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  • General Chemistry  (12,444)
  • Lunar and Planetary Science and Exploration  (4,686)
  • Cell & Developmental Biology  (3,483)
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  • 2000-2004  (4,111)
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  • 201
    Publication Date: 2018-06-11
    Description: Assigning the material species to each asteroid spectral type and finding out the corresponding meteorite category is crucial to make the global material map in the whole asteroid belt and to understand the evolution of the asteroid belt. Recent direct observations by spacecrafts are revealing new intriguing aspects of asteroids which cannot be obtained solely from ground-based observations or meteorite studies. However identification of the real material species constituting asteroids and their corresponding meteorite analogs are still ambiguous. Space weathering makes difficult to identify the true material, and there is still a great gap between the remote sensing data on the global surface and the local microscopic data from meteorites. Sample return from asteroids are inevitable to solve these problems. For this purpose sample return missions to asteroids belonging to various spectral classes are required. The HAYABUSA spacecraft (prelaunch name is MUSESC) launched last year is the first attempt on this concept. This report presents outline of the mission with special stress on its science.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Asteroids, Meteors, and Comets; LPI-Contrib-1197
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  • 202
    Publication Date: 2018-06-11
    Description: Several spacecraft missions have recently targeted asteroids to study their morphologies and physical properties (e.g. Galileo, NEAR Shoemaker), and more are planned. MUSES-C is a Japanese mission designed to rendezvous with a near-Earth asteroid (NEA). The MUSES-C spacecraft, Hayabusa, was launched successfully in May 2003. It will rendezvous with its target asteroid in 2005, and return samples to the Earth in 2007. Its target, 25143 Itokawa (1998 SF36), made a close approach to the Earth in 2001. We collected an extensive ground-based database of broadband photometry obtained during this time, which maximized the phase angle coverage, to characterize this target in preparation for the mission. Our project was designed to capitalize on the broadband UBVRI photometric observations taken with a series of telescopes, instrumentation, and observers. Photometry and spectrophotometry of Itokawa were acquired at Lowell, McDonald, Steward, Palomar, Table Mountain and Kiso Observatories. The photometric data sets were combined to calculate Hapke model parameters of the surface material of Itokawa, and examine the solar-corrected broadband color characteristics of the asteroid. Broadband photometry of an object can be used to: (1) determine its colors and thereby contribute to the understanding of its surface composition and taxonomic class, and (2) infer global physical surface properties of the target body. We present both colors from UBVRI observations of the MUSES-C target Itokawa, and physical properties derived by applying a Hapke model to the broadband BVRI photometry.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Asteroids, Meteors, and Comets; LPI-Contrib-1197
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  • 203
    Publication Date: 2018-06-11
    Description: The Mars Exploration Rovers carry four Panoramic Camera (Pancam) instruments (two per rover) that have obtained high resolution multispectral and stereoscopic images for studies of the geology, mineralogy, and surface and atmospheric physical properties at both rover landing sites. The Pancams are also providing significant mission support measurements for the rovers, including Sun-finding for rover navigation, hazard identification and digital terrain modeling to help guide long-term rover traverse decisions, high resolution imaging to help guide the selection of in situ sampling targets, and acquisition of education and public outreach imaging products.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Special Session: Mars Missions; LPI-Contrib-1197
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  • 204
    Publication Date: 2018-06-11
    Description: The Mars Exploration Rovers each carry a set of Magnetic Properties Experiments designed to investigate the properties of the air-borne dust in the Martian atmosphere. It is a preferred interpretation of previous experiments (Viking 1 & 2, 1976 and Mars Pathfinder, 1997) that the airborne dust in the Martian atmosphere is primarily composed by composite silicate particles containing one or more highly magnetic minerals as a minor constituent, this minor constituent probably being dominated by the mineral maghemite (gamma-Fe2O3). The ultimate goal of the magnetic properties experiments on the Mars Exploration Rover mission is to provide some information/constraints on whether the dust is formed by volcanic, meteoritic, aqueous, or other processes. In detail, the objectives are: a) To identify the magnetic mineral(s) in the dust, soil and rocks on Mars. b) To establish if the magnetic material is present in the form of nanosized (d 〈 10 nm) superparamagnetic crystallites embedded in the micrometer sized airborne dust part icles. c) To establish if the magnets are culling a subset of strongly magnetic particles or if essentially all particles of the airborne dust are sufficiently magnetic to be attracted by the magnets. d) Detect compositional differences between the airborne dust and the soil and rock sites which are investigated at two landing sites. To accomplish these goals the Mars Exploration Rovers each carry a set of permanent magnets of several different strengths and sizes. Each magnet has its own specific objective.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Special Session: Mars Missions; LPI-Contrib-1197
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  • 205
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    In:  CASI
    Publication Date: 2018-06-11
    Description: The Eucrite Parent Body (4 Vesta). The eucrites are basalts that contain approx. 18 wt% FeO and contain trace metal. The eucrites are very depleted in siderophile elements, so it appears that the source regions of these basalts once equilibrated with Fe-Ni metal. Therefore, it is of interest to ask what fo2 is required to precipitate metal from a liquid of eucrite composition. Or in other words, what f02 did eucrites form under? This fo2 has been determined experimentally by and was found to be IW-1. Therefore, eucrites formed at about IW-1. In addition, it is interesting to note that assuming X(sub feo) = alpha(sub FeO) allows calculation of eucrite fo2 (assuming equilibrium with Fe metal). This calculation yields the same result as the experiments to within approx. 0.25 log units, reinforcing this result.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Workshop on Oxygen in the Terrestrial Planets; 34; LPI-Contrib-1203
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  • 206
    Publication Date: 2018-06-11
    Description: We are currently investigating the biological population present in the highest and least explored perennial lakes on earth in the Bolivian and Chilean Andes, including several volcanic crater lakes of more than 6000 m elevation, in combination of microbiological and molecular biological methods. Our samples were collected in saline lakes of the Laguna Blanca Laguna Verde area in the Bolivian Altiplano and in the Licancabur volcano crater (27 deg. 47 min S/67 deg. 47 min. W) in the ongoing project studying high altitude lakes. The main goal of the project is to look for analogies with Martian paleolakes. These Bolivian lakes can be described as Andean lakes following the classification of Chong. We have attempted to isolate pure cultures and phylogenetically characterize prokaryotes that grew under laboratory conditions. Sediment samples taken from the Licancabur crater lake (LC), Laguna Verde (LV), and Laguna Blanca (LB) were analyzed and cultured using enriched liquid media under both aerobic and anaerobic conditions. All cultures were incubated at room temperature (15 to 20 C) and under light exposure. For the reported isolates, 36 hours incubation were necessary for reaching optimal optical densities to consider them viable cultures. Ten serial dilutions starting from 1% inoculum were required to obtain a suitable enriched cell culture to transfer into solid media. Cultures on solid medium were necessary to verify the formation of colonies in order to isolate pure cultures. Different solid media were prepared using several combinations of both trace minerals and carbohydrates sources in order to fit their nutrient requirements. The microorganisms formed individual colonies on solid media enriched with tryptone, yeast extract and sodium chloride. Cells morphology was studied by optical and electronic microscopy. Rodshape morphologies were observed in most cases. Total bacterial genomic DNA was isolated from 50 ml late-exponential phase culture by using the CTAB miniprep protocol. The 16S rRNA genes were amplified by PCR using both Bacteria- and Archaeauniversal primer sets: 27f and 1492r, 21f and 1492r respectively. Sequences of 16S rRNA gene were determined and initially compared with reference sequences contained in the EMBL nucleotide sequence database by using the BLAST program and were subsequently aligned with 16S rRNA reference sequences in the ARB package (http://www.mikro.biologie.tu-muenchen.de). Aligned sequences were inserted within a stable phylogenetic tree by using the ARB parsimony tool. In this work we report the morphology and phylogenetic characterization of two isolates belonged to Laguna Blanca sediments.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Astrobiology; LPI-Contrib-1197
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  • 207
    Publication Date: 2018-06-11
    Description: Mineralogical analysis is a critical component of planetary surface exploration. Chemical data alone leave serious gaps in our understanding of the surfaces of planets where complex minerals may form in combination with H, S, and halogens. On such planets (e.g., Mars) a single chemical composition may represent a range of mineral assemblages. For example, Viking chemical analyses of excavated duricrust indicate that Mg and S are correlated and ~10% MgSO4 (anhydrous weight) is a likely cementing agent. Pathfinder chemical data support a similar abundance of MgSO4 in the most altered materials. However, there are many possible Mg-sulfates with widely varying hydration states (including dehydrated and 1-, 2-, 3-, 4-, 5-, 6-, and 7-hydrates). In addition, other sulfate minerals such as gypsum (CaSO4 .2H2O) and other salts containing Cl may also exist. X-ray diffraction (XRD) has the ability to decipher mixtures of these phases that would be difficult, if not impossible to unravel using only chemical or spectral data.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: The Future of Mars Surface Exploration; LPI-Contrib-1197
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  • 208
    Publication Date: 2018-06-11
    Description: Aeolian abrasion is operative in many arid locations on Earth and is probably the dominant rock erosion process in the current Martian environment. Therefore, understanding the controlling parameters and rates of aeolian abrasion provides 1) insight into the stability of rocks on planetary surfaces and the environments under which the rocks abrade, and 2) a link between ventifact (a rock abraded by windblown particles) morphology and: a) abrasion conditions, b) possible ancient environments under which the rocks were abraded, and c) rock properties. promising and we plan further investigations in the wind tunnel and field. Our intent here is to discuss the basic technique, initial results, and upcoming plans.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: The Future of Mars Surface Exploration; LPI-Contrib-1197
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  • 209
    Publication Date: 2018-06-11
    Description: In order to minimize the forward contamination of Mars, spacecraft are assembled under cleanroom conditions that require several procedures to clean and sterilize components. Surface characteristics of spacecraft materials may contribute to microbial survival on the surface of Mars by protecting spores from sterilizing agents, including UV irradiation. The primary objective of this study was to evaluate the effects of surface characteristics of several spacecraft materials on the survival of Bacillus subtilis spores under simulated Martian conditions.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Astrobiology Stew: Pinch of Microbes, Smidgen of UV, Touch of Organics, and Dash of Meteorites; LPI-Contrib-1197
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  • 210
    Publication Date: 2018-06-11
    Description: We present data and results from an ongoing project of astrobiological high-altitude expeditions investigating the highest and least explored perennial lakes on Earth in the Bolivian and Chilean Andes, including several volcanic crater lakes nearing and beyond 6,000 m in elevation. In the next five years, they will provide the first integrated long-term astrobiological characterization and monitoring of lacustrine environments and their biology for such altitude. These extreme lakes are natural laboratories. They provide the field data missing beyond 4,000 m to complete our understanding of terrestrial lakes and biota. Research on the effects of UV has been performed in lower altitude lakes and models of UV flux over time are being developed. Lakes showing a high content of dissolved organic material (DOM) shield organisms from UV. DOM acts as a natural sunscreen as it influences the water transparency, therefore is a determinant of photic zone depth. In sparsely vegetated alpine areas, lakes are clearer and offer less protection from UV to organisms living in the water. Transparent water and high UV irradiance may maximize the penetration and effect of UV radiation. Shallow-water communities in these lakes are particularly sensitive to UV radiation. The periphyton can live on various susbtrates. While on rocks, it includes immobile species that cannot seek low UV refuges unlike sediment-dwelling periphyton or alpine phytoflagellates which undergo vertical migration. Inhibition of algal photosynthesis by UV radiation has been documented in laboratory and showed that phytoplankton production is reduced by formation of nucleic acid lesions or production of peroxides and free oxygen radicals. of peroxides and free oxygen radicals. Our project is providing the field data that is missing from natural laboratories beyond 4,000 m and will complement the vision of the effects of UV on life and its adaptation modes (or lack thereof).
