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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 487 records · Page 27
All sourcesNASA NTRSDOE OSTI
NASA NTRS2005

Surface Clutter Removal in Airborne Radar Sounding Data from the Dry Valleys, Antarctica

We have collected roughly 1,000 line-km of airborne radar sounding data over glaciers, rock/ice glaciers, permafrost, subsurface ice bodies, ice-covered saline lakes, and glacial deposits in Taylor and Beacon Valley. These data are being analyzed in order to develop techniques for discriminating between subsurface and off-nadir echoes and for detecting and characterizing subsurface interfaces. The identification of features on Mars exhibiting morphologies consistent with ice/rock mixtures, near-surface ice bodies and near-surface liquid water, and the importance of such features to the search for water on Mars, highlights the need for appropriate terrestrial analogs and analysis techniques in order to prepare for radar sounder missions to Mars. Climatic, hydrological, and geological conditions in the Dry Valleys of Antarctica are analogous in many ways to those on Mars. A crucial first step in the data analysis process is the discrimination of echo sources in the radar data. The goal is to identify all returns from the surface of off-nadir topography in order to positively identify subsurface echoes. This process will also be critical for radar data that will be collected in areas of Mars exhibiting significant topography, so that subsurface echoes are identified unambiguously. The positive detection and characterization of subsurface (including sub-ice) water is a primary goal of NASA's Mars exploration program. Our data over the Dry Valleys provides an opportunity to implement techniques we are developing to accomplish these goals.

Holt, J. W.↗
NASA NTRS1987

Presentations by participants (edited and condensed)

The utility of Geomagnetic Automonous Shuttle-Launched Probe (GASP) for studying the earth's crust can be characterized in terms of lithospheric contributions by past satellite programs. In contrast to the POGO and MAGSAT satellites, GASP will orbit at a lower elevation to provide better resolved lithospheric magnetic anomalies for more detailed and improved geologic analysis. In the geological representation of satellite magnetic anomaly data, two current approaches can serve the analysis of GASP observations. When global scale coverage is available, spherical harmonic expansions of the observations may be utilized. When satellite elevation data is used, a useful and efficient approach is to determine the physical properties of an array of point equivalent sources by least squares matrix inversion of the observations, which will closely duplicate the observed field. An important preliminary step in the representation of satellite magnetic observations by either approach, is to register the data at constant elevation over uniform intervals of latitude and longitude. Further applications of GASP are discussed.

Vonfrese, R. R. B.↗
NASA NTRS1988

Abrupt climate change and extinction events

There is a growing body of theoretical and empirical support for the concept of instabilities in the climate system, and indications that abrupt climate change may in some cases contribute to abrupt extinctions. Theoretical indications of instabilities can be found in a broad spectrum of climate models (energy balance models, a thermohaline model of deep-water circulation, atmospheric general circulation models, and coupled ocean-atmosphere models). Abrupt transitions can be of several types and affect the environment in different ways. There is increasing evidence for abrupt climate change in the geologic record and involves both interglacial-glacial scale transitions and the longer-term evolution of climate over the last 100 million years. Records from the Cenozoic clearly show that the long-term trend is characterized by numerous abrupt steps where the system appears to be rapidly moving to a new equilibrium state. The long-term trend probably is due to changes associated with plate tectonic processes, but the abrupt steps most likely reflect instabilities in the climate system as the slowly changing boundary conditions caused the climate to reach some threshold critical point. A more detailed analysis of abrupt steps comes from high-resolution studies of glacial-interglacial fluctuations in the Pleistocene. Comparison of climate transitions with the extinction record indicates that many climate and biotic transitions coincide. The Cretaceous-Tertiary extinction is not a candidate for an extinction event due to instabilities in the climate system. It is quite possible that more detailed comparisons and analysis will indicate some flaws in the climate instability-extinction hypothesis, but at present it appears to be a viable candidate as an alternate mechanism for causing abrupt environmental changes and extinctions.

