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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Variable features in the Valles Marineris region of Mars

Transient phenomena on Mars have long been recognized in Mariner and Viking images as well as in decades of Earth based telescopic observations. These events are of interest because of the information they present on currently active meteorological and geological processes. Changes in surface albedo patterns and atmospheric conditions can also affect the analysis and interpretation of data based on spectral or morphological properties of geologic units on the surface. The mechanism responsible for albedo pattern change is currently under investigation. Generation and subsequent transportation and deposition of dark sands has been interpreted in the Valles. However, the removal of a bright dust layer is more consistent with the rapid time period of the change (about two months) and with preliminary multispectral mapping results which suggest that the dark streak south of Eos and Coprates Chasmata is spectrally distinguishable from the dark saltating materials found elsewhere in the canyon system. If a layer of bright dust was removed to affect the albedo change, questions concerning how such micron-sized particles are mobilized by the winds during a normally quiescent season (Southern Hemisphere Autumn) should be addressed.

Geissler, Paul E.↗
NASA NTRS1990

Martian impact craters: Continuing analysis of lobate ejecta sinuosity

The lobate ejecta morphology surrounding most fresh Martian impact craters can be quantitatively analyzed to determine variations in ejecta sinuosity with diameter, latitude, longitude, and terrain. The results of such studies provide another clue to the question of how these morphologies formed: are they the results of vaporization of subsurface volatiles or caused by ejecta entrainment in atmospheric gases. Kargel provided a simple expression to determine the degree of non-circularity of an ejecta blanket. This measure of sinuosity, called 'lobateness', is given by the ratio of the ejecta perimeter to the perimeter of a circle with the same area as that of the ejecta. The Kargel study of 538 rampart craters in selected areas of Mars led to the suggestion that lobateness increased with increasing diameter, decreased at higher latitude, and showed no dependence on elevation or geologic unit. Major problems with the Kargel analysis are the limited size and distribution of the data set and the lack of discrimination among the different types of lobate ejecta morphologies. Bridges and Barlow undertook a new lobateness study of 1582 single lobe (SL) and 251 double lobe (DL) craters. The results are summarized. These results agree with the finding of Kargel that lobateness increases with increasing diameter, but found no indication of a latitude dependence for SL craters. The Bridges and Barlow study has now been extended to multiple lobe (ML) craters. Three hundred and eighty ML craters located across the entire Martian surface were studied. ML craters provide more complications to lobateness studies than do SL and DL craters - in particular, the ejecta lobes surrounding the crater are often incomplete. Since the lobateness formula compares the perimeter of the ejecta lobe to that of a circle, the analysis was restricted only to complete lobes. The lobes are defined sequentially starting with the outermost lobe and moving inward.

Barlow, Nadine G.↗
NASA NTRS2017

Lessons from Astrobiological Planetary Analogue Exploration in Iceland: Biomarker Assay Performance and Downselection

Understanding the sensitivity of biomarker assays to the local physicochemical environment, and the underlying spatial distribution of the target biomarkers in 'homogeneous' environments, can increase mission science return. We have conducted four expeditions to Icelandic Mars analogue sites in which an increasingly refined battery of physicochemical measurements and biomarker assays were performed, staggered with scouting of further sites. Completed expeditions took place in 2012 (location scouting and field assay use testing), 2013 (sampling of two major sites with three assays and observational physicochemical measurements), 2015 (repeat sampling of prior sites and one new site, scouting of new sites, three assays and three instruments), and 2016 (preliminary sampling of new sites with analysis of returned samples). Target sites were geologically recent basaltic lava flows, and sample loci were arranged in hierarchically nested grids at 10 cm, 1 m, 10 m, 100 m, and >1 km order scales, subject to field constraints. Assays were intended to represent a diversity of potential biomarker types (cell counting via nucleic acid staining and fluorescence microscopy, ATP quantification via luciferase luminescence, and relative DNA quantification with simple domain-level primers) rather a specific mission science target, and were selected to reduce laboratory overhead, require limited consumables, and allow rapid turnaround. All analytical work was performed in situ or in a field laboratory within a day's travel of the field sites unless otherwise noted. We have demonstrated the feasibility of performing ATP quantification and qPCR analysis in a field-based laboratory with single-day turnaround. The ATP assay was generally robust and reliable and required minimal field equipment and training to produce a large amount of useful data. DNA was successfully extracted from all samples, but the serial-batch nature of qPCR significantly limited the number of primers (hence classifications) and replicates that could be run in a single day. Fluorescence microscopy did not prove feasible under the same constraints, primarily due to the large number of person-hours required to view, analyze, and record results from the images; however, this could be mitigated with higher-quality imaging instruments and appropriate image analysis software.

