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  • LUNAR AND PLANETARY EXPLORATION  (723)
  • COMMUNICATIONS AND RADAR  (237)
  • 1985-1989
  • 1975-1979  (960)
  • 1977  (960)
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  • 1985-1989
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  • 1
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    The mass of Phobos (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Radio tracking data associated with the February 1977 encounters between the Martian satellite Phobos and the Viking Orbiter I spacecraft have been analyzed to determine the gravitational constant of Phobos. A linear error analysis was conducted to determine the selection of data and the parameter solution set which would yield the best estimate of the gravitational constant. This error analysis indicated that the optimal data set was a data arc beginning just prior to the closest encounter and spanning three consecutive spacecraft orbits; data near periapsis were deleted. The most feasible parameter solution set consisted of the Phobos gravitational constant and the spacecraft initial conditions. The result of the data analysis was an estimate of (7.3 plus or minus 0.7) x 10 to the -4th cu km/sq sec for the gravitational constant of Phobos.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Geophysical Research Letters; 4; Dec. 197
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  • 2
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    Spectrophotometric and color estimates of the Viking lander sites (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The spectral radiance and color of the Martian sky and soil and the spectral reflectance of soil features are estimated from six-channel (0.4-1.0 micron) spectral data obtained with the Viking lander cameras. Images taken near local noon from the two landers reveal a sky that is brighter near the horizon than the soil but with a similar spectral radiance shape and color. The scenes are predominantly moderate yellowish brown in color with only subtle variations except for some dark grey rocks. Most spectral reflectance estimates are similar: they rise rapidly with increasing wavelength between 0.4 and 0.8 micron and with only a few exceptions exhibit a pronounced minimum centered about 0.93 micron. These characteristics are consistent with an abundance of Fe(3+)-rich weathering products, notably nontronite. However, the delineation of the number and abundances of total mineral phases requires further analyses and laboratory comparisons. Reflectance estimates for rocks have not been repeatable, probably because most rocks have irregular pitted surfaces that introduce significant shadowing components.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Journal of Geophysical Research; 82; Sept. 30
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  • 3
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    A search for ultraviolet OH emission from meteors (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Observations of hydroxyl (OH) emission from meteors were made during the late summers of 1975 and 1976 from altitudes of 10,600 and 14,200 feet (3.2 km and 4.45 km). The observations were made with OH meteor photometers developed at the NASA-Langley Research Center. Two of the meteors were Perseids, and one was an Alpha Capricornid. The Perseid meteors produced a peak irradiance at a distance of 100 km from the meteors of about 0.00005 erg/sq cm per sec in the OH emission region. The zero-magnitude Alpha Capricornid meteor produced a spectral irradiance at 3100 A of 23 hundred-millionths erg/sq cm per A per sec. This may be indicative of significant amounts of H2O in these meteors.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Astrophysical Journal; vol. 217
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  • 4
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    Reducing greenhouses and the temperature history of earth and Mars (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: It has been suggested that NH3 and other reducing gases were present in the earth's primitive atmosphere, enhancing the global greenhouse effect; data obtained through isotopic archeothermometry support this hypothesis. Computations have been applied to the evolution of surface temperatures on Mars, considering various bolometric albedos and compositions. The results are of interest in the study of Martian sinuous channels which may have been created by aqueous fluvial errosion, and imply that clement conditions may have previously occurred on Mars, and may occur in the future.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Nature; 269; Sept. 15
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  • 5
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    Happy Canyon - A new type of enstatite achondrite (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Mineralogical and chemical characteristics of the Happy Canyon meteorite, found in 1971 near Wayside, Texas, show it to be a new type of enstatite achondrite occupying the gap between the recrystallized enstatite chondrites and the igneous, crystalline, unbrecciated enstatite chondrites. Although the bulk composition of the specimen is consistent with that of an E6 enstatite chondrite, it has a crystal cumulate texture. There are minor amounts of metal and troilite which have survived extensive weathering. The Happy Canyon meteorite may represent an E6 composition which has melted and reprecipitated at a slightly higher oxidation state, possibly in the core of a small parent body.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Meteoritics; 12; June 30
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  • 6
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    The upper ionosphere of Titan (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Photoionization of the upper atmosphere of Titan by sunlight is expected to produce a substantial ionospheric layer. One-dimensional forms of the mass, momentum, and energy conservation equations for ions and electrons have been solved along with electron number densities of about 1000/cu cm, using various model atmospheres. The significant ions in a CH4-H2 atmosphere are H(+), H3(+), CH5(+), CH3(+), and C2H5(+). Electron temperatures may be as high as 1000 K, depending on the abundance of hydrogen in the high atmosphere. Interaction of the solar wind with the ionosphere is also discussed.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Icarus; 31; May 1977
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  • 7
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    The rings of Uranus (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: A description is given of the observation of five brief occultations of the star SAO 158687 which occurred both before and after its occultation by Uranus on March 10, 1977. The events were observed with a three-channel occultation photometer, attached to a 91-cm telescope. The observations indicate that at least five rings encircle the planet Uranus. Possible reasons for the narrowness of the Uranus rings are discussed.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Nature; 267; May 26
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  • 8
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    Observations at the planet Mercury by the plasma electron experiment - Mariner 10 (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Two nightside encounters with Mercury's magnetosphere by Mariner 10 revealed bow shock and magnetosheath signatures in the plasma electron data that are entirely consistent with the geometry expected for an interaction between a planet-centered magnetic dipole and the solar wind. The geometrically determined distance between the planet's center and the solar wind stagnation point is 1.4 plus or minus 0.1 R sub M. Both diffuse and sharp shock crossings were observed on the two magnetosphere encounters.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Journal of Geophysical Research; 82; May 1
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  • 9
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    A radio lens in the ionosphere (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Using a modified version of the classical Cornu spiral, fading patterns in agreement with observations of radio signals on 140 and 360 MHz from the geostationary satellite ATS6, have been obtained. The particular fading patterns chosen show modulated quasi-periodic fading before and after a deep central minimum. It is shown that a cylindrical lens in the ionosphere required to produce this is only about 100 m across (an order of magnitude smaller than the size of the pattern on the ground) and if it were circular in cross-section would have a maximum plasma frequency of over 40 MHz. This suggests the reason why calculations based on a transparent phase screen did not give the observed fading pattern for 40 MHz signals. It was not possible to deduce the height of the lens above the ground, though we would incline to an E-region origin.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Journal of Atmospheric and Terrestrial Physics; 39; Mar. 197
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  • 10
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    Minor planets and related objects. XXII - Phase functions for /6/ Hebe (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Twenty-two light curves of Hebe are analyzed along with results of UBV photometry and photometric astrometry. A mean synodic period of approximately 7 hr 16 min 28.7 sec is adopted, and it is found that the amplitude of Hebe appears to vary directly with phase. The asteroid's magnitudes and colors are plotted against phase, its pole orientation is estimated, and the sidereal period is determined to be about 7 hr 16 min 28.01 sec from photometric astrometry. A color curve is plotted which shows that Hebe has a reddened region on its surface near the secondary minimum and that the asteroid is nearly spherical. Opposition effects are compared and found to be closely similar for Hebe, Ceres, Lydia, Massalia, and Vesta.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Astronomical Journal; 82; Mar. 197
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  • 11
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    Limitations on oceanographic use of beam-limited target-referenced radars (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: A general development is undertaken to determine the limitations on the use of beam-limited target-referenced radars in the measurement of ocean wave height. This class of radars is concerned only with the range extent of the target, not the range to the target. The nonzero range extent of a flat waveless sea and the compounding effect of pointing errors due to radar platform instability cause difficulty in measuring low wave heights and impose a maximum operating altitude on such systems. It is seen that it is impractical to obtain accurate measurements for wave heights of interest at altitudes above those used by commercial aircraft (10,000 m). Additionally, the typical ratio of dominant wavelength to significant wave height (SWH) of 30 for wind-driven gravity waves imposes an upper limit on the SWH measurable for a given altitude and beamwidth.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Antennas and Propagation; AP-25; May 1977
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  • 12
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    The Del Rio ataxite, Texas (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Basic data are presented on the Del Rio, Nordheim, and Monahans ataxites found in Texas. Results are reported for bulk-chemistry analysis, metallographic observations, and electron-microprobe analysis of the Del Rio meteorite. It is shown that Del Rio is distinctly different from the other two ataxites in terms of nickel, phosphorous, and carbon content, and is composed of at least three coarse grains in different crystallographic orientations. All the kamacite in Del Rio is found to have transformation structures that are probable shock products, and minor inclusions of daubreelite, schreibersite, and troilite are observed. It is concluded that Del Rio was apparently mildly shocked prior to its fall.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Meteoritics; 12; Mar. 31
