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  • GEOPHYSICS  (1,182)
  • SPACE RADIATION  (429)
  • COMMUNICATIONS  (315)
  • 1970-1974  (1,926)
  • 1950-1954
  • 1945-1949
  • 1935-1939
  • 1972  (1,926)
  • 1951
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  • 1970-1974  (1,926)
  • 1950-1954
  • 1945-1949
  • 1935-1939
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  • 1
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    Organic geochemistry of Early Precambrian sediments (1972)
    In:  Other Sources
    Details
    Publication Date: 2011-12-21
    Keywords: GEOPHYSICS
    Type: Life Sci. Publ., Vol. 2; 11 p
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  • 2
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    Chemistry of the upper atmosphere and the role of transport processes (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The important chemical reaction affecting the neutral composition of the upper stratosphere, mesosphere, and lower thermosphere is discussed. The role of atmospheric transport processes is emphasized and the problem of taking these into account is elucidated.
    Keywords: GEOPHYSICS
    Type: NASA, Washington Phys. of the Space Environment; p 147-155
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  • 3
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    Transient heating in the upper atmosphere (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The time-dependent response of the upper atmosphere to transient heat sources is considered. The basic problem is that of heating a compressible, heat-conducting fluid, which is described in the one-dimensional case by an analytic solution. Comparisons with satellite drag data of such first-order solutions are shown to be useful in determining energy requirements and in determining some constraints on the spatial distribution of the heating. Recent OGO-6 mass spectrometer and interferometric temperature measurements show that atmospheric disturbances during geomagnetic storms are much more prominent in the auroral zones. These results suggest that joule dissipation of auroral currents are important contributors to orbital perturbations of satellites.
    Keywords: GEOPHYSICS
    Type: NASA, Washington Phys. of the Space Environment; p 3-23
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  • 4
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    Dissipation of electric fields in the ionosphere (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The heating and movement of the upper atmosphere at ionospheric levels in response to electric currents are discussed. Joule dissipation, generation of winds, and pressure gradients are significant factors in the energetics of the ionospheric electric currents flowing during magnetic storms and also of the Sq current system.
    Keywords: GEOPHYSICS
    Type: NASA, Washington Phys. of the Space Environment; p 25-40
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  • 5
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    Antenna drive system for the Nimbus satellite (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: A two-axis drive system is described for pointing a high gain antenna. Motion about each axis is provided by identical drive mechanisms. Only three gear passes are required to obtain the necessary 900:1 gear reduction. The drive system is a primary element of an experiment that will provide a real time data link between Nimbus and ground stations. Data are transmitted from Nimbus to the applications technology satellite, which relays the data to ground stations.
    Keywords: COMMUNICATIONS
    Type: NASA. Ames Res. Center 6th Aerospace Mech. Symp.; p 117-120
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  • 6
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    The Intelsat 4 antenna positioner (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The Intelsat 4 communications satellite has two spot beam antennas which are pointed to selected land masses by gimbaled positioners. The positioners employ drive motors with electromagnetic brakes and jackscrews that are self-caging during the launch. The positioner uses dry lubricants for ball bearings, spur gears, screw and nut, and various journal bearings. A coefficient of friction of approximately 0.05 was demonstrated in vacuum operation. Success of the positioner was demonstrated on the first Intelsat 4 placed in orbit in January 1971. The developmental problems that were encountered and their solutions are discussed.
    Keywords: COMMUNICATIONS
    Type: NASA. Ames Res. Center 6th Aerospace Mech. Symp.; p 109-116
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  • 7
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    Nimbus observation of oceanic upwelling (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: Observing the development of upwelling on the northeast coast of Africa by measuring ocean surface emission with infrared radiometers on Nimbus satellites is reported. Using the temperature of the ocean as telemetered by the satellite, the biological potential of an area is estimated, and consequently the highest potential for fisheries.
    Keywords: GEOPHYSICS
    Type: Significant Accomplishments in Sci., 1970; p 14-17
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  • 8
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    Locations of solar radio bursts (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: Measurements of the positions of the sources of solar radio bursts at decameter wavelengths, 20- to 60-MHz range, provide information about physical conditions in a region of the corona extending from about one-half to several solar radii from the surface of the sun. Position measurements in the 20- to 60-MHz range were made with the Clark Lake sweep-frequency grating interferometer. Although the resolution of the instrument is sufficient to measure source position accurately, the highly variable effect of refraction in the earth's ionosphere severely limits the observations, distorting position determinations to such an extent as to make much of the position data useless unless ionospheric refraction can be taken into account. A method was developed for the removal of the refractive effect from the data to permit determination of true source position. With this technique it is considered possible to measure spatial extent of radio sources that will provide information about emission processes and physical parameters in the corona.
    Keywords: COMMUNICATIONS
    Type: Significant Accomplishments in Sci., 1970; p 149-153
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  • 9
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    Microwave emission of Arctic Sea ice (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The feasibility of carrying microwave radiometers on Nimbus E and F missions for sea ice surveys was studied in the arctic using aircraft. It was found that passive microwave signatures of Arctic Sea ice relate specifically to the structure and type of ice. It is concluded that a new tool for conducting ice surveys from aircraft and satellites with remote sensors was discovered.
    Keywords: GEOPHYSICS
    Type: Significant Accomplishments in Sci., 1970; p 18-21
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  • 10
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    Electron impact ionization of H (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The results of theoretical calculations for the reactions between electrons and negative hydrogen atoms are discussed for an electron colliding with a negative hydrogen ion and neutralizing the hydrogen ion by stripping the loosely bound electron from it, and the two free electrons moving away. A semi-quantum description of the process is presented in which the target is described in terms of quantum mechanics, and the projectile electron is described in a classical fashion.
    Keywords: GEOPHYSICS
    Type: Significant Accomplishments in Sci., 1970; p 58-62
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  • 11
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    Reduction of near-in sidelobes using phase reversal aperture rings (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: A technique is described for reducing near-in sidelobes in spacecraft antennas by cancellation. This technique takes a small portion of the radiation from the antenna aperture and generates the near-in lobes, which are then fed out of phase relative to the main signal. Results of sample cases indicate that the first three lobes can be nearly eliminated at a 40% reduction in aperture efficiency.
    Keywords: COMMUNICATIONS
    Type: JPL Quart. Tech. Rev., Vol. 1, No. 4; p 34-42
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  • 12
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    Cosmic ray experiment. Part A: Composition and energy spectra of solar cosmic ray nuclei (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The GE experiment consisted of two types of detectors: plastics and glasses located in panel 2 and the lower half of panel 3. In panel 2, the entire exposed detector area of 14.7 by 22.6 cm was composed of 31 sheets of 0.025-cm polycarbonate plastic 9070-112. In panel 3, 39 sheets of 0.02-cm cellulose triacetate with no plasticizer made up the major volume fraction. The lower part of panel 3 contained five types of glass detectors. Particles that entered the array after it was folded were recognized, if they crossed from one sheet to another, by means of a 2-mm relative shift of alternate sheets.
    Keywords: SPACE RADIATION
    Type: NASA. Lyndon B. Johnson Space Center Apollo 16 Prelim. Sci. Rept.; 9 p
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  • 13
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    Composition of interplanetary particles at energies from 0.1 to 150 MeV/nucleon, part B (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: During the Apollo 16 mission, a solar flare produced an enormous amount of low-energy nuclei, many orders of magnitude greater than the level inferred from studies of tracks in the window of the Apollo 12 spacecraft during a time when the sun was quiet. The differential energy spectrum of nuclei with Z less than or equal to 6 falls by seven orders of magnitude over the interval from 0.1 to 20 MeV/nucleon, then remains almost flat up to approximately 100 MeV/nucleon. The two parts correspond to contributions from the sun and from galactic cosmic rays. Any maximum in the spectrum occurs below the lowest energy studied.
