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At least 829 records · Page 46
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Viking lander location and spin axis of Mars - Determination from radio tracking data

Radio tracking data from the Viking lander have been used to determine the lander position and the orientation of the spin axis of Mars. The areocentric coordinates of the lander are 22.27 deg N, 48.00 deg W, and 3389.5 kilometers from the center of mass; the spin axis orientation, referred to earth's mean equator and equinox of 1950.0, is 317.35 deg right ascension and 52.71 deg declination.

Michael, W. H., Jr.↗
NASA NTRS1976

Location of ATS-5 by L-band trilateration

Near real-time ATS-5 satellite positions and short term position predictions were derived from an experimental L-band trilateration network. Satellite position accuracies of approximately 0.0002 degrees in latitude and longitude and 20 meters in earth center distance were demonstrated. Individual slant range measurements from the master ground station to the satellite were precise to within 12 meters; from the satellite to each of two automatic remote transponders, 23 meters. The trilateration network comprised a master ground station near Schenectady, New York and remote unmanned transponders in Buenos Aires, Argentina and near Wahiawa, Hawaii.

Brisken, A. F.↗
NASA NTRS1976

Locate and rescue system components

Two types of search and rescue systems not involving satellites are studied; one using a network radio communications link and the other a characteristic beacon signal. Line of slight limitation of VHF radio and beacon signals limit the range (approximately 25 miles) between the origin of the distress signal and the mobile rescue unit.

Source record↗
NASA NTRS1977

Acoustic source location in a jet-blown flap using a cross-correlation technique

The acoustic source strength distribution in a turbulent flow field was measured for two far field microphones at 45 deg above and below the plane of the flap surface. A processed signal from an inclined hot-film anemometry probe was cross correlated with the signal from the appropriate far field microphone. The contribution made by the sources associated with the fluctuating pressure on the flap surface to the sound received at far field microphone was estimated by cross correlating the processed signals of microphones which were embedded in the flap surface with the far field microphone signals. In addition, detailed fluid dynamic measurements were made in the flow field of the jet flap using dual sensor hot-film anemometry probes.

Becker, R. S.↗
NASA NTRS1977

Effect of LN2 injection station location on the drive fan power and LN2 requirements of a cryogenic wind tunnel

A theoretical analysis comparing the fan power and coolant (LN2) flow rates resulting from injection of the LN2 either upstream or downstream of the drive fan of a closed circuit transonic cryogenic tunnel is presented. The analysis is restricted to steady state tunnel operation and to the condition that the tunnel walls are adiabatic. The stagnation pressure and temperature range of the tunnel is from 1.0 to 8.8 atm and from 300 K to liquefaction temperature, respectively. Calculations are made using real gas properties of nitrogen. Results show that the fan power and LN2 flow rates are lower if the LN2 is injected upstream of the fan. The lower fan inlet temperature resulting from injecting upstream of the fan has a greater influence on the power than does the additional mass flow going through the fan.

Adcock, J. B.↗
NASA NTRS1977

Extreme-ultraviolet observations of coronal holes. I - Locations, sizes and evolution of coronal holes, June 1973-January 1974

The disk boundaries of coronal holes have been systematically determined from XUV observations taken during the manned Skylab missions (June 1973-January 1974). The resulting atlas was used to find the sizes, global distributions, differential rotation rates, growth/decay rates and lifetimes of holes during this period. The polar cap holes together covered 15% of the sun's total surface area, a number which remained surprisingly constant throughout Skylab despite the fact that each pole was independently evolving in time. Lower latitude holes contributed another 2 to 5%.

Bohlin, J. D.↗
NASA NTRS1977

Where do we locate the moon base

Because the lunar polar regions permit continuous solar energy collection and adjacent cryogenic temperature, they may be the preferred sites for early human occupation and use of the moon. If permafrost exists in the polar shaded regions, this preference will become dominant. Though not ideal from the point of view of all-sky coverage for astronomical observations, and also possibly subject to terminator-plane particle hazes near the surface, polar sites (especially the south polar region) may offer enough advantages (e.g., constant cryogenic telescope environments and unlimited tracking time) to be preferred sites for the first lunar observatories.

Burke, J. D.↗
NASA NTRS1979

Self-propelling, self-locating colonoscope

Articulated instrument moves by air actuated bladder, while defining position by ultrasonic or RF signals. Device allows optical inspection of large bowel from cecum to rectum with minimal discomfort or risk to patient.

Fazer, R. E.↗
NASA NTRS1977

Apollo 14 coarse fines (4-10 mm) sample location and classification

The 4 to 10 mm sieve fraction from the soil samples collected during the Apollo 14 Mission was identified and described. Examination and description of the fines were carried out in nitrogen-filled, stainless steel cabinets during a general examination of the Apollo 14 sample collection. Each particle was held between forceps, dusted in a jet of N2, and placed on a teflon-covered stage. They were examined with a binocular microscope, separated by lithology, and the lithologic types described. Weights of individual particles in the fraction ranged from about 0.10 to 0.50 gm, large enough in size for studies of age, chemistry, and petrology to be accomplished.

