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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Simulator model specification for the augmentor wing jet STOL research aircraft

The configuration and simulation studies of a C-8A (De Havilland Buffalo) aircraft are described. The modifications to STOL configuration consisted of augmentor-wing jet flaps, blown and drooped ailerons, and leading edge slats. The total simulator model includes a number of component parts for producing realistic visual, aural, tactile, vestibular, and kinesthetic cues for the pilot to assess the predicted behavior of the real airplane.

Rumsey, P. C.↗
NASA NTRS1972

A design support simulation of the augmentor wing jet STOL research aircraft

The modification of a C-8A (De Havilland Buffalo) aircraft to a STOL configuration is discussed. The modification consisted of the installation of an augmentor-wing jet flap system. System design requirements were investigated for the lateral and directional flight control systems, the lateral and directional axes stability augmentation systems, the engine and Pegasus nozzle control systems, and the hydraulic systems. Operational techniques for STOL landings, control of engine failures, and pilot techniques for improving engine-out go-around performance were examined. Design changes have been identified to correct deficiencies in areas of the airplane control sytems and to improve the airplane flying qualities.

Rumsey, P. C.↗
NASA NTRS1972

Predicted flight characteristics of the augmentor wing jet STOL research aircraft

An existing deHavilland C-8A airplane has been modified into an augmentor wing flight test vehicle. Research objectives are to verify the augmentor flap concept and to produce data for STOL airworthiness criteria. The Modified C-8A provides the means for jet-STOL flight research down to a 60 knot approach speed. The airplane has a high thrust-to-weight ratio, high-lift flap system, vectored thrust, powerful flight controls, and lateral-directional stability augmentation system. Normal performance and handling qualities are expected to be satisfactory. Analysis and piloted simulator results indicate that stability and control characteristics in conventional flight are rated satisfactory. Handling qualities in the STOL regime are also generally satisfactory, although pilot workload is high about the longitudinal axis.

Spitzer, R. E.↗
NASA NTRS1972

Random gravitational encounters and the evolution of spherical systems. III - Halo.

The accumulation of stars in the halo of a spherical stellar system, together with the escape of stars from the system, result from stellar encounters within a dense central core. The resultant halo structure is studied both analytically and numerically for an isolated system. On the assumption that conditions in the central core remain constant with time, a simple steady-state solution is obtained for the outermost halo, or 'fringe', defined as the region from which stars may escape after a few additional orbits through the central core of the system. In this steady-state solution the density in phase space, obtained from a simple integral equation for the fringe region, is found to vary nearly linearly with the total energy of a star per unit mass for energies which are less than the energy of escape.

Spitzer, L., Jr.↗
NASA NTRS1972

Use of the flight simulator in the design of a STOL research aircraft.

Piloted simulator tests on the NASA-Ames Flight Simulator for Advanced Aircraft motion base played a major role in guiding the design of the Modified C-8A 'Buffalo' augmentor wing jet flap STOL research airplane. Design results are presented for the flight control systems, lateral-directional SAS, hydraulic systems, and engine and thrust vector controls. Emphasis is given to lateral control characteristics on STOL landing approach, engine-out control and recovery techniques in the powered-lift regime, and operational flight procedures which affected airplane design.

Spitzer, R. E.↗
NASA NTRS1973

Exposure interlock for oscilloscope cameras

An exposure interlock has been developed for oscilloscope cameras which cuts off ambient light from the oscilloscope screen before the shutter of the camera is tripped. A flap is provided which may be selectively positioned to an open position which enables viewing of the oscilloscope screen and a closed position which cuts off the oscilloscope screen from view and simultaneously cuts off ambient light from the oscilloscope screen. A mechanical interlock is provided between the flap to be activated to its closed position before the camera shutter is tripped, thereby preventing overexposure of the film.

Spitzer, C. R.↗
NASA NTRS1973

Spectrophotometric results from the Copernicus satellite. I - Instrumentation and performance.

The Princeton telescope-spectrometer on the OAO spacecraft Copernicus scans stellar spectra with a resolution of about 0.05 A between 950 and 1450 A, and twice this in first order between 1650 and 3000 A. The pointing during several minutes is steady within .02 sec, and the measured photometric precision in the shorter wavelength range is limited only by the statistics of photon counts, with 14-sec counts of about 1000 on an unreddened B1 star, m(v) = 5.0, at 1100 A. In the 1650-3000 A wavelength range, phototube noise resulting from cosmic rays makes observations difficult on stars fainter than m(v) = 3.0.

Rogerson, J. B.↗
NASA NTRS1973

Spectrophotometric results from the Copernicus satellite. III - Ionization and composition of the intercloud medium.

Interstellar lines have been studied in the unreddened stars lambda Sco, upsilon Sco, alpha Leo, and alpha Eri, which are located between 20 and 150 pc from the sun. The lines are on the linear and saturated Doppler portions of the curve of growth. Preliminary analysis shows that processes producing large amounts of highly ionized species are not dominant. Doubly ionized C, N, Si, and S have been detected, but are all quite weak relative to the singly ionized species. Abundances relative to nitrogen are in the cosmic ratios or slightly lower, with some indication of general depletion of the heavier elements. Hydrogen number densities range from a measured value of 0.22 per cu cm for lambda Sco to a derived value of 0.02 per cu cm for alpha Leo assuming nitrogen to have its solar abundance relative to hydrogen.