    Keywords: SPACE RADIATION
    Type: NASA. Lyndon B. Johnson Space Center Apollo 16 Prelim. Sci. Rept.; 8 p
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  • 14
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    Solar cosmic ray, solar wind, solar flare, and neutron albedo measurements, part C (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: All mineral detectors exposed on Apollo 16 had high surface track densities probably produced by a solar flare that occurred during the mission. The heavy ions followed a power law spectrum with exponent approximately 3 down to approximately 200 KeV/nucleon. The abundance of low-energy particle tracks observed in this flare may explain the high track densities observed in lunar dust grains. Pristine heavy-particle tracks in feldspar give long tracks. Shallow pits similar to those expected from extremely heavy solar wind ions were observed in about the expected number. Initial results give a low apparent value of neutron albedo relative to theory.
    Keywords: SPACE RADIATION
    Type: NASA. Lyndon B. Johnson Space Center Apollo 16 Prelim. Sci. Rept.; 14 p
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  • 15
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    Solar flares, the lunar surface, and gas rich meteorites (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: Investigations on the Fe-group nuclei track density vs depth in lunar rocks and Surveyor 3 TV camera filter glass were critically examined considering more factors than previously. The analysis gives a firmer basis to the observation of the preferential leakage of low energy Fe nuclei from the accelerating region of the sun. The track density gradients in lunar rock 12022 and filter glass are used to determine the lunar erosion rate of 3 angstroms/yr. Track gradients are less steep than predicted from energy spectrum observed in the Surveyor glass, perhaps due to sputtering. High densities of etchable tracks were found at all depths down to 60 cm in fines from Apollo cores and also in thin sections of the Pesjanoe, Pantar, and Fayetteville gas-rich meteorites. It is felt unlikely that suprathermal heavy ions were responsible for the high track densities.
    Keywords: SPACE RADIATION
    Type: NASA, Washington Analysis of Surveyor 3 Mater. and Phot. Returned by Apollo 12; p 221-226
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  • 16
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    Bearing strength of the lunar soil (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: A discussion is presented on the bearing strength and bearing load-penetration relations in lunar soil. These were measured in air as a function of bulk density. It was found that the relation between bulk density and the logarithm of the bearing capacity is about linear. Shapes of the load vs penetration curves were observed to be similar to those obtained with particulate material of terrestrial origin.
    Keywords: GEOPHYSICS
    Type: NASA, Washington Analysis of Surveyor 3 Mater. and Phot. Returned by Apollo 12; p 227-232
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  • 17
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    Very heavy solar cosmic rays: Energy spectrum and implications for lunar erosion (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: Particle tracks were investigated in the glass plate of a neutral density (clear flint) optical filter housed in the Surveyor 3 TV camera but exposed directly to space. The track density vs depth curve was determined and descends sharply from approximately 2.6 million tracks/sq cm at a depth of 3.6 mg/sq cm to about 35/sq cm at 700 mg/sq cm. Several tracks were of V-shapes characteristic of high energy induced fission. The erosion rate on the moon due to solar wind ions was determined from the energy spectrum, and was found to be low (0 to 2 x 10 to the minus 8th power cm/yr).
    Keywords: SPACE RADIATION
    Type: NASA, Washington Analysis of Surveyor 3 Mater. and Phot. Returned by Apollo 12; p 213-216
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  • 18
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    Solar and galactic cosmic ray exposure of Surveyor 3 as determined from cosmogenic radionuclide measurements (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The proton-produced Na-22 content of samples of Surveyor 3 TV camera, surface sampler scoop, and other components was determined by nondestructive gamma ray spectrometry. The contributions of the nine most prominent solar flares to Na-22 production were calculated to be 18 dpm/kg. The observed activity in the Surveyor 3 samples was 62 + or - dpm/kg. This indicates a galactic proton contribution of about 44 dpm/kg, which adjusted for spallation of Al gives a value of 42 dpm/kg. This is compared to measurements of 88 dpm/kg in the Lost City meteorite which had an orbit extending to 2.35 AU, with a 4 pi bombardment as compared to the 2 pi bombardment of the samples on the lunar surface. The agreement between Na-22 production in Surveyor 3 and the Lost City meteorite offers evidence that the galactic cosmic ray flux is almost the same at 1 Au and at 2.35 AU.
    Keywords: SPACE RADIATION
    Type: NASA, Washington Analysis of Surveyor 3 Mater. and Phot. Returned by Apollo 12; p 196-200
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  • 19
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    The Goddard helical tape recorder (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: A spacecraft recorder was developed with the objective of functioning continuously for 5 years. The resulting design employed a metallic tape wound in a 200-turn helix. A direct drive, brushless dc torquer and servo speed control drove the recorder at 3 rpm for recording and 54 rpm for playback.
    Keywords: COMMUNICATIONS
    Type: 6th Aerospace Mech. Symp.; p 89-93
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  • 20
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    Long duration solar active regions (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: Nimbus 3 and 4 observations of ultraviolet active regions of the sun have been investigated. It is not clear what is producing these UV-active regions, however, it could be changes in the overall intensity of the solar continuum near the region of the temperature minimum, or the solar flux variations that have been seen could be due to a continuous type of absorption like that associated with the ionization limits of elements such as aluminum, silicon, or magnesium.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci., 1970; p 159-163
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  • 21
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    The stability of tangential discontinuities (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: Intuition regarding the stability of MHD tangential discontinuities of solar wind has been borne out by a linear stability analysis of the MHD equations. In performing the calculation, the model used had no plasma flow and thus corresponded to the solar wind rest frame. The method calculated the change in total energy, plasma plus magnetic, due to the perturbation. This type of stability analysis is analogous to the test of the stability of an equilibrium point in a mechanical potential.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci., 1970; p 134-139
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  • 22
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    Solar wind heat flow (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The ability of a theoretical solar wind model to predict the energy flux density due to heat conduction was investigated. In order to demonstrate this capability, the analysis used simultaneous data from the electron plasma experiment of Ogilvie and Lind, and the vector magnetic field data of Heppner and Sugiura on OGO-5. On the strength of two independent, different, and consistent experimental determinations of the conduction of heat flux by electrons at 149.6 gigameters(1 AU), it was determined that the models for the solar wind must be able to predict a value for the heat conduction in the range 0.007 to 0.008 in order to be in agreement with the observations.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci., 1970; p 144-148
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  • 23
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    Solar X-rays and particle acceleration (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The process of solar flare acceleration of interplanetary particles, as measured by the fifth orbiting solar observatory, is explained. Data show the acceleration proceeds in two stages: (1) particle acceleration by induced electric fields arising from annihilating magnetic fields at the beginning stages of flares, and (2) a Fermi acceleration mechanism operating in a shock front produced by the flare.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci., 1970; p 171-175
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  • 24
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    Comparison of probe and radar ionosphere temperatures (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The discrepancy in temperature measurements of ionospheric electrons by Langmuir electrostatic probes, and radar backscatter are discussed. The discrepancy occurs at altitudes from 350 to 800km, and the probe temperatures are consistantly higher than the radar temperatures. It is concluded that the non-Maxwellian energy distribution provides an explanation for the altitude and the lower radar temperatures.
    Keywords: GEOPHYSICS
    Type: Significant Accomplishments in Sci., 1970; p 43-45
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  • 25
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    Microwave measurements of sea state (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: Passive microwave measurements were studied for determining sea state. It was found that the brightness temperature increases due to the foam produced by winds, and that the surface wind can be determined by the brightness temperature.