Planetary↗
NASA NTRS1974

Evaluation and comparison of ERTS measurements of major crops and soil associations for selected test sites in the central United States

The author has identified the following significant results. Multispectral scanner data obtained by ERTS-1 over six test sites in the Central United States were analyzed and interpreted. ERTS-1 data for some of the test sites were geometrically corrected and temporally overlayed. Computer-implemented pattern recognition techniques were used in the analysis of all multispectral data. These techniques were used to evaluate ERTS-1 data as a tool for soil survey. Geology maps and land use inventories were prepared by digital analysis of multispectral data. Identification and mapping of crop species and rangelands were achieved throught the analysis of 1972 and 1973 ERTS-1 data. Multiple dates of ERTS-1 data were examined to determine the variation with time of the areal extent of surface water resources on the Southern Great Plain.

Baumgardner, M. F.↗
NASA NTRS2010

New Geologic Map of the Argyre Region of Mars: Deciphering the Geologic History Through Mars Global Surveyor, Mars Odyssey, and Mars Express Data

The primary objective of the mapping effort is to produce a geologic map of the Argyre basin and surrounding region at 1:5,000,000 scale in both digital and print formats that will detail the stratigraphic and crosscutting relations among rock materials and landforms (30 deg. S to 65 deg. S, 290 deg. E to 340 deg E). There has not been a detailed geologic map produced of the Argyre region since the Viking-era mapping investigation. The mapping tasks include stratigraphic mapping, crater counting, feature mapping, quantitative landform analysis, and spectroscopic/ stratigraphic investigation feature mapping. The regional geologic mapping investigation includes the Argyre basin floor and rim materials, the transition zone that straddles the Thaumasia plateau, which includes Argyre impactrelated modification, and the southeast margin of the Thaumasia plateau using important new data sets from the Mars Global Surveyor, Mars Odyssey, Mars Express, and Mars Reconnaissance Orbiter. The geologic information unfolded by this new mapping project will be useful to the community for constraining the regional geology, paleohydrology, and paleoclimate, which includes but is not limited to the assessment of: (1) whether the Argyre basin contained lakes, (2) the extent of reported flooding and glaciation, (3) existing interpretations of the origin of the narrow ridges located in the southeast part of the basin floor, and (4) the extent of Argyre-related tectonism and its influence on the surrounding regions.

Dohm, J. M.↗
NASA NTRS1975

Combined magnetic and gravity analysis

Efforts are made to identify methods of decreasing magnetic interpretation ambiguity by combined gravity and magnetic analysis, to evaluate these techniques in a preliminary manner, to consider the geologic and geophysical implications of correlation, and to recommend a course of action to evaluate methods of correlating gravity and magnetic anomalies. The major thrust of the study was a search and review of the literature. The literature of geophysics, geology, geography, and statistics was searched for articles dealing with spatial correlation of independent variables. An annotated bibliography referencing the Germane articles and books is presented. The methods of combined gravity and magnetic analysis techniques are identified and reviewed. A more comprehensive evaluation of two types of techniques is presented. Internal correspondence of anomaly amplitudes is examined and a combined analysis is done utilizing Poisson's theorem. The geologic and geophysical implications of gravity and magnetic correlation based on both theoretical and empirical relationships are discussed.

Hinze, W. J.↗
NASA NTRS1990

Remote sensing science for the Nineties; Proceedings of IGARSS '90 - 10th Annual International Geoscience and Remote Sensing Symposium, University of Maryland, College Park, May 20-24, 1990. Vols. 1, 2, & 3