Rogerson, J. B.↗
NASA NTRS1974

Development and evaluation of television tubes for space astronomy

An improved vidicon image sensor for space astronomy applications is developed that features reliably sealed ultraviolet transmitting windows and achieves acceptable photocathode quantum efficiency on these MgF2 windows. New preamplifier designs improve the dynamic range by reduction of the readout noise.

Spitzer, L.↗
NASA NTRS1974

On the theory of H2 rotational excitation

A number of mechanisms for exciting higher-J states in the ground vibrational level are considered. Attention is given to collisions with H atoms and electrons. Other mechanisms involve a cascading down from upper vibrational levels, following absorption and reemission of photons in the Lyman and Werner bands, or a cascading down from upper vibrational levels, following formation of hydrogen molecules in excited vibrational and rotational levels. Theoretical population densities of rotational levels are shown in a graph.

Spitzer, L., Jr.↗
NASA NTRS1974

Column densities of interstellar molecular hydrogen

Equivalent widths of some 50 lines in the 0-0 to 5-0 Lyman bands of H2 are reported in the spectra of 28 stars. Curves of growth are given and column densities for levels from J = 0 to J = 5 are tabulated, with a few values and upper limits for N(6) and N(7), together with values for b, the velocity spread parameter. In three Orion stars and in rho Leo pairs of components are detected, the difference in radial velocity is determined, and column densities are measured or estimated; tentative identifications are made with the components observed by Hobbs (1969) in the Na D-lines. Column densities for HD are given for 13 stars. Upper limits for column densities in the first and second vibrational levels are listed for several stars; the ratio of N(J = 0) in the v double prime = 1 level to that in the ground vibrational level is less than 2.4 x 10 to the minus 8th power in zeta Oph. Values of a rotational excitation temperature for the higher J levels are given for all the stars. Data are presented which show an apparent increase of velocity dispersion with J for a number of stars, as measured both from the curves of growth and from line widths.

Spitzer, L., Jr.↗
NASA NTRS1975

Ultraviolet studies of the interstellar gas

Sounding-rocket and satellite UV observations of interstellar gas clouds are reviewed with major attention given to Copernicus observations of interstellar absorption lines. Analysis of typical absorption-line data is outlined, and observations are reviewed for atomic hydrogen as well as interstellar H2, HD, and CO molecules. Investigations of atomic abundances in H I regions are summarized, measurements of atomic deuterium abundances in the interstellar gas are examined, and the properties of ionized interstellar gas are described. Theoretical analyses of the physical state of the interstellar gas are summarized with respect to ionization by energetic radiation, cool H I clouds, and the intercloud medium. The data obtained thus far are shown to indicate mean temperatures of about 80 K, particle densities between 10 and 1000 per cu cm, and a depletion of heavy elements that becomes greatly enhanced with increasing condensation temperature for those H I regions with strong H2 lines.

Spitzer, L., Jr.↗
NASA NTRS1976

Components in interstellar molecular hydrogen

Results are reported for precise spectrophotometric measurements of the profiles of selected Lyman absorption lines produced by hydrogen molecules in various rotational levels along the line of sight to 13 stars which have shown some evidence for an increase in line width with increasing rotational quantum number (J). The line profiles were measured by multiple scans with the Copernicus satellite telescope. Based on analysis of the radial velocities, derivations of the column densities, and line-profile fitting, the following conclusions are made: (1) the increase in interstellar H2 line width with increasing J results from the presence of the most shortward component, which is relatively weak at low J but becomes more important at higher J; (2) the relative column densities found for the different J levels in each component may be fitted by a theoretical model in which rotational excitation is due to absorption of UV photons followed by radiative quadrupole spontaneous transitions or collisionally induced downward transitions between different J levels; (3) the atomic hydrogen density is between 300 and 1000 per cu cm in the most shortward component for each of three stars; (4) the approaching gas which produces each shortward component must be in the form of thin sheets; and (5) the sheets are the compressed gas behind a shock front moving through the interstellar medium.

Spitzer, L., Jr.↗
NASA NTRS1976

Interstellar matter research with the Copernicus satellite

The use of the Copernicus satellite in an investigation of interstellar matter makes it possible to study absorption lines in the ultraviolet range which cannot be observed on the ground because of atmospheric absorption effects. A brief description is given of the satellite and the instrument used in the reported studies of interstellar matter. The results of the studies are discussed, giving attention to interstellar molecular hydrogen, the chemical composition of the interstellar gas, the coronal gas between the stars, and the interstellar abundance ratio of deuterium to hydrogen.

Spitzer, L., Jr.↗
NASA NTRS1976

The Vikings are coming

The exploration of Mars with the aid of the two Viking landers is discussed. The probable landing date for Viking Lander 1 will be July 4, 1976, and for Lander 2 September 4, 1976. The criteria used in selecting the landing site are considered along with the procedure to be employed in the final approach of the lander to the planet and the touchdown. A description is given of the studies to be conducted by the lander, taking into account the search for life and the collection of meteorological and seismological data. Attention is also given to technical data concerning the spacecraft, details regarding the software, and the ground facilities on earth which are used for the Viking project.

Spitzer, C. R.↗