    Keywords: GEOPHYSICS
    Type: Significant Accomplishments in Sci., 1970; p 22-27
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  • 26
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    Bias and spread in extreme value theory measurements of probability of error (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: Extreme value theory is examined to explain the cause of the bias and spread in performance of communications systems characterized by low bit rates and high data reliability requirements, for cases in which underlying noise is Gaussian or perturbed Gaussian. Experimental verification is presented and procedures that minimize these effects are suggested. Even under these conditions, however, extreme value theory test results are not particularly more significant than bit error rate tests.
    Keywords: COMMUNICATIONS
    Type: JPL Quart. Tech. Rev., Vol. 1, No. 4; p 58-68
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  • 27
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    Calibration of radar data from Apollo 16 results, part X (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: Predictions of surface and near surface blockiness using earth based radar measurements were made. Two polarizations of the radar echoes were measured - polarized and depolarized. Particular attention was given to the depolarized echoes. North Ray and South Ray Craters and a 512-m diameter lunar crater in the Flamsteed Ring were used for the study.
    Keywords: COMMUNICATIONS
    Type: NASA. Lyndon B. Johnson Space Center Apollo 16 Prelim. Sci. Rept.; 3 p
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  • 28
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    Bistatic-radar investigation (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The purpose of the reported experiment was to determine the principal electromagnetic and structural properties of the lunar surface from the observation of command and service module (CSM) radio transmissions that were reflected from the lunar surface and received on earth. These transmissions emanate from the CSM communication systems at wavelengths of 13 cm (S-band) and 116 cm (very high frequency (VHF)). Lunar crustal properties such as dielectric constant, average slope and slope probability, density, small-scale surface roughness, and embedded rocks to a depth of 20 m may be determined. The results are proving to be most useful in understanding the processes that have produced and modified the crust and in distingushing between adjacent and subjacent geological units. The experimental observations are also of intrinsic interest in the study of electromagnetic scattering.
    Keywords: COMMUNICATIONS
    Type: NASA. Lyndon B. Johnson Space Center Apollo 16 Prelim. Sci. Rept.; 13 p
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  • 29
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    The energy balance of wind waves and the remote sensing problem (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: Measurements of wave growth indicate an energy balance of the wave spectrum governed primarily by input from the atmosphere, nonlinear transfer to shorter and longer waves, and advection. The pronounced spectral peak and sharp low frequency cut-off characteristic of fetch-limited spectra are explained as a self-stabilizing feature of the nonlinear wave-wave interactions. The momentum transferred from the atmosphere to the wind waves accounts for a large part of the wind drag. These findings are relevant for remote microwave sensing of the sea surface by backscatter and passive radiometry methods.
    Keywords: GEOPHYSICS
    Type: NOAA Sea Surface Topography from Space, Vol. 2; 55 p
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  • 30
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    Comments on ocean circulation with regard to satellite altimetry (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: Basic features of sea surface topography are reviewed, to show those oceanographic results which may be of value to a geodetic satellite program: (1) the shape and magnitude of the large scale features of the mean sea surface, relative to a level surface; (2) the position and magnitude of the slopes across the western boundary currents, from a variety of data; (3) an estimate of the position of the geoid, tied into the U.S. leveling network; and (4) a documented change of 60 to 70 cm in mean sea level, with respect to the geoid, between the U.S. east and west coasts.
    Keywords: GEOPHYSICS
    Type: NOAA Sea Surface Topography from Space, Vol. 2; 17 p
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  • 31
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    The stable auroral red arc of October 31 - November 1, 1968 and its interaction with the neutral atmosphere (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: Satellite observations of electron temperature and the topside electron density structure are used to calculate the red arc according to the thermal conduction model. In this model, energy from the magnetosphere flows in the electron gas along geomagnetic field lines into the ionosphere. This energy heats the ambient F-region electrons sufficiently to excite the oxygen atoms to the O I(1D) level by collisional impact giving rise to the 6300 A emission characteristic of the arc. For the 31 October/1 November 1968 red arc, the calculated emission rate, geographical position, and horizontal extent of the red arc are in agreement with the photometric data obtained by airglow observatories. Almost all of the energy conducted into the red arc is ultimately transferred to the neutral gas through elastic and inelastic collisions. This energy drives a large thermal cell and the circulation extends the influence of the arc thousands of kilometers beyond the region of direct heat input. The calculated neutral gas temperature response to electron heating within the arc is small.
    Keywords: GEOPHYSICS
    Type: NASA, Washington Phys. of the Space Environment; p 45-69
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  • 32
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    Solar particle tracks in glass from Surveyor 3 (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: Samples of glass from the Surveyor 3 TV camera filter were examined for particle tracks by optical and scanning electron microscopy. The corrected density value is 1.7 million + or - 0.1 million tracks/sq cm, and the track density vs depth curve is determined. Comparisons with other estimated and calculated data are discussed, and lack of agreement between data sets is considered. It is felt that considerable erosion occurs, and that erosion also occurs by a flaking of small thicknesses of material, possibly caused by solar wind irradiation.
    Keywords: SPACE RADIATION
    Type: NASA, Washington Analysis of Surveyor 3 Mater. and Phot. Returned by Apollo 12; p 209-212
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  • 33
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    Enhanced emission of iron nuclei in solar flares (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: A silica glass window from Apollo 12 CM and a piece of flint glass from the Surveyor 3 camera filter were examined for Fe nuclei tracks. A large difference between observed and predicted track densitites was found. At low rigidity (or energy), the solar particle Fe/He ratio is much higher than the photospheric abundance ratio, but decreases with increasing rigidity until it approaches the photospheric value at a rigidity of about 500 MV. It is felt that the low-energy Fe tracks are of solar origin. The implications that heavy nuclei can be preferentially emitted from a source of energetic particles are discussed. Other conclusions are the following: Rocks exposed on the lunar surface for 10 million yr would accumulate about 6 x 10 to the 12th power tracks/sq cm, and the rate of radiation-induced erosion is about 10 to the -9 cm/yr. The lunar soil should contain heavily irradiated small grains, some with track densities of about 10 to the 12th power/sq cm that have flaked from radiation-damaged rock surfaces and some that were irradiated while at the top of the soil layer.
    Keywords: SPACE RADIATION
    Type: NASA, Washington Analysis of Surveyor 3 Mater. and Phot. Returned by Apollo 12; p 217-220
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    The composition of the upper atmosphere (1972)
    In:  CASI
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    Publication Date: 2005-11-30
    Description: Miniature mass spectrometers were developed and were carried on sounding rockets to determine the composition of the upper atmosphere. Techniques have been developed that accurately correct for the velocity and spin of the moving vehicle. Above 120 km N2, O2, and Ar appear to be in diffusive equilibrium. Most He concentration measurements show a more rapid decline with altitude than predicted by diffusive equilibrium. Because of the highly reactive nature of atomic oxygen, measurements of this species by mass spectrometry are low by an unknown factor.
    Keywords: GEOPHYSICS
    Type: NASA, Washington Phys. of the Space Environment; p 129-145
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    Hydrology of the Niger River from Nimbus HRIR (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The seasonal changes in aspect of the Niger River in the Republic of Mali, West Africa, as seen in daytime imagery obtained by the high-resolution infrared radiometer on Nimbus 3 are described. The identification of different plants by their reflectance is shown to provide an ecological map that changes with time. It is concluded that Nimbus imagery provides an integrated view of the entire watershed on a daily basis.
    Keywords: GEOPHYSICS
    Type: Significant Accomplishments in Sci., 1970; p 8-13
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    Air-sea interaction in the Pacific Ocean (1972)
    In:  CASI
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    Publication Date: 2005-11-30
    Description: Daily Tiros and ESSA satellite television nephanalysis over the Pacific Ocean were collected, and monthly cloud charts drawn to study the interaction of tropical oceans with the atmosphere. The data were correlated with climatological data for rainfall and surface temperatures.
