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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.

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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Lunar mascon basins - Lava filling, tectonics, and evolution of the lithosphere

The paper extends the study of the relationships among lunar mare filling, mare basin tectonics, and global thermal evolution to the major mascon maria: Imbrium, Crisium, Orientale, Humorum, Nectaris, Smythii, Grimaldi, and Serenitatis. For each of the eight major mascon mare basins on the moon, the paper describes the distribution and history of major mare units, the characteristics and geometry of basin-related tectonic features, the temporal relations between tectonic features and geologic units, the response of the lunar lithosphere to basalt loading as a function of space and time, and the relationship between loading stress and global thermal stress in controlling lunar tectonic history. The principal features of the volcanic, tectonic, and thermal history of the mascon maria are summarized.

Solomon, S. C.↗
NASA NTRS1979

Petrogenesis of Luna 16 aluminous mare basalts

Bulk compositions, petrology and mineralogy of Luna 16 aluminous mare basalt particles of less than 0.5 mm are described. The data rule out any close genetic relationships between Luna 16 and other major types of lunar mare basalts. Compared to high-Ti mare basalts, the Luna 16 basalts contain lower TiO2 and Ta and higher Al2O3 and REE abundances, suggesting that the Luna 16 source rocks crystallized later than (i.e. stratigraphically above) the ilmenite-bearing high-Ti basalt cumulate source rocks. The REE pattern for the Luna 16 basalts requires that the source material from which they were derived crystallized from a light REE enriched magma.

Ma, M.-S.↗
NASA NTRS1990

Proceedings of a workshop on Lunar Volcanic Glasses: Scientific and Resource Potential

This workshop on lunar mare volcanism was the first since 1975 to deal with the major scientific advances that have occurred in this general subject, and the first ever to deal specifically with volcanic glasses. Lunar volcanic glasses are increasingly being recognized as the best geochemical and petrologic probes into the lunar mantle. Lunar volcanic glasses, of which 25 compositional varieties are presently known, appear to represent primary magmas that were produced by partial melting of differentiated mantle source regions at depths of perhaps 400 to 500 km. These high-magnesian picritic magmas were erupted onto the lunar surface in fire fountains associated with the release of indigenous lunar volatiles. The cosmic significance of this volatile component, in an otherwise depleted Moon, remains a lingering puzzle. The resource potential, if any, of the surface-correlated volatile sublimates on the volcanic glass spherules had not been systematically addressed prior to this workshop.

Delano, John W.↗
NASA NTRS1992

Determination of lunar ilmenite abundance from remotely sensed data

Of fundamental importance in the utilization of indigenous resources for a future permanently manned lunar base is the identification and mapping of the abundance distribution of the mineral ilmenite, which is currently considered the most readily identifiable and most easily accessible source of oxygen needed for human consumables and spacecraft propellant. Solid state detector array technology now permits the use of ground based multispectral remote sensing techniques to produce maps with better than one kilometer spatial resolution and uncertainties of about two weight-percent TiO2 abundance. An empirical relationship between the weight-percent abundance of titanium dioxide and the 400/560 nm spectral ratio measured in returned lunar samples was used. Because this abundance correlation is valid only for mature lunar mare regolith, the distribution of immature mafic minerals which were found to be correlated primarily with steep slopes exposing bedrock was qualitatively mapped. The first mapping phase focused on the entire lunar nearside at 5.3 km per pixel, and on experiments with more sensitive spectral ratios. Relative spectrophotometry was employed to aid in identifying wavelengths that provide greater spectral contrast. It was found that the 400/730 nm ratio improved the abundance sensitivity by 37 percent, while the 950/730 nm ratio improved mafic mineral contrast about 100 percent. The second mapping phase utilized a large experimental CCD at 280 m per pixel to map the high titanium regions identified in the phase one mapping. The high resolution maps provide data on the small scale (500 m) variations in abundance and their relationship to morphological units.

