ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Inorganic Chemistry  (7,036)
  • LUNAR AND PLANETARY EXPLORATION  (3,213)
  • 1980-1984  (6,719)
  • 1910-1914  (3,530)
Collection
Publisher
Years
Year
  • 1
    Publication Date: 2019-01-25
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA, Lyndon B. Johnson Space Center, Lunar Bases and Space Activities in the 21st Century; p 69
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Bases and Space Activities in the 21st Century; p 48
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Bases and Space Activities in the 21st Century; p 1
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: The center-of-disk reflectivity of Jupiter in the wavelength range from 1500 A to 3000 A was computed from 31 low dispersion IUE spectra taken during solar maximum in 1979/80. The spectra were normalized to a reflectivity scale with the improved solar spectrum of July, 1980. Consideration of wavelength shifts between different IUE spectra and within the solar spectrum improved the apparent noise, especially longward of 2000 A. Six out of seven ammonia bands between 1900 A and 2200 A were detected. A vertically inhomogeneous radiative transfer program is used to compute model reflectivities for various stratospheric compositions. In addition to ammonia, the abundance of acetylene is also well determined because these molecules show narrow absorption bands in the ultraviolet. The abundances of the other molecules in the models (C3H4, C2H4, C4H2, C2H6, C3H6) are very uncertain and therefore are quoted only as upper limits. The best model fit is consistent with infrared observations by Voyager IRIS.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA. Goddard Space Flight Center Future of Ultraviolet Astronomy Based on Six Years of IUE Res.; p 129-132
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2019-01-25
    Description: The Orientale impact occurred in rugged highlands on the southwestern limb of the Moon and was the last of the major basin-forming events. Valuable insight concerning lateral and vertical changes in the composition of the lunar crust can be provided by studies of material exposed by lunar impact basins. These impacts have excavated material from a variety of depths and deposited this ejecta in a systematic manner. In order to investigate the composition of materials exposed on the interior of Orientale basin, near-infrared reflectance spectra were collected for units within the Cordillera ring.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar and Planetary Institute The 47th Ann. Meteoritical Soc. Meeting; 1 p
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2019-01-25
    Description: Experimental problems associated with metallic solid/metallic liquid partitioning investigations are evaluated. Of particular concern is the discrepancy of partition coefficient results obtained from experiments which were static (constant temperature for the duration of the experiment) and those which were dynamic (where an experimental charge is slowly drawn from the furnace).
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar and Planetary Institute The 47th Ann. Meteoritical Soc. Meeting; 1 p
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2019-01-25
    Description: The partitioning behavior of Pb in the three-phase system metal-troilite-sulfide liquid was investigated. Microscopic examination and electron microprobe analysis of a polished section showed three phases--Fe metal, troilite and an Fe-S-Pb-O metallic liquid. The Pb concentration of the metallic liquid was 1.4 wt.%; the Pb contents of both the troilite and the Fe metal were below the detection limit of the electron probe. To better define the Pb concentrations of the solid phases, the same sample was analyzed for Pb and Fe using the M.I.T., Harvard and Brown ion microprobe. Even at this level of precision, some conclusions and speculations are possible: (1) The D(Pb) (troilite/metallic liquid) is low (.01 to .001) and, contrary to expectation, troilite, like metal, excludes Pb very effectively during the crystallization of metallic liquids; (2) Pb in iron meteorites is conceivably concentrated in trace phases which are less susceptible to contamination than metal and troilite; and (3) taken at face value D(Pb)(metal/troilite) is 0.1, but given the Pb and Fe ion yields from simple endmember phases (Fe, FeS, Pb, PbS), this D is more likely to be 0.05 to 0.03.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar and Planetary Institute The 47th Ann. Meteoritical Soc. Meeting; 1 p
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2019-01-25
    Description: Conversion electron Mossbauer spectroscopy (CEMS) of samples from the Santa Catharina iron meteorite shows the presence of the ordered iron-nickel phase with 50% Ni, tetrataenite, and of the paramagnetic iron-nickel phase with 25% Ni. The FeNi phase with 50% Ni amounts to 70% of the iron-nickel alloys. Futhermore, the CEM spectra show the presence of small peaks from one or more spinel compounds. These small peaks are more pronounced when regions near the rim of the samples are analyzed. The X-ray diffraction of different areas of the samples, both optically dark and optically light areas, shows the presence of a diffraction pattern from a single f.c.c. lattice with a lattice parameter of a=3.58A This means that the two different Fe-Ni phases seen in the CEMS analysis occupy the same lattice. The X-ray photographs also show the presence of super-structure reflections from the ordered FeNi phase, and that the orientation of the f.c.c. lattice is the same within the whole sample.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar and Planetary Institute The 47th Ann. Meteoritical Soc. Meeting; 1 p
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: The lunar origin model considered involves processing of protolunar material through a circumterrestrial swarm of particles. Once such a swarm has formed, it can gain mass by capturing infalling planetesimals and ejecta from giant impacts on the Earth, although the angular momentum supply from these sources remains a problem. Examined is the first stage of formation of a geocentric swarm by capture of planetesimals from initialy heliocentric orbits. The only plausible capture mechanism that is not dependent on very low approach velocities is the mutual collision of planetesimals passing within Earth's sphere of influence. This capture scenario was tested directly by many body numerical integration of planetesimal orbits in near Earth space. Results agree that the systematic contribution of angular momentum is insufficient to maintain an orbiting swarm under heavy bombardment. Thus, a circumterrestrial swarm can be formed rather easily, but is hard to sustain because the mean net angular momentum of a many body swarm is small.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 54
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: The explanation that lunar origin involved giant impacts remains attractive. Large planetesimals are consistent with current accretion models, and may have been widely scattered in the early solar system; their existence is a reasonable, assumption in Moon origin models. Isotopic data require the Moon's formation primarily from local material resembling Earth's upper mantle, not material from elsewhere in the solar system. Giant impacts are stochastic, class predictable events that would provide the required type of ejected Earth mantle material without requiring large moons to form near other planets (a problem with less stochastic processes). Such material may have mixed with incoming meteorites during lunar formation, affecting lunar chemistry.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 52
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Publication Date: 2019-01-25
    Description: G. H. Darwin proposed that the primordial Earth may have rotated fast enough that the solar tidal period was nearly resonant with the fundamental free oscillation period of a fluid Earth and that a large and unstable tidal oscillation split off to become the moon. Jeffreys argumented that dissipation during resonance would be sufficient to prevent such an unstable oscillation greater than the tidal frequency (period - 2.68 hr). It is considered that solar tides have extracted angular momentum from the Earth-Moon system over 4.5 b.y. The correspondence of the primordial tidal and resonant frequencies is nearly exact. (The effect of central condensation of the proto earth is to increase both frequencies by a similar amount, though the resonance is not precisely known. This result, was unknown to Darwin or Jeffreys. The effects of resonance were evaluated. The resonance is likely to be too damped for fission. This argument is more general than Jeffreys', who considered friction between the oscillating mantle and a rigid core. It is argued that the fact that Q must be so great for fission that equilibrium can not be maintained; the fluid proto Earth passes so quickly through resonance that maximum amplitude is not reached. It is suggested that solar resonant tides acted as a brake on the spin of the primordial partially molten Earth. Certain proposed origins for the Moon do not necessarily involve addition of substantial amounts of angular momentum to the Earth-Moon system. The primordial Earth-Moon system may have had nearly the same angular momentum as it has today.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 34