    Keywords: GEOPHYSICS
    Type: Significant Accomplishments in Sci., 1970; p 28-31
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    Reginal Geology of Hadley Rille, part F (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: Local geology of Hadley Rille near the landing site of Apollo 15 is described. Orbital photography from the Hasselblad, metric, and panoramic cameras is used to study regional relationships of the rille. The shape of the rille due to various natural causes is examined, along with stratigraphic measurements of mare materials.
    Keywords: GEOPHYSICS
    Type: NASA. Manned Spacecraft Center Apollo 15 Prelim. Sci. Rept.; 5 p
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    Surface disturbances at the Apollo 15 landing site, part E (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: High resolution panoramic photographs taken from 110 km orbits of the command service module show the lunar module structure on the moon as evidenced by reflected light and by the shadow. Before and after photographs of the landing site are presented; the increased brightness or halo is attributed to mare surface materials.
    Keywords: GEOPHYSICS
    Type: NASA. Manned Spacecraft Center Apollo 15 Prelim. Sci. Rept.; 3 p
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    Solar wind composition experiment (1972)
    In:  CASI
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    Publication Date: 2005-11-30
    Description: The Apollo 16 SWC experiment is a continuation of the earlier experiments; however, an essential change was introduced in the solar wind particle collection technique. Platinum surfaces were incorporated in the collector foil, and use was made of a layer technique for distinguishing particles of different energies and different directions of arrival. The improvements and the expanded scope of the Apollo 16 experiment, relative to the earlier SWC experiments, can be summarized as follows: elimination of possible residual dust contamination by treating the platinum foil sections with dilute hydrofluoric acid before analysis; increased accuracy of solar wind argon abundance; determination of solar wind albedo; and search for helium in the energy range above approximately 40 KeV/nucleon.
    Keywords: SPACE RADIATION
    Type: NASA. Lyndon B. Johnson Space Center Apollo 16 Prelim. Sci. Rept.; 10 p
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  • 40
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    Tides and tsunamis (1972)
    In:  CASI
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    Publication Date: 2005-11-30
    Description: Although tides and tsunamis are both shallow water waves, it does not follow that they are equally amenable to an observational program using an orbiting altimeter on a satellite. A numerical feasibility investigation using a hypothetical satellite orbit, real tide observations, and sequentially increased levels of white noise has been conducted to study the degradation of the tidal harmonic constants caused by adding noise to the tide data. Tsunami waves, possibly a foot high and one hundred miles long, must be measured in individual orbits, thus requiring high relative resolution.
    Keywords: GEOPHYSICS
    Type: Sea Surface Topography from Space, Vol. 2; 30 p
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  • 41
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    The flare forecasting fiasco: Is everybody looking at the same sun? (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The passionate dream of the oppressed solar flare forecaster is the scientific discovery of the cause, the energy source, and the observable antecedent conditions for the solar flare. This tunnel vision has had a profound and deleterious effect on the state-of-the-art. It has diverted attention from many promising approaches and relegated them to limbo. More importantly, it has actually inhibited the scientific search for the underlying physical mechanisms. Examples of neglected aspects of the problem cover the entire range from observing techniques and equipment to the availability and accuracy of the archived scientific data. A cursory inspection of this data leads to an obvious conclusion: there are at least two suns up there.
    Keywords: SPACE RADIATION
    Type: NASA, Washington Phys. of the Space Environment; p 157-171
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  • 42
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    Radar augmentation device (1972)
    In:  CASI
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    Publication Date: 2005-11-30
    Description: The radar augmentation device (RAD) serves to increase the radar response of a target body and thus expedite radar acquisition. The design and development of the RAD are discussed with particular emphasis on technical problems that were encountered and solved. Discussions of the mode of operation of the RAD and the ground test history are also included.
    Keywords: COMMUNICATIONS
    Type: NASA. Ames Res. Center 6th Aerospace Mech. Symp.; p 65-72
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  • 43
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    Cracking of the lunar soil (1972)
    In:  CASI
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    Publication Date: 2005-11-30
    Description: Rather than a pattern of cracks in an apparently flat surface, the Apollo 12 photographs suggest an irregular surface that consists of clods or fragments. The impression of flat tiles and crusting, obtained by monoscopic viewing, is an illusion. Instead, the lunar soil deforms and cracks in the same manner as homogeneous isotropic terrestrial soils of moderate bulk density, having a small amount of cohesion.
    Keywords: GEOPHYSICS
    Type: NASA, Washington Analysis of Surveyor 3 Mater. and Phot. Returned by Apollo 12; p 233-235
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    Solar wind rare gas analysis: Trapped solar wind helium and neon in Surveyor 3 material (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The He-4 and Ne-20 contents in sections of the Surveyor 3 support strut samples were determined by optical and scanning electron microscopy and are compared to the results of the Apollo solar wind composition (SWC) experiments. The He-4/Ne-20 ratio in the samples from the sunlit side of the strut was approximately 300; the ratios determined in Apollo 12 lunar fines and SWC foil were below 100. The He-4/He-3 ratios were also determined, and the ratio obtained from Surveyor 3 material is higher than those found with Apollo 11 and 12 SWC experiments. The effects of spallation by cosmic rays or solar protons, stripping by cosmic ray or energetic solar alpha particles, recycling of solar wind He and radiogenic Ne, He from terrestrial atmosphere, mass discrimination near the moon, mass dependence of trapping probability, diffusion, and contamination by lunar dust are considered.
    Keywords: SPACE RADIATION
    Type: NASA, Washington Analysis of Surveyor 3 Mater. and Phot. Returned by Apollo 12; p 201-208
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    Magnetospheric radio noise (1972)
    In:  CASI
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    Publication Date: 2005-11-30
    Description: Observations, made by the RAE satellite, of earth magnetospheric noise are reported. The observations show radio noise exists at 700 kHz and below. The results are included in graphs.
    Keywords: COMMUNICATIONS
    Type: Significant Accomplishments in Sci., 1970; p 75-80
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  • 46
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    Preliminary geologic map of the region around the candidate Proclus Apollo landing site, part J (1972)
    In:  CASI
    Details
    Publication Date: 2005-11-30
    Description: The Proclus Crater region was mapped to test the value, for photogeologic mapping purposes, of Apollo 15 metric photographs and to estimate the scientific value of the area as a potential landing site. Adjacent frames of the metric photography were overlapped with the base frame to provide stereographic images. Because of the high quality of the photographs, it was found that the geologic units could be more definitely interpreted and dated than those of earlier maps. The photographs tend to confirm the earlier interpretation of the rugged area as composed of bedrock uplifted when the Crisium basin formed. They also suggest that an earlier predominantly volcanic interpretation of the terra in this area might be replaced by an interpretation in which mass wasting and fracturing play the major roles in producing different terrain types. It was concluded that because of apparent lithologic homogeneity, the terra of the Proclus region is an undesirable objective for an extensive manned lunar landing mission.
    Keywords: GEOPHYSICS
    Type: NASA. Manned Spacecraft Center Apollo 15 Prelim. Sci. Rept.; 4 p
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  • 47
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    Quasi-seasonal variation in the sun (1972)
    In:  CASI
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    Publication Date: 2005-11-30
    Description: The results of an investigation on the effects of earth seasonal changes on solar activity, particularly sunspots, are given. These results show corpuscular and electromagnetic activity increased during the equinoctial months. In addition the electromagnetic aspect tends to increase during the winter months. It was suggested that seasonal changes in sunspot numbers may be caused by the tidal forces and the processional torques exerted by the various planets in the solar atmosphere.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci., 1970; p 164-170
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  • 48
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    Hydromagnetic heating in the solar wind (1972)
    In:  CASI
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    Publication Date: 2005-11-30
    Description: Hydromagnetic heating in the solar wind was investigated using the heating model in which fast-mode hydromagnetic waves propagate outward from below the base and deposit energy by collisionless damping. Ray paths were found by solving Hamilton's equations. As the ray propagates along its path, it will damp, supplying thermal energy to the solar wind gas. The strong agreement of these results with observations is clear indication that the primary nonthermal heat source in the solar wind is the collisionless damping of hydromagnetic waves.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci., 1970; p 140-143
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  • 49
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    Magnetospheric boundaries (1972)
    In:  CASI
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    Publication Date: 2005-11-30
    Description: The location of the outer boundary of the geomagnetic field, or magnetopause, and the location of the earth's bow shock have been compiled based on data from the first six IMP satellites.