Crowley, Thomas J.↗
NASA NTRS2016

Using VSWIR Microimaging Spectroscopy to Explore the Mineralogical Diversity of HED Meteorites

We use VSWIR microimaging spectroscopy to survey the spectral diversity of HED meteorites at 80-µm/pixel spatial scale. Our goal in this work is both to explore the emerging capabilities of microimaging VSWIR spectroscopy, and to contribute to understanding the petrologic diversity of the HED suite and the evolution of Vesta. Using a combination of manual and automated hyperspectral classification techniques, we identify four major classes of materials based on VSWIR absorptions that include pyroxene, olivine, Fe-bearing feldspars, and glass-bearing/featureless materials. Results show microimaging spectroscopy is an effective method for rapidly and non-destructively characterizing small compositional variations of meteorite samples and for locating rare phases for possible follow-up investigation. Future work will include incorporating SEM/EDS results to quantify sources of spectral variability and placing observations within a broader geologic framework of the differentiation and evolution of Vesta.

Fraeman, Abigail A↗
DOE OSTI2024

Soft interface instability and gas flow channeling in low-permeability deformable media

Understanding gas percolation through a clay layer or a shale formation is of great importance for the development of a geologic repository for nuclear waste disposal, a subsurface system for gas storage, and an engineering approach for hydrocarbon extraction from unconventional reservoirs. Gas injection experiments have revealed complex dynamic behaviours of gas percolation through water saturated compacted bentonite, characterized by a high breakthrough pressure, rapid breakthrough, a pressure/stress decay after the breakthrough, a relatively high migration rate, high-frequency periodic/nonperiodic variations in flow rate, stepwise rate reductions during relaxation, and low gas saturation over the whole process, all indicating channelling nature of the processes. Using linear stability analyses, we show that this channelling can autonomously emerge from the instability of the deformable interface between the injected gas and the compacted bentonite matrix driven by local stress concentration, pore dilation, and hydrologic gradient. Channel patterns formed would possess a fractal geometry. We further show that, once a percolating channel is established, the gas injected would percolate through the channel in a chain of gas bubbles, also due to the interface instability, resulting in periodic/chaotic variations in gas flow rate. Our work provides a unified explanation for key features observed for gas percolation in low-permeability deformable media. The work also suggests a possibility of designing an engineered barrier system for a nuclear waste repository that can have controllable gas release while limit water transport.

Bentonite↗
NASA NTRS1977

Some geologic observations concerning lunar geophysical models

The distribution of lunar geologic units in space and time and their mode of origin were considered since they provided significant data which bear on a number of current problems in lunar geophysics. Observations and problems were discussed which deal with the characterization of the upper 25 km of the lunar crust, the tectonic style of the crust, the formation of mascons within major basins, analysis of lunar magnetic anomalies, and the history of the lunar crust.

Head, J. W.↗
NASA NTRS2021

Temperature Fluctuations and Boundary Layer Turbulence as seen by Mars Exploration Rovers Miniature Thermal Emission Spectrometer

The Mini-TES spectrometer carried by Spirit and Opportunity is a unique instrument that enabled vertical temperature profiles to be retrieved at high frequency (every 2 s, or “ICK”). Observations obtained from this instrument provide information on boundary layer activity. As an extension of previous work, we have retrieved ICK-by-ICK vertical temperature profiles to characterize turbulent behavior at each rover site for up to two Mars Years. We have also retrieved ICK-by-ICK near-surface (1.1 m) atmospheric temperatures and surface temperatures from dedicated atmospheric observations as well as geologic observations that extend the coverage of near-surface observations. The extension and increased frequency of retrievals as well as the additional observations provide a more complete view of the vertical and temporal variation of temperature fluctuations within the PBL. Temperature fluctuations are assessed using detrended temperature time-series data. The results show fluctuations can be as large as 10 K at the surface and 8 K aloft with timescales on the order of minutes. We have calculated the peak-to-peak amplitudes of temperature fluctuations and the corresponding timescales over which they occur. Spirit and Opportunity temperature fluctuation amplitudes decrease in magnitude vertically, where higher atmospheric levels show smaller fluctuations in amplitudes than at the surface. The magnitude of temperature fluctuations changes with the difference in surface and air temperature. This difference varies little as a function of season at both rover sites. Fluctuations are observed to quickly decrease in the late afternoon reaching a minimum near 17:00 LTST followed by moderately increased activity near sunset caused by forced convection. There is no significant change in the observed convective activity as a function of dust optical depth during regional dust storms. The few large temperature fluctuations that are concurrent with dust events are likely the result of large-scale systems.