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  • 13
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    Tracking performance of symbol synchronizers for Manchester coded data (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The implementation and tracking performance of symbol synchronizers for Manchester coded data is presented with motivation provided by maximum a posteriori (MAP) estimation theory. Certain physically relizable closed-loop structures, readily implemented in practice, are suggested by the theory for uncoded data symbols with arbitrary data transition probabilities. The tracking performance of these loops is optimized and comparisons are made among the various configurations over a wide range of system parameters. Although not the major intent of the paper, the acquisition problem is briefly addressed.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Communications; COM-25; Apr. 197
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  • 14
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    Wind enhanced planetary escape - Collisional modifications (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Effects of collisions and finite winds characteristic of a highly perturbed atmosphere on the thermal escape of terrestrial hydrogen and helium are investigated using a Monte Carlo approach. The limiting cases of vertical and horizontal winds are considered, and the relaxation layer between the collisionless exosphere and the collision-dominated thermosphere is modeled as a plane-parallel slab of given column density, depth, and atmospheric density. For both gases, the upwardly injected flux at the base of the relaxation layer is compared with the returning downward flux distribution at the same location; the technique is also applied to the atmosphere of Titan. The results show that inclusion of collisions in the escape model for terrestrial hydrogen with winds effectively throttles the escape process, that collisional throttling is negligible for helium when the exobase temperature is at least 5000 K, and that the escape of a planetary-atmosphere constituent depends on the ratio of its gravitational and kinetic energies as well as on the ratio of its mass to that of the background gas.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Journal of Geophysical Research; 82; Mar. 1
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  • 15
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    A low-frequency radio survey of the planets with RAE 2 (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Over one thousand occultations of each planet in the solar system have occurred during the period from mid-1973 through mid-1976 as seen from the lunar orbiting Radio Astronomy Explorer 2 (RAE 2) spacecraft. These occultations have been examined for evidence of planetary radio emissions in the 0.025-13.1 MHz band. Only Jupiter and the earth have given positive results. Lack of detection of emission from the other planets can mean that either they do not emit radio noise in this band or the flux level of their emissions and/or its occurrence rate are too low to be detected by RAE 2.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Journal of Geophysical Research; 82; Mar. 1
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  • 16
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    An antenna for limited scan in one plane - Design criteria and numerical simulation (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Aperture illumination is synthesized through the use of overlapping subarrays with independently controlled excitations. Detailed analysis and design criteria are provided for a specific limited-scan antenna configuration scanning in one plane. The number of phase shifts is the theoretical minimum corresponding to specified aperture size and field of view. Beam pointing and width are approximately constant for moderate frequency variation, and ultralow sidelobes outside the field of view can be produced at the cost of a slight loss of illumination efficiency. Accurate aperture illumination control makes for excellent independently specified sum and difference patterns in beamforming.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Antennas and Propagation; AP-25; Mar. 197
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  • 17
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    Lunar soil - Iron and titanium bands in the glass fraction (1977)
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    Publikationsdatum: 2011-08-17
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Science; 195; Mar. 11
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  • 18
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    On the reality of the Venus winds (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The article presents a rebuttal of Young's (1975) view that the 140 m/sec horizontal wind at 45 km reported by Venera 8 is anomalous or spurious. Some errors are discussed and the largest contribution is attributed to descent probe measurements designed to find the true probe descent rate. Young's suggestion of error in in situ measurement of winds due to selection of a reference speed and to unrecognized oscillator drift is scrutinized. Evidence is seen for a wide band of variable high-grade retrograde horizontal winds girdling Venus at the equator. Mariner 10 evidence (UV photographs) is taken into account. The band of winds at 45 km is seen to extend well beyond the top of the visible cloud, and an upper turbulent region is attributed to vertical convection currents carried along by high-speed horizontal winds.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Icarus; 30; Feb. 197
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  • 19
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    Optimum performance of suppressed carrier receivers with Costas loop tracking (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The performance of suppressed carrier receivers with Costas loop tracking is optimized by proper choice of loop arm filter bandwidth. In particular, it is shown that for a variety of passive arm filter types, there exists, for a given data rate and data signal-to-noise ratio, an optimum filter bandwidth in the sense of minimizing the loop's squaring loss. For the linear theory case, this is equivalent to minimizing the loop's tracking jitter. When symbol synchronization is known, it is shown that by replacing the passive arm filters with active filters, i.e., integrate-and-dump circuits, one can achieve an improvement in carrier-to-noise ratio of as much as 4 to 6 dB depending on the passive arm filter type used for comparison and the value of data signal-to-noise ratio.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Communications; COM-25; Feb. 197
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  • 20
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    Martian isotopic ratios and upper limits for possible minor constituents as derived from Mariner 9 infrared spectrometer data (1977)
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    Publikationsdatum: 2011-08-17
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Icarus; 32; Sept
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  • 21
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    Impulsive penetration of filamentary plasma elements into the magnetospheres of the earth and Jupiter (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Assuming that the solar wind plasma is usually nonuniform over distances of 10,000 km or less, it is shown that filamentary plasma elements stretched out from the sun can penetrate impulsively and become engulfed into the magnetosphere. The diamagnetic effects associated with these plasma inhomogeneities are observed in outer magnetospheres and magnetosheaths as dips or directional discontinuities in the magnetic field measurements. From the mean penetration distances of these diamagnetic plasma elements one can deduce a mean deceleration time, as well as an approximate value of the integrated Pedersen conductivity in the polar cusp of the earth and Jupiter.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Planetary and Space Science; 25; Sept
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  • 22
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    Distribution of molecular weight in glyceride polymerizates or aggregates of them after contact with lunar grains (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: An attempt is made to report on experiments in which a molecular-weight increase was determined in thin layers of triglyceride-containing glycerides after thin-layer contact for two years with lunar topsoil grains at 25 C without any thermal activation. It is noted that solidification was observed on both dielectric grains and metal-rich areas and that changes in viscosity and molecular weights were first detected by solidification of surface layers. Gel permeation chromatography is described which detected a general shift of the Gaussian distribution of the molecular-weight data toward generally higher molecular weights as well as an increase in mean molecular weight. Reaction mechanisms are considered, and results of spectrographic analysis are cited which support the interpretations of the molecular-weight data.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: The Moon; 16; May 1977
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  • 23
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    Possible Jovian methane emission at 76 GHz in coincidence with decameter activity (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The tentative detection of a methane line in emission at 76.2 GHz in the atmosphere of Jupiter is reported. The observed feature is well-correlated with the presence and absence of Jovian decameter-emission activity on successive days. The present results may represent the first detection of extraterrestrial methane microwave emission.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Astrophysical Journal; vol. 216
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  • 24
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    Optimum design and performance of Costas receivers containing soft bandpass limiters (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: This paper investigates several key questions concerning the mechanization and design of a Costas receiver for reconstruction of a carrier from a suppressed carrier signal. For baseband NRZ encoded data symbols and a soft bandpass limiter preceding the loop, several design issues which are considered herein and which affect acquisition and tracking performance are: (1) The choice of an IF bandwidth. (2) The optimum choice of the Costas arm filter bandwidths as well as the spectral roll-off characteristics. (3) The optimum choice of loop bandwidth to data rate ratio for a given signal-to-noise ratio. (4) The signal suppression factor and the combined limiter-squaring loss. (5) The variations in loop bandwidth and damping with signal level. (6) The choice of the limiter transfer characteristic. (7) Performance degradation due to the presence of a limiter. Various new results in system design are presented and typical numerical results are given and graphically demonstrated in SNR regions of practical interest. The theory is applicable to the design of carrier reconstruction loops required in the implementation of spread spectrum communication receivers.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Communications; COM-25; Aug. 197
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  • 25
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    Polarization loss of a satellite - Data collection sensor link (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: It is noted that the stringent economy of data-collection systems consisting of several widely dispersed satellite-monitored sensor platforms can be partially achieved by using an inexpensive linearly polarized antenna on each platform and that due to Faraday rotation of the ionosphere, the satellite antenna must be circularly polarized to avoid a prohibitive polarization loss. The cumulative probability distribution of polarization loss between a linearly polarized platform antenna and an elliptically polarized satellite antenna is computed for satellite-antenna axial ratios of 3 and 4 dB. The results indicate that a polarization loss of 4.5 dB must be expected for a reliability of 85% and an axial ratio of 3 dB. It is suggested that the conventional assignment of a 3-dB polarization loss to the communication link considered may not insure the required link reliability.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Aerospace and Electronic Systems; AES-13; July 197
