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At least 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
NASA NTRS1998

Mineral Mapping with Imaging Spectroscopy: The Ray Mine, AZ

Mineral maps generated for the Ray Mine, Arizona were analyzed to determine if imaging spectroscopy can provide accurate information for environmental management of active and abandoned mine regions. The Ray Mine, owned by the ASARCO Corporation, covers an area of 5700 acres and is situated in Pinal County, Arizona about 70 miles north of Tucson near Hayden, Arizona. This open-pit mine has been a major source of copper since 1911, producing an estimated 4.5 million tons of copper since its inception. Until 1955 mining was accomplished by underground block caving and shrinkage stope methods. (excavation by working in stepped series usually employed in a vertical or steeply inclined orebody) In 1955, the mine was completely converted to open pit method mining with the bulk of the production from sulfide ore using recovery by concentrating and smelting. Beginning in 1969 a significant production contribution has been from the leaching and solvent extraction-electrowinnowing method of silicate and oxide ores. Published reserves in the deposit as of 1992 are 1.1 billion tons at 0.6 percent copper. The Environmental Protection Agency, in conjunction with ASARCO, and NASA/JPL obtained AVIRIS data over the mine in 1997 as part of the EPA Advanced Measurement Initiative (AMI) (Tom Mace, Principal Investigator). This AVIRIS data set is being used to compare and contrast the accuracy and environmental monitoring capabilities of remote sensing technologies: visible-near-IR imaging spectroscopy, multispectral visible and, near-IR sensors, thermal instruments, and radar platforms. The goal of this effort is to determine if these various technologies provide useful information for envirorunental management of active and abandoned mine sites in the arid western United States. This paper focuses on the analysis of AVIRIS data for assessing the impact of the Ray Mine on Mineral Creek. Mineral Creek flows to the Gila River. This paper discusses our preliminary AVIRIS mineral mapping and environmental findings.

Clark, Roger N.↗
NASA NTRS1999

Slate Islands, Lake Superior, Canada: A mid-size, Complex Impact Structure

The target rocks of the 30-32-km diameter Slate Islands impact structure in northern Lake Superior, Canada, are Archean supracrustal and igneous rocks and supracrustal Proterozoic rocks. Shatter cones, pseudotachylites, impact glasses, and microscopic shock metamorphic features were formed during the contact and compression phase of the impact process, followed, during excavation and central uplift, by polymict, clastic matrix breccias in the uplifted target, and by allogenic fall-back breccias (suevite and bunte breccia). Monomict, autoclastic breccias were mainly observed on Mortimer Island and the other outlying islands of the archipelago and were probably generated relatively late in the impact process (central uplift and/or crater modification). The frequency of low index planar shock metamorphic features in quartz was correlated with results from shock experiments to estimate shock pressures experienced by the target rocks. The resulting shock attenuation plan across the archipelago is irregular, probably because the shock wave did not expand from a point or spherical source, and because of the destruction of an originally more regular shock attenuation plan during the central uplift and crater modification stages of the impact process. No impact melt rock bodies have been positively identified on the islands. An impact melt may be present in the annular trough around the islands, though and-based on a weighted mixture of target rocks-may have an intermediate-mafic composition. No such impact melt was found on the archipelago. An Ar-40-Ar-39 release spectrum of a pseudotachylite provides an age of about 436 Ma for the impact structure, substantiating age constraints based on various stratigraphic considerations.

Dressler, B. O.↗
NASA NTRS2000

Thermally Mobile Trace Elements in Carbonaceous Chondrites From Cold and Hot Deserts