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: The Moon's center of mass is displaced from its center of figure about 2 km in a roughly earthward direction. Most maria are on the side of the Moon which faces the Earth. It is assumed that the Moon was initially spherically symmetric. The emplacement of mare basalts transfers mass which produces most of the observed center of mass displacement toward the Earth. The cause of the asymmetric distribution of lunar maria was examined. The Moon is in a spin orbit coupled relationship with the Earth and the effect of the Earth's gravity on the Moon is asymmetric. The earth-facing side of the Moon is a gravitational favored location for the extrusion of mare basalt magma in the same way that the topographically lower floor of a large impact basin is a gravitationally favored location. This asymmetric effect increases inversely with the fourth power of the Earth Moon distance. The history of the Earth-Moon system includes: formation of the Moon by accretion processes in a heliocentric orbit ner that of the Earth; a gravitational encounter with the Earth about 4 billion years ago resulting in capture of the Moon into a geocentric orbit and heating of the Moon through dissipation of energy related to tides raised during close approaches to the Earth(5) to produce mare basalt magma; and evolution of the Moon's orbit to its present position, slowly at first to accommodate more than 500 million years during which magmas were extruded.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 32
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: While the oceans undoubtly contribute to energy dissipation, it seems implausible that such a small amount (0.02%) of the Earth's mass could play such a dominant role in lunar orbital evolution. An alternate hypothesis assumes that most of the dissipation is associated with solid-body tides. This mechanism is also capable of varying significantly over time for viscoelastic bodies. In such an analysis of orbital evolution, the bodies are modeled as incompressible, Kelvin-Voight solids. While this material is simplistic, it does provide an analytical characterization of solid-body dissipation and the resulting tidal moment. The orbital history of a two body system is traced back in time to develop constraints on the satellite's origin. These constraints suggest the Moon appeared in a significantly inclined orbit at a distance greater than ten Earth radii. This distance is outside of the Roche limit and would appear to alleviate some difficulties associated with capture hypotheses. Small eccentricity at close approach suggests an origin by accretion.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 30
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: The concept that the Moon was fissioned from the Earth after core separation is the most readily testable hypothesis of lunar origin, since direct comparisons of lunar and terrestrial compositions can be made. Differences found in such comparisons introduce so many ad hoc adjustments to the fission hypothesis that it becomes untestable. Further constraints may be obtained from attempting to date the volatile-refractory element fractionation. The combination of chemical and isotopic problems suggests that the fission hypothesis is no longer viable, and separate terrestrial and lunar accretion from a population of fractionated precursor planetesimals provides a more reasonable explanation.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 25
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Publication Date: 2019-01-25
    Description: The existence of subaqueous unicellular algae and bacteria from the Precambrian period is evidenced by strongly abundant fossilized structures consisting of many layers of usually darker algae-bacterial growth alternating with layers of usually lighter sediment-precipitate. The earliest of these are dated to 3.5 billion years ago. A form of these stromatolites, Anabaria juvensis was analyzed and a sinusoidal columnar growth pattern was interpreted to be a response of stromatolite forming microbes to the changing inclination of the Sun over the seasons, with microbe growth rate positively related to solar intensity. Additional specimens are being used to develop a systematic methodology for extracting data evidencing Earth-Moon-Sun dynamics at the time of stromatolite formation. In particular, stromatolites span the time from 1 to 2 billion years ago, critical for several theories of lunar formation and/or Earth/Moon near encounter. Such cataclysmic events would influence stromatolite formation.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 29
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Publication Date: 2019-01-25
    Description: There are good reasons to believe that lunar volcanic glasses originated from a deep interior source. The presence of a thin layer of surface correlated elements on these glasses may indicate that the Moon has some reservoirs that are enriched in volatiles. Since the glasses themselves do not show similar enrichment, the source should be of limited extent. Three scenarios are advanced for the origin of these elements. The mechanism for lunar volcanism differs from the mechanism for volcanism on Earth since the former produces bubbling and the latter explosive fountaining. From the condensation behavior of the volatile compounds, which leads to heterogeneous condensation, it is concluded that comparing element ratios of surface correlated elements gives little sense. It seems as if the volatile reservoirs are of rather limited extent and that they do not enlarge the volatile content of the bulk Moon significantly.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 23
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Publication Date: 2019-01-25
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Bases and Space Activities in the 21st Century; p 68
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Publication Date: 2019-01-25
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Bases and Space Activities in the 21st Century; p 25
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Publication Date: 2019-01-25
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Bases and Space Activities in the 21st Century; p 17
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Bases and Space Activities in the 21st Century; p 16
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Publication Date: 2019-01-25
    Description: The importance of ice sheet flow as part of the process of concentrating meteorites in Antarctica is discussed. Ford and Tabor were the first to surmise that some type of ice sheet transport of Antarctic meteorites was likely considering that the Thiel Mountains pallasite was found on glacier ice without evidence of impact. It was found that meteorites were carried by the ice to regions of high ablation where they were periodically uncovered. Three models of concentration have been proposed to explain the phenomena of meteorite accumulations on blue ice fields. Model 1, is a general picture relating meteorite fall and accumulation to the entire Antarctic continent. Model 2 is based upon the petrographic examination of an 8m ice core from the Allan Hills Icefield and suggests a local origin of ice from the catchment basin. The third model is presented by Whillans and Cassidy who infer, by using conventional ice flow concepts, a path length as long as 1,000km from the sites of fall to recovery for Allan Hills specimens. Despite achievement of these working hypotheses, a number of questions must be resolved before a comprehensive model can be presented.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar and Planetary Institute The 47th Ann. Meteoritical Soc. Meeting; 1 p
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Publication Date: 2019-01-25
    Description: The comminution of planetary surfaces by exposure to continuous meteorite bombardment was simulated by impacting the same fragmental gabbro target 200 times. The role of comminution and in situ gardening of planetary regoliths was addressed. Mean grain size continuously decreased with increasing shot number. Initially it decreased linearly with accumulated energy, but at some stage comminution efficiency started to decrease gradually. Point counting techniques, aided by the electron microprobe for mineral identification, were performed on a number of comminution products. Bulk chemical analyses of specific grain size fractions were also carried out. The finest sizes ( 10 microns) display generally the strongest enrichment/depletion factors. Similar, if not exactly identical, trends are reported from lunar soils. It is, therefore, not necessarily correct to explain the chemical characteristics of various grain sizes via different admixtures of materials from distant source terrains. Differential comminution of local source rocks may be the dominating factor.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar and Planetary Institute The 47th Ann. Meteoritical Soc. Meeting; 1 p
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Publication Date: 2019-01-25
    Description: Poorly characterized phases (PCP's) constitute up to 30 volume percent of some CM carbonaceous chondrites, and are therefore an important key to an understanding of the physico-chemical conditions attending matrix evolution. An iron rich form of the terrestrial phase tochilinite was recently identified as a common type of PCP. Tochilinite has the general formula 6Fe(0.9)S.5(Mg,Fe)(OH)2 and consists of alternating machinawite (FeS) and brucite ((Mg,Fe)(OH)2) sheets, with iron vacancies in the sulfide sheets. In iron rich tochilinite, ferrous hydroxide, called amakinite, replaces brucite. If CM carbonaceous kchondrites have underdone hydrothermal alteration, iron rich tochilinite, at least, probably grew from aqueous solutions characterized by low FO2, high FS2, pH 10 to 12, and at a temperature at or below 170 C.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar and Planetary Institute The 47th Ann. Meteoritical Soc. Meeting; 1 p
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Publication Date: 2019-01-25
    Description: The effects of gravitational body force must be considered in the formation of extraterrestrial materials such as meteoritic chondrules and lunar glasses. Solidification experiments conducted in microgravity as well as g values greater than Earth's gravitational force have demonstrated that gravitational force can have profound and sometimes unexpected effects upon the way materials solidify and, therefore, upon their physical and mechanical properties. Solutal, thermal and sedimentation effects differ from those experienced on Earth. Because buoyancy forces are reduced, materials of different densities may remain in close proximity. The spherical morphology of chondrules and many lunar glasses may reflect the tendency for free floating liquids to form spherical droplets in a microgravity environment, a form which minimizes surface energy. Under these conditions, surface energy forces dominate gravity forces. The formation of two common chondrule textures, barred and radiating chondrules, can be explained using observations from glass science.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar and Planetary Institute The 47th Ann. Meteoritical Soc. Meeting; 1 p