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  • 26
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    The clouds of Venus (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The current state of knowledge of the Venusian clouds is reviewed. The visible clouds of Venus are shown to be quite similar to low level terrestrial hazes of strong anthropogenic influence. Possible nucleation and particle growth mechanisms are presented. The Pioneer Venus experiments that emphasize cloud measurements are described and their expected findings are discussed in detail. The results of these experiments should define the cloud particle composition, microphysics, thermal and radiative heat budget, rough dynamical features and horizontal and vertical variations in these and other parameters. This information should be sufficient to initialize cloud models which can be used to explain the cloud formation, decay, and particle life cycle.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Space Science Reviews; 20; May 1977
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  • 27
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    The Pioneer Venus program (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Mission timetables, spacecraft, scientific objectives, and payloads of the two mission, Orbiter and Multiprobe, planned for launch and encounter with Venus during the 1978 Venus mission opportunity are described. Basically, the Orbiter mission has the goal of global mapping of the clouds, atmosphere and ionosphere of Venus by remote sensing and radio occultation, global studies by in situ measurements of the upper atmosphere and ionosphere and solar wind-ionosphere interaction region, and determination of gravitational field harmonics from perturbations of the spacecraft orbit. The Multiprobe mission will study the nature and composition of the clouds, the structure of the atmosphere, the circulation pattern, and the characteristics of the planetary environmental interaction with the solar wind.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Space Science Reviews; 20; May 1977
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  • 28
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    The exploration of Venus (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The paper outlines the evolution of the Pioneer Venus program from the initial meeting of a consortium of scientists to study the feasibility of a simple entry probe to Venus, through the Planetary Explorer missions, to the Orbiter Mission proposals. Major recommendations of the 1970 National Academy of Sciences study on Venus exploration planning and of the 1972 Pioneer Venus Science Steering Group report are mentioned.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Space Science Reviews; 20; May 1977
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    Composition and structure of the atmosphere of Venus (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Some of the main questions regarding the composition, structure, and origin of the atmosphere of Venus are posed. These questions are (1) the distribution of the constituents of the lower atmosphere, (2) cloud composition, (3) the planet's surface and interior as revealed by atmospheric data, (4) the state property profiles and their variation over the planet, (5) the reason for the high temperatures of the lower atmosphere, (6) composition and temperature profiles of the upper atmosphere and location of the homopause, (7) spatial and temporal variations in the upper atmosphere, (8) the cause of the stability of CO2 - global circulation or local turbulence, (9) influence of neutral composition on the thermal structure, (10) response of upper atmosphere to change in solar EUV and solar wind, (11) the source and destination of the atmosphere, and (12) the location of Venus's water. The main parameters to be measured which will aid in resolving these problems are enumerated.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Space Science Reviews; 20; May 1977
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    The surface and interior of Venus (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The present knowledge of Venus is reviewed with discussions of the nature and history of both the surface, crust and interior. Instrumentation on board the Pioneer Venus Orbiter, including the radar mapper, radio tracking and the fluxgate magnetometer, is described. Topographic, geological, Bouguer gravity, magnetic, and crustal thickness maps will be constructed from Orbiter data. These maps should provide information on composition and thermal history, the major geological or geophysical provinces, the rate of past and present tectonic activity, and evidence of past or present MHD dynamos.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Space Science Reviews; 20; June 197
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    The Venus ionosphere and solar wind interaction (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The current state of knowledge of the chemistry, dynamics and energetics of the upper atmosphere and ionosphere of Venus is reviewed together with the nature of the solar wind-Venus interaction. Because of the weak, though perhaps not negligible, intrinsic magnetic field of Venus, the mutual effects between these regions are probably strong and unique in the solar system. The ability of the Pioneer Venus Bus and Orbiter experiments to provide the required data to answer the questions outstanding is discussed in detail.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Space Science Reviews; 20; June 197
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    The thermal balance of the atmosphere of Venus (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Current knowledge of the temperature structure of the atmosphere of Venus is briefly summarized. The principal features to be explained are the high surface temperature, the small horizontal temperature contrasts near the cloud tops in the presence of strong apparent motions, and the low value of the exospheric temperature. In order to understand the role of radiative and dynamical processes in maintaining the thermal balance of the atmosphere, a great deal of additional data on the global temperature structure, solar and thermal radiation fields, structure and optical properties of the clouds, and circulation of the atmosphere are needed. The ability of the Pioneer Venus Orbiter and Multiprobe Missions to provide these data is indicated.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Space Science Reviews; 20; June 197
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  • 33
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    Dynamics, winds, circulation and turbulence in the atmosphere of Venus (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: With the possible exception of the lowest one or two scale heights, the dominant mode of circulation of Venus' atmosphere is a rapid, zonal, retrograde motion. Global albedo variations in the ultraviolet may reflect planetary scale waves propagating relative to the zonal winds. Other special phenomena such as cellular convection in the subsolar region and internal gravity waves generated in the interaction of the zonal circulation with the subsolar disturbance may also be revealed in ultraviolet imagery of the atmosphere. We discuss the contributions of experiments on the Orbiter and Entry Probes of Pioneer Venus toward unravelling the mystery of the planet's global circulation and the role played by waves, instabilities and convection therein
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Space Science Reviews; 20; June 197
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    The ionospheres of Saturn, Uranus, and Neptune (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Models of the ionospheres of Saturn, Uranus, and Neptune are presented. It is postulated that galactic cosmic-ray ionization is an important component of these ionospheres. For example, in the case of Neptune, the level of ionization caused by cosmic rays is comparable with that due to solar extreme-ultraviolet (EUV) radiation. The existence of cosmic-ray, as well as solar EUV-produced ionization, could be a valuable diagnostic tool for investigating the atmospheric thermal structure of those planets.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Astrophysical Journal; vol. 215
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  • 35
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    Lunar transient phenomena /LTP/ - Manifestations, site distribution, correlations and possible causes (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: More than 1400 observations of lunar transient phenomena (LTP), encompassing brightenings, darkenings, and gaseous, reddish, and bluish events, are analyzed in an attempt to determine the possible causes of LTP. Hypotheses considered include effects of earth tides on the moon, low-angle illumination, thermal luminescence, UV heating, solar-particle acceleration by the magnetopause of earth's magnetotail, terrestrial magnetotail bow-shock-front turbulence, cathode luminescence due to magnetotail effects, and solar-flare particle bombardment. Analysis are performed in terms of histograms of the number of observations vs. phase of anomalistic period and of number vs. moon's age, percentage of numbers of observed phenomena and percentage of expected numbers as well as their ratios, and albedo behavior over a lunation period of chosen permanent points in ten specific features. The results indicate that different phenomena may have different causes, strong tidal effects are dubious, correlations with sunrise are most frequent, and the distribution of all LTP sites is distinct from that of deep- and shallow-focus moonquake epicenters.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
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    Minor planets and related objects. XXIII - Photometry of asteroid /7/ Iris (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Analysis of light curves and UBV photometry yields a model for (7) Iris as an ellipsoid with axial ratios 3:4:5. The North Pole orientation is near 41 deg ecliptic latitude and 11 deg longitude.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Astronomical Journal; 82; June 197
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    Picture of Ganymede (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Spin-scan images of Ganymede obtained by the imaging photopolarimeter of Pioneer 10 in December 1973 are described and presented. Intensity measurements in the blue and red scans are provided. The width of the scan elements is 0.5 mrad which is the size of the aperture in the focal plane of the telescope; the height is also 0.5 mrad (1 millisec integration - or dwell-time at 5 rpm spin rate). The distance of Pioneer 10 from Ganymede was 7.8 x 10 to the fifth km, and the resolution is therefore 390 km. The spin-scan image is in general agreement with Lyot's visual observations (Dollfus, 1961). Preliminary results on polarimetry of Ganymede obtained during the flyby of Pioneer 10 are discussed with attention to the question of whether water frost, NaCl powdered crystals, or other substances is responsible for the observed pattern.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