Some decades ago, Anders and co-workers used RNAA to classify a number of trace elements as being volatile during nebular condensation and accretion into primitive objects based upon their strong depletion in (equilibrated) ordinary chondrites relative to C1 chondrites. Such elements, e.g. Ag, Bi, Cd, Cs, In, Se, Te, Tl, Zn and others, exhibit nearly constant, C1-normalized atomic abundances in C2 (CM2) and in C3 chondrites. They interpreted the near-constancy of these abundances according to a 2-component model in which volatiles were introduced into carbonaceous (and other) chondrites as C1 material which was diluted with differing proportions of high-temperature (i.e. volatile-free) components. In this view, mean volatile element abundances of 0.48 in C2 and 0.24-0.29 x C1 in C3 chondrites indicated that C2 and C3 chondrites are, respectively, about 1:1 and 1:2-3 mixtures of C1-like and high temperature materials. More recently, Xiao and Lipschutz found that C-normalized abundances of such volatile elements are nearly constant in most C2-6 chondrites (i.e. 25 non-Antarctic meteorites, nearly all falls, and 36 Antarctic finds) consistent with a 2-component mixing model. However, rather than being quantized, mean volatile element contents in each chondrite define a continuum from 0.92-0.14 x C1 for these 61 chondrites. A few carbonaceous chondrites, the first having been the NIPR consortium samples B-7904, Y-82162 and Y-86720, show an altered pattern: many of the volatile elements in each exhibit the usual constancy of C1-normalized atomic abundances, but modified by further depletion of Cd and other elements like Tl and Bi. These are the most mobile trace elements, i.e. those most readily vaporized and lost from primitive meteorites during week-long heating at greater than or equal to 400 C under low ambient pressures (initially 10(exp -5) atm H2), simulating metamorphic conditions in a primitive parent body. Similarities between mobile element data for B-7904, Y-82162 and Y-86720 with those for Murchison heated at 500-700 C, suggest that these Antarctic C1 - and C2-like chondrites were metamorphosed at temperatures like these in the interiors of their parent bodies. Metamorphic temperatures inferred from RNAA data and textural/mineralogic alterations are internally consistent, agreeing., with those evident in heated Murchison samples. These 3 chondrites were also heated late in their histories since all have lost cosmogenic He-3, presumably during close solar approach, and B-7904 and Y-86720 seem also to have lost substantial proportions of radiogenic He-4 and Ar-40 cf. data in. Similarities in spectral reflectance data for C-, G-, B- and F- asteroids, for these meteorites and for heated Murchison samples suggest that thermally metamorphosed interior materials in these asteroids were excavated by impacts and re-deposited on them, forming their present surfaces. Establishment of the thermal metamorphic histories of carbonaceous chondrites, then, is essential to establishing the evolution and present-day nature of C-type and related asteroids.

Lipschutz, M. E.↗
NASA NTRS1999

1999 Marsokhod Field Experiment: A Simulation of a Mars Rover Science Mission

A field experiment to simulate a rover mission to Mars was performed in February 1999. This experiment, the latest in a series of rover field experiments, was designed to demonstrate and validate technologies and investigation strategies for high-science, high-technology performance, and cost-effective planetary rover operations. Objectives: The experiment objectives were to: (1) train scientists in a mission configuration relevant to Surveyor program rover missions at a terrestrial analog field site simulating the criteria of high-priority candidate landing-sites on Mars; (2) develop optimal exploration strategies; (3) evaluate the effectiveness of imaging and spectroscopy in addressing science objectives; (4) assess the value and limitation of descent imaging in supporting rover operations; and (5) evaluate the ability of a science team to correctly interpret the geology of the field site using rover observations. A field site in the California Mojave Desert was chosen for its relevance to the criteria for landing site selection for the Mars Surveyor program. These criteria are: (1) evidence of past water activity; (2) presence of a mechanism to concentrate life; (3) presence of thermal energy sources; (4) evidence of rapid burial; and (5) excavation mechanisms that could expose traces of life.

Stoker, C.↗
NASA NTRS1999

The MSP 2001 Mars Environmental Compatibility Assessment (MECA)

A chemical analysis of soil-water mixtures and the first microscopic images of martian soil will be among the results to be returned by the Mars Environmental Compatibility Assessment (MECA) payload on the Mars Surveyor Program 2001 Lander. Sponsored by the Human Exploration and Development of Space (HEDS) enterprise, MECA's primary goal is to evaluate potential geochemical and environmental hazards that may confront future martian explorers, and to guide HEDS scientists in the development of high fidelity Mars soil simulants. As a survey of soil properties, the MECA data set will also be rich in information relevant to basic geology, paleoclimate, and exobiology. The integrated MECA payload contains a wet-chemistry laboratory, a microscopy station, an electrometer to characterize the electrostatics of the soil and its environment, and arrays of material patches to study the abrasive and adhesive properties of soil grains. MECA is allocated a mass of 10 kg and a peak power usage of 15 W within an enclosure of 35 x 25 x 15 cm. The Wet Chemistry Laboratory (WCL) consists of four identical cells that will accept samples from surface and subsurface regions accessible to the Lander's robotic arm, mix them with water, and perform extensive analysis of the solution. Ion-selective electrodes and related sensors will evaluate total dissolved solids, redox potential, pH, and the concentration of many soluble ions and gases. Cyclic voltammetry will address oxidants, and anodic stripping voltammetry will probe potentially hazardous trace metals. MECA's microscopy station combines optical and atomic-force microscopy (AFM) in a controlled illumination environment to image dust and soil particles from millimeters to nanometers in size. Careful selection of substrates and an abrasion tool allows experimental study of size distribution, adhesion, abrasion, hardness, color, shape, aggregation, magnetic and other properties. Mounted on the end of the robot arm, MECA's electrometer consists of four types of sensors: an electric field meter, several triboelectricity monitors, an ion gauge, and a thermometer. Tempered only by ultra-violet- light-induced ions and a low-voltage break-down threshold, the dry, cold, dusty martian environment presents an imposing electrostatic hazard to both robots and humans. In addition, the electrostatic environment is key to transport of dust and, consequently, martian meteorology. MECA will also observe natural dust accumulation on engineering materials. Viewed with the robot arm camera, the abrasion and adhesion plates are strategically placed to allow direct observation of the inter-action between materials and soils on a macroscopic scale. Materials of graded hardness are placed directly under the robot arm scoop to sense wear and soil hardness. A second array, placed on the lander deck, is deployed after the dust plume of landing has settled. It can be manipulated in a primitive fashion by the arm, first having dirt deposited on it from the scoop and subsequently shaken clean. Dust accumulation as a function of conductivity, magnetic field strength, and other parameters will be explored. The MECA instruments described above will assess potential hazards that the Martian soil might present to human explorers and their equipment. In addition, MECA will provide information on the composition of ancient surface water environments, observing microscopic evidence of geological (and biological?) processes, inferring soil and dust transport, comminution and weathering mechanisms, and characterizing soil horizons that might be encountered during excavation. Additional information is contained in the original extended abstract.

