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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Primordial Pb, radiogenic Pb and lunar soil maturation

Pb-204 is directly correlated with the reduced Fe measured by ferromagnetic resonance. A similar correlation has been noted for hydrolyzable carbon (Pillinger et al., 1974). An enrichment of these elements appears to have occurred during soil maturation. In contrast to Pb-204, radiogenic Pb is reported to be lost during soil maturation (Church et al., 1976). Radiogenic Pb is present in mineral grains and may be lost by solar wind sputtering (or volatilization) and not resupplied. Pb-204 coating grain surfaces acts as a reservoir to provide the Pb-204 being extracted in the reduced Fe formation process. Venting or some other volatile release mechanism may replenish the surface-related Pb-204.

Reed, G. W., Jr.↗
NASA NTRS1979

Microwave dielectric measurements of lunar soil with a coaxial line resonator method

A method is given for sensitive dielectric measurements at a series of microwave frequencies using a section of coaxial line. The line is used as a 1-port cavity resonator; it resonates when the electrical length of the center conductor equals 1, 2 . . . , N half-wave lengths. The dielectric properties of an Apollo 17 dried soil sample were measured in vacuum over a temperature range of 173 to 373 K. The relative permittivity and the loss tangent were determined and the frequency dependence was very small. The derivative with respect to temperature, per degree, was 0.00045 for the permittivity and 0.00002 for the loss tangent.

Bussey, H. E.↗
NASA NTRS1991

Electrolysis of lunar soil to produce oxygen and metals

The discussion of melt electrolysis consists of three sections. The implications of the chemistry and physics of fluxed and raw melts on melt electrolysis are discussed first. This includes discussion of the factor that influence melt resistivity, melt viscosity, oxygen production efficiency, and the theoretical energy required to produce oxygen. Second, the implications of phase equilibria and solubilities in silicate melts on the selection of materials for container and electrodes are discussed. The implications of proposed container and electrode materials on melt composition and how this effects expected resistivities, viscosities, as outlined in the first section are discussed. Finally, a general discussion of the basic features of both the fluxed and unfluxed melt electrolysis is given, including their advantages and disadvantages and how they compare with alternative processes.

Colson, Russell O.↗
NASA NTRS1991

Apollo 14 glasses and the origin of lunar soils

Electron microprobe for comparison with soil glass data were used to analyze homogeneous and heterogeneous glass clasts in four Apollo 14 regolith breccias (14042, 14301, 14313, and 14315). Glass types in the Apollo 14 samples were found to be dominated by highland compositions, which include KREEP, LKFM and highland basalt varieties. Only 14042 has a highland glass population similar to those of local Apollo 14 soils. Breccia 14301 stands out in that it is enriched in KREEP glasses with high K2O content, which are similar in composition to Apollo 12 ropy glasses. Only 14042 could be made from local present-day soils. Some of the ancient soils did not undergo breccia formation and closure, and they evolved by meteorite impact processing, by mixing together in various proportions, and by changes made by the addition of lithic fragments and other components. It is suggested that the Apollo 14 soils are made from mixtures of comminuted regolith breccias. A likely age sequence is presented.

Wentworth, S. J.↗
NASA NTRS2008

Percussive Excavation of Lunar Soil

It has been suggested using a percussive motion could improve the efficiency of excavation by up to 90%. If this is proven to be true it would be very beneficial to excavation projects on the Moon and Mars. The purpose of this study is to design, build and test a percussive tool which could dig a trench and then compare this data against that of a non-percussive tool of the same shape and size. The results of this test thus far have been inconclusive due to malfunctions in the testbed and percussive bucket; however, experimental results from small scale experiments confirm this higher efficiency and support further testing.

Whittaker, Matthew P.↗
NASA NTRS2010

Understanding the Reactivity of Lunar Dust for Future Lunar Missions

Fluorescence and EPR can be used to measure the reactivity of lunar soil. Lunar soil is highly activated by grinding. Reactivity is dependent upon soil maturity and locale. Maturity is based on the amount of nanophase iron (np-Fe) in a soil relative to the total iron (FeO). Lunar soil activity ia a direct function of the amount of np-Fe present. Reactive soil can be "deactivated" by humid atmosphere.

Wallace, W. T.↗
NASA NTRS2014

Plume Mitigation: Soil Erosion and Lunar Prospecting Sensor Project

Demonstrate feasibility of the simplest, lowest-mass method of measuring density of a cloud of lunar soil ejected by rocket exhaust, using new math techniques with a small baseline laser/camera system. Focus is on exploring the erosion process that occurs when the exhaust plume of a lunar rocket impacts the regolith. Also, predicting the behavior of the lunar soil that would be blasted from a lunar landing/launch site shall assist in better design and protection of any future lunar settlement from scouring of structures and equipment. NASA is gathering experimental data to improve soil erosion models and understand how lunar particles enter the plume flow.