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    Phobos and Deimos (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Ground-based and spacecraft observations of Phobos and Deimos are reviewed and the satellites' origin is discussed. The crater densities of both bodies are close to the saturation level. The largest impact events may have caused extensive fracturing of their surfaces. The surfaces are at least 1.5 billion years old and may date back to the early history of the solar system. The Martian satellites display large deviations from sphericity. As a result of tidal processes, they are in synchronous rotation. Several independent lines of evidence show that they have regoliths. Despite some provocative arguments, their internal strengths and the nature of their interior are poorly known at present. Photometric measurements suggest that they are made of either carbonaceous chondritic material or a basalt. Sinclair (1972), Born and Duxbury (1975) and Shor (1975) apparently have successfully determined Phobos' secular acceleration. Their value of approximately .001 deg/year/year implies that the interior of Mars has a low specific dissipation factor (about 100), may indicate that a portion of the Martian interior is experiencing partial melting. The low inclination of the satellites' orbits indicates that they were formed as part of the same process that resulted in Mars.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
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  • 39
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    Surface properties of a north ray crater soil /Apollo 16/ (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Surface properties of lunar fines sample 67481 have been investigated by measuring the adsorptions of nitrogen (at -196 C) and water (at 20 C). Characteristics of this sample are similar to those of samples from other locations on the lunar surface and include the more typical alteration reaction with adsorbed water. Although their maturities are markedly different, the surface properties of 67481 are very much like those of the more mature 63341 from the adjacent station 13. These results indicate that the surface properties of lunar soils attain an equilibrium state faster than other properties used to indicate maturity.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Earth and Planetary Science Letters; 35; 1, Ma; May 1977
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  • 40
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    Solar radiation incident on Mars and the outer planets - Latitudinal, seasonal, and atmospheric effects (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Calculations of the daily solar radiation incident at the tops of the atmospheres of Mars and the outer planets and its variability with latitude and season are presented in a series of figures and tables. The changes in the latitudinal and seasonal distributions of daily surface insolation during the great Martian dust storm of 1971 (when Martian atmospheric optical depth increased from about tau = 0.1 to 2.0) were significant and dramatically illustrate the effect of atmospheric aerosols on surface insolation; i.e., the mean annual daily insolation at the poles decreased by more than a factor of 100 as tau increased from 0.1 to 2.0.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Icarus; 31; May 1977
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    The deficiency of siderophile elements in the moon (1977)
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    Beschreibung: An attempt is made to reconcile a plausible origin of the moon with the observed deficiency of siderophile elements in the moon. A numerical analysis is performed which indicates that at least 1% metal was needed to extract nickel successfully from the moon and that the deficiency of lunar siderophiles can be explained on the basis of a fission hypothesis. It is suggested that leaching by liquid metallic iron caused the lunar deficiency and that the leaching took place in the protoearth from which the moon subsequently formed by fission.
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  • 42
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    Distribution and flux of micrometeoroids (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The mass distribution, flux, and distribution in space of the micrometeoroid complex at 1 AU are estimated on the basis of data from Apollo 17 rocks and recent calibrations of solar-flare track-production rates. It is found that the size frequency distribution of microcraters on lunar rocks suggests a bimodal mass distribution of micrometeoroids, but the precise form of the curve requires further definition, particularly insofar as the degree of depletion of particles producing craters 10 to 100 microns in diameter is concerned. Variations in slope with crater-diameter or particle-mass increments are shown to indicate that different processes affect one or more particle populations. Fluxes corresponding to varied lunar surface orientation and residence time are calculated, but no striking difference is observed between the flux of submicron-diameter particles with orbits in the plane of the ecliptic and fluxes of particles with orbits normal to the plane in the solar apex direction.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
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    A calculation of Saturn's gravitational contraction history (1977)
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    Beschreibung: A gravitational-contraction history is calculated for a homogeneous quasi-equilibrium Saturn model of solar composition without a rock-ice core and without allowance for the possible separation of hydrogen and helium. The calculations begin at the time when Saturn's radius was ten times its current value, and the subsequent gravitational contraction is followed for 4.5 billion years. The results obtained are given in terms of the path of the evolving model on the H-R diagram, the variation of central temperature with central density, the time variation of radius and internal luminosity, and the energy changes that take place during the evolution. These results are compared with those of similar calculations for Jupiter, and the internal structure of the evolutionary models is examined in detail. The Saturn calculations yield a radius at the current epoch that is 9% larger than the observed value and an excess luminosity comparable to that observed. It is noted that an inhomogeneous model containing a solar-mix envelope and a central rocky core has a radius equal to the observed value.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Icarus; 30; Jan. 197
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    The Apollo 17 'melt sheet' - Chemistry, age and Rb/Sr systematics (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Major, minor, and trace-element compositions, age data, and Rb/Sr systematics of Apollo 17 boulders have been compiled, and additional analyses performed on a norite breccia clast (77215) included in the Apollo 17, Station 7 boulder. The Apollo 17 boulders are found to be identical or nearly so in major, minor, and trace-element composition, suggesting that they all originated as an impact melt analogous to melt sheets found in larger terrestrial craters. The matrix dates (Ar-40/Ar-39) and Rb/Sr systematics available suggest that this impact melt formed by a single impact about 4 billion years ago. This impact excavated, shocked, brecciated, and melted norites, norite cumulates, and possibly anorthositic gabbros and dunites about 4.4 billion years old. The impact was likely a major one, possibly the Serenitatis basin-forming event.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Earth and Planetary Science Letters; 33; 3, Ja; Jan. 197
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    Preliminary findings of the Viking gas exchange experiment and a model for Martian surface chemistry (1977)
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    Beschreibung: Earlier results reported from the Viking Lander-1 experiment are reexamined and interpreted in terms of a model of the Martian soil surface morphology and chemistry. Major events in the gas exchange experiment (GEX) first cycle are tabulated and data are presented on the sample processing and transport environments experienced by the soil samples. Oxygen and CO2 evolved from humidified Martian soil in GEX and slight changes in N2 present are investigated. A soil model involving iron oxide coating on silicate material is entertained to yield a mechanistic explanation of the experimental findings, and invocation of biotic processes is eschewed.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Nature; 265; Jan. 13
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  • 46
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    Analysis of a discrete spectrum analyzer for the detection of radio frequency interference (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: As the radio frequency spectrum becomes increasingly overcrowded, interference with mission-critical DSN operations is rising at an alarming rate. To alleviate this problem the DSN is developing a wideband surveillance system for on-site detection and identification of potential sources of radio frequency interference (RFI), which will complement the existing frequency coordination activities. The RFI monitoring system is based on a wideband, multi-look discrete spectrum analyzer operating on fast Fourier transform principles. An extensive general statistical analysis is presented of such spectrum analyzers and derives threshold detection performance formulas for signals of interest. These results are then applied to the design of the RFI spectrum analyzer under development.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network; p 83-98
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    Walsh transforms and signal detection (1977)
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    Beschreibung: The detection of signals using Walsh power spectral estimates is analyzed. In addition, a generalization of this method of estimation is evaluated. The conclusion is that Walsh transforms are not suitable tools for the detection of weak signals in noise.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network; p 127-131
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    Radio frequency interference from near-earth satellites (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: A pessimistic statistical model was developed for predicting the extent of radio frequency interference (RF1). Based on the assumptions underlying the model, DSN S-band operations can expect one RF1 interruption every 4.1 days, with the average incident lasting 24 s. This implies that 52 or more such satellites, with uncorrelated orbital trajectories, will cause in excess of 5 min of RF1 per day at a DSN station.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network; p 69-77
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    Asteroid families - Observational evidence for common origins (1977)
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    Beschreibung: Colors of minor planets in the UBV system indicate compositions quite distinct from those of the field population in each of three Hirayama families. The Eos and Koronis families apparently originated from the collisional fragmentation of undifferentiated silicate bodies, and the Nysa group from a geochemically differentiated parent body
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Science; 197; July 15
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  • 50
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    Formation of the outer planets and satellites (1977)
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    Beschreibung: A mechanism for the formation of the outer planets is proposed, the basis of which is the idea that the giant planets contain an excess of chemically condensable materials over solar composition. Planetary cores were formed by the clumping together of chemically condensed bodies forming a thin disk in the solar nebula. Gas surrounding a core becomes unstable against collapse onto the core. In the case of Jupiter and Saturn, much of the collapsing gas goes into orbit about the formed planet, forming a relatively thin circumplanetary disks with differential rotation in the prograde sense. For Uranus and Neptune, the dynamical collapse mechanism is unlikely. A disk of gas around Uranus may have been formed during a collision of the protoplanet with a large body. The circumplanetary disks then form the basis for formation of satellite systems, in which the Goldreich-Ward instability mechanism plays a role.