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Astrobiology Stew: Pinch of Microbes, Smidgen of UV, Touch of Organics, and Dash of Meteorites; LPI-Contrib-1197
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  • 211
    Publication Date: 2018-06-11
    Description: We have developed and tested a theoretical model of impact cratering in aerogels that derives the impact crater dimensions directly from the energy and momentum deposition of the projectile. In this paper, our work is outlined.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Big Dust, Little Dust, and Aerogel; LPI-Contrib-1197
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  • 212
    Publication Date: 2018-06-11
    Description: In the robotic search for life on Mars, different proposed missions will analyze the chemical and biological signatures of life using different platforms. The analysis of samples via analytical instrumentation on the surface of Mars has thus far only been attempted by the two Viking missions. Robotic arms scooped relogith material into a pyrolysis oven attached to a GC/MS. No trace of organic material was found on any of the two different samples at either of the two different landing sites. This null result puts an upper limit on the amount of organics that might be present in Martian soil/rocks, although the level of detection for each individual molecular species is still debated. Determining the absolute limit of detection for each analytical instrument is essential so that null results can be understood. This includes investigating the trade off of using pyrolysis versus liquid solvent extraction to release organic materials (in terms of extraction efficiencies and the complexity of the sample extraction process.) Extraction of organics from field samples can be accomplished by a variety of methods such utilizing various solvents including HCl, pure water, supercritical fluid and Soxhelt extraction. Utilizing 6N HCl is one of the most commonly used method and frequently utilized for extraction of organics from meteorites but it is probably infeasible for robotic exploration due to difficulty of storage and transport. Extraction utilizing H2O is promising, but it could be less efficient than 6N HCl. Both supercritical fluid and Soxhelt extraction methods require bulky hardware and require complex steps, inappropriate for inclusion on rover spacecraft. This investigation reports the efficiencies of pyrolysis and solvent extraction methods for amino acids for different terrestrial samples. The samples studied here, initially created in aqueous environments, are sedimentary in nature. These particular samples were chosen because they possibly represent one of the best terrestrial analogs of Mars and they represent one of the absolute best case scenarios for finding organic molecules on the Martian surface.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Astrobiology; LPI-Contrib-1197
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  • 213
    Publication Date: 2018-06-11
    Description: Palagonitic tephra from certain areas on Mauna Kea Volcano (Hawaii) are well-established spectral and magnetic analogues of high-albedo regions on Mars. By definition, palagonite is "a yellow or orange isotropic mineraloid formed by hydration and devitrification of basaltic glass." The yellow to orange pigment is nanometer-sized ferric oxide particles (np-Ox) dispersed throughout the hydrated basaltic glass matrix. The hydration state of the np-Ox particles and the matrix is not known, but the best Martian spectral analogues contain allophane-like materials and not crystalline phyllosilicates. Martian low-albedo regions are also characterized by a palagonite-like ferric absorption edge, but, unlike the highalbedo regions, they also show evidence for absorption by ferrous iron. Thermal emission spectra (TES) obtained by the Mars Global Surveyor Thermal Emission Spectrometer suggest that basaltic (surface Type 1) and andesitic (surface Type 2) volcanic compositions preferentially occur in southern (Syrtis Major) and northern (Acidalia) hemispheres, respectively. The absence of a ferric-bearing component in the modeling of TES spectra is in apparent conflict with VNIR spectra of Martian dark regions, as discussed above. However, the andesitic spectra have also been interpreted as oxidized basalt using phyllosilicates instead of high-SiO2 glass as endmembers in the spectral deconvolution of surface Type 2 TES spectra. We show here that laboratory VNIR and TES spectra of rinds on basaltic rocks are spectral endmembers that provide a consistent explanation for both VNIR and TES data of Martian dark regions.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars: Remote Sensing and Terrestrial Analogs; LPI-Contrib-1197
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  • 214
    Publication Date: 2018-06-11
    Description: We have examined the influence of a regolith on the water cycle with a focus on high obliquity periods on Mars. Our findings show that while the regolith will almost certainly interact with the atmosphere initially, it is only a transient effect, and ice will form on the surface once the regolith is effectively isolated from the atmosphere. These low latitude deposits could conceivably be ice deposits formed at high obliquity and are certainly presently out of thermal equilibrium, but remain due to the insulating effect of a dust lag.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Special Session: Mars Climate Change; LPI-Contrib-1197
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  • 215
    Publication Date: 2018-06-11
    Description: The Sensor Web is a macroinstrument concept that allows for the spatio-temporal understanding of an environment through coordinated efforts between multiple numbers and types of sensing platforms, including, in its most general form, both orbital and terrestrial and both fixed and mobile. Each of these platforms, or pods, communicates within its local neighborhood and thus distributes information to the instrument as a whole. The result of sharing and continual processing of this information among all the Sensor Web elements will result in an information flow and a global perception of and reactive capability to the environment. As illustrated, the Sensor Web concept also allows for the recursive notion of a web of webs with individual distributed instruments possibly playing the role of a single node point on a larger Sensor Web instrument. In particular, the fusion of inexpensive, yet sophisticated, commercial technology from both the computation and telecommunication revolutions has enabled the development of practical, fielded, and embedded in situ systems that have been the focus of the NASA/JPL Sensor Webs Project (http://sensorwebs.jpl.nasa.gov/). These Sensor Webs are complete systems consisting of not only the pod elements that wirelessly communicate among themselves, but also interfacing and archiving software that allows for easy use by the end-user. Previous successful deployments have included environments as diverse as coastal regions, Antarctica, and desert areas. The Sensor Web has broad implications for Earth and planetary science and will revolutionize the way experiments and missions are conceived and performed. As part of our current efforts to develop a macrointelligence within the system, we have deployed a Sensor Web at the Central Avra Valley Storage and Recovery Project (CAVSARP) facility located west of Tucson, AZ. This particular site was selected because it is ideal for studying spatio-temporal phenomena and for providing a test site for more sophisticated hydrological studies in the future.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Missions and Instruments: Hopes and Hope Fulfilled; LPI-Contrib-1197
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  • 216
    Publication Date: 2018-06-11
    Description: Much of the surface of Mars has been intensely reworked by aeolian processes and key evidence about the history of the Martian environment seems to be hidden beneath a widespread layer of debris (paleo lakes and rivers, faults, impact craters). In the same way, the recent geological and hydrological history of the eastern Sahara is still mainly hidden under large regions of wind-blown sand which represent a possible terrestrial analog to Mars. The subsurface geology there is generally invisible to optical remote sensing techniques, but radar images obtained from the Shuttle Imaging Radar (SIR) missions were able to penetrate the superficial sand layer to reveal parts of paleohydrological networks in southern Egypt.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars: Radar, Gamma Ray Spectrometer, and Cratering Mineralogy; LPI-Contrib-1197
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  • 217
    Publication Date: 2018-06-11
    Description: High-resolution images from the Mars Orbiter Camera reveal impact craters as small as 10 m [1], and still smaller craters (〈 0.5 m) have been inferred from surface boulders at the Pathfinder landing site [2]. Any small-scale impact environment at scales of meters or smaller would obviously be a potent contributor to erosive processes on Mars, to the small-scale evolution of its surface, and to mineralogic/ compositional alterations of its surface materials. It is not very clear from the analysis of Viking and Pathfinder images, however, what the smallest craters are on Mars. As a consequence, it might be informative to consult atmospheric-entry calculations that specify the smallest meteoroid able to survive passage through the present martian atmosphere. We conducted such calculations and perceive them as providing useful constraints for understanding small-scale surface processes on Mars and as possible guides for the interpretation of surface images from past and future lander missions.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars Impact Cratering; LPI-Contrib-1197
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  • 218
    Publication Date: 2018-06-11
    Description: Characterizing alteration of the rocks on Mars is difficult, but some guidelines can be made through comparison with terrestrial volcanic alteration. Subaerial volcanic activity on the Hawaiian islands and subglacial volcanic activity on Iceland have led to the formation of a variety of silicate and iron oxide-rich alteration products that may serve as models for chemical alteration on Mars. Multiple samples have been collected from palagonitized tuffs, altered pillow lavas, altered tephra, and S-rich vents for study in the lab. Variations in the kinds of alteration products have been observed depending on the sample environment. We are defining associations between the alteration products and formation conditions that can be used to provide information about environmental conditions on Mars. In particular, we are providing definitions for palagonitic, pedogenic and solfataric alteration that can be used to characterize these alteration processes.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars: Remote Sensing and Terrestrial Analogs; LPI-Contrib-1197
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  • 219
    Publication Date: 2018-06-11
    Description: We report on laboratory experiments that have produced dilute brines under controlled conditions meant to simulate past and present Mars. We allowed an SNC-derived mineral mix to react with pure water under a simulated present-Mars atmosphere for seven months. We then subjected the same mineral mix to a similar aqueous environment for one year, but with a simulated Mars atmosphere that contained the added gases SO2, HCl and NO2. The addition of acidic gases was designed to mimic the effects of volcanic gases that may have been present in the martian atmosphere during periods of increased volcanic activity. The experiments were performed at one bar and at two different temperatures in order to simulate subsurface conditions where liquid water and rock are likely to interact on Mars. The dominant cations dissolved in the solutions we produced were Ca(2+), Mg(2+), Al(3+) and Na(+), while the major anions are dissolved C, F(-), SO4(2-) and Cl(-). Typical solution pH was 4.2 to 6.0 for experiments run with a Mars analog atmosphere, and 3.6-5.0 for experiments with acidic gases added. Abundance patterns of elements in the synthetic sulfate-chloride brines produced under acidic conditions were distinctly unlike those of terrestrial ocean water, terrestrial continental waters, and those measured in the martian fines at the Mars Pathfinder and Viking 1 and 2 landing sites. In particular, the S/Cl ratio in these experiments was about 200, compared with an average value of approx. 5 in martian fines. In contrast, abundance patterns of elements in the brines produced under a present day Mars analog atmosphere were quite similar to those measured in the martian fines at the Mars Pathfinder and Viking 1 and 2 landing sites. This suggests that salts present in the martian regolith may have formed over time as a result of the interaction of surface or subsurface liquid water with basalts in the presence of a martian atmosphere similar in composition to that of today, rather than in an atmosphere higher in acidic volatiles.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars: Gullies, Fluids, and Rocks; LPI-Contrib-1197