    Keywords: GEOPHYSICS
    Type: Significant Accomplishments in Sci., 1970; p 81-85
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  • 50
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    Ionospheric profile inversion using oblique-incidence ionograms (1972)
    In:  CASI
    Details
    Publication Date: 2006-03-12
    Description: Some of the elementary methods used in deriving true-height profiles from oblique-incidence ionograms are reviewed. The two principal methods presented are oblique-to-vertical transformation and direct inversion of the oblique-incidence ionogram. Limitations in oblique-incidence inversion due to magnetic-field effects, horizontal gradients, and absolute time delay are discussed.
    Keywords: GEOPHYSICS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 12 p
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    Automatic N(h,t) profiles of the ionosphere with a digital ionosonde (1972)
    In:  CASI
    Details
    Publication Date: 2006-03-12
    Description: A method is described to accomplish automatic data selection and profile inversion to obtain ionospheric electron density profiles from digitized radio soundings. The profile inversion is based on a well-established formulation by which the optimum radio frequency sounding intervals can be specified from an approximate knowledge of the profile; the expected virtual height coordinates (h) at these frequencies (f) are estimated, and procedures are then used to select h(f) observations nearest the predicted coordinates from a subsequent digital ionogram. From these the next profile is obtained. The process adaptively follows the changing shape and detail of the profile. The procedure requires an average of 15 sec per profile on a standard data processing computer, and can be adapted, with benefit to online real-time use in a digital ionosonde.
    Keywords: GEOPHYSICS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 11 p
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    The P prime(f) to N(h) inversion problem in ionospheric soundings (1972)
    In:  CASI
    Details
    Publication Date: 2006-03-12
    Description: A general review is given of the inversion techniques used to derive the ionospheric electron density N as a function of altitude h from group path P versus frequency f measurements obtained by vertical incidence ionospheric sounders. The paper discusses the medium under investigation, the experimental techniques used to obtain the P(f) data, the theoretical considerations leading to the integral equation relating P(f) to N(h), and the assumptions made in the inversion process. The lamination inversion technique is then presented, with special attention given to mathematical difficulties arising from discontinuities in the P(f) function, infinities in the integrand, and in some cases unknown integration limits. Methods outlined for minimizing the uncertainties due to discontinuities include the use of redundant information - that is the two distinct P(f) functions available for a given N(h) profile - and the use of models based on statistical data. Mathematical procedures are discussed that increase significantly the efficiency and accuracy of the required numerical integrations. The accuracy of the inversion technique is deduced by comparing the resulting N(h) profile with N(h) data obtained by simultaneous but independent observations.
    Keywords: GEOPHYSICS
    Type: Math. of Profile Inversion; 13 p
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    Error analysis of bent ray radio occultation measurments (1972)
    In:  CASI
    Details
    Publication Date: 2006-03-12
    Description: There are two types of experimental measurement errors of the Doppler data associated with the radio occultation, random and systematic. Random errors are due to thermal noise in the transmission channel, and the phase lock loop, and quantization error in the digital circuitry. These are called noise type errors. The systematic errors are due to geometric uncertainty and equipment phase instability. Considered is the amount of uncertainty, due to random measurement errors, in the refractivity profiles reconstructed by this type of indirect sensing experiment. A class of refractivity profiles is defined which approximately fit the set of measured data. Bounds are placed on the extent of this class of solution profiles. To accomplish this, the sensivity of the reconstructed refractivity profiles to errors in the measured quantity and the statistics of the errors in the measurement are examined.
    Keywords: COMMUNICATIONS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 5 p
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    Statistical retrieval techniques for sounding the meteorological structure of the atmosphere (1972)
    In:  CASI
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    Publication Date: 2006-03-12
    Description: Statistical retrieval methods for remote sounding are reviewed. Methods are given for constraining an essentially incomplete problem by means of the known statistical behavior of the solution. Information content of the observations and the meteorological structure are discussed. Linear versions of maximum probability and minimum variance methods are given in some detail, and extensions to the nonlinear case are described.
    Keywords: GEOPHYSICS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 10 p
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    A review of some aspects of inferring the ozone profile by inversion of ultraviolet radiance measurements (1972)
    In:  CASI
    Details
    Publication Date: 2006-03-12
    Description: The mathematical inversion of light-scattering observations to obtain the atmospheric ozone profile is discussed in terms of the filtering properties of the physical and mathematical processes for different spatial scales. Within this context, it is shown that the physical process of scattering acts as a low pass filter; which transfers large-scale profile information efficiently to radiance observations but very strongly attenuates small- or fine-scale profile information. To avoid domination of the mathematical inversion by the random error of radiance measurements, an equivalent spatial-scale filtering in the inversion procedure is essential. The available evidence suggests that mathematical inversion to obtain the low level ozone profile below 25 to 30 km is either inferior to or no better than the statistical estimation of the profile using total ozone as predictor. However, inversion profiles for high level ozone above 25 to 30 km appear to have moderately good accuracy.
    Keywords: GEOPHYSICS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 24 p
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  • 56
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    Some special cases of the electromagnetic inverse problem (1972)
    In:  CASI
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    Publication Date: 2006-03-12
    Description: A review of exact techniques for determining the surface of a three-dimensional perfectly conducting body is given, followed by some new results on the uniqueness question concerning the number of measurements that may be required to explicitly determine the surface of the body. It is then shown that the inhomogeneous but spherically symmetric dielectric electromagnetic case is reducible to a scalar inverse problem that can be treated by known techniques.
    Keywords: COMMUNICATIONS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 11 p
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    A review of nonstatistical techniques for the estimation of vertical atmospheric structure from remote infrared measurements (1972)
    In:  CASI
    Details
    Publication Date: 2006-03-12
    Description: Mathematical techniques used in atmospheric profile inversion are reviewed, with the discussion limited to methods that do not require extensive information on the statistical properties of the profiles. The basic problem of the calculation of vertical profiles from noise contaminated infrared spectral measurements is examined. Three specific examples of methods of solution are given: the iterative minimum estimation method, a second linear iterative method, and the algorithm of Chahine. Satellite data are used in an empirical comparison of the methods. Several factors are considered, including the stability of solutions, convergence behavior of the iterative methods, and dependence of the solutions on the first guess, a factor that is particularly important in the treatment of data from other planets.
    Keywords: GEOPHYSICS
    Type: Math. of Profile Inversion; 14 p
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    Spacecraft ion beam noise effects (1972)
    In:  CASI
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    Publication Date: 2006-02-22
    Description: An estimate of the antenna noise temperature and the uplink signal-to-noise ratio has been made for Bremsstrahlung radiation emitted by a spacecraft ion beam; a worst-case situation in which the spacecraft antenna is located in the exit plane of the ion beam and directed at varying angles into the ion beam is assumed. Numerical results of the antenna noise temperature versus antenna pointing angle are given for a typical set of ion beam and antenna pattern parameters. The uplink signal-to-noise ratio due to the ion beam noise alone is given in terms of a critical range in AU at which a typical ranging transmission is received with S/N = 0 db. The effects of the ion beam divergence angle and antenna distance on the ion beam are also presented. Results of the study show typical increases in the antenna noise temperature of about 0.2 K and critical ranges of the order of 3-5 AU. An ion engine thus generally introduces an undetectable level of noise into a spacecraft receiver.