TechPort↗
NASA NTRS1993

Twenty-Fourth Lunar and Planetary Science Conference. Part 3: N-Z

Papers from the conference are presented, and the topics covered include the following: planetary geology, meteorites, planetary composition, meteoritic composition, planetary craters, lunar craters, meteorite craters, petrology, petrography, volcanology, planetary crusts, geochronology, geomorphism, mineralogy, lithology, planetary atmospheres, impact melts, K-T Boundary Layer, volcanoes, planetary evolution, tectonics, planetary mapping, asteroids, comets, lunar soil, lunar rocks, lunar geology, metamorphism, chemical composition, meteorite craters, planetary mantles, and space exploration.

Source record↗
NASA NTRS1994

The Twenty-Fifth Lunar and Planetary Science Conference. Part 1: A-G

Papers from the conference are presented, and the topics covered include the following: planetary geology, meteorites, planetary composition, meteoritic composition, planetary craters, lunar craters, meteorite craters, petrology, petrography, volcanology, planetary crusts, geochronology, geomorphism, mineralogy, lithology, planetary atmospheres, impact melts, volcanoes, planetary evolution, tectonics, planetary mapping, asteroids, comets, lunar soil, lunar rocks, lunar geology, metamorphism, chemical composition, meteorite craters, and planetary mantles.

Source record↗
NASA NTRS2005

A New Model of Size-graded Soil Veneer on the Lunar Surface

Introduction. We propose a new model of distribution of submillimeter sized lunar soil grains on the lunar surface. We propose that in the uppermost millimeter or two of the lunar surface, soil-grains are size graded with the finest nanoscale dust on top and larger micron-scale particles below. This standard state is perturbed by ejecta deposition of larger grains at the lunar surface, which have a coating of dusty layer that may not have substrates of intermediate sizes. Distribution of solar wind elements (SWE), agglutinates, vapor deposited nanophase Fe0 in size fractions of lunar soils and ir spectra of size fractions of lunar soils are compatible with this model. A direct test of this model requires bringing back glue-impregnated tubes of lunar soil samples to be dissected and examined on Earth.

Basu, Abhijit↗
NASA NTRS1971

Cracking of lunar mare soil.

Demonstration that lunar soil deforms and cracks in the same manner as homogeneous isotropic terrestrial soil s of moderate bulk density with a small amount of cohesion. This conclusion is made from an analysis of Surveyor 3 TV pictures and of Apollo 11 closeup picture of lunar surface disturbances by bearing tests and instrument pressure.

Jaffe, L. D.↗
NASA NTRS2007

Granular Mechanics and Surface Systems Lab

The cratering of sand under gas jets is observed to further understanding of soil in hopes to further understand lunar soil. Lunar soil is important to understand because it is causing problems with the materials taken into space including the shuttle. Lunar soil is not rounded like beach sand. Lunar soil is sharp like little particles of glass, and some times when blown they can hook on to one another and become bigger particles. The experiments are designed to help to understand some of the basic physics in how the shuttle jets will interact with lunar soil and how to control the lunar soil. These experiments investigate the diameter of the gas jet and the size of the sand grains to determine how these parameters affect the erosion rate and the cratering processes. Therefore, the experiments preformed will point out what is dependent and what is independent.

Randle, Leah↗
NASA NTRS2004

Vapor Deposition and Solar Wind Implantation on Lunar Soil-Grain Surfaces as Comparable Processes

Vapor deposited patinas (VDP) on lunar soil grains consist of a thin (less than 1 micron) layer of amorphous silicate (glass) embedded with nanoscale Fe(sup 0) globules as seen in many TEM images. VDPs are also present on larger space-weathered lunar rocks; these larger samples will not be discussed here although the process of vapor deposition is common to exposed grains of all sizes. Whether or not the majority of the Fe(sup 0) globules present in lunar soils reside in vapor deposited patina is a matter of some concern. Some Fe(sup 0) globules are clearly seen to reside within the glass of agglutinates and might represent remobilized Fe(sup 0) in agglutinitic melts. remobilized Fe(sup 0) in agglutinitic melts. We argue that because VDP coatings are present only on the surfaces of lunar soil grains, their distribution as a surface correlated component (SCC) of lunar soils should parallel those of Solar Wind Elements (SWE) implanted in the outermost rinds of lunar soil grains. SWE residing in the interior of soils grains make up the volume correlated component (VCC). Relative to Fe(sup 0) in VDP, the distribution of various SWE have been studied well. The reason is understandable because instrumentation for nanoscale imaging is not ubiquitous. In this study we use the distribution of SWE in lunar soils as a guide to understanding the fate of Fe(sup 0) in VDP.

Basu, A.↗