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  • 220
    Publication Date: 2018-06-11
    Description: Gullies on Devon Island, High Arctic, which form by melting of transient surface ice and snow covers and offer morphologic and contextual analogs for gullies reported on Mars are reported to display enhancements in biological activity in contrast to surrounding polar desert terrain.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars: Gullies, Fluids, and Rocks; LPI-Contrib-1197
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  • 221
    Publication Date: 2018-06-11
    Description: While Mars is now largely a dry and barren place, recent data have indicated that water has flowed at specific locations within the last approx. 10(exp 6) y. This had led to a resurgence of interest in theoretical and experimental work aimed at understanding the behavior of water on Mars. There are several means whereby the stability of liquid water on Mars could be increased, one being the presence solutes that would depress the freezing point. Salt water on Earth is about 0.5M NaCl, but laboratory experiments suggest that martian salt water is quite different. We recently began a program of laboratory measurements of the stability of liquid water, ice and ice-dust mixtures under martian conditions and here report measurements of the evaporation rate of 0.25M brine.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars: Gullies, Fluids, and Rocks; LPI-Contrib-1197
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  • 222
    Publication Date: 2018-06-11
    Description: Gullies are recognized as having an incised (often sinuous) channel, alcove, and apron morphology as defined. Previous detailed work has focused on the characteristics of southern hemisphere gullies; here we examine the distribution, morphology and depth of northern hemisphere gullies. Gully locations (both hemispheres) were compiled from the literature, not a global search, and thus the gullies studied here are the subset of the whole for which corresponding MOLA tracks are available. We find that the heads of the majority of N. hemisphere gullies commence in a specific cliff-forming layer, and average 250 m below the local surface. This observation suggests that the rock layer has a genetic relationship to gullies and is difficult at present to reconcile with gully formation from snowmelt, which predicts no correlation to rock layers. Gully locations and depths correspond to specific geologic units. We propose that in addition to ground ice and a melting mechanism, gully formation requires groundwater flow along or within specific rock units.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars: Gullies, Fluids, and Rocks; LPI-Contrib-1197
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  • 223
    Publication Date: 2018-06-11
    Description: The Lunar Soil Characterization Consortium (LSCC) has obtained samples of Luna 16, 20 and 24 soils. Although these particular samples encountered contamination during processing, preliminary results are consistent with previous integrated analyses and expand the soil data to three additional sites.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Lunar Sample Analysis; LPI-Contrib-1197
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  • 224
    Publication Date: 2018-06-11
    Description: Spectral measurements of Mercury's surface indicate low or no FeO content as determined from the absence of absorptions centered near 0.9 and 1.2 m. These observations support previous observations. At the Moon these ab-sorption bands are ubiquitous at varying depths. We have obtained spectra from the Moon with the same instrumentation and telescope for comparison. The lunar results are shown in a companion abstract.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mercury, Top to Bottom; LPI-Contrib-1197
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  • 225
    Publication Date: 2018-06-11
    Description: We have undertaken laboratory electromagnetic characterization of the total set of minerals identified by TES on the Martian surface in order to investigate experimentally the dielectric properties of the sediments covering it in the frequency range from 1 to 30 MHz. Volcanic Rocks with a well defined mineralogy and petrology from potential terrestrial analogues sites have also been included in the study. Our primary objective is to evaluate the range of electrical and magnetic losses that may be encountered by the various Radar sounding and imaging experiments dedicated to map the Martian subsurface searching for underground water. The electromagnetic properties of these Mars-like materials will be presented as a function of various geophysical parameters, such as porosity, bulk density and temperature. The secondary objective, is to locate regions were surface dielectric conditions are suitable for subsurface sounding.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars: Radar, Gamma Ray Spectrometer, and Cratering Mineralogy; LPI-Contrib-1197
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  • 226
    Publication Date: 2018-06-11
    Description: The Mars Exploration Rovers Spirit and Opportunity will arrive at their respective landing sites of Gusev Crater and Terra Meridiani in January 2004. During the 2001 and 2003 Mars Oppositions both landing sites were targeted for a series of radar observations using the telescopes of the Goldstone Deep Space Communications Complex (GDSCC). This paper will present results of terrestrial delay- Doppler radar observations of the landing sites, predictions for the surface properties that will be encountered, and, after successful landings, correlation between the predicted and observed surface properties. The in-situ observations made by both missions serve as ground truth for the validation of the high resolution radar mapping results.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars: Radar, Gamma Ray Spectrometer, and Cratering Mineralogy; LPI-Contrib-1197
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  • 227
    Publication Date: 2018-06-11
    Description: Recent results from gamma-ray and neutron spectrometers on Mars Odyssey indicate the presence of a hydrogen-rich layer tens of centimeters thick in the uppermost meter in high latitudes (greater than 60) on Mars. This hydrogen-rich layer correlates to regions of ice stability. Thus, the subsurface hydrogen is thought to be water ice constituting 35 plus or minus 15% by weight near the north and south polar regions. We refine the location of subsurface ice deposits at a less than km scale by combining existing spectroscopy data with surface features indicative of subsurface ice. A positive correlation between spectroscopy data and geomorphic ice indicators has been previously suggested for high latitudes. Here we expand the comparative study to northern mid latitudes (30 degrees N- 65 degrees N).
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Special Session: Mars Climate Change; LPI-Contrib-1197
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  • 228
    Publication Date: 2018-06-11
    Description: Although the Apollo 16 mission landed in the feldspathic lunar highlands, mass-balance models suggest that there is a 5-6% mare component in the mature soils collected at the site. Only one mare basalt greater than 1 cm was found and two surveys of 2-4 mm particles found that less than 1% of this size fraction is mare basalt. Similar surveys of the less than 1 mm size fraction of A16 soils found very little lithic mare basalt, but several percent of basaltic green, yellow, and orange glass. The green glass beads were identified as VLT picritic glass and the orange/yellow glass shards were a mix of high and low Ti mare-like glass, high-Al basaltic glass, and KREEPy glasses. Most previous studies of glasses in the A16 regolith were surveys that identified a high proportion of feldspathic glass because most of the glass is produced by local impacts. Because the number of mafic glasses found was low, few compositional groupings were identified. As part of our ongoing study of the mafic components of the Apollo 16 site, we specifically targeted mafic glasses from Apollo 16, selecting against the more feldspathic glasses. In this way we were able to identify over 300 mafic glasses (greater than 10 wt % FeO). We present here the major- and trace-element chemistry of the main glass groups and discuss the likely provenance of each group.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Lunar Crust as Sampled by Basins and Craters; LPI-Contrib-1197
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  • 229
    Publication Date: 2018-06-11
    Description: The complex pyroxene exsolution texture of the Moore County cumulate eucrite was interpreted by Miyamoto and Takeda as indicating initial cooling at 160 C/Ma followed by a sudden temperature rise and final cooling at 0.35 C/yr. They suggested initial cooling at a depth of approx. 8 km near the base of Vesta s crust, followed by impact excavation to its surface. Young Sm-Nd ages of approx. 4456, 4460, and 4410 Ma, respectively, for the Moore County, Moama, and Serra de Mag cumulate eucrites are puzzling because closure to Nd isotopic exchange would occur in only a few Ma at the above initial cooling rate. The exception to young ages among the cumulate eucrites is EET87520, with a 147Sm-147 - Nd-143 age of 4547-4598 Ma. We report here initial results of a combined mineralogical/chronological study of the Yamato 980318 feldspar-cumulate eucrite.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Achondrites: An Awesome Assortment; LPI-Contrib-1197
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  • 230
    Publication Date: 2018-06-11
    Description: Eucrites are basaltic meteorites of the howardite-eucrite-diogenite (HED) suite that originated on a differentiated asteroid, possibly 4 Vesta. Basaltic eucrites are divided into three subgroups based on composition: main group, Stannern-trend, and Nuevo Laredo-trend. The main group and Nuevo Laredo-trend define a sequence formed by fractional crystallization of pigeonite and plagioclase from primitive parent melts [2, 3]. The Stannern-trend cannot be explained this way, but may rather represent a partial-melt sequence of their parent body. However, this model seems inadequate to explain eucrite siderophile element contents, and it is difficult to develop a single unifying model for petrogenesis of all eucrites. Until recently, there were only four Stannern- trend eucrites. One is an anomalous partial cumulate. There is little geochemical variation among these meteorites, so the Stannern-trend was poorly defined. Geochemical studies have identified four additional eucrites as members of the Stannern-trend; one extends the Stannern-trend closer to the main group [5]. No detailed descriptions of these rocks have been published. In order to better integrate these eucrites into the suite, we have done petrologic study of them. They are: LEW 88010, PCA 82501, PCA 91006 and PCA 91179.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Achondrites: An Awesome Assortment; LPI-Contrib-1197
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  • 231
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    In:  CASI
    Publication Date: 2018-06-11
    Description: The howardite, eucrite and diogenite (HED) clan is the largest suite of crustal rocks available from a differentiated asteroid. Attempts to unravel the petrogenetic history of the HED parent body have tacitly assumed that the suite is representative of the crust, and thus can be used to understand the differentiation history of the entire parent body. This assumption is a holdover from a time when we knew little about the HED parent body. Much has changed. Is this assumption still valid? HED Geochemistry: The HED suite is composed
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Achondrites: An Awesome Assortment; LPI-Contrib-1197
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  • 232
    Publication Date: 2018-06-11