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: Two calcium titanium oxide spherules (CTS) and an iron chromium nickel oxide one (FCN) were obtained from a segment of ice core collected at Mizuho Station, East Antarctica. An anomalous REE abundance pattern enriched in Sm by a factor of about 10 relative to the typical pattern of terrestrial perovskites was found. Subsequently, more than forty spherules from ten other depth ranges of the ice core were analyzed: (1) both CTS and FCN occur in every depth range; (2) CTS, FCN, and other are in the ratio of about 2:21 among all the analyzed spherules; (3) all of CTS show the same chemical and mineralogical characteristics as those previously obtained; (4) CTS contains some amounts of Cr and Fe, and/or FCN contains Ca and Ti; and (5) two composite particles exist among all the spherules. It is implied that CTS and FCN had originated in a common natural material and from a common natural process.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar and Planetary Institute The 47th Ann. Meteoritical Soc. Meeting; 1 p
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: A metallographic study was undertaken to seek support for the idea that Santa Catharina is really massive cloudy taenite. Available metal-rich nuggets of Santa Catharina appear to have been single crystals of taenite in the few centimeter size range, separated from each other by grain boundaries occupied by troilite and schreibersite. Metallographic and electron microprobe data allow one to postulate the following cooling and structural development history: (1) single crystal taenite formed at high temperature; (2) phosphate formed within the taenite and grain boundary schreibersite formed at interfaces with troilite or with other taenite crystals; (3) schreibersite began to precipitate within taenite at about 650 C; (4) at about 450 C the meteorite entered the three phase field at which point kamacite precipitated and started growing; and (5) kamacite/schreibersite interface measurements indicate that cooling continued down to about 350 C, with large Ni diffusion gradients developing within schreibersites.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar and Planetary Institute The 47th Ann. Meteoritical Soc. Meeting; 1 p
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: A quantitative model to estimate the degree of annealing of nuclear tracks in mineral grains subjected to a variable temperature history was proposed. This model is applied to study the track annealing records in different meteorites resulting from their atmospheric heating. Scale lengths were measured of complete and partial track annealing, delta X sub 1 and delta X sub 2, respectively. In mineral grain close to fusion crust in about a dozen meteorites. Values of delta X sub 1 and delta X sub 2 depend on extent and duration of heating during atmospheric transit and hence on meteorite entry parameters. To estimate track annealing, the temperature history during atmospheric heating at different distances from the crusted surface of the meteorite is obtained by solving heat conduction equation in conjunction with meteorite entry model, and use of the annealing model to evaluate the degree of annealing of tracks. It is shown that the measured values of delta X sub 1 and delta X sub 2 in three of the meteorites studied are consistent with values using preatmospheric mass, entry velocity and entry angle of these meteorites.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar and Planetary Institute The 47th Ann. Meteoritical Soc. Meeting; 1 p
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: Chrondrule textural types were studied for size sorted chondrules from the ordinary chondrites Dhajala, Eston and Chainpur and the CM chondrite Murchison. Aliquot samples from size sorted Dhajala chondrules were studied for their oxygen isotopic composition and chondrules from Weston were studied for their precompaction irradiation records by nuclear track technique. Correlations between chondrule textural types and oxygen isotope or track data were identified. A distinct dependence of chondrule textural type on chondrule size was evident in the data for both Dhajala and Weston chondrules. No significant deviation was noticed in the abundance pattern of nonporphyritic chondrules within individual size fractions in the 200 to 800 micron size interval. Overabundance is found of nonporphyritic chondrules in the 100 to 200 micron size fraction of Murchison chondrules, the trend is not as distinct for Chainpur chondrules. Two hundred microns is suggested as the cutoff size below which radiative cooling is extremely efficient during the chondrule forming process. It is suggested that this offers a possibility for use of physical and chemical characteristics of small chondrules to constrain the temperature history during the chondrule formation process.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar and Planetary Institute The 47th Ann. Meteoritical Soc. Meeting; 1 p
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Publication Date: 2019-01-25
    Description: Geochemical evidence is discussed which advocates the theory that the Moon was formed by impact induced fission of the Earth. The Earth's mantle exhibits a number of geochemical peculiarities which make our planet a unique object in the solar system. Terrestrial basalts are compared with those from the Eucrite parent body and the Shergotty parent body. Also the Moon's composition is very close to the Earth's in all details except the lower FeO content which is explained. Evidence is discussed for the plausible physical process of formation of the Moon by impact induced fission. Also the theory that impact induced fission occurred at the moment at which accretion of the Earth was not totally complete is briefly discussed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 48
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: The similarities in siderophile abundances strongly suggest that the Moon was derived from the Earth's mantle after the Earth's core had formed. The energy required to remove material from the Earth's mantle and place it into geocentric orbit can be supplied most readily by impact processes during accretion of the Earth. Impacts of late-accreting, high-velocity planetismals would evaporate many times their masses of mantle material. These gases would be accompanied by a massive spray of shock-melted silicate droplets. It is suggested that the gases produced from such near-equatorial impacts were rapidly spun out into equatorial geocentric orbit. The evaporated material was selectively recondensed, and, accompanied by the shock melted, devolatilized silicate droplets, accreted to form a sediment ring of Earth-orbiting planetismals. This sediment ring also captured a significant proportion of Earth-bound planetismals. The Moon was formed by accretion from planetismals comprising the sediment ring.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 46
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: Some classes of influential events in solar system history are class-predictable but not event-predictable. Theories of lunar origin should not ignore class-predictable stochastic events. Impacts and close encounters with large objects during planet formation are class-predictable. These stochastic events, such as large impacts that triggered ejection of Earth-mantle material into a circum-Earth cloud, should not be rejected as ad hoc. A way to deal with such events scientifically is to investigate their consequences; if it can be shown that they might produce the Moon, they become viable concepts in theories of lunar origin.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 39
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: The dynamic problem of the tidal disruption of a rocky planetismal was solved by a direct integration of the fully three-dimensional, nonlinear equations of motion. The hypothesis that any object that passes within the Roche limit is disrupted was disproven. A time dependent solution was performed numerically, treating the planetismal as a fluid with a Murnaghan equation of state in the solid regions and zero pressure otherwise. Calculations show that a rocky body which passes by the Earth on a parabolic orbit with a perigee within the Roche limit is not tidally disrupted. Objects on hyperbolic orbits would experience even less tidal disruption. The results herein do not apply to bodies with very low viscosity. It is shown, however, that tidal disruption can be ruled out as a mechanism for reducing planetismal masses. Mechanisms for forming the Moon which rely upon tidal disruption are unlikely to be correct.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 37
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Publication Date: 2019-01-25