Kramer, F. E.↗
NASA NTRS1977

On the relative locations of the bow shocks of the terrestrial planets

The observed bow shock encounters at Mercury, Venus and Mars are least square fit using the same technique so that their sizes and shapes can be intercompared. The shock front of Mercury most resembles the terrestrial shock in shape, and the shock stand off distance is consistent with the observed moment. The shapes of the Venus and Mars shock fronts more resemble each other than the earth's and the stand off distances are consistent with direct interaction of the solar wind with the ionosphere on the dayside. The Venus shock is closer to the planet than the Mars shock suggesting more absorption of the solar wind at Venus.

Russell, C. T.↗
NASA NTRS1978

Low-speed test limit of V/STOL model located vertically off-center

A vertically off-centered V/STOL model - a 2-ft-diam three-bladed aluminum propeller operating in a rotor mode - is tested in an 8 by 12 ft wind tunnel with and without ground plane along with an associated 3 by 4.5 ft test section insert. The objective was to assess the effect of the vertically off-centered model on the low-speed test limit. The aerodynamic data of the model at a constant negative angle of attack (-3 deg) are recorded at selected tunnel dynamic pressures to provide adequate data points to define the model lift variation with respect to the tip speed ratio. The adverse effect of the rotor low-speed test limit is observed in the form of lift change with respect to the tip speed ratio. A major conclusion is that for rotors tested with a ground plane or in the vicinity of the floor, the ratio of distance between floor and model to rotor radius defines the low-speed test limits.

Shindo, S.↗
NASA NTRS1978

Io-phase motion and jovian decametre source locations

A second-order effect in the relationship between jovian decameter storms and the departure of Io from superior geocentric conjunction is explained on the basis of latitudinal variations in the earth-Jupiter viewing geometry. These variations are defined by the 12-year cycle in the jovicentric declination of the earth. In addition, it is found that the emission of the jovian decameter storm source Io-B (Io-C) is beamed from the northern (southern) magnetic latitudes. These conclusions are compatible with source positions derived from polarimetry and from considerations of planetary-limb shadowing.

Desch, M. D.↗
NASA NTRS1977

Effects of detector threshold, location of the sun, and flight altitude upon spectral variations in remote sensing over water

Photographic flights with Hasselblad cameras were flown on August 28, 1975, at altitudes from 2.66 and 5.3 kilometers over an ocean acid waste dump site while acid dumping was in progress. Repeated flights resulted in broadband spectral radiance data between the wavelengths of 500 to 900 nanometers for sun elevation angles that varied from 26 to 48 degrees, and at all sun azimuth angles over the range of off-nadir angles from 0 to 35 degrees. From film densitometer data, it is shown that before spectral variations in remotely sensed data can be used to quantify substances in water, the longer wavelength data must be above the detection level of the detector, radiance data between + or - 45 degrees in the direction of the sun must be avoided, and off-nadir camera correction factors must be applied to the observed radiance data.

Bressette, W. E.↗
NASA NTRS1978

The locations of Alpha-2 Herculis and Alpha-2 Scorpii along the line of sight

The theory of line formation along the line of sight to the visual companions of M stars undergoing spherically symmetric mass loss is developed. The theory is then used to determine the position of the companions relative to the primary. It is found that Alpha-2 Her is 1470 AU further along the line of sight than Alpha-1 Her for an adopted distance of 150 pc; Alpha-2 Sco is 420 AU closer than Alpha-1 Sco for an adopted distance of 185 pc.

Bernat, A. P.↗
NASA NTRS1978

Location of unidentified weak X-ray sources by the HEAO-1 scanning modulation collimator

Four weak sources for which precise positions have been obtained from the HEAO-1 Scanning Modulation Collimator (MC) experiment are discussed. One source (4U 0446+44) with the center of the cluster of galaxies containing 3C129 and 3C129.1 has been identified, and its angular size has been measured. One source with a galactic star is identified, although it is at galactic latitude b = 51 deg. The other two sources, 2A 0526-328 and 2A 0922-317, remain unidentified.

Schwartz, D. A.↗
NASA NTRS1978

A preliminary test of the application of the Lightning Detection and Ranging System (LDAR) as a thunderstorm warning and location device for the FHA including a correlation with updrafts, turbulence, and radar precipitation echoes

Results of a test of the use of a Lightning Detection and Ranging (LDAR) remote display in the Patrick AFB RAPCON facility are presented. Agreement between LDAR and radar precipitation echoes of the RAPCON radar was observed, as well as agreement between LDAR and pilot's visual observations of lightning flashes. A more precise comparison between LDAR and KSC based radars is achieved by the superposition of LDAR precipitation echoes. Airborne measurements of updrafts and turbulence by an armored T-28 aircraft flying through the thunderclouds are correlated with LDAR along the flight path. Calibration and measurements of the accuracy of the LDAR System are discussed, and the extended range of the system is illustrated.

Poehler, H. A.↗