Mars, atmosphere↗
NASA NTRS2007

2007 Lunar Regolith Simulant Workshop Overview

The National Aeronautics and Space Administration (NASA) vision has as a cornerstone, the establishment of an Outpost on the Moon. This Lunar Outpost will eventually provide the necessary planning, technology development, and training for a manned mission to Mars in the future. As part of the overall activity, NASA is conducting Earth-based research and advancing technologies to a Technology Readiness Level (TRL) 6 maturity under the Exploration Technology Development Program that will be incorporated into the Constellation Project as well as other projects. All aspects of the Lunar environment, including the Lunar regolith and its properties, are important in understanding the long-term impacts to hardware, scientific instruments, and humans prior to returning to the Moon and living on the Moon. With the goal of reducing risk to humans and hardware and increasing mission success on the Lunar surface, it is vital that terrestrial investigations including both development and verification testing have access to Lunar-like environments. The Marshall Space Flight Center (MSFC) is supporting this endeavor by developing, characterizing, and producing Lunar simulants in addition to analyzing existing simulants for appropriate applications. A Lunar Regolith Simulant Workshop was conducted by MSFC in Huntsville, Alabama, in October 2007. The purpose of the Workshop was to bring together simulant developers, simulant users, and program and project managers from ETDP and Constellation with the goals of understanding users' simulant needs and their applications. A status of current simulant developments such as the JSC-1A (Mare Type Simulant) and the NASA/U.S. Geological Survey Lunar Highlands-Type Pilot Simulant (NU-LHT-1M) was provided. The method for evaluating simulants, performed via Figures of Merit (FoMs) algorithms, was presented and a demonstration was provided. The four FoM properties currently being assessed are: size, shape, density, and composition. Some of the Workshop findings include: simulant developers must understand simulant users' needs and applications; higher fidelity simulants are needed and needed in larger quantities now; simulants must be characterized to allow "apples-to-apples" comparison of test results; simulant users should confer with simulant experts to assist them in the selection of simulants; safety precautions should be taken in the handling and use of simulants; shipping, storing, and preparation of simulants have important implications; and most importantly, close communications among the simulant community must be maintained and will be continued via telecoms, meetings, and an annual Lunar Regolith Simulant Workshop.