Larson, S. M.↗
NASA NTRS2004

Lunar and Planetary Science XXXV: Moon and Mercury

The session" Moon and Mercury" included the following reports:Helium Production of Prompt Neutrinos on the Moon; Vapor Deposition and Solar Wind Implantation on Lunar Soil-Grain Surfaces as Comparable Processes; A New Lunar Geologic Mapping Program; Physical Backgrounds to Measure Instantaneous Spin Components of Terrestrial Planets from Earth with Arcsecond Accuracy; Preliminary Findings of a Study of the Lunar Global Megaregolith; Maps Characterizing the Lunar Regolith Maturity; Probable Model of Anomalies in the Polar Regions of Mercury; Parameters of the Maximum of Positive Polarization of the Moon; Database Structure Development for Space Surveying Results by Moon -Zond Program; CM2-type Micrometeoritic Lunar Winds During the Late Heavy Bombardment; A Comparison of Textural and Chemical Features of Spinel Within Lunar Mare Basalts; The Reiner Gamma Formation as Characterized by Earth-based Photometry at Large Phase Angles; The Significance of the Geometries of Linear Graben for the Widths of Shallow Dike Intrusions on the Moon; Lunar Prospector Data, Surface Roughness and IR Thermal Emission of the Moon; The Influence of a Magma Ocean on the Lunar Global Stress Field Due to Tidal Interaction Between the Earth and Moon; Variations of the Mercurian Photometric Relief; A Model of Positive Polarization of Regolith; Ground Truth and Lunar Global Thorium Map Calibration: Are We There Yet?;and Space Weathering of Apollo 16 Sample 62255: Lunar Rocks as Witness Plates for Deciphering Regolith Formation Processes.

Source record↗
NASA NTRS1982

A preliminary analysis of lunar extra-mare basalts - Distribution, compositions, ages, volumes, and eruption styles

Extra-mare basalts occupy 8.5% of the lunar basalt area and comprise 1% of the total mare basalt volume. They are preferentially located where the crust is thin and topographically low. In terms of age, eruption style, and composition they are as variable as the mare basalts. In some instances extrusion in extra-mare craters was preceded by floor-fracturing whereas in other cases it apparently was not. The volume of lava erupted may have been controlled more by the volume of magma produced than by hydrostatic effects. A minimum of nearly 1300 separate basalt eruptions is indicated; the true value could be nearer 30,000 separate eruptions.

Whitford-Stark, J. L.↗
NASA NTRS1984

Morphology of buried craters: Lava thickness estimates by simulated flooding

Partially and completely buried craters on planetary surfaces are used as probes to determine the thickness and extent of the overlying material as well as the composition of underlying terrain units. Rims of craters protruding through mare basalts on the Moon have been used extensively by DeHon (1977, 1979) to develop isopach maps of both the circular and irregular maria. Such estimates are possible because of Apollo topographic data and the extensive coverage by Lunar Orbiter photographs at various sun angles. On planetary surfaces without such data, however, shadow measurements can only be made by pixel listings with appropriate assumptions concerning support data. In addition, high resolution geochemical data is not available to determine whether the exposed crater rim is composed of material dissimilar from the lavas. Because of the need for lava thickness data, flooding of lunar mare and highland craters was simulated in order to determine empirical relationships between dimensions observed in orbital images and the thickness of the lava.

Maxwell, T. A.↗
NASA NTRSDate not supplied

Thermochemical Interactions of Yttria-Stabilized Zirconia and Molten Lunar Regolith Simulants

Oxygen produced from lunar resources through in-situ resource utilization (ISRU) is critical to maintaining a permanent human presence on the lunar surface. Molten regolith electrolysis and carbothermal reduction are two promising ISRU techniques for generating oxygen directly from lunar regolith, which is primarily a mixture of oxide minerals; however, both processes require operating temperatures of 1600C to melt lunar regolith and dissociate the molten oxides. These conditions limit the use of many oxide refractory materials, such as Al2O3 and MgO, due to rapid degradation resulting from reactions between the refractory materials and molten lunar regolith. Yttria-stabilized zirconia (YSZ) is a promising refractory oxide to provide containment of molten regolith while demonstrating limited reactivity. This work focuses on corrosion studies of YSZ powders and dense YSZ crucibles in contact with molten lunar mare and highlands regolith simulants at 1600C. The interactions between YSZ and molten regolith are characterized using SEM/EDS, XRD, and EBSD with an emphasis on elemental and microstructural analysis to assess reactivity and degradation of YSZ. Due to lunar regolith’s similar composition to calcium-magnesium-aluminosilicates (CMAS) and YSZ’s usage as a thermal barrier coating, these interactions can serve to inform YSZ/CMAS behavior by simulating cases of elevated CMAS/YSZ ratios and for higher than intended gas turbine temperatures.