    Keywords: COMMUNICATIONS
    Type: JPL Quart. Tech. Rev., Vol. 2, No. 2; p 61-71
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    Interplex: An analysis of optimized power allocations for two and three channel PSK/PM telecommunications systems (1972)
    In:  CASI
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    Publication Date: 2006-02-22
    Description: Optimal design concepts are presented for two- and three-channel telemetry modes in the context of the Mariner Venus-Mercury 1973 mission and the usefulness of interplex modulation techniques is discussed. These ideas are applied as an example to one Mariner Venus-Mercury 1973 telemetry mode to demonstrate that interplex can reduce the required total average power by more than 2 dB in some cases.
    Keywords: COMMUNICATIONS
    Type: JPL Quarterly Tech. Rev., Vol. 2, No. 1; p 143-151
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    Analysis of the failure of a polyester peripheral drive belt on the Mariner Mars 1971 flight tape recorder (1972)
    In:  CASI
    Details
    Publication Date: 2006-02-22
    Description: A peripheral drive belt on the Mariner Mars 1971 tape recorder failed when a thin longitudinal strip separated off one edge. Analysis showed that the most probable cause of failure occurred from flexural fatigue initiating in mechanically weak locations which are introduced into the belt during fabrication. Methyl ethyl ketone, which is employed as a cleaning solvent during fabrication, was found to cause permanent reduction in engineering properties of polyester and could have contributed to the reduction of the fatigue resistance. Fatigue properties of the polyester drive belt are reviewed for the operating condition, as well as the sensitivity of polyester to cleaning solvents and the origin of mechanically weak locations.
    Keywords: COMMUNICATIONS
    Type: JPL Quarterly Tech. Rev., Vol. 2, No. 1; p 82-99
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    Studies on the frictional behavior of magnetic recording tapes (1972)
    In:  CASI
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    Publication Date: 2006-02-22
    Description: Methods were developed for measuring frictional forces acting on a magnetic tape in motion or at rest, as well as the extent of stick slip. The effects of factors such as temperature, humidity, kind of gaseous atmosphere, and tape speed on the frictional interaction between various tapes and heads were investigated. Results were instrumental in the selection of a tape for the Mariner Mars 1971 spacecraft. Studies are reported on the stick slip behavior of tapes and the performance of a metallic tape, compared with the usual plastic tapes.
    Keywords: COMMUNICATIONS
    Type: JPL Quarterly Tech. Rev., Vol. 2, No. 1.; p 100-106
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    Apparatus for investigation of the amplitude frequency response of the ionospheric scattering channel (1972)
    In:  CASI
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    Publication Date: 2006-04-26
    Description: Equipment for studying the amplitude frequency response of the ionospheric scattering channel is described, having multipath signal propagation. Experimental results are reported, including nonuniformity in the channel's amplitude frequency response.
    Keywords: GEOPHYSICS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 39-45
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    Parameters of small scale ionization inhomogeneities in the F region of the ionosphere (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: The results of the parameters of small-scale ionization inhomogeneities study of the ionosphere's F-region for October-November 1965 and January-February 1966 are presented. It is shown that the most probable values of the inhomogeneity parameters are as follows: degree of anisotropy 1.4-2; vertical dimension 200-400 m; horizontal dimensions along major and minor axes 400-1000 and 200-600 m, respectively; rate of chaotic motions 30-60 m/sec; lifetime 6-9 sec.
    Keywords: GEOPHYSICS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 23-29
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    Results from simultaneous radar-television observations (1972)
    In:  CASI
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    Publication Date: 2006-04-24
    Description: The results of the reduction of simultaneous observations of 29 meteors are presented in tabular form. Fragmentation of the observations is discussed along with the 50 meteors not yet reduced.
    Keywords: COMMUNICATIONS
    Type: Meteor Res. Program; p 83-99
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    Analysis procedure for television observations and simultaneous observations (1972)
    In:  CASI
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    Publication Date: 2006-04-24
    Description: The procedures used in the analysis of television and simultaneous observations are described. Starting with the right ascension and declination of the meteor, the celestrial triangle formed by Sidell and the meteor is solved, and the epochs of the beginning and end of the meteor observation as recorded on the video tape are determined.
    Keywords: COMMUNICATIONS
    Type: Meteor Res. Program; p 69-76
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    Simultaneous observations by television camera and radar (1972)
    In:  CASI
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    Publication Date: 2006-04-24
    Description: The original image-orthicon equipment used for simultaneous radar and optical observations is described. The adaptations made to enhance its usefulness for meteor observations, and the specialized calibration and photometric procedures developed for this purpose are also described. Some brief comments concerning the use of the secondary electron conduction vidicon are included.
    Keywords: COMMUNICATIONS
    Type: Meteor Res. Program; p 29-36
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    Statistical accuracy of cosmic radiation neutron component recorders (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: A method is examined for calculating the error of experimental data from a standard neutron monitor with the multiplicity of neutron generation. It is shown that use of the Poisson distribution to estimate the real statistical error is inadequate. The method proposed is for analysis of low-amplitude periodicities in the cosmic-ray variations.
    Keywords: SPACE RADIATION
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 79-81
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  • 68
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    Receiving antenna installation for ionospheric scattering links (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: Smearing of the scattered-energy flux density over a range of angles of arrival permits the use of a receiving-end antenna with a height lower than theoretical.
    Keywords: GEOPHYSICS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 65-68
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  • 69
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    The ionosphere above Alma Ata during a solar eclipse (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: The eclipse effect was manifested during the second phase: the ionization of the F1- and F2-layers decreased and the minimum effective heights of E and F2 increased due to recombination processes. The manner in which electron density is distributed over the levels was ascertained from analysis of N(t) curves.
    Keywords: GEOPHYSICS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 35-38
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  • 70
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    Radioastronomical measurement of absorption (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: Diurnal and seasonal absorption curves measured by a radio astronomical method at Alma-Ata during the IQSY (1964-1965) are submitted. The apparatus is described. The dependence of absorption on solar flares is also indicated.
    Keywords: GEOPHYSICS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 30-34
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  • 71
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    The state of the ionosphere above Alma Ata (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: The basic patterns are described in the behavior of critical frequencies and minimum effective heights of the ionosphere's reflecting E, F1, and F2 layers, according to ionospheric recorder measurements from 1943 to 1967. The variations of critical frequencies and virtual heights are compared with the relative sunspot numbers and the flux of the sun's radio emission at 10.7 cm.
    Keywords: GEOPHYSICS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 1-6
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  • 72
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    On the selection of a vertical base in the ionosphere (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: The problem of selecting a vertical base in the ionosphere that permits registration of vertical motions of small-scale ionization inhomogeneities of the ionosphere's F-region is discussed. The accuracy of calculation of the vertical drift-velocity component is estimated.
    Keywords: GEOPHYSICS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 7-12
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  • 73
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    Results of measurement of radio wave absorption in the ionosphere by the AI method (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: Median noon absorption values for each month from 1964 through 1967, the diurnal variations of absorption on the regular world days, and the seasonal variations of absorption are given. The dependence of the absorption coefficient on sunspot number is analyzed.
    Keywords: COMMUNICATIONS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 99-112
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  • 74
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    Cosmic ray variations during PCA type absorption (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: It is shown based on data on the cosmic-ray neutron component, ionospheric soundings, and measurements of cosmic radio-emission absorption at Vostok station (Antarctica) that the ionization of the lower ionosphere increases during low intensity of Forbush-type cosmic rays. This is manifested in increased absorption and the appearance of strong sporadic layers in the E-region.