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    Saturn's rings - A new survey (1977)
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    Beschreibung: Observations of radar returns from Saturn's rings, together with radio interferometry of their absorption of radiation from the disk, combine to require an effective radius of ring particles of about 6 cm or larger. It is suggested that the ring particles may also include, in addition to the known ice constituent, a mixture of the clathrated hydrate of methane and ammonia hydrate. A two-density model for ring particles is possible in which a matrix of low density contains many nodules of higher-density ice particles; in this case, radii nearly as large as the observed ring thickness would be possible. Improved resolution in radio observations at 21 cm or, if necessary, at longer wavelengths for narrow ring openings is perhaps the most useful method for determining upper limits on the particle size.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
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    Relative crater production rates on planets (1977)
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    Beschreibung: The relative numbers of impacts on different planets, estimated from the dynamical histories of planetesimals in specified orbits (Wetherill, 1975), are converted by a described procedure to crater production rates. Conversions are dependent on impact velocity and surface gravity. Crater retention ages can then be derived from the ratio of the crater density to the crater production rate. The data indicate that the terrestrial planets have crater production rates within a factor ten of each other. As an example, for the case of Mars, least-squares fits to crater-count data suggest an average age of 0.3 to 3 billion years for two types of channels. The age of Olympus Mons is discussed, and the effect of Tharsis volcanism on channel formation is considered.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Icarus; 31; June 197
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    Detection of rings around Uranus (1977)
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    Beschreibung: A description is presented of partial occultations of SAO 158687 by a series of rings around the planet Uranus. A 61-cm telescope at Perth Observatory in Western Australia was used in the investigations. Measurements were made using a conventional single-channel photometer equipped with an RCA C31034B photomultiplier. Uranus was centered in a 28-arc sec diameter aperture during the observations. An occultation of SAO 158687 by Uranus itself did not occur at Perth. However, five brief partial occultations of SAO 158687 were detected with the chart recorder. The midtimes, durations, and depths of these events are listed in a table.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Nature; 267; May 26
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    Lunar magnetic permeability studies and magnetometer sensitivity (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: A regression of quiet magnetic field components simultaneously measured by the two Explorer 35 magnetometers reveals uncertainties in effective sensitivity factors of up to a few percent in one or both of these instruments. Given this, the validity of previous lunar permeability studies based on Explorer 35/ALSEP regressions, wherein inferences are drawn from regression line slopes differing from unity by the order of one percent, is called into question. We emphasize the need to critically address the question of small deviations in magnetometer sensitivity factors from nominal values as a part of any two-magnetometer lunar permeability study.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Geophysical Research Letters; 4; Apr. 197
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    An improved value of the lunar moment of inertia (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The lunar gravitational research reported on by Gapcynski et al., (1975) has been extended to include an additional 600 days of the time variation of ascending node for the Explorer 49 spacecraft. Analysis of these additional data resulted in an improved value of the second-degree zonal harmonic coefficient C(20) = (-2.0219 equal to 0.0091) times 10 to the minus 4. This value of C(20) used in conjunction with the parameters beta equal to libration (631.27 + or - 0.03) times 10 to the minus 6 and gamma to (227.7 + or - 0.7) times 10 to the minus 6 yields a more accurate definition of the lunar moment of inertia ratio equal to 0.391 + or - 0.002.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Journal of Geophysical Research; 82; Apr. 10
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    Yes, Kakangari is a unique chondrite (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The position of the Kakangari chondrite as the representative of a new class of chondrites is considered, taking into account the results of the analysis of a 17.1-mg piece of Kakangari for 20 elements. Elemental concentration data are compared for Kakangari and other meteorite groups. Data for the most similar groups, C2, C3(V), L, and E4 chondrites are represented in a graph along with Kakangari data. It is found that pronounced differences exist between Kakangari and the other meteorite classes.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Nature; 265; Jan. 20
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    Modification of the DSN radio frequency angular tropospheric refraction model (1977)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: The previously derived DSN Radio Frequency Angular Tropospheric Refraction Model contained an assumption which was subsequently seen to be at a variance with the theoretical basis of angular refraction. The modification necessary to correct the model is minor in that the value of a constant is changed.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network; p 184-186
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  • 58
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    Synchronization strategies for RFI channels (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: An RFI channel to be a multiple-access channel is defined in which no sender can know when any other starts, and the problem of determining the relative phases of the senders at the receiver is studied. A new result is proved about binary DEBruijn sequences.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network; p 103-108
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  • 59
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    Proportionality between Doppler noise and integrated signal path electron density validated by differenced S-X range (1977)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: Observations of Viking differenced S-band/X-band (S-X) range are shown to correlate strongly with Viking Doppler noise. A ratio of proportionality between downlink S-band plasma-induced range error and two-way Doppler noise is calculated. A new parameter (similar to the parameter epsilon which defines the ratio of local electron density fluctuations to mean electron density) is defined as a function of observed data sample interval (Tau) where the time-scale of the observations is 15 Tau. This parameter is interpreted to yield the ratio of net observed phase (or electron density) fluctuations to integrated electron density (in RMS meters/meter). Using this parameter and the thin phase-changing screen approximation, a value for the scale size L is calculated. To be consistent with Doppler noise observations, it is seen necessary for L to be proportional to closest approach distance a, and a strong function of the observed data sample interval, and hence the time-scale of the observations.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network; p 172-183
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  • 60
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    The Deep Space Network-Mariner Jupiter/Saturn 1977 flight project telecommunications compatibility (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The DSN-Mariner Jupiter/Saturn 1977 telecommunications compatibility tests conducted during the periods 15-20 November 1976, 7-16 December 1976 and 5 January 1977, are an ongoing series of engineering level tests to determine the flight-ground interface compatibility and performance characteristics between these two systems.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network; p 16-37
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  • 61
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    Selectable polarization at X-band (1977)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: The X-band feeds in the Deep Space Network were upgraded to include selectable polarization in time for the Voyager missions to the outer planets. The modified antenna feed has the following major items added: two circular waveguide rotary joints, drive motor and gear reducer, gear assembly, two microswitches, and a polarization control junction box. The overall length of the feed remains the same because circular waveguide spacing sections were designed into the original feed to readily permit such modifications. There is no significant increase in antenna noise temperature compared to the original feed.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network, Vol. 39; p 177-180
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    DSS 13 automated antenna pointing subsystem phase 1 hardware (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: An automated antenna pointing subsystem (APS) is being installed at DSS 13 as part of the unattended station project. The function of the APS is to track an instructed position with the 26 meter antenna and to monitor the antenna servo system and meteorological conditions to ensure a proper operational environment. This article discusses the now-completed first phase of the digital hardware portion of the APS development.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network; p 100-109
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  • 63
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    X-band antenna gain and system noise temperature of 64-meter deep space stations (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: A set of measured data on the X-band performance of the three 64-meter deep space stations was obtained for use in future mission telecommunication design and predictions. The test configuration and measurement procedure is described. A method of modelling attenuation due to the atmosphere is given. Radio source brightness temperature and flux density are reviewed.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network, Vol. 39; p 76-99
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  • 64
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    Investigation of package sealing using organic adhesives (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: A systematic study was performed to evaluate the suitability of adhesives for sealing hybrid packages. Selected adhesives were screened on the basis of their ability to seal gold-plated Kovar butterfly-type packages that retain their seal integrity after individual exposures to increasingly severe temperature-humidity environments. Tests were also run using thermal shock, temperature cycling, mechanical shock and temperature aging. The four best adhesives were determined and further tested in a 60 C/98% RH environment and continuously monitored in regard to moisture content. Results are given, however, none of the tested adhesives passed all the tests.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA. Marshall Space Flight Center Proc. of the 1977 NASA(ISHM Microelectronics Conf.; p 77-94