Kevin Yu↗
NASA NTRS2005

DEVELOPMENT OF STANDARDIZED LUNAR REGOLITH SIMULANT MATERIALS

Lunar exploration activities require scientific and engineering studies that use standardized testing procedures and ultimately support flight certification of hardware and the development of technologies for their use on the lunar surface. It is necessary to anticipate the full range of source materials and environmental constraints that are expected on the Moon and Mars, and to evaluate in-situ resource utilization (ISRU) coupled with testing and development. Historical use of lunar simulants has focused on physical aspects of the lunar regolith for landing and transportation activities. Lunar mare simulants MLS-1 and JSC-1 have been developed, but supplies have been exhausted. Renewed emphasis on exploration and ISRU activities requires development of standardized simulant reference materials that are traceable interlaboratory standards for testing and simulate the lunar regolith in terms of physical, chemical, and mineralogical properties. This new generation of lunar regolith simulants must therefore support both technological development and testing methods. These issues were extensively discussed at the 2005 Lunar Regolith Simulant Materials Workshop.

Carpenter, P.↗
NASA NTRS2010

Measurement of the Solar Absorptance and Thermal Emittance of Lunar Simulants

The first comparative study of the reflectance spectra of lunar simulants is presented. All of the simulants except one had a wavelength-dependent reflectivity, rho(lambda), near 0.10 over the wavelength range of 8 to 25 microns, so they are highly emitting at room temperature and lower. The 300 K emittance, epsilon, of all the lunar simulants except one ranged from 0.884 to 0.906. The 300 K epsilon of JSC Mars-1 simulant was 0.927. There was considerably more variation in the lunar simulant reflectance in the solar spectral range (250 to 2500 nm) than in the thermal infrared. Larger particle size simulants reflected much less than those with smaller particle size. As expected, the lunar highlands simulants were more reflective in this wavelength range than the lunar mare simulants. The alpha of the simulants ranged from 0.413 to 0.817 for those with smaller particles and 0.669 to 0.906 for large particles. Although spectral differences were observed, the total integrated alpha for the simulants appears to be similar to that of lunar soils (0.65 to 0.88). These data are now available to be used in modeling the effects of dust on thermal control surfaces.

Gaier, James R.↗
NASA NTRS2010

Measurement of the Solar Absorptance and Thermal Emittance of Lunar Simulants

The first comparative study of the reflectance spectra of lunar simulants is presented. All of the simulants except one had a wavelength-dependant reflectivity ( ( )) near 0.10 over the wavelength range of 8 to 25 m, so they are highly emitting at room temperature and lower. The 300 K emittance ( ) of all the lunar simulants except one ranged from 0.884 to 0.906. The 300 K of JSC Mars-1 simulant was 0.927. There was considerably more variation in the lunar simulant reflectance in the solar spectral range (250 to 2500 nm) than in the thermal infrared. Larger particle size simulants reflected much less than those with smaller particle size. As expected, the lunar highlands simulants were more reflective in this wavelength range than the lunar mare simulants. The integrated solar absorptance ( ) of the simulants ranged from 0.413 to 0.817 for those with smaller particles, and 0.669 to 0.906 for those with larger particles. Although spectral differences were observed, the for the simulants appears to be similar to that of lunar soils (0.65 to 0.88). These data are now available to be used in modeling the effects of dust on thermal control surfaces.

Gaier, James R.↗
NASA NTRS2001

Using Remotely Sensed Observations of Ancient Mare Deposits on the Moon as Possible Analogs to the Intercrater Plains on Mercury

Two commonly held models for the formation of the mercurian intercrater plains are: a global volcanic resurfacing event or basin-ejecta material. Although Mariner 10 images have provided morphologic and limited compositional information of the intercrater plains, the origin of these materials remains ambiguous. We examine whether Mariner 10 image at 355 (UV (ultraviolet)) and 575 nm (orange) can be used to distinguish between these models. Here we use Clementine image data (415 and 750 nm) for ancient lunar mare deposits to evaluate this suggestion. The inventorying of 'hidden' volcanic deposits is important to mercurian studies because they provide evidence of ancient volcanism, which yields clues to the thermal evolution of the planet. The greater abundance of intercrater plains on Mercury, relative to the intercrater plains observed within the lunar highlands, suggests that the resurfacing was comparably more intense. Mercury may represent an intermediate member of planet resurfacing; with the extremes being the Moon (approximately 17% resurfacing) and Venus (global resurfacing). Additional information is contained in the original extended abstract.

Gillis, J. J.↗
NASA NTRS1985

Hadley Rille, lava tubes and mare volcanism at the Apollo 15 site

Hadley Rille appears to be a collapsed lava tube/channel, whose formation history may be more intimately related to the mare units sampled at 15 than was previously thought. More work is needed relating samples and observations from Apollo 15 to the rille and its geologic evolution. As the only sinuous rille visited during the Apollo missions, Hadley Rille represents a data source that is directly applicable to the deciphering of processes involved in lunar mare volcanism.