    Description: We have shown that partial melts of devolatilized Allende chondrite (CV3) have bulk compositions generally similar to those of angrites. Here we show that the recently described D'Orbigny and Sahara 99555 angrites are virtually identical in major-element composition to specific Allende experimental melts from. This observation has petrogenetic significance for the origins of the angrite clan.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Achondrites: An Awesome Assortment; LPI-Contrib-1197
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  • 233
    Publication Date: 2018-06-11
    Description: The science capabilities and features of an innovative and revolutionary approach to remote sensing imaging systems, aimed at increasing the return on future space science missions many fold, are described. Our concept, called Multiple Instrument Distributed Aperture Sensor (MIDAS), provides a large-aperture, wide-field, diffraction-limited telescope at a fraction of the cost, mass and volume of conventional telescopes, by integrating optical interferometry technologies into a mature multiple aperture array concept that addresses one of the highest needs for advancing future planetary science remote sensing.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Outer Solar System; LPI-Contrib-1197
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  • 234
    Publication Date: 2018-06-11
    Description: Knowledge of the global distribution of Europan geologic units in time and space is a necessary step for the synthesis of the results of the Galileo mission and in preparation for future exploration (namely, by JIMO) of the satellite. We have initiated the production of the first Global Geological Map of Europa. As a base map, we use the recently published global photomosaic of Europa (U.S.G.S. Map I-2757) and additional Galileo SSI images at their original resolution. The map is being produced entirely on GIS format for analysis and combination with other datasets [1]. One of the main objectives of this project is to establish a global stratigraphic framework for Europa. In the absence of a well-developed cratering record, this goal will be achieved using the satellite s global network of lineaments (ridges, ridge complexes and bands; cf. [2]). Here we present the preliminary stratigraphic framework synthesized from the sequence of lineaments derived for the northern trailing hemisphere of Europa (Figure 1, below), and we discuss its significance and some emerging implications.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Outer Solar System; LPI-Contrib-1197
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  • 235
    Publication Date: 2018-06-11
    Description: A long-popular model for producing Ganymede s bright terrain involves flooding of low-lying graben with liquid water, slush, or warm, soft ice. The model suffers from major problems, however, including the absence of obvious near-surface heat sources, the negative buoyancy of liquid water, and the lack of a mechanism for confining the flows to graben floors. We show that topography - such as a global set of graben - causes subsurface (a hydrostatic) pressure gradients that can "suck" subsurface liquid water upward onto the floors of topographic lows (graben). As the low areas become full, the pressure gradients disappear and the resurfacing ceases. This provides an explanation for the observed straight dark-bright terrain boundaries: water cannot overflow the graben, so surfacing rarely embays craters and other rough topography. Subsurface liquid water must exist for the scenario to exist, of course, and is plausibly provided by tidal heating during an ancient orbital resonance. This abstract is a summary of Showman et al. recently submitted to Icarus.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Outer Solar System; LPI-Contrib-1197
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  • 236
    Publication Date: 2018-06-11
    Description: The Spitzer Space Telescope, formerly known as SIRTF, is now operational and delivers unprecedented sensitivity for the observation of Solar System targets. Spitzer's capabilities and first general results were presented at the January 2004 AAS meeting. In this poster, we focus on Spitzer's performance for moving targets, and the first Solar System results. Spitzer has three instruments, IRAC, IRS, and MIPS. IRAC (InfraRed Array Camera) provides simultaneous images at wavelengths of 3.6, 4.5, 5.8, and 8.0 microns. IRS (InfraRed Spectrograph) has 4 modules providing low-resolution (R=60-120) spectra from 5.3 to 40 microns, high-resolution (R=600) spectra from 10 to 37 m, and an autonomous target acquisition system (PeakUp) which includes small-field imaging at 15 m. MIPS (Multiband Imaging Photometer for SIRTF) does imaging photometry at 24, 70, and 160 m and low-resolution (R=15-25) spectroscopy (SED) between 55 and 96 microns. Guaranteed Time Observer (GTO) programs include the moons of the outer Solar System, Pluto, Centaurs, Kuiper Belt Objects, and comets
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Outer Solar System; LPI-Contrib-1197
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  • 237
    Publication Date: 2018-06-11
    Description: The objective of this investigation is to develop a prototype floodwater detection algorithm for Hyperion imagery. It will be run autonomously onboard the EO-1 spacecraft under the Autonomous Sciencecraft Experiment (ASE). This effort resulted in the development of two classifiers for floodwater, one of several classifier types that have been developed and will be uploaded to EO-1 in early 2004 in order to detect change related to transient processes such as volcanism, flooding, and ice formation and retreat.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Image Processing and Earth Observations; LPI-Contrib-1197
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  • 238
    Publication Date: 2018-06-11
    Description: Planetary geologists, geomorphologists, and hydrologists have hypothesized that Mars is a dynamic, water-enriched planet since the Mariner and Viking missions based on geologic, geomorphic, and topographic information. Recent acquisition of Gamma Ray and Neutron Spectrometer information has added further credence to this hypothesis. A unique investigation is underway to work towards being able to successfully map the extent and depth of water on Mars. Researchers from the University of Arizona and members of the Autonomous Sciencecraft Experiment (ASE) have been compiling multiple layers of information in time and space at the Central Avra Valley Storage and Recovery Project (CAVSARP) site, Tucson, Arizona, for eventual comparative analysis. This information has been acquired from a variety of observational/scientific platforms in controlled conditions. CAVSARP facility:
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Image Processing and Earth Observations; LPI-Contrib-1197
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  • 239
    Publication Date: 2018-06-11
    Description: The MARIE instrument aboard the 2001 Mars Odyssey spacecraft detects energetic charged particles in the Galactic Cosmic Radiation (GCR) and during solar particle events (SPE) [1]. As of this writing (January 2004), MARIE has been turned off, after losing communication with the spacecraft during the large SPE of October 28, 2003. However, during the prior 20 months, MARIE collected data almost continuously, observing several solar events and the nearly-constant GCR. There is still a possibility the instrument can be recovered, and troubleshooting efforts are scheduled to begin in May 2004, following the completion of the primary missions of MER-A (Spirit) and MER-B (Opportunity). At present, Odyssey is acting as a telecommunications relay for the rovers and only routine science operations are permitted in this mode.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Human Occupation of Space: Radiation, Risk, and Refuse; LPI-Contrib-1197
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  • 240
    Publication Date: 2018-06-11
    Description: Astronaut missions to Mars may be decades in the future, but contemporary estimates of the physical capabilities of the crewmembers upon arrival after prolonged transit can guide development of operational requirements to be imposed on them. Requirements for functional capacities will differ depending on whether they land in a spartan ascent vehicle or in a well-equipped habitat, but each of those options brings with it certain operational risks. Rehabilitation will be an important factor for crew health, safety and efficiency after the multi-month transit from Earth. Specific recommendations will be stipulated for the time to be allotted for on-planet rehabilitation before the first planned surface excursion, such as the transfer from the ascent-lander to the habitat-lander. Three sequential workshops (the third including extramural experts in appropriate fields) examined the likely capabilities of crewmembers shortly after landing on Mars, the predicted operational requirements they will face, and the near-term steps to close the gap between the requirements and capabilities.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Human Occupation of Space: Radiation, Risk, and Refuse; LPI-Contrib-1197
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  • 241
    Publication Date: 2018-06-11
    Description: One of the many questions of Martian exploration is to uncover the history of Mars, through analysis of the polar layered deposits (PLD). Martian polar ice caps hold most of the exposed water ice on the surface of Mars and yet their history and physical processes involved in their formation are unclear. In this work we present the latest imaging data acquired by the Mars Odyssey THermal EMission Imaging System (THEMIS) from the South Polar Residual Deposits (SPLD). We will concentrate our analysis on differences observed by THEMIS in winter/early spring and summer periods.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars Polar Processes: Land and Sky; LPI-Contrib-1197
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  • 242
    Publication Date: 2018-06-11
    Description: With the increasing challenges of planetary missions, and especially with the prospect of human exploration of the moon and Mars, the need for earth-based mission simulations has never been greater. The current focus on science as a major driver for planetary exploration introduces new constraints in mission design, planning, operations, and technology development. Analogue missions can be designed to address critical new integration issues arising from the new science-driven exploration paradigm. This next step builds on existing field studies and technology development at analogue sites, providing engineering, programmatic, and scientific lessons-learned in relatively low-cost and low-risk environments. One of the most important outstanding questions in planetary exploration is how to optimize the human and robotic interaction to achieve maximum science return with minimum cost and risk. To answer this question, researchers are faced with the task of defining scientific return and devising ways of measuring the benefit of scientific planetary exploration to humanity. Earth-based and spacebased analogue missions are uniquely suited to answer this question. Moreover, they represent the only means for integrating science operations, mission operations, crew training, technology development, psychology and human factors, and all other mission elements prior to final mission design and launch. Eventually, success in future planetary exploration will depend on our ability to prepare adequately for missions, requiring improved quality and quantity of analogue activities. This effort demands more than simply developing new technologies needed for future missions and increasing our scientific understanding of our destinations. It requires a systematic approach to the identification and evaluation of the categories of analogue activities. This paper presents one possible approach to the classification and design of analogue missions based on their degree of fidelity in ten key areas. Various case studies are discussed to illustrate the approach.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Human Occupation of Space: Radiation, Risk, and Refuse; LPI-Contrib-1197
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  • 243
    Publication Date: 2018-06-11
    Description: We use data from over 500 premapping orbits of Mars Global Surveyor magnetometer data to present statistical results on the characteristics of the plasma waves in the near Mars space. We find that plasma waves in the dayside Martian magnetosheath are primarily compressional waves (i.e. magnetosonic or mirror mode waves) and in the nightside magnetosheath and tail regions that the waves are primarily associated with ion gyromotion. Some of these waves are produced by gyrating oxygen ions and as such represent observations of the ongoing erosion of the Martian atmosphere by the solar wind.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars Polar Processes: Land and Sky; LPI-Contrib-1197