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  • 65
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    The 26-meter S-X Conversion Project (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The 26-meter S-X conversion project provides for the conversion of an existing 26-meter S-band subnet to a 34-meter S- and X-band subnet. The subnet chosen for conversion consists of the following stations: DSS 12 near Barstow, DSS 44 in Australia, and DSS 62 in Spain. The main subsystems effected by this project are the antenna mechanical, antenna microwave, and receiver-exciter. In addition to these, there are many project-related electronic equipments that have been added to the existing station equipment. The major subsystems are essentially through the design stage with the antenna mechanical subsystem completed through detail design with procurement in process.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network, Vol. 39; p 157-167
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  • 66
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    Minimum-weight codewords in the (128,64) BCH (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Techniques of combinational algebra and computer simulation are combined to determine the number of weight 22 codewords in the (128,64) BCH code which is being studied for use on future deep-space missions.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network p92-94 (SEE N78-24161 15-12)
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  • 67
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    Complex mixer system modifications (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Modifications of the complex mixer system to increase bandwidth and number of channels were made. Three modified complex mixers were installed at DSS 14 and were used to process planetary radar signals in March and April of 1977.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network; p 88-91
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  • 68
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    Viking extended mission support (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The period from 1 July through 31 August 1977 is covered and included is the remainder of post DSN Mark 3 Data Subsystem Implementation Project Viking-related testing at DSS14. Also included are reports on the Viking DSN Discrepancy Reporting System, Viking command support, tracking support, and periodic tests conducted with the Viking spacecraft.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network; p 28-33
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  • 69
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    Voyager flight project: DSN Telecommunications Compatibility Test Program (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The Voyager Flight Project - DSN Telecommunications Compatibility Test Program consisted of three phases: Subsystem Design, System Design, and System Verification Tests. Subsystem Design Tests were performed during mid 1976. System Design Tests were performed during late 1976 and early 1977. System Verification Tests were performed during the spring and summer of 1977. This article describes the System Design Tests and test results that provided the basis for establishment of telecommunications design between the DSN and the Voyager Flight Project.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network; p 13-27
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  • 70
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    DSN radio science system description and requirements (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The data system created to collect the functions performed by the Deep Space Network in support of spacecraft radio science experiments is described. Some of the major functional requirements presently being considered for the system are delineated.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network, Vol. 39; p 119-129
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  • 71
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    Lunar Rb-Sr chronology (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: It has been established with the aid of Rb-Sr studies that lunar chronology consists of five episodes, including the formation of the moon approximately 4.6 AE ago (1 AE = 1000 million years), a period of intense bombardment by planetary debris resulting in the formation of the major lunar basins, the end of this period at 3.9-4.0 AE ago, a period of mare flooding extending from 3.9 to 3.2 AE ago, and a relatively quiescent period from 3.2 AE ago to the present. In addition, Rb-Sr-studies have provided valuable constraints on the geochemical evolution of the moon through the determination of the initial Sr-87/Sr-86 ratios which limit the Rb/Sr ratios of the source materials for lunar rocks. Attention is given to the characteristics of the Rb-Sr method, the analytical techniques, the ages of lunar mare basalts, the non-mare rocks, the studies conducted in connection with the various Apollo missions, the lunar cataclysm, lunar soils, and aspects of crustal contamination.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Physics and Chemistry of the Earth; 10; 2, 19; 1977
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  • 72
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    Volatile elements, carbon, nitrogen, sulfur, sodium, potassium and rubidium in the lunar regolith (1977)
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    Publikationsdatum: 2011-08-17
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Physics and Chemistry of the Earth; 10; 1, 19; 1977
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  • 73
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    EMI survey for maritime satellite 1535-1645-MHz shipboard terminal (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: A 15,690-ton commercial container ship was selected as lead ship for an onboard electromagnetic-interference (EMI) survey prior to installation of 1535-1645-MHz (L-Band) shipboard terminals for communication via a maritime satellite. In general, the EMI survey revealed tolerable interference levels on board ship. Radiometer measurements indicate antenna-noise temperatures less than 70 K at elevation angles of 5 deg and greater at 1559 MHz at the output terminals of the 1.2-m diameter parabolic-dish antenna for the L-band shipboard terminal. Other EMI measurements include field intensity from 3-cm and 10-cm wavelength pulse radars, and conducted-emission tests of primary power lines to both onboard radars.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Electromagnetic Compatibility; EMC-19; Nov. 197
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  • 74
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    Structure of the atmosphere of Mars in summer at mid-latitudes (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Instruments onboard Viking 1 and 2 landers were used to measure the structure of Mars' atmosphere in situ from near the surface to an altitude of 120 km. Atmospheric structure was found to be well defined by the instruments and relatively similar at the two sites. Viking 1 and 2 surface pressures were 7.62 and 7.81 mbar, and temperatures were 238 K and 236 K, respectively, with pressures at the elevation of the reference ellipsoid of 6.74 and 6.30 mbar. Mean temperature was found to decrease with a lapse rate of about 1.6 K/km (significantly subadiabatic) from above the boundary layer to about 40 km. The temperature was then near isothermal with a large-amplitude wave superimposed (attributed to the diurnal thermal tide). It is suggested that the mean profile is governed by radiative equilibrium. The obtained density data are found to merge well with those obtained by an upper-atmosphere spectrometer (at 200 km). The temperature wave is found to continue above 100 km while increasing in wavelength and amplitude.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Journal of Geophysical Research; 82; Sept. 30
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  • 75
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    Search for color changes and brightening of Io upon eclipse reappearance (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Medium-resolution spectra were made of Io as it emerged from two eclipses in December 1975. In the wavelength range 4000-5800 A, no spectral changes greater than the standard deviations were observed when the spectrum of Io just after reappearance was divided by the spectrum of Io 20 min later. No substantial increase in total brightness was observed over the same time interval. These observations were made at a time when the sub-earth point was in Io's northern hemisphere; therefore, prediction of positive posteclipse brightening in this circumstance is not confirmed.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Icarus; 32; Oct. 197
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  • 76
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    VLBI (Very Long Baseline Interferometry) instrumental effects, part 1 (1977)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Very Long Baseline Interferometry (VLBI) is a method for observation of extragalactic radio sources which appears to have potential for precise long-distance earth surveying, clock synchronization and spacecraft navigation. Many researchers have been working to establish the accuracy of VLBI observations. The intent of the work reported here is to review the principal components of the VLBI instrument in order to estimate and/or bound the systematic error contributions. In this first of a series of articles, the definitions and tools which are needed in order to apply filter transfer-function analysis to the VLBI receiver are established and they are used to estimate the sensitivity of the VLBI receiver to plausible filter variations.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: The Deep Space Network; p 54-80
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  • 77
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    Mariner 9 Ultraviolet Spectrometer Experiment: Mars Atomic Oxygen 1304-A Emission (1977)
    In:  CASI
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    Publikationsdatum: 2011-06-29
    Beschreibung: Selected results are presented for an analysis of Mariner 9 1304-A data from the first 100 passes. Based on a comparison of limb data, the exospheric temperature appears lower on several Mariner 9 passes than when Mariner 6 and 7 encountered the planet in 1969. Temperatures of 300 and 350 K are considered in the atmospheric modeling. At 300 K, derived values of the atomic oxygen concentration are typically between 0.5 and 1 percent of the total density at 135 km, based on fitting theoretical intensities to limb data from several passes. Structure in the limb data below 200 km suggests the possibility that approximately 0.2 kR of the observed approximately 0.8 kR near 150 km is due to dissociative excitation of CO2. There is variability in limb profiles indicating changes in the O distribution with time. The variability does not appear to follow a recognizable pattern. Interpretation of the 1304-A disc data shows a correlation in intensity with the 10.7 cm solar flux and larger O concentrations in the afternoon than in the morning. The correlation in intensity with the 10.7 cm flux is probably due largely to variation in the solar 1304-A fluxes. Selected disc data show localized and random enhancements in the intensity.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