    Description: A theory for the formation of the Moon which involves the dynamic fission of a rapidly rotating protoplanet, which might then result in the formation of the Earth and the Moon is discussed. The fission hypothesis was originally based on analytic, linearized models of the growth of asymmetry in homogenous bodies. The fully nonlinear evolution of the dynamic instability in inviscid, compressible bodies was calculated by numerical techniques. It was found that the dynamic instability degenerates into the ejection of a ring of matter with a substantial fraction of the mass, leaving behind a central body with most of the mass. The linearized analytical approach and the numerical approach were used to show that dynamic fission probably does not occur in rocky protoplanets. The numerical calculations are performed with a fully three dimensional hydrodynamical code, which allows the nonlinear, time evolution of the instability to be followed. Sequences of uniformly rotating equilibria were constructed and are used as the initial models for the fission calculations. An initially imposed asymmetry consisting of a 10% binary perturbation in the density was found to disappear on the rotational period time scale. No dynamic instability occurred. This result are verified by including the velocity dissipation terms in the linearized analysis of the stability of a Maclaurin spheroid: the dynamic instability disappears when the simulated viscous dissipation terms are included. It is concluded that any rocky body, even with considerable partial melt or a molten core, should be stable to dynamic fission; any rotational instability that occurs can only result in equatorial mass loss.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 36
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Publication Date: 2019-01-25
    Description: The evolution of the Moon's orbit which is governed by tidal dissipation in the Earth while the evolution of its spin is controlled by its own internal dissipation is discussed. Lunar laser ranging data from August 1969 through May 1982 yields the values of both of these parameters. It is suggested that if the Moon was orbited the Earth since its formation, this must be an anomalously high value presumably due to changes in dissipation in the oceans due to continental drift. The explanation that the dissipation occurs at the interface between the mantle and a liquid core of shell is preferred.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 31
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: The Rb-Sr analyses of some lunar samples which indicate that the Moon is close to the age of primitive meteorites are only reliable to within about 100 m.y. A potentially more precise chronometer is the I-Pu-Xe system. I129 has a 17 m.y. halflife and decays to Xe129; Pu244, with an 82 m.y. halflife, produces Xe131 to Xe136 in fission. The I129/Pu244 ratio has a halflife of 21 m.y. Xenon retention for the Earth could have begun as late as the event that gave birth to the Moon. For the Moon, it is hard to imagine that xenon retention could have begun before re-accretion of the fissioned (and initially dispersed?) material, particularly if that material got hot enough to account for the depletion of the volatile elements. Thus, if fission model are correct, xenon retention in the Earth certainly began no later than in the Moon, and possibly began earlier. Therefore, the I-Pu-Xe system is only marginally consistent with a fission origin. If further study confirms that the I/U ratio of the Moon is .01 or less, or if gas-rich lunar highland breccias with higher ratios of I129 to Pu244 are found, it would be difficult to explain the results in an earth-fission model of lunar origin.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 24
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Publication Date: 2019-01-25
    Description: Supporting arguments for the lunar fusion hypothesis include the low density of the Moon corresponding to the density of the Earth's mantle and the low volatile content of the lunar rocks vs. those of terrestrial origin. Vapor pressures of the alkali elements and their oxides increase in the following order: Na, K, Rb and Cs. The Moon should, therefore, be more depleted in Cs relative to Rb, Rb relative to K, and K relative to Na than the Earth if the fission model is correct. Analyses of lunar mare basalts and terrestrial mid-ocean ridge and other young basalts indicate that this behavior is not observed. It is possible that monovalent alkali elements might be lost from silicate materials in a different order than that inferred from elemental and oxide vapor pressures, as a result of differences in the way they are bound in silicate materials. To test this hypothesis a series of experiments was conducted to investigate alkali loss at high temperatures. Analyses indicate that the behavior of volatiles dissolved in a silicate melt is similar to that inferred from elemental and oxide vapor pressures. It is concluded that alkali element ratios in the Earth and Moon are not readily interpreted in terms of the fission hypothesis.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 22
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Publication Date: 2019-01-25
    Description: The Fra Mauro breccias at Apollo 14 contain distinctive suites of mare basalts and highland crustal rocks that contrast significantly with equivalent rocks from other Apollo sites. These contrasts imply lateral heterogeneity of the lunar crust and mantle on a regional scale. This heterogeneity may date back to the earliest stages of lunar accretion and differentiation. Current theories requiring a Moon-wide crust of Ferroan Anorthosite are based largely on samples from Apollo 16, where all but a few samples represent the FAN suite. However, at the nearside sites, FAN is either scarce (A-15) or virtually absent (A-12, A-14, A-17). It is suggested that the compositional variations could be accounted for by the acceleration of a large mass of material (e.g., 0.1 to 0.2 moon masses) late in the crystallization history of the magma ocean. Besides adding fresh, primordial material, this would remelt a large pocket of crust and mantle, thereby allowing a second distillation to occur in the resulting magma sea.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 21
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Publication Date: 2019-01-25
    Description: The FeO content of the Moon is substantially higher than the present FeO content of the Earth's mantle. If the Moon formed by fission from the Earth's mantle, then the conclusion that the Earth's mantle must have been much richer in FeO at the time of fission appears firm. If the Moon formed independently in geocentric orbit, then the FeO contents of the two bodies should be similar, because both would be accreting from the same source of silicate material. Therefore, Earth's mantle at the time of lunar formation probably had an FeO content quite similar to the present FeO content of the Moon. This conclusion, if valid, has profound implications in two areas: (1) the differentiation history of the Earth's mantle and core; and (2) the processes responsible for governing the bulk compositions of the terrestrial planets. If Earth had more FeO than previously thought, then the composition differences between Earth and Mars are less than previously believed. This suggests that condensation temperature and heliocentric distance may have been less important in governing planetary compositions and other mechanisms, including iron/silicate fractionation may have been more important. The implication of this model for the compositions of the Moon and the other terrestrial planets are discussed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 20
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: Compositional data for nonmare (highlands) samples suggest that the Moon's mg ratio (MgO/FeO) is higher than general estimates. Geochemically representative highlands soils have mg ratios of 0.66 (Apollo 16), 0.69 (Luna 20) and 0.73 (ALHA81005). These soils are mixtures of unrelated pristine nonmare rocks, of which there are at least three groups: Mg-rich rocks, ferroan anorthosites, and KREEP. Other than Mg-rich rocks, virtually all pristine rocks have mg 0.65. Thus, assuming the mixing process that sampled Mg-rich materials was random, the average mg of Mg-rich parent magmas was probably at least 0.70. More direct evidence can be derived from the Mg-rich rocks themselves. Nine of them have bulk-rock mg 0.87. Two (15445 A and 67435 PST) contain Fo(92) olivine. Production of melts that crystallized Fo(92) olivine implies that the mg ratios of source regions in lunar mantle were commensurably high. A quantification of this constraint is developed assuming that the parent melts formed by equilibrium (batch) partial melting. Implications of the model are discussed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 19
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Publication Date: 2019-01-25
    Description: Regardless of the origin of the Moon, metal segregation must have occurred within the moon in order to account for its low siderophile element abundances relative to the Earth or chondrites. Germanium is a strongly siderophile element whose bulk distribution coefficient indicates that it is not fractionated during igneous processes on the Moon. The variability in absolute Ge abundances in mare basalts and pristine highland rocks, rather than elemental ratios, can be used to infer lunar mantle abundances and processes. Literature data have been compiled for Ge abundances in mare basalts and pristine highland rocks. For some landing sites, samples with 12 ppb Ge were considered to be extreme outliers and are not included. The Apollo 15 samples are enriched in Ge by a factor of 2.5 over the Apollo 12, 16 and 17 samples. Other siderophile element variations have been found in the Moon. Based on this data, best estimate of the average Ge abundance in the silicate portion of the Moon is 3.52 ppb. The Moon is depleted, relative to chondritic abundances, by a factor of 38,000 normalized to Si. Two possible explanations for the observed variations in Ge abundance in the Moon are: (1) more metal may have segregated from some regions of the Moon than from others; or Ge-bearing material may been been added later in the evolution of the Moon.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 16
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Publication Date: 2019-01-25
    Description: The earliest metal phases to crystallize from the least-fabricated low Ti mare basalts contain about 30% Ni and 2 to 7% of Co. Experimental investigations of partitioning of Ni and Co between primitive lunar basaltic magmas and metal phases are currently in progress. Preliminary results show that the metal phase crystallizing near the liquidus of Green Glass (185 ppm Ni, 70 ppm Co) would contain about 40% Ni and 2.3% Co. It seems, therefore, that if a lunar core does exist, as suggested by the results of (2), it is relatively rich in Ni (30-40%) and Co (2-7%). This composition presents a remarkable contrast to that of the Earth's core which is estimated to contain about 6% Ni and 0.3% Co. Explanations for the differing densities of Earth and Moon are imvestigated.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 14
