric disturbances. The experiment continuously monitors the wave polarization of signals transmitted by the geostationary satellite ATS 3. One year of single-station data has been compiled for synoptic study. When observed at three stations, in addition to the period of the wave, the horizontal phase velocity can be determined. An attempt has been made to link the experimentally determined ionospheric parameters with the neutral atmospheric parameters by using a crude theory. The result suggests that a better theory should be developed, so that the diagnosis of these thermospheric parameters can be made by making traveling disturbance observations. In doing so, many previously ignored factors should be reexamined, especially the effect produced by high thermospheric winds.

Yeh, K. C.↗
NASA NTRS1972

Electric discharges in air - Near infrared emission spectrum.

The emission from glow discharges in flowing air has been investigated in the 1- to 5-micron wavelength region with a vacuum spectrometer. Most of the spectral features observed in the pressure range of .5 to 10 torr are identified, including atomic lines of OI, NI, and HI and molecular bands of N2, NO, N2O, CO2, and CO. The spectra are presented as a function of pressure and a table compiled of the atomic lines. Of particular interest are the contrasts between the emission of the air discharge and that of the pure gases, nitrogen and oxygen. In addition, the results of studies of several discharge modes, employing steady voltages and pulsed, provide data on details of the energy flow within the plasma.

Benesch, W. M.↗