Greeley, R.↗
NASA NTRS2026

High Temperature Dielectric Properties and Differential Scanning Calorimetry of Lunar Simulants

To guide development of microwave process technology that could be used during in situ construction on the Moon, we measured the high-temperature basic dielectric properties (εʹ and εʺ) of 17 lunar simulants and related materials. In order to confidently use these data one needs to understand the data’s strengths and weaknesses. Therefore, a goal of this publication is to provide insights into the comparative effects of sample composition, pre-treatments, experimental variables, high temperatures, and other factors on the measured response. The dielectric measurements were performed using the cavity perturbation method over a temperature range between room temperature to 1000 °C, or higher, and provided the real and imaginary components of permittivity at six frequencies. The utility of the original values was limited by the varying density of the pellets used in the measurement. Therefore, all of the εʹ and εʺ measurements at the frequency of 2466 MHz have been scaled to a constant density, 1.75 g/cm 3 . Here the data are presented as graphs chosen to aid analysis within and across simulant groups. To gain additional insight into the processes happening at the elevated temperatures in the dielectric measurements, heat capacity data was obtained using differential scanning calorimetry (DSC) on several of the simulant materials. Our data show that over the frequency range 397 MHz – 2985 MHz a material’s behavior does not greatly change, as compared to the scale of differences observed between lunar mare and highland simulants at high temperatures. For example at 1000 °C, the mare simulant JSC-1A absorbs 10 times more power than the highland simulant NUW-LHT-5M. We observe that as melting temperatures are reached both permittivity and dielectric loss rise non-linearly, helping to explain thermal runaway during microware heating. Our data show that even less than a few weight % of many non-lunar minerals, and the use of mixtures in simulants can affect the dielectric behavior at higher temperatures. A comparison of our results with published dielectric data for Apollo samples and with remote sensing of the Moon supports the conclusion the simulants and lunar material at room temperature have very similar dielectric values.

Differential Scanning Calorimetry↗
NASA NTRS1981

Ridge systems of Mars

Mare-type ridges on the Planet Mars were mapped and described based on Viking images. The ridges mapped range from 5 to 400 km long and 1 to 8 km wide. Most ridges on Mars are on plains and plateau units; 4,321 ridges with a total length of 153,835 km were mapped on these unit types. Ridges which resemble lunar mare ridges were also mapped in craters, basins, and several volcanic calderas on Mars. Mapping of ridges on a global scale reveals that they are preferentially developed in older, thinner plains units probably of flood basalt origin. Measuring the trends of ridges in plains units on Mars shows that there is a planetwide predominance of north, northwest and northeast trends. It is proposed that ridges are compressional tectonic features which have formed in response to changes in the planet's rotational equilibrium figure early in its history. In addition, the Tharsis uplift has created a regional stress system which accounts for the trends of ridges in areas near by. Ridges in craters and basins are similarly caused by shortening across the basin in response to regional stresses.

Gifford, A. W.↗
NASA NTRS1993

Potassium isotope cosmochemistry, volatile depletion and the origin of the Earth

We report the first results obtained by our techniques for the precise and accurate determination of the isotopic composition of potassium to constrain the mechanism of volatile element depletion in the formation of the Earth, Moon, and meteorites. Our measurements of delta(K-41) for six chondrites and ten terrestrial rocks attained an average precision of the individual measurement of plus or minus 0.4 percent (2 sigma; plus or minus 0.2 percent/a.m.u. and yield a net chondrite-Earth difference unresolved at the 99 percent confidence limit, delta(K-41) = 0.32 plus or minus 0.35 percent (3 delta). This sets a firm upper limit of 1.3 plus or minus 1.4 percent Rayleigh evaporation of terrestrial potassium (using alpha = square root of 41/39), compared with an observed approximately equals 85 percent chemical depletion of K relative to C1 chondrites. Similar conclusions are reached for the SNC meteorites, Shergotty and Zagami, for 15495 (lunar mare gabbro), and for the eucrite Juvinas. Our conclusion is that direct evaporation of volatile elements from planets (e.g. from silicate vapor atmospheres following giant impact) can be ruled out, and the cause of volatile loss must be sought elsewhere, e.g. nebular processes. Our present findings do not support the conclusions of Hinton et al., the discrepancy to be resolved at a later date. We also find lunar soil 64801, delta(K-41) = +4.99 plus or minus 0.53 percent, to be distinctly heavy in accord with Garner et al.

Humayun, M.↗