Hecht, M. H.↗
NASA NTRS2000

Space Resources Roundtable 2

Contents include following: Developing Technologies for Space Resource Utilization - Concept for a Planetary Engineering Research Institute. Results of a Conceptual Systems Analysis of Systems for 200 m Deep Sampling of the Martian Subsurface. The Role of Near-Earth Asteroids in Long-Term Platinum Supply. Core Drilling for Extra-Terrestrial Mining. Recommendations by the "LSP and Manufacturing" Group to the NSF-NASA Workshop on Autonomous Construction and Manufacturing for Space Electrical Power Systems. Plasma Processing of Lunar and Planetary Materials. Percussive Force Magnitude in Permafrost. Summary of the Issues Regarding the Martian Subsurface Explorer. A Costing Strategy for Manufacturing in Orbit Using Extraterrestrial Resources. Mine Planning for Asteroid Orebodies. Organic-based Dissolution of Silicates: A New Approach to Element Extraction from LunarRegohth. Historic Frontier Processes Active in Future Space-based Mineral Extraction. The Near-Earth Space Surveillance (NIESS) Mission: Discovery, Tracking, and Characterization of Asteroids, Comets, and Artificial Satellites with a microsatellite. Privatized Space Resource Property Ownership. The Fabrication of Silicon Solar Cells on the Moon Using In-Situ Resources. A New Strategy for Exploration Technology Development: The Human Exploration and Development of Space (HEDS) Exploratiori/Commercialization Technology Initiative. Space Resources for Space Tourism. Recovery of Volatiles from the Moon and Associated Issues. Preliminary Analysis of a Small Robot for Martian Regolith Excavation. The Registration of Space-based Property. Continuous Processing with Mars Gases. Drilling and Logging in Space; An Oil-Well Perspective. LORPEX for Power Surges: Drilling, Rock Crushing. An End-To-End Near-Earth Asteroid Resource Exploitation Plan. An Engineering and Cost Model for Human Space Settlement Architectures: Focus on Space Hotels and Moon/Mars Exploration. The Development and Realization of a Silicon-60-based Economy in CisLunar Space. Our Lunar Destiny: Creating a Lunar Economy. Cost-Effective Approaches to Lunar Passenger Transportation. Lunar Mineral Resources: Extraction and Application. Space Resources Development - The Link Between Human Exploration and the Long-term Commercialization of Space. Toward a More Comprehensive Evaluation of Space Information. Development of Metal Casting Molds by Sol-Gel Technology Using Planetary Resources. A New Concept in Planetary Exploration: ISRU with Power Bursts. Bold Space Ventures Require Fervent Public Support. Hot-pressed Iron from Lunar Soil. The Lunar Dust Problem: A Possible Remedy. Considerations on Use of Lunar Regolith in Lunar Constructions. Experimental Study on Water Production by Hydrogen Reduction of Lunar Soil Simulant in a Fixed Bed Reactor.

Ignatiev, A.↗
NASA NTRS2001

Complex Cooling Histories of Lunar Troctolite 76535 and Stillwater Orthoyroxenite SC-936

Fe-Mg site occupancy determinations of orthopyroxene from troctolite 76535 yield closure temperatures of ordering of 500-550 C and cooling rates of 1-10 C per year corresponding to shallow burial. 76535 was excavated from deep lunar crust before it had cooled to approx. 550 C. Additional information is contained in the original extended abstract.