McLemore, Carole A.↗
NASA NTRS2007

2007 Lunar Regolith Simulant Workshop Overview

The National Aeronautics and Space Administration (NASA) vision has as a cornerstone, the establishment of an Outpost on the Moon. This Lunar Outpost will eventually provide the necessary planning, technology development, and training for a manned mission to Mars in the future. As part of the overall activity, NASA is conducting Earth-based research and advancing technologies to a Technology Readiness Level (TRL) 6 maturity under the Exploration Technology Development Program that will be incorporated into the Constellation Project as well as other projects. All aspects of the Lunar environment, including the Lunar regolith and its properties, are important in understanding the long-term impacts to hardware, scientific instruments, and humans prior to returning to the Moon and living on the Moon. With the goal of reducing risk to humans and hardware and increasing mission success on the Lunar surface, it is vital that terrestrial investigations including both development and verification testing have access to Lunar-like environments. The Marshall Space Flight Center (MSFC) is supporting this endeavor by developing, characterizing, and producing Lunar simulants in addition to analyzing existing simulants for appropriate applications. A Lunar Regolith Simulant Workshop was conducted by MSFC in Huntsville, Alabama, in October 2007. The purpose of the Workshop was to bring together simulant developers, simulant users, and program and project managers from ETDP and Constellation with the goals of understanding users' simulant needs and their applications. A status of current simulant developments such as the JSC-1A (Mare Type Simulant) and the NASA/U.S. Geological Survey Lunar Highlands-Type Pilot Simulant (NU-LHT-1 M) was provided. The method for evaluating simulants, performed via Figures of Merit (FoMs) algorithms, was presented and a demonstration was provided. The four FoM properties currently being assessed are: size, shape, density, and composition. Some of the Workshop findings include: simulant developers must understand simulant users' needs and applications; higher fidelity simulants are needed and needed in larger quantities now; simulants must be characterized to allow "apples-to-apples" comparison of test results; simulant users should confer with simulant experts to assist them in the selection of simulants; safety precautions should be taken in the handling and use of simulants; shipping, storing, and preparation of simulants have important implications; and most importantly, close communications among the simulant community must be maintained and will be continued via telecoms, meetings, and an annual Lunar Regolith Simulant Workshop.

McLemore, Carole A.↗
NASA NTRS1973

ERTS Applications in earthquake research and mineral exploration in California

Examples that ERTS imagery can be effectively utilized to identify, locate, and map faults which show geomorphic evidence of geologically recent breakage are presented. Several important faults not previously known have been identified. By plotting epicenters of historic earthquakes in parts of California, Sonora, Mexico, Arizona, and Nevada, we found that areas known for historic seismicity are often characterized by abundant evidence of recent fault and crustal movements. There are many examples of seismically quiet areas where outstanding evidence of recent fault movements is observed. One application is clear: ERTS-1 imagery could be effectively utilized to delineate areas susceptible to earthquake recurrence which, on the basis of seismic data alone, may be misleadingly considered safe. ERTS data can also be utilized in planning new sites in the geophysical network of fault movement monitoring and strain and tilt measurements.

Abdel-Gawad, M.↗
NASA NTRS1991

Wave interactions with continuous fractal layers

Many natural structures possess self-similar multiscales which can be characterized by power law spectra. Under appropriate conditions, knowledge of the strength of these scale sizes provides information on the physical processes which formed these objects. In this paper, we investigate wave interactions with continuous fractal layers which model geological and variegated structures. Since fractal characteristics of the layers are embedded in the scattered field, they can be retrieved under appropriate conditions. This inversion can be performed in either the frequency or the time domain as desired.

Kim, Y.↗
NASA NTRS2014

Geologic Mapping of Vesta

We report on a preliminary global geologic map of Vesta, based on data from the Dawn spacecraft's High- Altitude Mapping Orbit (HAMO) and informed by Low-Altitude Mapping Orbit (LAMO) data. This map is part of an iterative mapping effort; the geologic map has been refined with each improvement in resolution. Vesta has a heavily-cratered surface, with large craters evident in numerous locations. The south pole is dominated by an impact structure identified before Dawn's arrival. Two large impact structures have been resolved: the younger, larger Rheasilvia structure, and the older, more degraded Veneneia structure. The surface is also characterized by a system of deep, globe-girdling equatorial troughs and ridges, as well as an older system of troughs and ridges to the north. Troughs and ridges are also evident cutting across, and spiraling arcuately from, the Rheasilvia central mound. However, no volcanic features have been unequivocally identified. Vesta can be divided very broadly into three terrains: heavily-cratered terrain; ridge-and-trough terrain (equatorial and northern); and terrain associated with the Rheasilvia crater. Localized features include bright and dark material and ejecta (some defined specifically by color); lobate deposits; and mass-wasting materials. No obvious volcanic features are evident. Stratigraphy of Vesta's geologic units suggests a history in which formation of a primary crust was followed by the formation of impact craters, including Veneneia and the associated Saturnalia Fossae unit. Formation of Rheasilvia followed, along with associated structural deformation that shaped the Divalia Fossae ridge-and-trough unit at the equator. Subsequent impacts and mass wasting events subdued impact craters, rims and portions of ridge-and-trough sets, and formed slumps and landslides, especially within crater floors and along crater rims and scarps. Subsequent to the formation of Rheasilvia, discontinuous low-albedo deposits formed or were emplaced; these lie stratigraphically above the equatorial ridges that likely were formed by Rheasilvia. The last features to be formed were craters with bright rays and other surface mantling deposits. Executed progressively throughout data acquisition, the iterative mapping process provided the team with geologic proto-units in a timely manner. However, interpretation of the resulting map was hampered by the necessity to provide the team with a standard nomenclature and symbology early in the process. With regard to mapping and interpreting units, the mapping process was hindered by the lack of calibrated mineralogic information. Topography and shadow played an important role in discriminating features and terrains, especially in the early stages of data acquisition.