    Keywords: SPACE RADIATION
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 74-77
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  • 75
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    A method of investigating the phase response characteristic of the ionospheric scattering communications channel (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: A method is proposed for measuring the phase difference fluctuations between vibrations at different frequencies that result from scattering properties of the medium. The measurement equipment is described, along with an ideal communication channel.
    Keywords: GEOPHYSICS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 47-54
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  • 76
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    Radio wave propagation at frequencies exceeding MUF-F2 in the short wave band (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: The results of measurements of field strength and signal/noise ratio on experimental ionospheric-scattering short wave radio links are presented. It is shown that the seasonal and diurnal variations of field strength are determined by features of solar and meteoric activity. The role of the sporadic E-layer in propagation of short radio waves at frequencies exceeding MUF-F2 is noted.
    Keywords: GEOPHYSICS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 55-59
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  • 77
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    Ionospheric magnetic phenomena associated with proton flares (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: The state of the ionosphere above stations in Kazakhstan is examined in connection with the proton flares of 7 July, 28 August, and 2 September 1966. Universal time is used. It is established that a proton flare causes increased radio absorption (the ionization of the D-region is enhanced, and the minimum reflected frequencies decrease). Magnetic storms and ionospheric disturbances are observed on the earth one-and-a-half to two days after some proton flares.
    Keywords: GEOPHYSICS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 17-22
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  • 78
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    Influence of vertical drift of small scale ionization inhomogeneities on the diurnal variation of f0F2 (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: The diurnal variations of the critical frequencies of the ionospheric F2 region may be influenced substantially by the 12-hour component of the vertical drift of small-scale ionization inhomogeneities. The appearance of the forenoon maximum of F2 and the evening ionization maximum are examined.
    Keywords: GEOPHYSICS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 13-16
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  • 79
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    Variations of cosmic rays associated with chromospheric flares on the sun (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: Features of the cosmic-ray variations in the geomagnetic pole region and a smooth decrease in the cosmic rays intensity as a result of increased solar activity are reported. A 66-day variation of the cosmic rays was registered, in agreement with the maximum frequency and power of solar chromospheric flares.
    Keywords: SPACE RADIATION
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 113-116
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  • 80
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    Estimates of the electric fields in the lower ionosphere above the magnetic equator (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: The electric fields at the solar activity minimum on the magnetic equator are evaluated based on data from rocket studies of the vertical profiles of the ionospheric-current magnetic fields and electron concentration. The electric field strength is 1-4 X 100 CGSM units. In addition, the electric field has altitude and time distributions. Its maximum is observed at a height of 110 km, and at 90 and 140 km, it is smaller by a factor of 3-4 than at the 110-km height. The maximum values are registered around noon.
    Keywords: GEOPHYSICS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 82-89
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  • 81
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    On the possibility of explaining features of the latitude variations of Sq(H) and Sq(Z) in the equatorial region by electrical modelling (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: 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.
    Keywords: GEOPHYSICS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 90-94
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  • 82
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    Occupancy of the radio frequency spectrum in the 16-23 MHz band (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: Measurement results are presented for actual utilization of the short wave frequency band, obtained by continuous registration of the number of radio stations in the 16-23 MHz band over an annual cycle (1965). It is shown that there is a relation between the number of radio stations and the variations of MUF-F2. During years of minimum solar activity and at night, segments free of radio stations operating by normal reflection, can be selected in the 18-23-MHz band for ionospheric-scattering links.
    Keywords: GEOPHYSICS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 60-64
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  • 83
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    Analysis procedure for radar observations (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-24
    Description: Based on the assumption that the ionized column left behind a moving meteroroid is underdense, it is shown that radar observations of the column yield resonable aproximations to the meteoriod's speed and trajectory. The principles and procedures for finding a meteor's position and vector velocity from the observed data are also presented.
    Keywords: COMMUNICATIONS
    Type: Meteor Res. Program; p 51-68
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  • 84
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    Antenna calibration at Havana (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-24
    Description: The procedures for calibrating the antenna patterns of the Havana radar system are described along with the reduction of the measurements made using a dipole towed behind an airplane. The power-gain pattern for the north, south, and joint troughs of sites 3 and 4 are plotted.
    Keywords: COMMUNICATIONS
    Type: Meteor Res. Program; p 37-50
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  • 85
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    Description of eight station radar near Havana, Illinois (1972)
    In:  CASI
    Details
    Publication Date: 2006-04-24
    Description: A general description is given of the eight-station system at Havana which incorporated high-gain antennas and a powerful transmitter to reach faint meteors on the order of magnitude of plus 12. The station location, principle of system design, systems connections, transmitter, receivers, logics, range measurement, and recording are described.
    Keywords: COMMUNICATIONS
    Type: Meteor Res. Program; p 19-27
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  • 86
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    Acoustic radar sounding of the lower atmosphere (1972)
    In:  CASI
    Details
    Publication Date: 2006-03-12
    Description: Acoustic radar sounding techniques were used to measure the wind velocity and direction in the first 300 m of the atmosphere. Angle-of-arrival and Doppler techniques were developed to obtain two independent measurements of the wind field. These techniques and preliminary experimental results are described briefly.
    Keywords: GEOPHYSICS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 11 p
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  • 87
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    Statistical versus nonstatistical temperature inversion methods (1972)
    In:  CASI
    Details
    Publication Date: 2006-03-12
    Description: Vertical temperature profiles are derived from radiation measurements by inverting the integral equation of radiative transfer. Because of the nonuniqueness of the solution, the particular temperature profile obtained depends on the numerical inversion technique used and the type of auxiliary information incorporated in the solution. The choice of an inversion algorithm depends on many factors; including the speed and size of computer, the availability of representative statistics, and the accuracy of initial data. Results are presented for a numerical study comparing two contrasting inversion methods: the statistical-matrix inversion method and the nonstatistical-iterative method. These were found to be the most applicable to the problem of determining atmospheric temperature profiles. Tradeoffs between the two methods are discussed.
    Keywords: GEOPHYSICS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 7 p
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  • 88
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    The inversion of VLF-LF sounder data to obtain D-region electron-density distributions (1972)
    In:  CASI
    Details
    Publication Date: 2006-03-12
    Description: The direct problem is to compute reflection coefficients for an assumed electron-density profile, using a full-wave solution. The inverse problem is treated numerically, using derivatives of the reflection matrix with respect to model parameters. A technique for the rapid computation of the derivatives is described. An algorithm for determining resolution in the profile is discussed.
    Keywords: GEOPHYSICS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 7 p
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  • 89
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    The calculation of electron density profiles from topside ionograms: Method and applications (1972)
    In:  CASI
    Details
    Publication Date: 2006-03-12
    Description: A method for converting topside sounder ionograms into topside electron density profiles is discussed. The lamination method used is modified to take into account the variation of electron density and magnetic field within each lamination. Also included is a change of variable to produce a finite integrand of the integral involved, an iteration scheme that permits convergence on an initially unknown density, a second iteration scheme to overcome the problem of an uncertainty in the electron density at the satellite, and a modification to compensate for the changing satellite altitude over the duration of the sounding. Two applications of the technique are discussed: field-aligned traces for computing field-aligned profiles and computer-aided systems for scaling ionograms.
    Keywords: GEOPHYSICS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 11 p
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  • 90
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    An occultation satellite system for determining pressure levels in the atmosphere (1972)
    In:  CASI
    Details
    Publication Date: 2006-03-12
    Description: An operational two-satellite microwave occultation system will establish a pressure reference level to be used in fixing the temperature-pressure profile generated by the SIRS infrared sensor as a function of altitude. In the final error analysis, simulated data for the SIRS sensor were used to test the performance of the occultation system. The results of this analysis indicate that the occultation system is capable of measuring the altitude of the 300-mb level to within 24 mrms, given a maximum error of 2 K in the input temperature profile. The effects of water vapor can be corrected by suitable climatological profiles, and improvements in the accuracy of the SIRS instrument should yield additional improvements in the performance of the occultation system.
