Photometric investigations of simulated lunar surfaces.
Photometric investigations of simulated lunar surfaces confirm high porosity and low albedo without postulating necessity for fine dust layer
PHOTOMETRY↗
SEARCH · Search NASA
Results for “LUNAR COMPOSITION”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Mineral deposits on the moon.
Mineral deposits on moon noting probable magmatic segregation, fumarole products, carbonaceous deposits, etc
MINERALOGY↗
System for non-dispersive analysis of lunar X- rays from Apollo
Apollo command service module nondispersive X ray detection system for lunar composition map compilation, discussing design and performance
Adler, I.↗
Viscosity of liquid anorthite.
The viscosity of liquid anorthite has been determined over the temperature ranges between 1450 to 1620 C and 820 to 950 C. The high-temperature data agree well with previous experimental data and with predictions of the Bottinga and Weill model. The overall log (viscosity) versus 1/T relation exhibits pronounced and rather continuous curvature. The viscosity of anorthite is higher at any given temperature and more strongly temperature-dependent than that of the anorthite-rich lunar compositions 14259, 14310, and 15418. The room-temperature density of glassy anorthite (2.64 gm/cu cm) and the thermal expansion coefficients of glassy and liquid anorthite have also been determined. The volume expansion coefficient for the glass is about 0.000018 per deg C, and that for the liquid is about 0.000048 per deg C. These values are used to relate the high-temperature flow data to the predictions of free-volume theories.
Cukierman, M.↗
Passive seismic experiment
The network of seismometers installed by the Apollo 17 and other Apollo missions is described. The effects of the impacts of lunar modules and S-4B stages on the lunar surfaces are discussed. The information concerning lunar composition which is obtained by analyzing the seismic signals generated by moonquakes and meteoroid impacts are analyzed. It is concluded that the seismic activity within the moon is extremely low compared to that with the earth. The moon is characterized by a rigid, dynamically inactive outer shell, approximately 1000 kilometers thick, surrounding a core that has markedly different elastic properties.
Latham, G. V.↗
Crystallization behavior of anorthite
The growth rate of anorthite crystals from the melt is studied as a function of temperature with undercooling in the ranges 52-152 and 402-652 degrees C. The triclinic form is invariably observed as the crystallization product, growth is preferentially in the c direction, and the interface morphology is faceted. Significant growth rate anisotropy is indicated. The maximum growth rate of anorthite from the melt is higher than for anorthite-rich lunar compositions. Recent computer studies are combined with experimental data to estimate the heat of fusion of anorthite as 28000-45000 cal/mol; the corresponding range for entropy of fusion is (7.8-12)R (where R is the gas constant). The observations and kinetic data support Jackson's predictions concerning materials with large entropies of fusion and his suggestion that entropy of fusion is an important parameter for characterizing the crystal-liquid interface and the nature of the crystallization process.
Klein, L.↗
The kinetics of lunar glass formation, revisited
The nucleation frequency of Lunar Composition 70019, a lithified soil breccia from the center of a small crater in the Taurus-Littrow Valley, is determined using a relation that describes nucleation throughout the volume of a liquid together with measurements of the time required at temperatures of 780 to 930 C to obtain sensibly crystalline bodies. Curves indicating the time required at a given temperature to reach a particular fraction crystallized are shown to have the general form predicted by kinetic analysis. Nucleation frequencies are evaluated by applying such analysis to a curve representing the transition between glassy material and material with a sensible degree of crystallinity. The results obtained are found to be in excellent agreement with the values expected from the classical theory of homogeneous nucleation, indicating that such nucleation represents the dominant contribution to crystal formation, at least over the range of undercoolings covered (250 to 400 C).
Klein, L. C.↗
Planetary gamma-ray spectroscopy
The measured intensities of certain gamma rays of specific energies escaping from a planetary surface can be used to determine the abundances of a number of elements. The fluxes of the more intense gamma-ray lines emitted from 32 elements were calculated using current nuclear data and existing models for the source processes. The source strengths for neutron-capture reactions were modified from those previously used. The fluxes emitted form a surface of average lunar composition are reported for 292 gamma-ray lines. These theoretical fluxes were used elsewhere to convert the data from the Apollo gamma-ray spectrometers to elemental abundances and can be used with measurements from future missions to map the concentrations of a number of elements over a planet's surface. Detection sensitivities for these elements are examined and applications of gamma-ray spectroscopy for future orbiters to Mars and other solar-system objects are discussed.