Vesta↗
NASA NTRS2022

Geologically Recent Areas as One Key Target for Identifying Active Volcanism on Venus

The recently selected NASA VERITAS and DAVINCI missions, the ESA EnVision, the Roscosmos Venera-D will open a new era in the exploration of Venus. One of the key targets of the future orbiting and in-situ investigations of Venus is the identification of volcanically active areas on the planet. The study of the areas characterized by recent or ongoing volcano-tectonic activity can inform us on how volcanism and tectonism are currently evolving on Venus. Following this key target, the manuscript by Brossier et al. (2022) (https://doi.org/10.1029/2022GL099765) extends the successful approach and methodology used by previous works to Ganis Chasma in Atla Regio. We comment here on the main results of the manuscript published by Brossier et al. (2022) (https://doi.org/10.1029/2022GL099765) and discuss the important implications of their work for the future orbiting and in-situ investigations of Venus. Their results add further lines of evidence indicating possibly recent volcanism on Venus.

Solar system↗
DOE OSTI2024

Groundwater Circulation Within the Mountain Block: Combining Flow and Transport Models With Magnetotelluric Observations to Untangle Its Nested Nature

Abstract Mountains are vital water sources for humans and ecosystems, continuously replenishing lowland aquifers through surface runoff and mountain recharge. Quantifying these fluxes and their relative importance is essential for sustainable water resource management. However, our mechanistic understanding of the flow and transport processes determining the connection between the mountain block and the basin aquifer remains limited. Traditional conceptualizations assume groundwater circulation within the mountain block is predominantly shallow. This view neglects the role of deep groundwater flowpaths significantly contributing to the water, solute, and energy budgets. Overcoming these limitations requires a holistic characterization of the multiscale nature of groundwater flow along the mountain‐to‐valley continuum. As a proof‐of‐concept, we use a coupled groundwater flow and transport model to design a series of numerical experiments that explore the role of geology, topography, and weathering rates in groundwater circulation and their resulting resistivity patterns. Our results show that accumulating solutes near stagnation zones create contrasting electrical resistivity patterns that separate local, intermediate, and regional flow cells, presenting a target for magnetotelluric observations. To demonstrate the sensitivity of magnetotelluric data to features in our resistivity models, we use the MARE2DEM electromagnetic modeling code to perform forward and inverse simulations. This study highlights the potential of magnetotelluric surveys to image the resistivity structure resulting from multiscale groundwater circulation through relatively impervious crystalline basement rocks in mountainous terrains. This capability could change our understanding of the critical zone, offering a holistic perspective that includes deep groundwater circulation and its role in conveying solutes and energy.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1982

An investigation into the utilization of HCMM thermal data for the discrimination of volcanic and Eolian geological units

The nature of the HCMM data set and the general geologic application of thermal inertia imaging using HCMM data were studied. The CCT's of five sites of interest were obtained and displayed. The upgrading of the image display system was investigated. Fragment/block size distributions in various terrain types wre characterized with emphasis on volcanic terrain. The SEASAT L-band radar images of volcanic landforms at Newberry Volcano, Oregon, were analyzed and compared to imagery from LANDSAT band 7.