Various papers on remote sensing (RS) for the nineties are presented. The general topics addressed include: subsurface methods, radar scattering, oceanography, microwave models, atmospheric correction, passive microwave systems, RS in tropical forests, moderate resolution land analysis, SAR geometry and SNR improvement, image analysis, inversion and signal processing for geoscience, surface scattering, rain measurements, sensor calibration, wind measurements, terrestrial ecology, agriculture, geometric registration, subsurface sediment geology, radar modulation mechanisms, radar ocean scattering, SAR calibration, airborne radar systems, water vapor retrieval, forest ecosystem dynamics, land analysis, multisensor data fusion. Also considered are: geologic RS, RS sensor optical measurements, RS of snow, temperature retrieval, vegetation structure, global change, artificial intelligence, SAR processing techniques, geologic RS field experiment, stochastic modeling, topography and Digital Elevation model, SAR ocean waves, spaceborne lidar and optical, sea ice field measurements, millimeter waves, advanced spectroscopy, spatial analysis and data compression, SAR polarimetry techniques. Also discussed are: plant canopy modeling, optical RS techniques, optical and IR oceanography, soil moisture, sea ice back scattering, lightning cloud measurements, spatial textural analysis, SAR systems and techniques, active microwave sensing, lidar and optical, radar scatterometry, RS of estuaries, vegetation modeling, RS systems, EOS/SAR Alaska, applications for developing countries, SAR speckle and texture.

Source record↗
NASA NTRS1978

Skylab EREP Investigations Summary

The problems in the areas of agriculture, range and forestry; land use and cartography; geology and hydrology; oceans atmosphere, and data analysis techniques were investigated and summarized using Earth Resources Experiment Package (EREP) data.

Pierson, W. J.↗
NASA NTRS1981

Geologic remote sensing

Remote-sensing techniques based on the analysis of spectral reflectance, spectral emittance, thermal inertia, and radar measurements are reviewed. Specific applications of Landsat multispectral scanner are examined with emphasis on mineral exploration. The potential of satellite systems for detailed lithologic mapping is pointed out.

Goetz, A. F. H.↗
NASA NTRS1981

Structure, composition and thermal state of the crust in Brazil

Efforts in support of a geomagnetic survey of the Brazilian area are described. Software to convert MAGSAT data tapes to the Burroughs/B-6700 binary format was developed and tested. A preliminary analysis of the first total intensity anomaly map was performed and methodologies for more intensive analysis were defined. The sources for correlative geological, aeromagnetic, and gravimetric data are described.

Pacca, I. I. G.↗
NASA NTRS1985

Practical applications of Landsat data

Some practical applications of Landsat MSS and TM data are discussed, including renewable resource inventory and monitoring; water resources inventory and assessment; and urban land use analysis. Consideration is also given to the geological applications of Landsat MSS and TM data. These applications include: mapping major geological units; rock-type recognition; mapping volcanic surface deposits; and mapping linears. The TM and MSS spectral bands corresponding to the data applications are listed in a table.

Conner, P. K.↗
NASA NTRS1988

Terrestrial imaging spectroscopy

Recent advances in imaging spectroscopy for remote sensing applications are discussed, reviewing the results of recent investigations. The advantages offered by the higher spectral resolution of imaging spectroscopy relative to scanners such as Landsat MSS and TM are explained; the design and performance of the Airborne Imaging Spectrometer (Vane et al., 1984) are described and illustrated with drawings, photographs, and sample images; data processing and analysis techniques are outlined; and applications to geological and botanical research are considered.

Vane, Gregg↗
NASA NTRS1992

Pax permanent Martian base: Space architecture for the first human habitation on Mars, volume 5

America at the Threshold: Report of the Synthesis Group on America's Space Exploration Initiative (the 'Synthesis Report,' sometimes called the Stafford Report after its astronaut chair, published in 1991) recommended that NASA explore what it called four 'architectures,' i.e., four different scenarios for habitation on Mars. The Advanced Design Program in Space Architecture at the University of Wisconsin-Milwaukee supported this report and two of its scenarios--'Architecture 1' and 'Architecture 4'--during the spring of 1992. This report investigates the implications of different mission scenarios, the Martian environment, supporting technologies, and especially human factors and environment-behavior considerations for the design of the first permanent Martian base. The report is comprised of sections on mission analysis, implications of the Martian atmosphere and geologic environment, development of habitability design requirements based on environment-behavior and human factors research, and a full design proposed (concept design and design development) for the first permanent Martian base and habitat. The design is presented in terms of a base site plan, master plan based on a Mars direct scenario phased through IOC, and design development details of a complete Martian habitat for 18 crew members including all laboratory, mission control, and crew support spaces.