    Keywords: GEOPHYSICS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 13 p
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  • 91
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    Fine structure of the lower atmosphere as seen by high resolution radar (1972)
    In:  CASI
    Details
    Publication Date: 2006-03-12
    Description: A ground-based vertically pointing FM-CW radar is described that permits remote probing of the refractive index structure in the troposphere. The radar has the characteristics of extremely high sensitivity, ultrahigh range resolution, and close minimum detection range without clutter. The sounder routinely detects layer structures in the lower troposphere. These layers are always associated with gradients in the vertical refractive index profile, and are frequently very thin, approaching the resolution of the radar (1 m). Very often they are perturbed by wave motions. Examples of various wave patterns are presented, and an explanation is given for organized substructures frequently superimposed on larger scale wave motions.
    Keywords: GEOPHYSICS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 8 p
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  • 92
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    The mathematical-physical problem of P prime(f) to N(h) inversion for anisotropic media (1972)
    In:  CASI
    Details
    Publication Date: 2006-03-12
    Description: The requirements for a numerical inversion method to calculate electron density profiles from ionograms are discussed. A systematic investigation about the independence of the two magnetoionic components shows that the extent to which the range of ambiguity can be reduced depends mainly on the magnetic latitude. Error estimates and first-order corrections for less elaborate methods are included.
    Keywords: GEOPHYSICS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 13 p
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  • 93
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    Numerical methods for reduction of topside ionograms (1972)
    In:  CASI
    Details
    Publication Date: 2006-03-12
    Description: Several alternative methods for solving the group height equation are presented. Three of these are now in operation at Ames Research Center and use data contained in a single ionogram trace. From the data an electron density profile N(h) is computed. If the ionogram also exhibits other traces, reverse ionogram traces are computed, using the N(h) profile, for comparison with the redundant data. When agreement is poor, the initial data trace is reinterpreted, another N(h) profile computed, and the reverse traces generated once again. This process is repeated until a desired degree of consistency is achieved. To reduce the necessity for human intervention and eliminate decision making required in conjunction with the preceding methods, a method is proposed that accepts as input, all data from a single ionogram. In general, no electron density function will satisfy these data exactly, but a best N(h) profile can be computed. Finally, a method is described that eliminates the need to assume that the ionosphere is spherically stratified. Horizontal gradients in electron density are detected and accounted for by processing several ionograms from the same satellite pass simultaneously. This idea is derived as an extension of one of the basic methods.
    Keywords: GEOPHYSICS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 10 p
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  • 94
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    Precision signal power measurement (1972)
    In:  CASI
    Details
    Publication Date: 2006-02-22
    Description: Accurate estimation of signal power is an important Deep Space Network (DSN) consideration. Ultimately, spacecraft power and weight is saved if no reserve transmitter power is needed to compensate for inaccurate measurements. Spectral measurement of the received signal has proved to be an effective method of estimating signal power over a wide dynamic range. Furthermore, on-line spectral measurements provide an important diagnostic tool for examining spacecraft anomalies. Prototype equipment installed at a 64-m-diameter antenna site has been successfully used to make measurements of carrier power and sideband symmetry of telemetry signals received from the Mariner Mars 1971 spacecraft.
    Keywords: COMMUNICATIONS
    Type: JPL Quart. Tech. Rev., Vol. 2, No. 2; p 18-24
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  • 95
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    The effect of secondary autoionization on dielectronic recombination. (1972)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Demonstration that, during the process of dielectronic recombination, the energy of a recombined ion after a resonance capture and subsequent stabilization may still be higher than the first ionization limit. If that happens, a secondary autoionization can take place and reduce the recombination coefficient. The importance of this effect is considered for iron ions Fe(9+) to Fe(13+).
    Keywords: SPACE RADIATION
    Type: Astrophysical Letters; 10; Apr. 197
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  • 96
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    Metagalactic gamma rays from relativistic-electron bremsstrahlung interactions. (1972)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Evaluation of gamma-ray spectra calculated for relativistic-electron bremsstrahlung interactions at cosmological distances under the assumption of a single power-law source spectrum for the electrons. It is concluded that such spectra cannot match the form of the observed cosmic gamma-ray spectrum above 1 MeV, as has previously been suggested.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 171; Jan. 15
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  • 97
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    The shadow band phenomenon. (1972)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Observation of shadow bands during the solar eclipse of Mar. 7, 1970. Data were gathered by recording onto magnetic tape of the output from six collimated photocells whose spectral responses ranged from the ultraviolet to the infrared, and by visual and mechanical measurement of the orientation and motion of the bands. The recorded data were later processed using the output from a frequency spectrum analyzer. Most of the energy of the shadow bands ranges between 1 and 25 Hz, and appears not unlike plots of scintillation spectra. The onset, amplitude, and duration of the shadow bands seem to be spectrally related to the limb darkening of the sun's photosphere. Other results of the experiment conclusively indicate that the shadow band phenomenon is a manifestation of atmospheric turbulence in the form of air packets of different density from that of their environment (density schlieren), made visible by the light from the crescent sun.
    Keywords: GEOPHYSICS
    Type: Journal of Atmospheric and Terrestrial Physics; 34; Apr. 197
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  • 98
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    Mode coupling in partial reflections from the ionosphere at vertical incidence. (1972)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: The effect of mode coupling has been calculated for radio waves partially reflected from the lower ionosphere at vertical incidence. Calculations were made for parameters appropriate to the partial reflection experiments (Belrose, 1970). The four reflection coefficients (two direct and two coupled) are calculated for a plane discontinuity using a matrix perturbation analysis. The ratios of coupled to direct reflection coefficients are calculated for a general one-dimensional reflecting layer using the coupled equations of Clemmow and Heading (1954). At the highest electron density considered, 10,000 per cu cm, about 10% of the reflected extraordinary wave amplitude might be due to coupling from the incident ordinary wave. The effect is smaller at lower electron density.
    Keywords: COMMUNICATIONS
    Type: Radio Science; 7; Apr. 197
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  • 99
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    Atmospheric density variations at 140 kilometers deduced from precise satellite radar tracking data. (1972)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Discussion of the technique of evaluating density values from precise radar-tracking data of satellites in the altitude region from 130 to 140 km. Inclinations of these satellites were between 106 and 112 deg. A detailed examination of all elements of the density-reduction techniques was conducted, and consideration was given to recent advances in geodesy, drag-coefficient modeling, and orbit-determination techniques. Ten days of high-resolution density data deduced from orbital decay of each of three satellites are presented. Three types of density variations at 140 km are discernible in these data: periodic daily density variations with a density amplitude of about 10%; density increases of up to 35% associated with enhanced geomagnetic activity during which the planetary geomagnetic index Kp reached a value of 8 units; and an observed semiannual variation of about 20%, which indicates a total semiannual variation of 35 to 40%.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 77; Apr. 1
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  • 100
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    Heavy ions from interplanetary dust. (1972)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Most atoms that are evaporated from interplanetary dust near the sun are quickly ionized and are probably carried away by the interplanetary magnetic field and the solar wind. The contribution of these heavy ions to the solar-wind flux has been estimated by using estimates of the mass required to maintain the zodiacal cloud. This contribution appears to be small compared with the heavy-ion flux of coronal origin. Many ions from dust remain singly ionized; some of these, such as Ca(+), can resonantly scatter solar radiation. The contribution of this interplanetary glow to the background of twilight glow has been estimated. Interplanetary glow may be detectable. Some atoms from dust may be accelerated by radiation pressure before being ionized. Estimates of velocities and fluxes for Fe indicate that this acceleration is not very effective.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 77; Apr. 1
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