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  • 244
    Publication Date: 2018-06-11
    Description: One of the objectives of the Mars Scout mission, Phoenix, is to characterize the present state of water in the martian environment, in a location where water may play a significant role in the present and past habitability of Mars. Given the generally dry and cold climate of Mars today any substantial amount of water is expected to occur in the form of ground ice (subsurface ice) within the regolith. The Mars Odyssey Gamma Ray Spectrometer has indicated abundant subsurface hydrogen and inferred ground ice at high latitudes. Therefore, the Phoenix mission will be targeted to land in the northern high latitudes (approximately 65 degrees N - 75 degrees N) where ground ice is expected to be abundantly available for analysis. The lander will be capable of excavating, sampling, and analyzing, dry and water-rich/icy soils. The location and depth of excavation necessary to achieve the goals of sampling and analysis of icy material become important parameters to assess. In the present work we ask two key questions: 1) At what depth within the regolith do we expect to find ice? 2) How might this depth vary over the region of potential landing sites? Numerous lines of evidence can be employed to provide an indication of the presence or absence of shallow ground ice at the potential landing sites. For example geomorphology, neutrons, gamma rays, and theory each contribute clues to an overall understanding of the distribution of ice. Orbital observations provide information on a variety of spatial scales, typically 10 s of meters (patterned ground) to 100 s of kilometers (gamma rays). While information on all of these scales are important, of particular interest is how the presence and depth of ground ice might vary on spatial scales comparable to the lander and its work area. While ground ice may be stable (and present) on a regional scale, local-scale slopes and changes in the physical characteristics of soils can result in significant variations in the distribution of ice.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars Polar Processes: Land and Sky; LPI-Contrib-1197
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  • 245
    Publication Date: 2018-06-11
    Description: Water-ice in the Martian atmosphere was first identified in the Mariner 9 Infrared Interferometer Spectrometer (IRIS) spectra. The Viking Imaging Subsystem (VIS) instruments aboard the Viking orbiter also observed water-ice clouds and hazes in the Martian atmosphere. The MGS TES instrument is an infrared inferometer/spectrometer which covers the spectral range 6-50 micron with a selectable sampling resolution of either 5 or 10 per cm. Using the relatively independent and distinct spectral signatures for dust and water-ice, these two retrieved quantities have been retrieved simultaneously. Although the interrelations among the two quantities have been analyzed by Smith et al. and the retrievals are thought to be robust, understanding the impact of each quantity on the other during their retrievals as well as the impact from the surface for retrievals is important for correctly interpreting the science, and therefore requires close examination. An understanding of the correlation or a-correlation between dust and water-ice would aid in understanding the physical processes responsible for the transport of aerosols in the Martian atmosphere. In this presentation, we present an investigation of the correlation between water-ice and dust in the MGS TES data set.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars Polar Processes: Land and Sky; LPI-Contrib-1197
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  • 246
    Publication Date: 2018-06-11
    Description: Recent compelling evidence has been presented to suggest the presence of near-surface water or water ice on Mars. The Mars Orbiter Camera (MOC) has photographed relatively young fluvial features in the form of gullies which have been attributed to groundwater seepage. The Gamma Ray Spectrometer (GRS) from the Mars Odyssey spacecraft has detected large amounts of hydrogen in the Martian soil, inferred to come from water or water ice within the upper meter of the surface. We explore the model of groundwater seepage as the mechanism of gully formation as opposed to other mechanisms. We investigate the abundance of hydrogen to the depth at which gully-like features form. We see a positive correlation, which implies the presence of a groundwater system for Mars.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars: Hydrology, Drainage, and Valley Systems; LPI-Contrib-1197
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  • 247
    Publication Date: 2018-06-11
    Description: This study examines the relationships between three temporally distinct indicators of water on Mars: ancient craters with fluidized ejecta, relatively more recent gullies inside those craters, and current abundance of near surface hydrogen around those craters. We find an association between gully occurrence and large-scale geologic features; analysis indicates unique depth/diameter ratios for gullied craters in Sirenum Terra. Numerical comparisons of fluidized and non-fluidized, gullied and non-gullied craters suggest that the Argyre region could have had a near-surface water table that receded before recent times, while Sirenum Terra may have had an ancient water table that persists to this day.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars: Hydrology, Drainage, and Valley Systems; LPI-Contrib-1197
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  • 248
    Publication Date: 2018-06-11
    Description: The recent discovery of small Martian gullies has stimulated debate about the role that water plays on the Martian surface under current or recent conditions. Of critical importance in evaluating various gully hypotheses is reliable morphometric and orientation data. The former centers on such questions as whether the water (or another fluid) emanated from a surface or sub-surface source and the duration of flow. The latter ties into whether solar insolation has an important effect on formation of the initial water source and subsequent mobilization. Initial studies of gullies indicated a poleward orientation dependence, an observation which has recently been challenged. Herein we investigate the orientation of Martian gullies and the dependence of various parameters on the orientation. Whereas previous studies have been global or through most of the southern hemisphere, we focus on several specific regions. This approach offers some advantages in that regional variations are factored out, such that of lithology, ground water table depth (if any), surface thermal properties, and other parameters are more or less the same in a given region. Differences in gully attributes as a function of orientation within a region can more easily be attributable to solar insolation effects than is the case for global statistics. We use the orientation to constrain several classes of gully formation hypotheses. 1) A favored orientation toward the pole across all regions could indicate a process dominated by melting of cold trapped ice, snow, or condensed volatiles from incident sunlight during summer under current conditions. 2) Variations among all regions would be more consistent with mechanisms less strongly tied to current solar insolation, such as geothermal heating of ice. 3) Favored orientations within specific regions, but differing among regions, could indicate a preference for poleward ices and melting, with orientation being a function of age and dependent on variations in obliquity and precision. We find that the gullies fall into either categories 2 or 3, but not 1, indicating the recent melting of cold trapped condensates is unlikely the sole formation mechanism.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars: Hydrology, Drainage, and Valley Systems; LPI-Contrib-1197
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  • 249
    Publication Date: 2018-06-11
    Description: It has long been recognized that the high temperatures of the inner solar nebula (within approx. 3 AU) would not have allowed water to be incorporated into solids. However, the presence of water on the surface of Earth, as well as evidence for it on the surface of an early Mars imply that water was incorporated into solid bodies in this region. How this water was delivered to the solid bodies has yet to be identified. In this abstract we explore the possibility that hydrous minerals, such as phyllosilicates, formed somewhere in the asteroid belt region of the solar nebula or beyond, and then migrated inward where they would be accreted into larger bodies.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Origin of Planetary Systems; LPI-Contrib-1197
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  • 250
    Publication Date: 2018-06-11
    Description: To date, approximately 120 planet-sized objects have been discovered around other stars, mostly through the radial-velocity technique. This technique can provide information about a planet s minimum mass and its orbital period and distance; however, few other planetary data can be obtained at this point in time unless we are fortunate enough to find an extrasolar giant planet that transits its parent star (i.e., the orbit is edge-on as seen from Earth). In that situation, many physical properties of the planet and its parent star can be determined, including some compositional information. Our prospects of directly obtaining spectra from extrasolar planets may improve in the near future, through missions like NASA's Terrestrial Planet Finder. Most of the extrasolar giant planets (EGPs) discovered so far have masses equal to or greater than Jupiter's mass, and roughly 16% have orbital radii less than 0.1 AU - extremely close to the parent star by our own Solar-System standards (note that Mercury is located at a mean distance of 0.39 AU and Jupiter at 5.2 AU from the Sun). Although all EGPs are expected to have hydrogen-dominated atmospheres similar to Jupiter, the orbital distance can strongly affect the planet's temperature, physical, chemical, and spectral properties, and the abundance of minor, detectable atmospheric constituents. Thermochemical equilibrium models can provide good zero-order predictions for the atmospheric composition of EGPs. However, both the composition and spectral properties will depend in large part on disequilibrium processes like photochemistry, chemical kinetics, atmospheric transport, and haze formation. We have developed a photochemical kinetics, radiative transfer, and 1-D vertical transport model to study the atmospheric composition of EGPs. The chemical reaction list contains H-, C-, O-, and N-bearing species and is designed to be valid for atmospheric temperatures ranging from 100-3000 K and pressures up to 50 bar. Here we examine the effect of stellar distance (e.g., incident ultraviolet flux, atmospheric temperature) on the chemical properties of EGPs. The model is applied to two generic Class II and III intermediate temperature EGPs located at 3.3 and 0.27 AU from a solar-like parent star, and the results are compared with a model for Jupiter at 5.2 AU.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Origin of Planetary Systems; LPI-Contrib-1197
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  • 251
    Publication Date: 2018-06-11
    Description: Numerous geologic features suggest the presence of ice flow on the surface of mars. These features include lobate debris aprons, concentric crater fill, and lineated valley fill. The lateral extent of these features can range from 100 meters to over 20 km. Previous work has demonstrated that these features could not have formed in current Martian conditions. It has long been speculated that changes in Mars orbital properties, namely its obliquity, eccentricity, and argument of perihelion, can result in dramatic changes to climate. Recent climate model studies have shown that at periods of increased obliquity north polar water ice is mobilized southward and deposited at low ad mid latitudes. Mid latitude accumulation of ice would provide the necessary conditions for rock glaciers to form. A time-marching, finite element glacier model is used to demonstrate the ability of ice and ice-rock mixtures to flow under Martian paleoclimate conditions. Input to this model is constrained by the NASA Ames Mars General Circulation Model (MGCM).