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: Two independent techniques used to infer the electrical conductivity of the interior of the Moon are discussed. The first is the measurement of an incident spectrum of electromagnetic waves in the solar wind near the Moon and the separate measurement of the incident plus reflected spectrum on the surface of the Moon. The second is the measurement of the distortion of the ambient magnetic field of the geomagnetic tail lobes by the conducting Moon. The size of the conducting region was found to be greater than 400 km in radius.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 7
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-01-25
    Description: A 0.2 arc second phase shift in the 18.6 year forced precession of the lunar figure was inferred from analysis of lunar laser ranging data. The source of the phase shift is either viscous friction at a lunar core mantle boundary or solid friction caused by tidal flexing of the Moon by the Earth. Core mantle viscous coupling will explain the signature if the core radius R sub c approximately equals 330 km. On the other hand, solid friction can account for the signature only if the lunar solid friction 0 approximately equals 30 is abnormally small compared with that observed for, say, Mars (approximately equals 100 - 200). Although the inferred core radius is certainly within the limits imposed by the Apollo seismic experiment, it is significantly smaller than estimates of order 400-500 km from electromagnetic sounding. How accurate is the estimate of the R sub c derived from the phase shift? The effect of uncertainties in the frictional coupling mechanism, core density and ellipticity on the inferred core radius are discussed. The excitation of lunar free librations by core turbulence vis-a-vis other mechanisms (e.g., cometary or asteroidal impacts) and the influence of changes in lunar precession in the past on lunar dynamo generation are also examined.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 6
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Publication Date: 2019-01-25
    Description: The early fractionation of the Moon as a result of melting the outer layer of the Moon is discussed. This melting can be attributed to the accretional heating of the moon. Computations of the early thermal evolution of the Earth and Moon based on the assumption that these bodies accreted independently were carried out. The results are consistent with many observations. The concept of geochemical reservoirs was also applied to the Moon.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Planetary Inst. Conf. on the Origin of the Moon; p 3
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Publication Date: 2018-12-01
    Description: It is thought likely that extension of civilization beyond earth may include a permanent settlement on the moon. An analysis of the American civilian space program shows that the required technology for establishing a base on the moon will exist before the end of this century. A manned lunar base is discussed in terms of three distinct functions. The first is related to the scientific investigation of the moon and the application of special properties of the moon to research problems. In connection with the second, attention is given to the development of the capability to utilize the materials of the moon for beneficial purposes throughout the earth-moon system. The last involves research and development leading to a self-sufficient and self-supporting lunar base.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: IAF PAPER 84-197
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Publication Date: 2013-08-31
    Description: A detailed study of the magnetic field data from both Voyagers 1 and 2 has revealed several interesting properties of the near and distant Jovian magnetotail. During the first encounter, as Voyager 1 passed between 80 and 140 R sub J from Jupiter in the near tail, the spacecraft was almost entirely in the northerm lobe magnetic field. The frequency spectrum of magnetic fluctuation in this region cannot be characterized by a power law and does not appear to be turbulent. The distant tail spectra from Voyager 2 are compared with similar spectra obtained from Voyager 1 when it was in near radial alignment with Voyager 2. Although the gross properties of the tail and solar wind fields in most respects differ considerably, the shape and power levels of the spectra of the magnetic fluctuations are very similar, especially between .0001 and .001 Hz. At lower frequencies (.00001 to .0001 Hz) the spectra of magnetic helicity do differ.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NAS 1.15:86159 , NASA-TM-86159
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Publication Date: 2013-08-31
    Description: Unlike Earth, long wavelength gravity anomalies and topography correlate well on Venus. Venus's admittance curve from spherical harmonic degree 2 to 18 is inconsistent with either Airy or Pratt isostasy, but is consistent with dynamic support from mantle convection. A model using whole mantle flow and a high viscosity near surface layer overlying a constant viscosity mantle reproduces this admittance curve. On Earth, the effective viscosity deduced from geoid modeling increases by a factor of 300 from the asthenosphere to the lower mantle. These viscosity estimates may be biased by the neglect of lateral variations in mantle viscosity associated with hot plumes and cold subducted slabs. The different effective viscosity profiles for Earth and Venus may reflect their convective styles, with tectonism and mantle heat transport dominated by hot plumes on Venus and by subducted slabs on Earth. Convection at degree 2 appears much stronger on Earth than on Venus. A degree 2 convective structure may be unstable on Venus, but may have been stabilized on Earth by the insulating effects of the Pangean supercontinental assemblage.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NAS 1.26:176173 , NASA-CR-176173
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Publication Date: 2013-08-31
    Description: The morphological characteristics and evolutionary development of rock labyrinths on Earth (in sandstone, volcanics, and carbonates) are compared with those on Mars. On Earth rock labyrinths originate as parallel, an echelon, or intersecting narrow grabens, or develop where fault and joint networks are selectively eroded. Labyrinths frequently contain both downfaulted and erosional elements. Closed labyrinths contain depressions; open labyrinths do not, they are simple part of a fluvial network generally of low order. As closed labyrinths made up of intersecting grabens or made up of connected erosional depressions are extremely common on Mars, the research focussed on an understanding of these labyrinth types. Field investigations were carried out in Canyonlands National Park, Utah, and in the Chirachahua Mountains of Arizona. Martian labyrinths were investigated using Viking orbiter images. In addition, research was undertaken on apparent thermokarst features in Lunae Planum and Chryse Planitia where closed depressions are numerous and resemble atlas topography.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NAS 1.26:175511 , NASA-CR-175511
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Publication Date: 2013-08-31
    Description: The Viking Lander 1 wind sensor data during the period between sols 45 and 375 were corrected. During this period, the heating element of the quadrant sensor which provided the primary signal used for determining wind direction had failed, but both hot film wind sensors were functioning normally. The wind speed and direction corrections are explained.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-CR-174349 , NAS 1.26:174349
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Publication Date: 2013-08-31
    Description: Trajectory and mission requirement data are presented for Earth-Mars opposition class and conjunction class round trip stopover mission opportunities available during the time period year 2000 to year 2045. The opposition class mission employs the gravitational field of Venus to accelerate the space vehicle on either the outbound or inbound leg. The gravitational field of Venus was used to reduce the propulsion requirement associated with the opposition class mission. Representative space vehicle systems are sized to compare the initial mass required in low Earth orbit of one mission opportunity with another mission opportunity. The interplanetary space vehicle is made up of the spacecraft and the space vehicle acceleration system. The space vehicle acceleration system consists of three propulsion stages. The first propulsion stage performs the Earth escape maneuver; the second stage brakes the spacecraft and Earth braking stage into the Mars elliptical orbit and effects the escape maneuver from the Mars elliptical orbit. The third propulsion stage brakes the mission module into an elliptical orbit at Earth return. The interplanetary space vehicle was assumed to be assembled in and depart from the space station circular orbit.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-TM-86477 , NAS 1.15:86477
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2013-08-31