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  • 78
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    Viking Radio Occultation Measurements of the Martian Atmosphere and Topography: Primary Mission Coverage (1977)
    In:  Other Sources
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    Publikationsdatum: 2016-11-16
    Beschreibung: Radio occultation measurements were made at approximately 50 locations on Mars with the Viking Orbiter 1 S (2.3 GHz) and X (8.4 GHz) band tracking links during October 1976. The measurements have been used to study the topography and atmosphere of Mars at latitudes ranging from about 75 deg S to 70 deg N. By using the ingress and egress times obtained from the observed limb diffraction effects together with the best ephemerides available for the orbiter and the planet we have determined the surface elevations at the occultation points relative to the reference areoid. The observations agree with Mariner 9 and radar data to within 2 km. The mean atmospheric pressure at the areoid level was found to be 5.9 mbar during the northern midsummer season, a value which agrees quite well with data obtained at the landing sites. By comparing the new electron density measurements with earlier Mariner data we have determined that the temperature and the plasma scale height of the upper atmosphere appear to be functions of solar activity.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Journal of Geophysical Research; Volume 82; No. 28; 4317-4324
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    Some Martian Volcanic Features as Viewed from the Viking Orbiters (1977)
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    Publikationsdatum: 2016-11-16
    Beschreibung: A summary is presented of the results of some new observations on Martian volcanic features made from the Viking orbiters. Most of these observations are concerned with the Tharsis and Alba regions. The youth, size, and style of the volcanic features in these areas render them particularly susceptible to analysis. Excellent coverage was also acquired of Apollinaris Patera. It has many features of the Tharsis shields, with a cliff around its circumference and a large central caldera. Olympus Mons and its vicinity are examined, taking into account the shield of Olympus Mons, mass movement features along the basal scarp, the basal plains, the relative ages of Olympus Mons and the basal plains, and grooved terrain.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Journal of Geophysical Research; Volume 82; No. 28; 3985–4015
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    Statistical assessment of speech system performance (1977)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: Methods for the normalization of performance tests results of speech recognition systems are presented. Technological accomplishments in speech recognition systems, as well as planned research activities are described.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NADC, Proceedings: Voice Technology for Interactive Real-Time Command(Control Systems Application; p 265-284
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  • 81
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    The Army word recognition system (1977)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: The application of speech recognition technology in the Army command and control area is presented. The problems associated with this program are described as well as as its relevance in terms of the man/machine interactions, voice inflexions, and the amount of training needed to interact with and utilize the automated system.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NADC, Proceedings: Voice Technology for Interactive Real-Time Command(Control Systems Application; p 207-215
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  • 82
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    Speech systems research at Texas Instruments (1977)
    In:  CASI
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    Beschreibung: An assessment of automatic speech processing technology is presented. Fundamental problems in the development and the deployment of automatic speech processing systems are defined and a technology forecast for speech systems is presented.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NADC, Proceedings: Voice Technology for Interactive Real-Time Command(Control Systems Application; p 289-299
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  • 83
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    Automatic speech recognition research at NASA-Ames Research Center (1977)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: A trainable acoustic pattern recognizer manufactured by Scope Electronics is presented. The voice command system VCS encodes speech by sampling 16 bandpass filters with center frequencies in the range from 200 to 5000 Hz. Variations in speaking rate are compensated for by a compression algorithm that subdivides each utterance into eight subintervals in such a way that the amount of spectral change within each subinterval is the same. The recorded filter values within each subinterval are then reduced to a 15-bit representation, giving a 120-bit encoding for each utterance. The VCS incorporates a simple recognition algorithm that utilizes five training samples of each word in a vocabulary of up to 24 words. The recognition rate of approximately 85 percent correct for untrained speakers and 94 percent correct for trained speakers was not considered adequate for flight systems use. Therefore, the built-in recognition algorithm was disabled, and the VCS was modified to transmit 120-bit encodings to an external computer for recognition.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NADC, Proceedings: Voice Technology for Interactive Real-Time Command(Control Systems Application; p 143-170
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  • 84
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    Multi-user real time word recognition system (1977)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: Technological accomplishments in speech recognition systems are presented. A discrete word recognition system which contains an audio spectrum analyzer is described in detail.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NADC, Proceedings: Voice Technology for Interactive Real-Time Command(Control Systems Application; p 301-304
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  • 85
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    Practical applications of interactive voice technologies: Some accomplishments and prospects (1977)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: A technology assessment of the application of computers and electronics to complex systems is presented. Three existing systems which utilize voice technology (speech recognition and speech generation) are described. Future directions in voice technology are also described.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NADC, Proceedings: Voice Technology for Interactive Real-Time Command(Control Systems Application; p 217-234
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  • 86
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    Mars Gravity Field: Combined Viking and Mariner 9 Results (1977)
    In:  Other Sources
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    Publikationsdatum: 2016-11-16
    Beschreibung: A Martian gravity field of sixth degree and order has been determined from an analysis of a combination of Viking and Mariner 9 spacecraft Doppler tracking data. A short-arc technique utilizing approximately 4 hours of data centered at periapsis was used, and the data covered 16 arcs from Mariner 9 and 17 arcs from the Viking orbiters. The data were selected so as to obtain a uniform distribution of periapsis longitudes over the surface of Mars, and both S band and X band data were used where possible to eliminate charged particle effects. Inclusion of the Viking data arcs altered the Martian geoid features, as defined by previous short-arc analysis techniques of Mariner 9 data, by about 80 m in the southern hemisphere and about 140 m in the northern hemisphere.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Journal of Geophysical Research; Volume 82; No. 28; 4325-4327
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  • 87
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    Geological Observations in the Cydonia Region of Mars from Viking (1977)
    In:  Other Sources
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    Publikationsdatum: 2016-11-16
    Beschreibung: During the Viking mission, three broad areas of the northern plains were investigated as possible landing sites for Viking lander 2. We present a geological map of the area designated the B1 landing site in Cydonia centered on 45 deg N latitude, 4 deg W longitude. Viking imagery of this area has given detailed coverage, allowing the northern plains to be examined in more detail over wider areas than was possible from Mariner 9. Some plains areas with polygonal fracture patterns are considered to be pediments in ancient southern hemisphere rocks. The fracture patterns predate at least some of the younger northern plains material. Several northern plains units are distinguished as well as surface textures of unknown origin. Viking pictures provide good data for future studies of stratigraphy and surface process in this region and others like it in northern latitudes.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Journal of Geophysical Research; Volume 82; No. 28; 4111-4120
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  • 88
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    Geology of Chryse Planitia (1977)
    In:  Other Sources
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    Publikationsdatum: 2016-11-16
    Beschreibung: Chryse Planitia, the site of the first successful landing on Mars by Viking 1, is an asymmetrical basin, centered at 45 deg W and 24 deg N, about 2000 km northeast of Valles Marineris. High-resolution Viking orbiter images show Chryse Planitia to be much more complex than had been suspected from Mariner 9 images. On the basis of a study of the Viking pictures it is concluded that the geological history of Chryse Planitia involves a complex sequence of impact cratering, mantling by extensive deposits of unknown origin, redistribution of mantling and crater materials by erosion and deposition with concurrent eruptions of flood-type basalts, and aeolian activity.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Journal of Geophysical Research; Volume 82; No. 28; 4093-4109
    Format: text
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  • 89