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science XXXV: Mars Polar Science and Exploration; LPI-Contrib-1197
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  • 252
    Publication Date: 2018-06-08
    Keywords: Lunar and Planetary Science and Exploration
    Type: International Society for Optical Engineering (SPIE)'s Electroactive Polymer Actuators and Devices (EAPAD) Conference; San Diego, CA; United States
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  • 253
    Publication Date: 2018-06-08
    Keywords: Lunar and Planetary Science and Exploration
    Type: IEEE Aerospace Conference 2004; Big Sky, MT; United States
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  • 254
    Publication Date: 2018-06-08
    Description: We describe Bacillus odysseyi sp. nov., isolated from the surface of the Mars Odyssey spacecraft, whose round spores are resistanct to UV and gamma radiation, H2O2 and desiccation.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Journal of systematic and evolutionary microbiology; Volume 54; no. 1; 195-201
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  • 255
    Publication Date: 2018-06-12
    Description: We present for the first time detailed maps of charged temperatures and winds in Jupiter's stratosphere, from infrared spectra acquired during the Cassini swingby of Jupiter. The maps reveal a high-altitude equatorial jet 1140 m s-', as strong as the cloud-top winds. It may result from wave forcing and be analogous to the quasi-biennial oscillation in the earth's stratosphere. The maps give the best characterization of the motions of stratospheric waves, and they better define the vertical penetration of the auroral hot spots into the stratosphere.
    Keywords: Lunar and Planetary Science and Exploration
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  • 256
    Publication Date: 2018-06-11
    Description: In the 23'd Annual SFCG meeting in San Diego, CA, the SFCG created SFCG Action Item No. 23/10 to provide a readable summary of the work done by the Mars Interim Working Group (MIWG). The SFCG created the MIWG to develop a frequency plan for future Mars missions. The working group has produced a number of documents resulting in a recommendation, SFCG Rec 22-1 [1], titled Frequency Assignment Guidelines for Communications in Mars Region, including a frequency plan for the Mars Region. This document is prepared in response to the SFCG Action Item to provide an overview of the considerations taken when selecting the frequencies and to point out where detailed information of the considerations can be found.
    Keywords: Lunar and Planetary Science and Exploration
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  • 257
    Publication Date: 2019-07-18
    Description: The surface of Jupiter's moon Europa is peppered by topographic domes, interpreted as sites of intrusion and extrusion. Diapirism is consistent with dome morphology, but thermal buoyancy alone cannot produce sufficient driving pressures to create the observed dome elevations. Instead, diapirs may initiate by thermal convection that induces compositional segregation. Exclusion of impurities from warm upwellings allows sufficient buoyancy for icy plumes to create the observed surface topography, provided the ice shell has a small effective elastic thickness (0.2 to 0.5 km) and contains low-eutectic point impurities at the few percent level. This model suggests that the ice shell may be depleted in impurities over time.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Geophysical Research Letters; 31
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  • 258
    Publication Date: 2019-07-18
    Description: Europa is a rocky object of radius 1565 km (slightly smaller than Earth s moon) and has an outer shell of water composition estimated to be of order 100 km thick, the surface of which is frozen. The total volume of water is about 3 x 10(exp 9) cubic kilometers, or twice the amount of water on Earth. Moreover, like its neighbor Io, Europa experiences internal heating generated from tidal flexing during its eccentric orbit around Jupiter. This raises the possibility that some of the water beneath the icy crust is liquid. The proportion of rock to ice, the generation of internal heat, and the possibility of liquid water make Europa unique in the Solar System. In this chapter, we outline the sources of data available for Europa (with a focus on the Galileo mission), review previous and on-going research on its surface geology, discuss the astrobiological potential of Europa, and consider plans for future exploration.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Jupiter: The Planet, Satellites and Magnetosphere; 329-362
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  • 259
    Publication Date: 2019-07-18
    Description: At the temperatures and stresses associated with the onset of convection in an ice I shell of the Galilean satellites, ice behaves as a non-Newtonian fluid with a viscosity that depends on both temperature and strain rate. The convective stability of a non-Newtonian ice shell can be judged by comparing the Rayleigh number of the shell to a critical value. Previous studies suggest that the critical Rayleigh number for a non-Newtonian fluid depends on the initial conditions in the fluid layer, in addition to the thermal, rheological, and physical properties of the fluid. We seek to extend the existing definition of the critical Rayleigh number for a non-Newtonian, basally heated fluid by quantifying the conditions required to initiate convection in an ice I layer initially in conductive equilibrium. We find that the critical Rayleigh number for the onset of convection in ice I varies as a power (-0.6 to -0.5) of the amplitude of the initial temperature perturbation issued to the layer, when the amplitude of perturbation is less than the rheological temperature scale. For larger-amplitude perturbations, the critical Rayleigh number achieves a constant value. We characterize the critical Rayleigh number as a function of surface temperature of the satellite, melting temperature of ice, and rheological parameters so that our results may be extrapolated for use with other rheologies and for a generic large icy satellite. The values of critical Rayleigh number imply that triggering convection from a conductive equilibrium in a pure ice shell less than 100 km thick in Europa, Ganymede, or Callisto requires a large, localized temperature perturbation of a few kelvins to tens of kelvins to soften the ice and therefore may require tidal dissipation in the ice shell.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Journal of Geophysical Research; 109
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  • 260
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    Publication Date: 2019-07-18
    Description: Working in the Educational Programs Office, my task this summer is to model a 3D habitat that will be part of a future Mars base. With the President's charge to further explore mars by way of robotic-led and human-led missions, there has been a surge in the activity regarding the "red planet". Since all present designs are merely conjecture, I have some creative freedom in deciding what the habitat will look like. To get ideas for what a Mars habitat might be like, I looked at several references including websites and NASA documents. One of these was a NASA Technical Memorandum about Space Transportation Systems that I looked at to get insight on spaceship design. Information about the planet's environment, such as the gravity and the weather, is useful as well when designing the structure. The main software that I am using is Lightwave 3D and Modeler 7.5 that comes along with it. Lightwave is very complex in that it lets you model, surface, and animate so there was a lot to learn. To learn the software I watched a series of instructional videos, looked at online tutorials, and referenced several books. Modeling is like shaping clay with a computer. Every item modeled is made of smaller shapes called polygons. For example, each side of a box would be a different polygon. Modelers must be careful to design with users' systems in mind. Having a model made with too many polygons can slow down a walk-through, but it usually improves the small details on a model. Getting speed and quality proved tricky. An important thing for me to remember when modeling the habitat was to save space. Also, I must consider that technology in the future will be much different than now, so I must be especially creative. My project will be used in an educational walkthough simulation in which users can interact with the environment. I worked closely with intern Stephen Henke who built a Mars Rover, terrain and programmed code for the simulation. This summer's project will help me with future aspirations in computer graphics. Modeling is a valuable skill that I appreciate having the chance to learn and practice.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Research Symposium I
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  • 261
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    Publication Date: 2019-07-18
    Description: January 14th 2004, President George Bush announces his plans to catalyst the space program into a new era of space exploration and discovery. His vision encompasses a robotics program to explore our solar system, a return to the moon, the human exploration of Mars, and to promote international prosperity towards our endeavors. We at NASA now have the task of constructing this vision in a very real timeframe. I have been chosen to begin phase 1 of making this vision a reality. I will be working on creating an Educational Mars Simulation of human exploration of Mars to stimulate interest and involvement with the project from investors and the community. GRC s Computer Services Division (CSD) in collaboration with the Office of Education Programs will be designing models, constructing terrain, and programming this simulation to create a realistic portrayal of human exploration on mars. With recent and past technological breakthroughs in computing, my primary goal can be accomplished with only the aid of 3-4 software packages. Lightwave 3D is the modeling package we have selected to use for the creation of our digital objects. This includes a Mars pressurized rover, rover cockpit, landscape/terrain, and habitat. Once we have the models completed they need textured so Photoshop and Macromedia Fireworks are handy for bringing these objects to life. Before directly importing all of this data into a simulation environment, it is necessary to first render a stunning animation of the desired final product. This animation with represent what we hope to capture out of the simulation and it will include all of the accessories like ray-tracing, fog effects, shadows, anti-aliasing, particle effects, volumetric lighting, and lens flares. Adobe Premier will more than likely be used for video editing and adding ambient noises and music. Lastly, V-Tree is the real-time 3D graphics engine which will facilitate our realistic simulation. Additional information is included in the original extended abstract.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Research Symposium I
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  • 262
    Publication Date: 2019-07-18
    Description: Recent NASA mission plans for the human exploration of our Solar System has set new priorities for research and development of technologies necessary to enable a long-term human presence on the Moon and Mars. The recovery and processing of metals and oxides from mineral sources on other planets is under study to enable use of ceramics, glasses and metals by explorer outposts. We report initial results on the production of sol-gel precursors for ceramic products using mineral resources available in martian or lunar soil. The presence of SO2, TiO2, and Al2O3 in both martian (44 wt.% SiO2, 1 wt.% TiO2, 7 wt.% Al2O3) and lunar (48 wt.% SiO2, 1.5 wt.% TiO2, 16 wt.% Al2O3) soils and the recent developments in chemical processes to solubilize silicates using organic reagents and relatively little energy indicate that such an endeavor is possible. In order to eliminate the risks involved in the use of hydrofluoric acid to dissolve silicates, two distinct chemical routes are investigated to obtain soluble silicon oxide precursors from lunar and martian soil simulars. Clear solutions of sol-gel precursors have been obtained by dissolution of silica from lunar soil similar JSC-1 in basic ethylene glycol (C2H4(OH)2) solutions to form silicon glycolates. Similarly, sol-gel solutions produced from martian soil simulars reveal higher contents of iron oxides. Characterization of the precursor molecules and efforts to further concentrate and hydrolyze the products to obtain gel materials will be presented for evaluation as ceramic precursors.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Space Resource Roundtable Conference; Nov 01, 2004 - Nov 03, 2004; Golden, CO; United States
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  • 263
    Publication Date: 2019-07-18
    Description: Far-IR space interferometers will provide observational access to a spectral region containing many important cooling and diagnostic spectral lines and the bulk of the thermal emission from dust at angular scales critical to advancing our understanding of the star and planet formation process. We will describe concepts for the Space Infrared Interferometric Telescope (SPIRIT) and the Submillimeter Probe of the Evolution of Cosmic Structure (SPECS). Both of these candidate NASA missions are imaging and spectral Michelson interferometers operating in the wavelength range -40 - 800 microns. SPIRIT, which could be launched in a decade as a NASA Origins Probe, is built on a deployable boom and has a maximum baseline length of -30 - 50 m, yielding sub-arcsecond resolution in the far-IR. SPIRIT will thus provide far-IR/sub-mm measurements complementary to the near- and mid-IR measurements obtainable with the James Webb Space Telescope (JWST), and well matched to JWST observations in angular resolution. Ultimately SPECS, a NASA Vision Mission, will use formation flying to attain baseline lengths up to 1 km, and thus angular resolution comparable to that of the Hubble Space Telescope and the Atacama Large Millimeter Array. We will report preliminary results of the NASA-sponsored SPIRIT and SPECS mission studies, which are now underway.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Astrophysics Conference; Oct 11, 2004 - Oct 13, 2004; College Park, MD; United States
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  • 264
    Publication Date: 2019-07-18
    Description: The Cassini Plasma Spectrometer (CAPS) instrument is scheduled to observe the plasma environment at Titan October 26,2004 from the Cassini Orbiter. Preliminary CAPS ion measurements from this encounter will be compared with measurements made by the Voyager I Plasma Science Instrument (PSI). The comparison will be used to evaluate previous interpretations and predictions of the Titan plasma environment that have been made using PSI measurements. The comparisons will focus on the composition and nature of the ambient plasma and pickup ions. Using the CAPS ion measurements, some of the questions to be addressed, as stimulated by the previous interpretations and predictions made evaluating PSI data, are the following: A) Are H+ and N+ the major ion components of Saturn's rotating magnetosphere in the vicinity of Titan? B) Are other ambient ions present? C) Are finite gyroradius effects apparent in ambient N+ as the result of its interaction with Titans atmosphere? D) Are the principal pickup ions composed of H+, H2+, N+, N2+ and CH4+? E) Is the dominant pickup ion closest to Titan's ionopause N2+? F) Is there evidence of slowing down of the ambient plasma due to pickup ion mass loading? F) If so, does the ambient plasma slow down rapidly, as the ionopause is approached and heavier pickup ions like N2+ are added? During the Voyager I flyby, Titan was in Saturn's magnetosphere. If Titan is in Saturn's magnetosheath or the solar wind at the encounter, questions similar to the above will be addressed as appropriate.