Reedy, R. C.↗
Evolution of the moon between 4.6 and 3.3 AE
A model of lunar evolution is proposed. At 4.6 AE an outer shell 60-100 km thick of an initially homogeneous moon was totally molten following accretion. 'Highland basalt' represents remnants of the chilled crust of this molten layer and, therefore, the mean lunar composition. Melt from the partially molten region below the outer shell intruded into it, enriching it in FeO, SiO2, radiogenic, and trivalent trace LIL (large ion lithop) elements. Fractional crystallization of the outer shell produced toward its base a mafic cumulate zone less than 40 km thick, the upper 60 km being anorthosite. The radiogenic elements concentrated together with dense residual melt in the upper parts pf the mafic cumulate zone. Between 4.6 and 4.3 AE a second differentiation led to localized enrichment from below of radiogenic elements in the plagioclase-rich, high-Mg/Mg + Fe residuum below the outer 100-km-thick shell. Melting at these enriched sites at about 4.0 AE produced to KREEP basalts. Later melting at sites of radiogenic element enrichment in the outer 100-km-thick shell produced the mare basalts.
Hollister, L. S.↗
Crystallization of a lunar magma ocean
The results of applying the presently most detailed thermal model to the cooling, crystallization and differentiation of a lunar magma ocean are used to delineate its general features, i.e., those features that are model independent within reasonable variations in ocean characteristics. Two primitive lunar compositions are used to illustrate the effect of different compositions and phase equilibria on the solidification time and mineralogy of magma oceans. The magma ocean thermal model led to some inferences about the thermal evolution of the outer portion of the moon modeled as isolated magma pods rather than as a magma ocean.
Minear, J. W.↗
Planetary gamma-ray spectroscopy
The measured intensities of certain gamma rays of specific energies escaping from a planetary surface can be used to determine the abundances of a number of elements. The fluxes of the more intense gamma ray lines emitted from 32 elements have been calculated using current nuclear data and existing models for the source processes. The fluxes emitted from a surface of average lunar composition are reported for 292 gamma ray lines. Detection sensitivities for various elements are examined and applications of gamma ray spectroscopy for future orbiters to Mars and other solar system objects are discussed.
Reedy, R. C.↗
Contribution of the mantle to the lunar asymmetry
Evidence of three kinds indicates a lunar compositional asymmetry: mare basalts are much more abundant on the near side; the incompatible rich KREEP component is mainly observed in near-side soils; and materials on the far side are less dense than those of the near side, as indicated by the 2-km offset between the center of mass and center of figure. Recent models to explain the 2-km offset are based on near side-far side differences in the thickness of crustal units. The most widely discussed model calls for a thickness of anorthosite of about 24 km greater on the far side than on the near side, but no satisfactory method of generating such a large difference has been proposed. It is suggested that much of the offset reflects longitudinal differences in mantle composition, primarily resulting from earlier (or more rapid) crystallization of the magma ocean on what is not the far-side hemisphere. As a result, the far-side mantle would be more magnesian and thus less dense than the near-side mantle.
Wasson, J. T.↗
On the barrier to crystal nucleation in lunar glasses
The paper describes an analytical method for calculating in detail the size distributions of small crystallites and nuclei in supercooled liquids as they are being quenched to form a glass and subsequently reheated above the glass transition to produce crystallization. This method is applied to experiments performed using differential thermal analysis (DTA) to estimate the barriers to crystal nucleation and the cooling rates required to form glasses or bodies with various degrees of crystallinity. DTA data and derived nucleation barriers are reported for anorthite and for the following lunar compositions: 15498, 15418, matrix and intrusion compositions of breccia 15286, Apollo 15 green glass, Luna 24 highland basalt, and 65016.