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    Automatic speech recognition technology development at ITT Defense Communications Division (1977)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: An assessment of the applications of automatic speech recognition to defense communication systems is presented. Future research efforts include investigations into the following areas: (1) dynamic programming; (2) recognition of speech degraded by noise; (3) speaker independent recognition; (4) large vocabulary recognition; (5) word spotting and continuous speech recognition; and (6) isolated word recognition.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NADC, Proceedings: Voice Technology for Interactive Real-Time Command(Control Systems Application; p 305-316
    Format: application/pdf
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  • 90
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    The relationship of surface chemistry and albedo of lunar soil samples (1977)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: A relation between the albedo and the surface iron concentration (determined by Auger electron spectroscopy) of lunar soil samples is described. The effect of solar wind sputtering on the surface chemistry and albedo of the soil is discussed.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Format: text
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  • 91
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    Air radiation in photographic meteor spectra (1977)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: Air radiation (N, O, N2) is present in major amounts in the spectra of three high-geocentric-velocity photographic meteor spectra. These spectra are high-definition spectra with over 50 identifiable features in each. These meteor spectra are compared with N2 radiation from a Geissler tube and with calculated N2 first-positive band intensities. An 'effective vibrational temperature' of about 20,000 K is obtained from the nitrogen first-positive band relative intensities. Electron excitation is indicated as the primary excitation process.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Journal of Geophysical Research; 82; Jan. 1
    Format: text
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  • 92
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    Charge exchange in a planetary corona - Its effect on the distribution and escape of hydrogen (1977)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: The theory for a spherical collisionless planetary corona is extended to include charge-exchange collisions between H(+) and H, which are assumed to constitute intermingled gases with different kinetic temperatures. The treatment is based on the conventional concept of a critical level (or exobase) above which the only collisions considered in the Boltzmann equation are those that resonantly exchange charge. Although the geometry treated is an oversimplification for a real planet, numerical examples are given for an idealized earth and Venus. For earth, an ion temperature of 4 times the neutral temperature, an ion density at the exobase of 14,000 per cu cm, and a plasmapause at 1.5 earth radii will raise the escape flux of H by a factor of 6. The total H above the exobase is changed by less than 1%. For Venus, conditions are examined that would account for the peculiar H distribution observed from Mariner 5. The plasma conditions required are not obviously outrageous by terrestrial standards, but the Mariner 5 ionosphere measurements did not show a high plasmapause at, say, 1.25 or 1.5 planetary radii, a fact that might argue against a charge-exchange model.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Journal of Geophysical Research; 82; Jan. 1
    Format: text
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  • 93
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    Verification by Viking landers of earlier radio occultation measurements of surface atmospheric pressure on Mars (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-17
    Beschreibung: The landing of Viking 1 in Chryse Planitia on July 20, 1976 provided the first opportunity to obtain measurements of atmospheric pressure directly from the surface of Mars. A computation was conducted to predict the atmospheric pressure at the landing site before the landing itself. The relative altitude between occultation points and the Viking 1 site was obtained with the aid of earth-based planetary radar data taken in 1967. The data cover Martian latitudes from 19 deg N to 24 deg N. The investigation indicates that the radio occultation results from Mariner 9 closely correspond to the actual surface pressure on Mars.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Nature; 265; Jan. 6
    Format: text
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  • 94
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    Discovering Jupiter. II (1977)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: Data derived from Pioneer 10 and Pioneer 11 and other sources on the Jovian magnetosphere, the circum-Jovian radiation belts, and Jupiter's radio emission are presented at some length, descriptions are given of the principal Jovian satellites (Io, Europa, Ganymede, Callisto), and inferences are drawn on the origin of the planet and its place in the solar system. The inner, middle, and outer regions of the magnetosphere, the bow shock wave, and the particularly heavy intensity of the inner radiation belt region (within 1.44 million km of the planet) are discussed. All of the major satellites except Callisto lie immersed in the intense radiation belts. Jupiter's failure to become a stellar companion to the sun, Io's action in 'switching on' Jovian radio emission, and other Pioneer discoveries relating to asteroids, the solar system in general, and trans-Jovian space, are discussed
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Spaceflight; 19; Jan. 197
    Format: text
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  • 95
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    Diogenite exposure ages (1977)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: He, Ne and Ar isotopes have been measured in six, and Al-26 in two diogenites. Cosmic-ray exposure ages corrected for shielding effects using Ne-22/Ne-21 ratios are generally concordant. Five diogenites have a group age of 14 Myr and three others may have a group age of 24 Myr, implying that two collisions may have produced 8 of the 9 diogenites.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Geochimica et Cosmochimica Acta; 41; Jan. 197
    Format: text
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  • 96
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    Magnetic field experiment for Voyagers 1 and 2 (1977)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: The magnetic field experiments of the Voyager program involve studies of the planetary fields of Jupiter, Saturn, possibly Uranus, and several satellites; the solar wind and satellite interactions with the planetary fields, as well as large- and micro-scale features of the interplanetary magnetic field will also be investigated. Dual low field and high field magnetometer systems with dynamic ranges of + or - 0.5 G and + or - 20 G respectively provide high reliability for the missions and permit the separation of the spacecraft and ambient fields. Quantization uncertainty, rms noise levels and data compaction schemes of the magnetometer systems are also mentioned.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Space Science Reviews; 21; Dec. 197
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 97
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    The Voyager mission photopolarimeter experiment (1977)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: A general purpose filter photometer/polarimeter capable of measuring the intensity and linear polarization of scattered light at eight wavelengths in the 2350-7500 A spectral region has been adopted for the Voyager mission photopolarimeter experiment. Objectives of the experiment include determination of the vertical atmospheric aerosol distributions for Jupiter, Saturn and Titan, definition of cloud micro- and macro-structures, and identification of any regular crystalline particles in the clouds. In addition, the density of the satellite atmospheres will be assessed, and the sodium vapor distributions near Io and in the Jovian magnetosphere will be mapped. Particle size and optical depth of Saturn's rings will also be investigated.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Space Science Reviews; 21; Nov. 197
    Format: text
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  • 98
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    Voyager imaging experiment (1977)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: The Voyager imaging experiment, which involves two independently operated television systems (a narrow- and a wide-angle camera), is designed to conduct investigations of the atmospheres and surface properties of Jupiter, Saturn, their satellites and Saturn's rings. Objects of the investigations include the horizontal and vertical structure of visible clouds, the vertical structure of high, optically thin scattering layers on Jupiter and Saturn, the Great Red Spot, the South Equatorial Belt, chromophores on Io and Titan, the geology of several satellites, the masses, spin axes and periods of rotation of several satellites, the radial distribution of material in Saturn's rings, and the optical scattering properties of the primaries, rings, and satellites at a variety of wavelengths and phase angles.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Space Science Reviews; 21; Nov. 197
    Format: text
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  • 99
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    Radio science investigations with Voyager (1977)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: Radio links to and from the Voyager spacecraft will be used for occultation measurements of planetary and satellite atmospheres and ionospheres, the rings of Saturn, the solar corona, and the general-relativistic time delay for radio wave propagation through the solar gravity field. In addition, the radio link measurements may provide information on the gravity fields of the planets, the masses of the satellites, properties of the interplanetary medium, and long-wavelength gravitational radiation propagation in the solar system.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Space Science Reviews; 21; Nov. 197
    Format: text
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  • 100
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    The Voyager infrared spectroscopy and radiometry investigation (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-17
    Beschreibung: Two interferometers covering the spectral ranges 17 to 170 microns and 1.4 to 10 microns and a radiometer covering the range 0.4 to 1.2 microns are employed in the Voyager infrared spectroscopy and radiometry investigation. The study will focus on cloud and gas composition of planets and satellites with substantial atmospheres (including isotopic ratios), haze scale height, atmospheric vertical thermal structure, local and planetary circulation, and planetary energy balance. Surface temperatures and thermal properties of satellites with tenuous atmospheres will also be assessed, and the particle size distribution and thermal characteristics of Saturn's rings will be analyzed.
    Schlagwort(e): LUNAR AND PLANETARY EXPLORATION
    Materialart: Space Science Reviews; 21; Nov. 197
    Format: text
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