    Keywords: Lunar and Planetary Science and Exploration
    Type: AGU Fall Session; Dec 13, 2004 - Dec 17, 2004; San Francisco, CA; United States
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  • 265
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    Publication Date: 2019-07-18
    Description: Mars appears to be cold dry and dead world. However there is good evidence that early in its history it had liquid water, more active volcanism, and a thicker atmosphere. Mars had this earth-like environment over three and a half billion years ago, during the same time that life appeared on Earth. The main question in the exploration of Mars then is the search for a independent origin of life on that planet. Ecosystems in cold, dry locations on Earth - such as the Antarctic - provide examples of how life on Mars might have survived and where to look for fossils. Fossils are not enough. We will want to determine if life on Mars was a separate genesis from life on Earth. For this determination we need to access intact martian life; possibly frozen in the deep old permafrost. Human exploration of Mars will probably begin with a small base manned by a temporary crew, a necessary first start. But exploration of the entire planet will require a continued presence on the Martian surface and the development of a self sustaining community in which humans can live and work for very long periods of time. A permanent Mars research base can be compared to the permanent research bases which several nations maintain in Antarctica at the South Pole, the geomagnetic pole, and elsewhere. In the long run, a continued human presence on Mars will be the most economical way to study that planet in detail. It is possible that at some time in the future we might recreate a habitable climate on Mars, returning it to the life-bearing state it may have enjoyed early in its history. Our studies of Mars are still in a preliminary state but everything we have learned suggests that it may be possible to restore Mars to a habitable climate. Additional information is contained in the original extended abstract.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Mars Society Meeting; Aug 19, 2004 - Aug 22, 2004; Chicago, IL; United States
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  • 266
    Publication Date: 2019-07-18
    Description: With judicious selection of parameters, computed tomography can provide high precision density data. Such data can lead to a non-destructive determination of the phases and phase distribution within large solid objects. Of particular interest is the structure of the Mundrabilla meteorite, which has 25 volumes, percent of a sulfide within a metallic meteorite. 3D digital imaging has enabled a quantitative evaluation of the distribution and contiguity of the phases to be determined.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Microscopy and Microanalysis 2004 Conference; Aug 01, 2004 - Aug 05, 2004; Savannah, GA; United States
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  • 267
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    Publication Date: 2019-07-18
    Description: This talk is for elementary school children and exposes them to the solar system, the Sun, and how they interact with Earth.
    Keywords: Lunar and Planetary Science and Exploration
    Type: NASA Outreach; Nov 08, 2004; Guatemala City; Guatemala
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  • 268
    Publication Date: 2019-07-18
    Description: Tremendous strides have been made in our understanding of interstellar material over the past twenty years thanks to significant, parallel developments in observational astronomy and laboratory astrophysics. Twenty years ago the composition of interstellar dust was largely guessed at, the concept of ices in dense molecular clouds ignored, and the notion of large, abundant, gas phase, carbon rich molecules widespread throughout the interstellar medium (ISM) considered impossible. Today the composition of dust in the diffuse ISM is reasonably well constrained to cold refractory materials comprised of amorphous and crystalline silicates mixed with an amorphous carbonaceous material containing aromatic structural units and short, branched aliphatic chains. In the dense ISM, the birthplace of stars and planets, these cold dust particles are coated with mixed molecular ices whose composition is very well constrained. Lastly, the signature of carbon-rich polycyclic aromatic hydrocarbons (PAHs), shockingly large molecules by early interstellar chemistry standards, is widespread throughout the Universe. The first part of this talk will describe how infrared studies of interstellar space, combined with laboratory simulations, have revealed the composition of interstellar ices (the building blocks of comets) and the high abundance and nature of interstellar PAHs. The laboratory database has now enabled us to gain insight into the identities, abundances, and physical state of many interstellar materials. Within a dense molecular cloud, and especially in the presolar nebula, the materials frozen into the interstellar/precometary ices are photoprocessed by ultraviolet light and produce more complex molecules. The remainder of the presentation will focus on the photochemical evolution of these materials and the possible role of these compounds on the to the carbonaceous components of micrometeorites, they are likely to have been important sources of complex materials on the early Earth and their composition may be related to the origin of life.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Department Colloquium Series; Mar 21, 2000 - Mar 23, 2000; Atlanta, Ga; United States
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  • 269
    Publication Date: 2019-07-18
    Description: Amino acids and other organic compounds important to the chemistry of life are thought to have been delivered to early Earth by asteroids and comets. The survivability of such compounds upon high speed entry is not well understood. If molecular processing occurs during entry, the nature of the new molecules produced by such processing is also an open question. To address this question, we have initiated a study of the ablation of glycine, the simplest amino acid, upon the high speed entry of a comet or meteoroid into an atmosphere. The study assumes glycine is distributed on the surface of the comet/meteoroid. The high speed impact creates electrons, ions, and radicals in the atmosphere that react with the surface and either desorb glycine or break it up. The ablation process is studied as a function of entry speed and atmospheric composition. The AURORA code from the commercially available software package CHEMKIN is used in the study.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Astrobiology Science Conference 2004; Mar 28, 2004 - Apr 01, 2004; Moffett Field, CA; United States
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  • 270
    Publication Date: 2019-07-18
    Description: The principle source of pickup ions at Titan is its neutral exosphere, extending well above the ionopause into the magnetosphere of Saturn or the solar wind, depending on the moon's orbital position. Thermal and nonthermal processes in the thermosphere generate the distribution of neutral atoms and molecules in the exosphere. The combination of these processes and the range of mass numbers, 1 to over 28, contribute to an exospheric source structure that produces pickup ions with gyroradii that are much larger or smaller than the corresponding scale heights of their neutral sources. The resulting phase space distributions are dependent on the spatial structure of the exosphere as well as that of the magnetic field and background plasma. When the pickup ion gyroradius is less than the source gas scale height, the pickup ion velocity distribution is characterized by a sharp cutoff near the maximum speed, which is twice that of the ambient plasma times the sine of the angle between the magnetic field and the flow velocity. This was the case for pickup H(sup +) ions identified during the Voyager 1 flyby. In contrast, as the gyroradius becomes much larger than the scale height, the peak of the velocity distribution in the source region recedes from the maximum speed. Iri addition, the amplitude of the distribution near the maximum speed decreases. These more beam like distributions of heavy ions were not observed from Voyager 1 , but should be observable by more sensitive instruments on future spacecraft, including Cassini. The finite gyroradius effects in the pickup ion velocity distributions are studied by including in the analysis the possible range of spatial structures in the neutral exosphere and background plasma.
    Keywords: Lunar and Planetary Science and Exploration
    Type: 2004 Spring AGU Meeting; May 17, 2004 - May 19, 2004; Montreal; Canada
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  • 271
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    Publication Date: 2019-07-18
    Description: I will contribute (i.e. join in writing the TPF-C Report) for the following workshop topics: 1) Science Topics (target list): I describe a new target list for the TPF-C based on General TPF target list maintained at the US Naval Observatory; 2) Science Topics (spectroscopy): I describe the need for optical, imaging, pulse-counting detectors for spectroscopy of terrestrial planets; 3) Simulation and Modeling Techniques: I describe work at Goddard Space Flight Center to simulate wide-band imagery and spectroscopic imagery that will be obtained by TPF-C.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Terrestrial Planet Finder Workshop; Feb 02, 2004 - Feb 06, 2004; Leiden; Netherlands
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  • 272
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    Publication Date: 2019-07-18
    Description: One of the goals of NASA's Exploration Systems Education and Outreach team is to provide educators and students authentic, relevant opportunities and activities. In celebration of the World Year of Physics 2005, there will be several NASA-sponsored events and classroom activities geared to the teaching and learning of physics. Proposed events and activities include a contest for high school classes to design a reduced gravity experiment or demonstration for flight on an aircraft executing a parabolic flight path, amusement park activities with a NASA twist, and a symposium bringing together prominent leaders in the diverse areas of physics research.