Domeneghetti, M. Chiara↗
NASA NTRS2002

Crater Deposits in 2003 MER Landing Sites

At the Mars Exploration Rover Hematite landing site, impact melt and lake deposits from a 140 km diameter crater have been excavated by an 18 km diameter crater and probably deposited at the surface of the landing site ellipse. Crater deposits may also be present in the Gusev and Isidis landing sites. Additional information is contained in the original extended abstract.

Newsom, H. E.↗
NASA NTRS1992

Robot Handcontroller

The PER-Force robotic handcontroller provides a sense of touch or "feel" to an operator manipulating robots. The force simulation and wide range of motion greatly enhances the efficiency of robotic and computer operations. The handcontroller was developed for the Space Station by Cybernet Systems Corporation under a Small Business Innovation Research (SBIR) contract. Commercial applications include underwater use, underground excavations, research laboratories, hazardous waste handling and in manufacturing operations in which it is unsafe or impractical for humans to work.

Source record↗
NASA NTRS2002

Planetary Geophysics and Tectonics

We have carried out several studies that explore explanations for the role of chemical density variations in Moon s evolution. Meaningful models for the evolution of the Moon must explain a number of important magmatic characteristics. Volcanic activity subsequent to the formation of its anorthositic crust was dominated by the eruption of mare basalt. 1) The main phase of mare volcanism began approx. 500 Myr after the crystallization of the anorthositic crust and continued for approx. l Gyr. 2) The picitic glasses, considered to be representative of mare basalt least affected by low pressure, near-surface fractionation, were generated by melting, at 400-600 km depth, of a source containing components that, on the basis of the magma ocean hypothesis, should have crystallized at much shallower depth during fractionation of the anorthositic crust. 3) Mare basalts occur primarily in one region of the Moon. Recent topographic data demonstrate that the earlier idea that mare basalt flooded areas of low elevation is not correct. Large areas of very low elevation do not contain mare basalt. The hemispheric asymmetry of mare basalt distribution on the lunar surface must be explained in some other way. 4) A region of the surface roughly correlating with that containing mare basalts also is thought to contain high subsurface concentrations of KREEP which was excavated during the formation of large impact basins. This so-called Procellarum KREEP Terrane (PKT) is responsible for the Imbrium basin-centered thorium anomaly mapped by Lunar Prospector.

Parmentier, E. Marc↗
NASA NTRS2003

Effects of Pre-Existing Target Structure on the Formation of Large Craters

The shapes of large-scale craters and the mechanics responsible for melt generation are influenced by broad and small-scale structures present in a target prior to impact. For example, well-developed systems of fractures often create craters that appear square in outline, good examples being Meteor Crater, AZ and the square craters of 433 Eros. Pre-broken target material also affects melt generation. Kieffer has shown how the shock wave generated in Coconino sandstone at Meteor crater created reverberations which, in combination with the natural target heterogeneity present, created peaks and troughs in pressure and compressed density as individual grains collided to produce a range of shock mineralogies and melts within neighboring samples. In this study, we further explore how pre-existing target structure influences various aspects of the cratering process. We combine experimental and numerical techniques to explore the connection between the scales of the impact generated shock wave and the pre-existing target structure. We focus on the propagation of shock waves in coarse, granular media, emphasizing its consequences on excavation, crater growth, ejecta production, cratering efficiency, melt generation, and crater shape. As a baseline, we present a first series of results for idealized targets where the particles are all identical in size and possess the same shock impedance. We will also present a few results, whereby we increase the complexities of the target properties by varying the grain size, strength, impedance and frictional properties. In addition, we investigate the origin and implications of reverberations that are created by the presence of physical and chemical heterogeneity in a target.

Barnouin-Jha, O. S.↗
NASA NTRS2003

Impact Lithologies and Post-Impact Hydrothermal Alteration Exposed by the Chicxulub Scientific Drilling Project, Yaxcopoil, Mexico

The Chicxulub Scientific Drilling Project recovered a continuous core from the Yaxcopoil-1 (YAX-1) borehole, which is approx.60-65 km from the center of the Chicxulub structure, approx.15 km beyond the limit of the estimated approx.50 km radius transient crater (excavation cavity), but within the rim of the estimated approx.90 km radius final crater. Approximately approx.100 m of melt-bearing impactites were recoverd from a depth of 794 to 895 m, above approx.600 m of underlying megablocks of Cretaceous target sediments, before bottoming at 1511 m. Compared to lithologies at impact craters like the Ries, the YAX-1 impactite sequence is incredibly rich in impact melts of unusual textural variety and complexity. The impactite sequence has also been altered by hydrothermal activity that may have largely been produced by the impact event.