Head, J. W., III↗
NASA NTRS1995

Mars Global Surveyor Mission: Environmental Assessment

This environmental assessment addresses the proposed action to complete the integration and launch the Mars Global Surveyor (MGS) spacecraft from Cape Canaveral Air Station (CCAS), Florida, during the launch window in November 1996. Mars Global Surveyor is part of the Solar System Exploration Program to the inner planets designed to maintain a sufficient level of scientific investigation and accomplishment so that the United States retains a leading position in solar system exploration through the end of the century. The Program consists of a specific sequence of missions, based on technological readiness, launch opportunities, rapidity of data return, and a balance of scientific disciplines. The purpose of the MGS mission would be to deliver a spacecraft platform to a low-altitude polar orbit around Mars where it would collect global observations of basic geological, geophysical, and climatological processes of the planet. To satisfy this purpose, the MGS mission would support a scientific set of objectives. Detailed global maps of surface topography, the distribution of minerals, the planet's mass, size, and shape, the characterization of Mars gravitational and magnetic fields, and the monitoring of global weather, collected over the period of one Martian year (about two Earth years), would help answer some of the questions about the evolution of Mars. Such an investigation would help scientists better understand the current state of water on Mars, the evolution of the planet's atmosphere, and the factors that led to major changes in the Martian climate. It would also provide much needed information on the magnetic field of Mars. Data collected from this mission would provide insight into the evolution of both Earth and the solar system, as well as demonstrate technological approaches that could be applicable to future Mars missions.

Source record↗
NASA NTRS2014

Importance of Geodetically Controlled Topography to Constrain Rates of Volcanism and Internal Magma Plumbing Systems

Investigation of lava flow deposits is a key component of Investigation II.A.1 in the VEXAG Goals, Objectives and Investigations. Because much of the Venus surface is covered in lava flows, characterization of lava flow emplacement conditions(eruption rate and eruption duration) is critical for understanding the mechanisms through which magma is stored and released onto the surface as well as for placing constraints on rates of volcanic resurfacing throughout the geologic record preserved at the surface.

GEODETICALLY↗
NASA NTRS2015

Geologic Investigations Spurred by Analog Testing at the 7504 Cone-SP Mountain Area of the San Francisco Volcanic Field

The SP Mountain area of the San Francisco Volcanic Field, AZ, has been used as an analog mission development site for NASA since 1998. This area consists of basaltic cinder cones, lava flows and maar craters that have been active since mid-Miocene, with the youngest events occurring within the last 10,000 years. The area has been used because its geologic and topographic resemblance to lunar and Martian terrains provides an ideal venue for testing hardware and science operations practices that might be employed on planetary surfaces, as well as training astronauts in field geology. Analog operations have often led to insights that spurred new scientific investigations. Most recently, an investigation of the 7504 cone was initiated due to perceptions that Apollo-style traverse plans executed during the Desert RATS 2010 mission had characterized the area incorrectly, leading to concerns that the Apollo traverse planning process was scientifically flawed. This investigation revealed a complex history of fissure eruptions of lava and cinders, cinder cone development, a cone-fill-and-spill episode, extensive rheomorphic lava flow initiation and emplacement, and cone sector collapse that led to a final lava flow. This history was not discernible on pre-RATS mission photogeology, although independent analysis of RATS 2010 data and samples develped a "75% complete solution" that validated the pre-RATS mission planning and Apollo traverse planning and execution. The study also pointed out that the development of scientific knowledge with time in a given field area is not linear, but may follow a functional form that rises steeply in the early period of an investigation but flattens out in the later period, asymptotically approaching a theoretical "complete knowledge" point that probably cannot be achieved. This implies that future human missions must be prepared to shift geographic areas of investigation regularly if significant science returns are to be forthcoming.

Eppler, Dean B.↗