Yinnon, H.↗
Analytic expression for epithermal neutron spectra amplitudes as a function of water content
The epithermal portion of an equilibrium neutron spectrum in a planetary body is a function of the water content of its material. The neutrons are produced at high energies but are moderated by elastic and inelastic scattering until they either are captured by surrounding nuclei or escape. We have derived an expression that explicitly shows the dependance of epithermal neutron spectra on water content. Additionally, we compared its predictions to calculations done by Boltzman transport code for infinite media for silicon, oxygen, and a possible lunar composition, and we have obtained very good agreement.
Drake, Darrell↗
International Lunar Network (ILN) Anchor Nodes
This slide presentation reviews the United States' contribution to the International Lunar Network (ILN) project, the Anchor Nodes project. The ILN is an initiative of 9 national space agencies to establish a set of robotic geophysical monitoring stations on the surface of the Moon. The project is aimed at furthering the understanding of the lunar composition, and interior structure.
Cohen, Barbara A.↗
Experimental Fractional Crystallization of the Lunar Magma Ocean
The current paradigm for lunar evolution is of crystallization of a global scale magma ocean, giving rise to the anorthositic crust and mafic cumulate interior. It is thought that all other lunar rocks have arisen from this differentiated interior. However, until recently this paradigm has remained untested experimentally. Presented here are the first experimental results of fractional crystallization of a Lunar Magma Ocean (LMO) using the Taylor Whole Moon (TWM) bulk lunar composition [1].
Rapp, J. F.↗
Experimental Study into the Partitioning Behavior of Fluorine, Chlorine, Hydroxyl, and Sulfur (S2-) Between Apatite and a Synthetic Kreep Basalt Melt
The mineral apatite (Ca5 (PO4)3(F, Cl, OH)) is known for its ability to constrain the petrogenesis of the rock in which it is hosted and for its ubiquity throughout the Solar System, as it is found in lunar, martian, and terrestrial rocks alike (McCubbin et. al, 2015). The abundance of volatile elements, and for this particular study, the elevated abundance of sulfur (S2-) in high-Al basalt samples bearing apatite, could provide more insight for inquiries posed about the behavior of volatiles in lunar and martian magmatic systems (Boyce et. al, 2010). Oxygen fugacity will be an important parameter for these experiments, as the Moon, Mars, and Earth have different redox states (Herd, 2008). The objective of this experimental endeavor is to determine apatite-melt partition coefficients for the volatile elements (F-, Cl-, OH-, S2-) that make up the X-site (i.e., the typically monovalent anion site) in the mineral apatite in a lunar melt composition under lunar oxygen fugacity conditions approx.1-2 log units below the iron-wüstite buffer). All experiments will be conducted at NASA, Johnson Space Center in the High Pressure Experimental Petrology Laboratory. In order to conduct apatite-melt partition experiments with oxygen fugacity as an additional parameter, we will create a synthetic mix of the lunar KREEP basalt 15386, a sample retrieved during Apollo 15 that is believed to represent an indigenous volcanic melt derived from the lunar interior (Rhodes, J.M et. al, 2006). Other geochemically significant elements including C, Co, Ni, Mo, and rare earth elements will be included in the mix at trace abundances in order to assess their partitioning behavior without effecting the overall behavior of the system. The synthetic mix will then be loaded into a piston cylinder, an apparatus used to simulate high-pressure/high-temperature conditions of planetary interiors, and exposed to 0.5 GPa of pressure, the pressure observed in the upper mantle of the Moon, and heated to the melting temperature of the materials. To make sure crystals grow large enough for the necessary analyses, the sample will be kept at the crystallization temperature for 8 hours. This extended run time should also allow the sample to achieve a steady state which is necessary to accurately assess the partitioning of these elements between apatite and melt. The results from this experimental study will allow us to determine the fate of F-, Cl-, OH-, and S2- during the magmatic evolution of the Moon.
Turner, Amber↗
Compositional analysis of lunar and planetary surfaces using neutron capture gamma rays, 1 October - 31 December 1969
Design of experiment for compositional analysis of lunar and planetary surfaces using neutron analytical techniques
Mandler, J. W.↗