Huebner-Moths, Janis↗
NASA NTRS2023

Validity of the Landsat Surface Reflectance Archive for Aquatic Science: Implications for Cloud-Based Analysis

Originally developed for terrestrial science and applications, the US Geological Survey Landsat surface reflectance (SR) archive spanning ~ 40 yr of observations has been increasingly utilized in large‐scale water‐quality studies. These products, however, have not been rigorously validated using in situ measured reflectance. This letter quantifies and demonstrates the quality of the SR products by harnessing a sizeable global dataset ( N = 1100). We found that the Landsat 8/9 SR in the green and red bands marginally meet the targeted accuracy requirements (30%), whereas the uncertainties in the blue and coastal‐aerosol bands ranged from 48% to 110%. We further observed > +25% biases in the visible bands of Landsat 5/7 SR, which can introduce an apparent downward trend when applied in time‐series analyses combined with Landsat 8/9. Users must exercise caution when using this archive for trend analyses, and progress in atmospheric correction is required to foster advanced applications of the Landsat archive for aquatic science.

Landsat, lakes, harmful algal blooms↗
NASA NTRS1998

Introduction to special section: early Mars

Ongoing studies of the evolution of the Martian cratered highlands, the nature of the planet's early climate, and the recent announcement of possible evidence of ancient life in the ALH 84001 meteorite have reinvigorated interest in the conditions that prevailed on Mars during its first billion years of geologic history. To address this interest and assess our current understanding of these issues, the Lunar and Planetary Institute hosted a 4-day Conference on Early Mars in Houston in April of 1997. The papers contained in this special section are a product of that meeting. The purpose of the conference was twofold: (1) to consider how impacts, volcanism, and the presence of abundant water affected the physical and chemical environment that existed on Mars 4 Gyr ago, particularly as it related to the nature of the global climate, the origin of the valley networks, the geologic and mineralogic evolution of the surface, the aqueous geochemistry of groundwater, and the existence of local environments that may have been conducive to the development of indigenous life and the preservation of its signature in the geologic record; and (2) to discuss what observations or experiments might he included in future spacecraft missions to test the ideas and expectations arising from purpose 1. While pertinent issues of early atmospheric and solar evolution were also addressed, the primary discussion at the conference focused on the evidence and constraints provided by the geologic records of Earth, the Moon, and Mars and analysis of the SNC meteorites. The papers contained in this special section span the full range of these topics, including the stability of the early atmosphere to erosion by the solar wind, the geologic environment from which the SNC meteorites originated, geomorphic evidence regarding the nature of the early Martian climate and hydrologic cycle, the potential impact of the past and present environment on the preserved signature of ancient life, and a discussion of the capabilities of a lander-based X ray diffraction and fluorescence instrument to assess the potential for past fossilization from the mineralogy of the current local surface environment. The issues raised at the conference, and by the papers included in this special section, will be the focus of ongoing attention as the intensity and scope of Mars exploration increases over the next decade.

NASA Center ARC↗
NASA NTRS1982

Resolution versus speckle relative to geologic interpretability of spaceborne radar images - A survey of user preference

A survey conducted to evaluate user preference for resolution versus speckle relative to the geologic interpretability of spaceborne radar images is discussed. Thirteen different resolution/looks combinations are simulated from Seasat synthetic-aperture radar data of each of three test sites. The SAR images were distributed with questionnaires for analysis to 85 earth scientists. The relative discriminability of geologic targets at each test site for each simulation of resolution and speckle on the images is determined on the basis of a survey of the evaluations. A large majority of the analysts respond that for most targets a two-look image at the highest simulated resolution is best. For a constant data rate, a higher resolution is more important for target discrimination than a higher number of looks. It is noted that sand dunes require more looks than other geologic targets. At all resolutions, multiple-look images are preferred over the corresponding single-look image. In general, the number of multiple looks that is optimal for discriminating geologic targets is inversely related to the simulated resolution.

Ford, J. P.↗
NASA NTRS1984

Preliminary Geologic/spectral Analysis of LANDSAT-4 Thematic Mapper Data, Wind River/bighorn Basin Area, Wyoming

A LIDQA evaluation for geologic applications of a LANDSAT TM scene covering the Wind River/Bighorn Basin area, Wyoming, is examined. This involves a quantitative assessment of data quality including spatial and spectral characteristics. Analysis is concentrated on the 6 visible, near infrared, and short wavelength infrared bands. Preliminary analysis demonstrates that: (1) principal component images derived from the correlation matrix provide the most useful geologic information. To extract surface spectral reflectance, the TM radiance data must be calibrated. Scatterplots demonstrate that TM data can be calibrated and sensor response is essentially linear. Low instrumental offset and gain settings result in spectral data that do not utilize the full dynamic range of the TM system.

Lang, H. R.↗