    Description: High-temperature creep in orthoenstatite under conditions of controlled oxygen fugacity was studied. It was found that creep was conttrolled by the extremely thin layer of SiO2 which wetted the grain boundaries. Slight reduction of the (Mg, Fe)SiO3 enstatite during hot pressing produced microscopic particles of Fe and the thin film of intergranular SiO2. This result highlights another complication in determining the flow properties of iron bearing silicates which constitute the bulk of terrestrial planets and moons. The Phenomenon may be important in the ductile formation of any extraterrestrial body which is formed in a reducing environment. The rheology of dirty ice was studied. This involves micromechanical modeling of hardening phenomena due to contamination by a cosmic distribution of silicate particles. The larger particles are modeled by suspension theory. In order to handle the distribution of particles sizes, the hardening is readed as a critical phenomenon, and real space renormalization group techniques are used. Smaller particles interact directly with the dislocations. The particulate hardening effect was studied in metals. The magnitude of such hardening in ice and the defect chemistry of ice are studied to assess the effects of chemical contamination by methane, ammonia, or other likely contaminants.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: USC-TR-84-9 , NASA-CR-174024 , NAS 1.26:174024
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Publication Date: 2013-08-31
    Description: Progress is reported on a project to determine the properties and boundaries of high pressure phases of the H2-He-H2O-NH3-CH4 system that are needed to constrain theoretical models of the interiors of the major planets. This project is one of the first attempts to measure phase equilibria in binary fluid-solid systems in diamond anvil cells. Vibrational spectroscopy, direct visual observations, and X-ray diffraction crystallography of materials confined in externally heated cells are the primary experimental probes. Adiabats of these materials are also measured in order to constrain models of heat flow in these bodies and to detect phase transitions by thermal anomalies. Initial efforts involve the NH3-H2O binary. This system is especially relevant to models for surface reconstruction of the icy satellites of Jupiter and Saturn. Thermal analysis experiments were completed for the P-X space, p4GPa:0 or = 0.50, near room temperature. The cryostat, sample handling equipment, and optics needed to extend the optical P-T-X work below room temperature was completed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-CR-174032 , NAS 1.26:174032
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Publication Date: 2013-08-31
    Description: The extreme ultraviolet EUV emission produced by particle excitation of the hydrogen atmospheres of Jupiter and Saturn is examined using model calculations to determine the nature of the energy deposition process and the effect of such processes on atmospheric structure. Tasks ranging from examination of phenomenologically related processes on Saturn and Titan to analysis of experimental laboratory data required to allow accurate modeling of emissions from hydrogenic atmospheres are investigated. An explanation of the hydrogen H Ly(alpha) bulge in Jupiter's emission from the equatorial region is presented. It is proposed that Saturn, rather then Titan is the major source of the extended hydrogen cloud. The atomic hydrogen detected at the rings of Saturn may originate predominantly from the same source. A cross calibration is obtained between the Pioneer 10 EUV photometer and the Voyager EUV spectrometers, thus providing a direct measure of the temporal morphology of Jupiter between a minimum and a maximum in solar activity. Atomic and molecular data required for the research program are analyzed. An extrapolation of conditions in the upper atmospheres of Jupiter and Saturn produces a predicted condition at Uranus in terms of excitation and hydrogen escape rates that may be observed at Voyager-Uranus encounter.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NAS 1.26:173930 , NASA-CR-173930
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Publication Date: 2013-08-31
    Description: Images from three filters of the Voyager 1 wide angle camera are used to measure the continuum reflectivity and spectral gradient near 6000 A and the 6190 A band methane/continuum ratio for a variety of cloud features in Jupiter's atmosphere. The dark barge features in the North Equatorial Belt have anomalously strong positive continuum spectral gradients suggesting unique composition. Methane absorption is shown at unprecedented spatial scales for the Great Red Spot and its immediate environment, for a dark barge feature in the North Equatorial Belt, and for two hot spot and plume regions in the North Equatorial Belt. Methane absorption and five micrometer emission are correlated in the vicinity of the Great Red Spot but are anticorrelated in one of the plume hot spot regions. Methane absorption and simultaneous maps of five micrometer brightness temperature is quantitatively compared to realistic cloud structure models which include multiple scattering at five micrometer as well as in the visible. Variability in H2 quadrupole lines are also investigated.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NAS 1.26:173567 , NASA-CR-173567
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2013-08-31
    Description: Four tests are examined: (1) investigation of volcanism on Io; Interim results of thermal and structural modeling of volcanism on Io are presented, (2) a study of the ancient heavily cratered regions on Ganymede, (3) a geologic comparison of the cratering record on Ganymede and Callisto, and (4) a geological and chemical investigation of internal resurfacing processes on the Saturnian satellites. Tasks 2, 3, and 4 utilize Voyager imaging data.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NAS 1.26:173497 , NASA-CR-173497
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Publication Date: 2013-08-31
    Description: Antarctic meteorites, achondrites, carbonaceous chondrites, ions, and stony-irons are classified.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-TM-85559 , NAS 1.15:85559
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Publication Date: 2013-08-31
    Description: The observed spectrum of Jovian atmosphere exhibits spectral features of H2, CH4, C2H6, NH3, H2O, GeH4 and CH3D. Analytical programs were developed for radiative transfer calculations and for retrieval of lower atmospheric composition of Jupiter from the observed infrared spectrum. The program models developed are based line by line transmittance calculations with appropriate convolution of the instrument function. The constituent inversion programs were evaluated for accuracy by analyzing synthetic data for retrievals of NH3 profiles. The inversion programs were employed for retrieval of NH3 profiles from the Voyager infared data with results generally in agreement with the accepted values.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NAS 1.26:174196 , NASA-CR-174196
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Publication Date: 2013-08-31
    Description: Progress on a project to elucidate the geological and topographic setting of the Martian polar volatiles is reported. The following accomplishments are enumerated: (1) all of the Mariner 9 imaging data sets available through JPL were acquired and copied; (2) Mariner 9 imagery was investigated in terms of the accuracy of the imaging footprints, dark current, and residual image; (3) the transfer functions of both vidicons were investigated; and (4) the magnitude of the atmospheric scattering was examined.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-CR-174089 , NAS 1.26:174089
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Publication Date: 2013-08-31
    Description: Current theoretical models of Saturn's ionosphere are difficult to reconcile with the ionospheric electron density profiles obtained from the Pioneer and Voyager radio occultation observations and the large diurnal variation of maximum ionospheric electron density deduced from studies of Saturn lightning discharges. A model of Saturn's ionosphere is proposed in which water plays a major role as a minor constituent present by virtue of downward diffusion from an external source. This model of the Saturn ionosphere is a classical 'F2' type layer resulting from the photodissociative production of H(+) from H2 and rapid chemical loss due to a series of charge exchange reactions with water. A planet-wide influx of about 4x10 to the 7th power molecules/sec/sq cm of water from the rings is consistent with the observed ionospheric electron densities and estimates of influx due to micrometeoride bombardment of the rings. An enhanced influx of water occurs at latitudes (-38 deg, +44 deg) magnetically connected to the inner edge of Saturn's B ring which results from an electromagnetic erosion process contributing substantially to the (local) upper atmosphere water content. Present day influx at these latitudes is possibly as large as 2x10 to the 9th power molecules/sec/sq cm.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-TM-86144 , REPT-695 , NAS 1.15:86144
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Publication Date: 2013-08-31
    Description: Global and regional patterns on Mars were inferred from surface aeolian features, such as wind streaks and dune deposits, which were visible in Viking Orbiter images. Precise measurements of the dimensions of topographic obstacles, i.e., craters, hills, ridges, on Mars as well as their associated wind streaks were used to determine the aerodynamic shape of an obstacle affects near surface airflow. A classification of Martian wind streaks was developed on the basis of albedo contrast and the presence or absence of either topographic obstacles or sediment deposits at the point of origin of the wind streaks. It was concluded that local meteorological conditions, such as the stability of the atmospheric boundary layer, play a major role in determining why some Martian craters produce depositional wind streaks while others produce erosional ones.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-CR-173982 , NAS 1.26:173982
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Publication Date: 2013-08-31
    Description: Photographic and cartographic comparisons of geographic features on Mercury, the Moon, Earth, Mars, Ganymede, Callisto, Mimas, and Tethys are presented. Planetary structures caused by impacts, volcanism, tectonics, and other natural forces are included. Each feature is discussed individually and then those of similar origin are compared at the same scale.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-TM-86147 , NAS 1.15:86147