Kring, David A.↗
NASA NTRS1999

Investigating Atmospheric Effects on Impact Ejecta Morphology: Possible Tool for Determining Past Climate Conditions on Mars?

The combined use of impact crater morphology and mechanics provides important information on the physical conditions of both planetary atmospheres and planetary and asteroid surfaces present during crater formation, while an understanding of the rate of crater production on the surface of asteroids provides information of their surface and spin rate evolution. The research performed with support from this project improves our understanding of (1) the mechanics of impact cratering in order to gain insights on the evolution of these physical surface conditions on planets with atmospheres and asteroids, and (2) how impact flux across an asteroid surface may vary due to anisotropic distribution of impactors in the solar system. As part of this project, we have undertaken three studies. In the first study, we investigate atmospheric effects on the morphology of ejecta excavated during a cratering event in order to determine the atmospheric and target conditions from observed crater morphologies. In the second study, we use the physical and morphological consequences of oblique impacts on an asteroid to understand how the asteroid Mathilde (recently imaged by the Near Earth Asteroid Rendezvous - NEAR- spacecraft) could have survived the formation of five giant craters. In a third study, we use a Monte Carlo method to calculate the impact flux on an asteroid given a distribution of impactors on elliptical orbits. In the following section, we present the result obtained from all three studies.

Appleby, John F.↗
NASA NTRS2002

Rootless Cones on Mars: A Consequence of Lava-Ground Ice Interaction

Fields of small cratered cones on Mars are interpreted to have formed by rootless eruptions due to explosive interaction of lava with ground ice contained within the regolith beneath the flow. Melting and vaporization of the ice, and subsequent explosive expansion of the vapour, act to excavate the lava and construct a rootless cone around the explosion site. Similar features are found in Iceland, where flowing lava encountered water-saturated substrates. The martian cones have basal diameters of c. 30-1000 m and are located predominantly in the northern volcanic plains. High-resolution Mars Orbiter Camera images offer significant improvements over Viking data for interpretation of cone origins. A new model of the dynamics of cone formation indicates that very modest amounts of water ice are required to initiate and sustain the explosive interactions that produced the observed features. This is consistent with the likely low availability of water ice in the martian regolith. The scarcity of impact craters on many of the host lava flows indicates very young ages, suggesting that ground ice was present as recently as less than 10 - l00 Ma, and may persist today. Rootless cones therefore act as a spatial and temporal probe of the distribution of ground ice on Mars, which is of key significance in understanding the evolution of the martian climate. The location of water in liquid or solid form is of great importance to future robotic and human exploration strategies, and to the search for extraterrestrial life.

Fagents, S. A.↗
NASA NTRS2003

Comparing Run-Out Efficiency of Fluidized Ejecta on Mars with Terrestrial and Martian Mass Movements

We broadly characterize the rheology of fluidized ejecta on Mars as it flows during its final stages of emplacement by using the concept of run-out efficiency. Run-out efficiency for ejecta can be obtained through an energy balance between the kinetic energy of the excavated ejecta, and the total work lost during its deposition. Such an efficiency is directly comparable to run-out efficiency (i.e., L/H analyzes where L is the run-out distance and H is onset height) of terrestrial and extraterrestrial mass movements. Determination of the L/H ratio is commonly used in terrestrial geology to broadly determine the type and rheology of mass movements

Barnouin-Jha, O. S.↗
NASA NTRS2003

Ar-39-Ar-40 Ages of Eucrites and the Thermal History of Asteroid 4-Vesta

New Ar-Ar ages of several cumulate and unbrecciated eucrites cluster at approx.4.48 Gyr. We suggest that this age cluster was produced by interruption of eucrite metamorphism within the Vesta parent asteroid by a giant impact, which excavated and rapidly cooled these meteorites. We see no evidence for younger formation ages of the cumulate eucrites, as previously proposed.

Bogard, Donald↗
NASA NTRS2002

Use of GPR Surveys in Historical Archaeology Studies at Gainesville, Mississippi (22HA600)

Ground Penetrating Radar (GPR) is used to study the underground remains of historic structures on the grounds of Stennis Space Center (SSC) in this viewgraph presentation. The main goal of the project described is to research, develop, and validate Remote Sensing (RS) and Geographic Information System (GIS) methods for aiding cultural resource assessments within SSC. The project georeferences historic imagery and maps to assist archaeological RS, field surveys, and excavations.

Goodwin, Ben↗