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Publication Date: 2013-08-31
    Description: Spectrophotometric observations of emission line intensities over the spectral range 1400 A to 9600 A were made in five positions in the planetary nebula NGC 3242. In two of the positions, both the weakness of the 1548 A, 1550 A C IV resonance lines and the steepness of the Balmer decrement suggest the possibility of internal dust in the nebula. The measured electron temperature varies little from the average value of 11,100 K, which is in reasonably good agreement with the less accurate value of 12,900 K measured from the Balmer continuum. The 4267 A C II line implies a C(2+) abundance that is much higher than that determined from the 1906 A, 1908 A C III lines. This discrepancy decreases with increasing distance from the central star. Equations used to correct for the existence of elements in other than the optically-observable ionization stages give results that are consistent and in agreement with abundances calculated using ultraviolet lines. This discrepancy decreases with increasing distance from the central star. Equations used to correct for the existence of elements in other than the optically-observable ionization stages give results that are consistent and in agreement with abundances calculated using ultraviolet lines. The logarithmic abundances are He=10.96, 0=8.64, N=7.96, Ne=8.04, C=8.41, Ar=6.15, and S=6.51.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-CR-173914 , NAS 1.26:173914
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Publication Date: 2013-08-31
    Description: A listing of meteorites found in Antarctica is provided, along with a description of some of the less common types. Petrographic and physical descriptions, weight data, and locations of the less common meteorites are given.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-TM-85385 , NAS 1.15:85385
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Publication Date: 2013-08-31
    Description: The vibrational and rotational excitation of the CO molecule in cometary comae were investigated using a model which includes IR vibrational pumping by the solar flux, vibrational and rotational radiative decay, and collisional coupling among rotational states. Steady state was not assumed in solving the rate equations. The evolution of a shell of CO gas was monitored as it expanded from the nucleus into the outer coma. Collisional effects were treated using a kinetic temperature profile derived from theoretical work on the coma energy balance. The kinetic temperature was assumed to be extremely cold in the inner coma; this has significant consequences for the CO excitation. If optical depth effects are ignored, only low J transitions will be significantly excited in comets observed at high spatial resolution. Ground-based observations of CO co-vibrational and rotational transitions will be extremely difficult due to lack of sensitivity and/or terrestrial absorption. However, CO should be detectable from a large comet with favorable observing geometry if the CO is a parent molecule present at the 10% level (or greater) relative to H2O. Observations using cooled, spaceborne instruments should be capable of detecting CO emission from even moderately bright comets.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-TM-86122 , NAS 1.15:86122
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Publication Date: 2013-08-31
    Description: An eclipse of the Sun by the Moon as seen by the Lageos satellite can affect the orbital semimajor axis at the centimeter level. The weakened radiation pressure acting on Lageos perturbs the orbit differently from that due to full sunlight. This difference amounted to less than 2 mm in the semimajor axis for 23 of the 30 eclipses Lageos experienced between launch in 1976 and the end of 1983. However, it was 17.6 mm for the eclipses on 28 March 1979 and 11.2 mm for the one on 15 December 1982. Differences such as these generate large enough along-track errors to make it worthwhile to include eclipses in complex orbit determination programs such as GEODYN which integrate the orbit. Eclipses cannot explain the presently unmolded variations in along-track acceleration which have a magnitude of about 3 x 10(-12) ms(-2).
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-TM-86076 , NAS 1.15:86076
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Publication Date: 2013-08-31
    Description: Observations of the solar wind close to Jupiter, by the Voyager 1 and Voyager 2 spacecraft in 1978 and 1979, are compared with the hectometer wavelength radio emission from the planet. A significant positive correlation is found between variations in the solar wind plasma density at Jupiter and the level of Jovian radio emission output. During the 173-day interval studied for the Voyager 2 data, the radio emission displayed a long term periodicity of about 13 days, identical to that shown by the solar wind density at Jupiter and consistent with the magnetic sector structure association already proposed for groundbased observations of the decameter wavelength emission.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NAS 1.15:86073 , NASA-TM-86073
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Publication Date: 2013-08-31
    Description: Ray tracing studies of Jovian low frequency emissions were studied. A comprehensive three-dimensional ray tracing computer code for examination of model Jovian decametric (DAM) emission was developed. The improvements to the computer code are outlined and described. The results of the ray tracings of Jovian emissions will be presented in summary form.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-CR-175462 , JPL-9950-981 , NAS 1.26:175462
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Publication Date: 2013-08-31
    Description: The technique of harmonic splines allows direct estimation of a complete planetary gravity field (geoid, gravity, and gravity gradients) everywhere over the planet's surface. Harmonic spline results of Venus are presented as a series of maps at spacecraft and constant altitudes. Global (except for polar regions) and local relations of gravity to topography are described.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-CR-174295 , NAS 1.26:174295
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Publication Date: 2013-08-31
    Description: Findings are summarized from research conducted to develop a detailed classification of all kinds of meteorites in an effort to determine the conditions in the solar nebula, the processes that produced chemical fractionations in chondrites and formed chondrules, as well as ascertain the processes that occurred in the parent bodies of differentiated meteorites (which preserve a partial record of the chondritic materials from which they formed). Fractionation patterns within iron meteorite groups are analyzed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-CR-174201 , NAS 1.26:174201
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Publication Date: 2013-08-31
    Description: Recovered samples from shock recovery experiments on single crystal calcite were subjected to thermogravimetric analysis to determine the amount of post-shock CO2, the decarbonization interval and the activation energy, for the removal of remaining CO2 in shock-loaded calcite. Comparison of post-shock CO2 with that initially present determines shock-induced CO2 loss as a function of shock pressure. Incipient to complete CO2 loss occurs over a pressure range of approximately 10 to approximately 70 GPa. Optical and scanning electron microscopy reveal structural changes, which are related to the shock-loading. The occurrence of dark, diffuse areas, which can be resolved as highly vesicular areas as observed with a scanning electron microscope are interpreted as representing quenched partial melts, into which shock-released CO2 was injected. The experimental results are used to constrain models of shock-produced, primary CO2 atmospheres on the accreting terrestrial planets.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-CR-174197 , NAS 1.26:174197 , CONTRIB-4166
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Publication Date: 2013-08-31
    Description: Progress in the following research supported under NSG 7386 is reported: (1) measurement of differential cross sections for atomic and molecular collisions relevant to analysis and modeling of data from Pioneer 11, Pioneer 12, Voyager 1, and Voyager 2; (2) analysis of measured differential cross section results to provide scattering data in forms that are easy to apply to atmospheric modeling work; (3) analysis of the data to give basic information on the molecular potentials involved in the scattering process; and (4) development and initial use of apparatus to study dissociative processes in neutral molecules.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-CR-174142 , NAS 1.26:174142
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Publication Date: 2013-08-31
    Description: Detailed geomorphic and structural mapping of five Martian basins and preliminary study of eleven other basins reveal four characteristic styles of modification that relate to the degree and age of past tectonic activity. Within regions that exhibit no evidence for tectonic activity, the modification style can be used to distinguish areas dominated by different exogenic processes. A framework for understanding these different styles of basin modification is provided.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: LPI-CONTRIB-537 , NAS 1.26:174074 , NASA-CR-174074
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Publication Date: 2013-08-31
    Description: The observed properties of bow waves and the associated plasma flows are outlined, along with those features identified that can be described by a continuum magnetohydrodynamic flow theory as opposed to a more detailed multicomponent particle and field plasma theory. The primary objectives are to provide an account of the fundamental concepts and current status of the magnetohydrodynamic and gas dynamic theories for solar wind flow past planetary bodies. This includes a critical examination of: (1) the fundamental assumptions of the theories; (2) the various simplifying approximations introduced to obtain tractable mathematical problems; (3) the limitations they impose on the results; and (4) the relationship between the results of the simpler gas dynamic-frozen field theory and the more accurate but less completely worked out magnetohydrodynamic theory. Representative results of the various theories are presented and compared. A number of deficiencies, ambiguities, and suggestions for improvements are discussed, and several significant extensions of the theory required to provide comparable results for all planets, their satellites, and comets are noted.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-CR-174132 , NAS 1.26:174132
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Publication Date: 2013-08-31
    Description: The shape and orbital characteristics of Phobos, the larger and innermost of Mars' two irregular moons, are discussed and illustrated. Also presented are the high resolution pictures of Phobos that were obtained during the close flybys of Viking Orbiters 1 and 2. The viewing geometry is also given for each picture.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NAS 1.61:1109 , NASA-RP-1109
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Publication Date: 2013-08-31
    Description: Observations of large amplitude magnetohydrodynamic (MHD) waves upstream of the Jovian bow shock were previously interpreted as arising from a resonant electromagnetic ion beam instability. That interpretation was based on the conclusion that the observed fluctuations were predominantly right elliptically polarized in the solar wind rest frame. Because it was noted that the fluctuations are, in fact, left elliptically polarized, a reanalysis of the observations was necessary. Several mechanisms for producing left hand polarized MHD waves in the observed frequency range were investigated. Instabilities excited by protons appear unlikely to account for the observations. A resonant instability excited by relativistic electrons escaping from the Jovian magnetosphere is a likely source of free energy consistent with the observations. Evidence for the existence of such a population of electrons was found in both the Low Energy Charged Particle experiments and Cosmic Ray experiments on Voyager 2.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NAS 1.15:86131 , NASA-TM-86131
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Publication Date: 2013-08-31
    Description: The role of impact vaporization acting during the formation of the Jovian and Saturnian satellites is examined in an attempt to explain the observed density in terms of composition of these rock and ice objects. A hypothesis is examined which states that the smaller satellites of Saturn having mean densities in the 1.1 to 1.4 Mg/cu m range represent primordial accreted planetesimal condensates formed in the proto-Jovian and Saturnian accretionary planetary discs. These densities are in the range expected for water-ice/silicate mixtures constrained in the solar values of O/Si and O/Mg atomic ratios. It is demonstrated that if the large satellites accreted from the same group of planetesimals which formed the small Saturnian satellites impact vaporization of water upon accretion in a porous regolith, at low H2O partial pressure, can account for the increase in mean planetesimal density from 1.6 Mg/cu m (43% H2O + 57% silicate) to a mean planetary density of 1.9 Mg/cu m for Ganymedean-sized water silicate objects. If impact volatilization of initially porous planetesimals is assumed, it can be demonstrated starting with planetesimals composed of 54% H2O and 40% silicate partial devolatilization upon accretion will yield a Ganymede-sized planet, having a radius of 2600 km and a density of 1.85 kg/cu m, similar to that of Ganymede, Callisto, and Titan.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-CR-173767 , NAS 1.26:173767
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Publication Date: 2013-08-31
    Description: Spectra of Io obtained during eclipse show a narrow deep absorption feature at 4.871 microns, the wavelength of the Nu sub 1 + Nu sub 3 band of solid SO2. The 4 micron radiation comes from volcanic hot spots at a temperature too high for the existence of solid SO2. It is concluded that the spectral feature results from SO2 particles suspended in plumes above the hot spots. The derived abundance of approximately 0.0003 gm/sq cm may imply an SO2 solid-to-gas ratio of roughly one for the Loki plume, which would in turn suggest that it is driven by the SO2 rather than by sulfur.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NAS 1.26:175414 , NASA-CR-175414
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2013-08-31
    Description: Radar investigations of asteroids, including observations during 1984 to 1985 of at least 8 potential targets and continued analyses of radar data obtained during 1980 to 1984 for 30 other asteroids is proposed. The primary scientific objectives include estimation of echo strength, polarization, spectral shape, spectral bandwidth, and Doppler shift. These measurements yield estimates of target size, shape, and spin vector; place constraints on topography, morphology, density, and composition of the planetary surface; yield refined estimates of target orbital parameters; and reveals the presence of asteroidal satellites.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NAS 1.26:175348 , NASA-CR-175348
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2018-12-01
    Description: The Venus Radar Mapper (VRM) mission is sponsored by NASA to put a single spacecraft in orbit around Venus to map the surface of Venus using a synthetic aperture mapping radar. The spacecraft is scheduled to be launched in April 1988 using a Shuttle-Centaur G combination. The spacecraft arrives at Venus in late July 1988 and begins its mapping mission which lasts for one Venus rotation or 243 days. This paper describes the VRM mission at its present state of design. The science objectives and project constraints are described. Key features of the spacecraft system and radar system are discussed. The interplanetary and mapping orbit design are covered. Navigation strategy is explained, including trajectory maneuvers and mapping phase orbit determination. Finally, the mapping sequences to optimize planet coverage are described.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: AIAA PAPER 84-0212
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2014-09-18
    Description: The present state and evolution of the physical features which are visible on the Moon's surface are emphasized herein. Lunar craters, their distribution and stratigraphy, and the cratering processes are addressed. Homologous material is presented for lunar basins. Terra breccias, maria, and mare basalts are discussed. Lunar geologic history is also considered.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: JPL The Geol. of the Terrest. Planets; p 107-206
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2014-09-18
    Description: The nature of comets and asteroids is reviewed briefly. The formation of planets is examined. Meteorites and chondrites a meteoritic subclass, are discussed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: JPL The Geol. of the Terrest. Planets; p 5-12
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2014-09-18
    Description: The following aspects of the planet Mars are addressed: general properties of the surface, the atmosphere and surface volatiles, craters and crater ages, volcanoes, wind erosion, and the polar regions.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: JPL The Geol. of the Terrest. Planets; p 207-264
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2014-09-18
    Description: The following aspects of the planet Venus are discussed: orbit, rotation, composition, wind erosion, topography, surface roughness, gravity, and tectonics. The Venera satellites, Pioneer space probes, and Mariner space probes involved in Venusian exploration are enumerated.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: The Geol. of the Terrest. Planets; p 57-78
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2014-09-17
    Description: Definition of laboratory data; sources of data and data volume, required support documentation for lab data; urgency of building a computerized archieve; software needed for management of lab data; analysis of data; and location and access to the data archive are discussed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Planetary Data Workshop, Pt. 1; p 120-130
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Publication Date: 2014-09-17
    Description: The satellite system of Neptune is so irregular that some formation mechanism or subsequent dynamical evolution that sets it apart from the other, more regular, satellite systems is obviously indicated. McKinnon argued that satellite capture is the most likely possibility and has shown that tidal circularization of Triton's presumably highly eccentric initial orbit probably resulted in melting of the satellite's interior. The satellite system of Uranus, although somewhat bland, also has a number of special features that indicate an interesting dynamical history. These include the anomalously high orbital inclination of Miranda and the probable coexistence of small satellites and narrow rings inside the plant's Roche limit. The possibility that orbital evolution due to tidal dissipation is involved in both of these phenomena is discussed. Other topics discussed are: the origin of rings; the formation of coorbital satellites; the lack of stable orbit-orbit resonances in the Uranian satellite system; and chaos, tidal heating and the shapes of Miranda and Ariel.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: JPL Uranus and Neptune; p 377-404
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86