    Keywords: Lunar and Planetary Science and Exploration
    Type: American Association of Physics Teachers at 2005 Winter Meeting; Jan 08, 2005 - Jan 12, 2005; Albuquerque, NM; United States
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  • 273
    Publication Date: 2019-07-18
    Description: Carbonaceous meteorites are relatively enriched in soluble organic compounds. The Murchison and Murray meteorites contain numerous compounds of interest in the study of early solar system organic chemistry and organic compounds of potential importance for the origin of life. These include: amino acids, amides, carboxylic acids, and polyols. This talk will focus on the enantiomeric and isotopic analysis of individual meteoritic compounds - primarily polyol acids. The analyses will determine if, in addition to certain amino acids from Murchison, another potentially important class of prebiotic compounds also contains enantiomeric excesses, i.e., excesses that could have contributed to the current homochirality of life. Preliminary enantiomeric and isotopic (C- 13) measurements of Murchison glyceric acid show that it is indeed extraterrestrial. C-13 and D isotope analysis of meteoritic sugar alcohols (glycerol, threitol, ribitol, etc.) has shown that they are also indigenous to the meteorite.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Presentation at Exobiology PI Symposium; Aug 25, 2003 - Aug 29, 2003; Moffett Field, CA; United States
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  • 274
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    Publication Date: 2019-07-18
    Description: Both in the United States and in Europe, teams of scientists and engineers are exploring the feasibility of the Terrestrial Planet Finder (TPF) and Darwin missions, which are designed to search for Earth-like planets in the habitable zone of nearby stars. In the US, the TPF Science Working Group is studying four options - small (4m by 6 m primary mirror) and large (4m by 10 m primary mirror) coronagraphs for planet detection at visible wavelengths, and structurally connected and free-flyer interferometers at thermal infrared wavelengths. The US TPF-SWG is charged with selecting an option for NASA by the end of 2006. In Europe the Darwin Terrestrial Exo-planet Advisory Team (TE- SAT) is exploring the free-flyer interferometer option only at this time. I will discuss the vurtures and difficulties of detecting and characterizing extra-solar planets in both wavelength regions as well as some of the technical challenges and progress in the past year.
    Keywords: Lunar and Planetary Science and Exploration
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  • 275
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    Publication Date: 2019-07-18
    Description: Grant NAGS12158 addressed a major NASA objective concerning the possibility of a palm ocean or large lake in the northern lowlands of Mars. Our overall approach for this study was an analysis of the graben-bounded giant polygons of Utopia Planitia, but specifically those grabens that define circles rather than open polygons. These circular grabens overlie buried impact craters, and the grabens form because of differential compaction of the overlying material over crater rims and floors. Several years ago, I predicted that the graben circles would bound depressions, and that the depths of these depressions would scale with the diameters of the graben circles. These predictions have been verified by earlier analysis. During this one-year grant (with one-year no-cost extension) we greatly increased the sample size and validated the earlier research robustly. What remained unexplained was why most of the graben circles in Utopia Planitia were double. A new model, involving volumetric compaction rather than simply 2-D compaction, satisfactorily explains the double rings and also provides a measure of relative thickness of the cover material burying the craters as a function of radial distance from the center of the Utopia Basin. Only two materials are likely candidates for the compacting cover material: volcanic ash, or wet sediment. The water in the wet sediment is largely responsible for the volumetric compaction; dry ash will compact vertically but experiences very limited lateral shrinkage. Thus the depressions within the circular grabens and the model explaining the double rings strongly favor wet sediment and thus provide evidence in favor of a past body of standing water in the northern lowlands. Publications supported entirely or in part by this grant are listed below.
    Keywords: Lunar and Planetary Science and Exploration
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  • 276
    Publication Date: 2019-07-18
    Description: Longitudinal magnetograms obtained with thc SOLIS Vector Spectromagnetograph (VSM) during a cross-calibration period are compared with similar data from the NASA/NSO Spectromagnetograph (SPM) at the NSO/Kitt Peak Vacuum Telescope as well as with SOHO/MDI and GONG magnetogram. The VSM began observation at the University of Arizona agricultural test site and collaborative observations were obtained with both the VSM and SPM from 2003 Aug 05 through 2003 Sep 21 where the SPM was officially retired. The VSM replaces the SPM and continues the 3O-year NSO/Kitt Peak synoptic magnetogram record. Magnetograms are compared by equating histograms and, for selected examples, by pixel-by-pixel comparison of co-registered images. The VSM was not corrected for polarization crosstalk and was operated without hast guiding. Solar activity was at best moderate during this period. Over the range of observed fields, the VSM magnetograms show greatly improved sensitivity but are otherwise virtually identical with "raw" SPM magnetogram. GONG magnetograms are also closely comparable with the SPM while MDI flux values tend to be stronger by a factor of 1.2 - 1.4. Dependence of the results on seeing will be discussed. Partial funding for this work was provided through Solar and Heliospheric Research Supporting Research and Technology grants from NASA's Office of Space Sciences.
    Keywords: Lunar and Planetary Science and Exploration
    Type: 204th American Astronomical Society Meeting; May 30, 2004 - Jun 03, 2004; Denver, CO; United States
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  • 277
    Publication Date: 2019-07-18
    Description: Crystalline silicates, by their apparent absence in the ISM, are dust grains that experienced high temperatures in the solar nebula. Mg-rich crystalline silicates formed either by condensation from hot nebular gases (1450 K) or by the annealing of Mg-rich amorphous silicates (approx. 1000 K) in shocks in the 5-10 AU region or by radial transport into and out of the hot inner zones, e.g., T(sub d) 〉 1000 K at r(sub h) 〈 5 AU, 10(exp -6) - 10(exp -5) M(sub O)/yr, alpha = 10(exp -4) of the early solar nebula. Mg-rich crystalline silicates are found in interplanetary dust particles (IDPs) and produce IR spectral features in many Oort cloud comets. In May 2004, we discovered strong crystalline silicate features in the dynamically new Oort cloud comet C/2001 Q4 (NEAT). Thermal emission modeling of comets Q4 and C/1995 O1 (Hale-Bopp) demonstrate that both these comets have similar, high silicate crystalline-to-amorphous ratios of 2.4 and 2.1, respectively, indicating that these icy planetesimals aggregated from similar reservoirs of material or that crystalline silicates were widely distributed within the comet-forming zone. This argues for efficient annealing mechanisms and radial mixing.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Chondrites and the Protoplanetary Disk; Nov 08, 2004 - Nov 11, 2004; Lihue, HI; United States
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  • 278
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    Publication Date: 2019-07-18
    Description: In an earlier paper, we proposed that Jupiter's alternating wind bands are a manifestation of the global interaction between rotation and convection in a shallow layer. The model, however, was obtained from linearization of the 2D equations of motions. At HKUST/Hong Kong, we are now trying to study this problem by rigorous numerical simulation. Using a three-dimensional spectral numerical code, we compute models for the outermost layer of Jupiter's convective envelope. Two cases have been studied. In one the atmospheric pressure varies from 1 to 23 bar, and in the other from 1 to 115 bar. The physical parameters (internal energy flux, rotation rate) are chosen to be close to those expected, but solar heating, chemistry, as well as dynamical influences from deeper layers are ignored. The models generate wind field patterns that contain alternating jet streams with resemblance to the Jovian bands. Instantaneous values of the mean zonal flow at the equator reach 80 m/sec. Yet the mean meridional flows are less than 1% of such value. The meridional temperature profile at the cloud top level also shows a double hump structure of a few degrees (as observed) in the subtropics. Though there is not complete quantitative agreement (caused perhaps by neglected effects like solar radiation), these models demonstrate, in principle, the feasibility of generating a Jovian type wind pattern through the interaction of fast rotation and convection in a thin shell.
    Keywords: Lunar and Planetary Science and Exploration
    Type: 38th Meeting of the American Astronomical Society Division of Planetary Science; Nov 08, 2004 - Nov 12, 2004; Louisville, KY; United States
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  • 279
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    In:  Other Sources
    Publication Date: 2019-07-18
    Description: Knowledge management for space exploration is part of a multi-generational effort at recognizing, preserving and transmitting learning. Each mission should be built on the learning, of both successes and failures, derived from previous missions. Knowledge management begins with learning, and the recognition that this learning has produced knowledge. The Mars Exploration Rover mission provides us with an opportunity to track how learning occurs, how it is recorded, and whether the representations of this learning will be optimally useful for subsequent missions. This paper focuses on the MER science and engineering teams during Rover operations. A NASA team conducted an observational study of the ongoing work and learning of the these teams. Learning occurred in a wide variety of areas: how to run two teams on Mars time for three months; how to use the instruments within the constraints of the martian environment, the deep space network and the mission requirements; how to plan science strategy; how best to use the available software tools. This learning is preserved in many ways. Primarily it resides in peoples memories, to be carried on to the next mission. It is also encoded in stones, in programming sequences, in published reports, and in lessons learned activities, Studying learning and knowledge development as it happens allows us to suggest proactive ways of capturing and using it across multiple missions and generations.
    Keywords: Lunar and Planetary Science and Exploration
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  • 280
    Publication Date: 2019-07-18
    Description: Pre-biotic organic materials appear to be common on many small bodies in the outer Solar System, as evidenced by the color properties of these objects. We report on our continuing study of color properties in connection with the presence of complex organic solids (tholins) among the planets and their satellites, the asteroids, and the trans- Neptunian objects (Kuiper Belt objects). Most small, icy bodies in the Solar System, whether they have high or low surface reflectance (albedo), show a pronounced downward slope in reflectance at wavelengths shorter than approx. 1 micron. This increasing absorption of sunlight toward shorter wavelengths is characteristic of pi-bonds in hydrocarbons having chains or rings of conjugated C atoms. Tholins, which contain polycyclic aromatic and aliphatic hydrocarbons, exhibit these color properties. Using the complex refractive indices of tholins in models of the reflectance spectra of icy bodies in the Solar System, we find that these complex organic materials satisfactorily account for the coloration so widely observed. The new results presented here show that the wide variety of colors of Kuiper Belt objects can be fit very well with tholins, as can the colors of Pluto and Triton. The implications of these fits of Kuiper Belt objects is that complex organic material is created on their surfaces by energetic particle bombardment of native ices, and also may be accreted from external sources. In the cases of Pluto and Triton, photochemistry of their weak N2 + CH4 + CO atmospheres produces complex organic molecules that precipitate to the surface, providing local color.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Committee on Space Research; Jul 18, 2004 - Jul 25, 2004; Paris; France
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  • 281
    Publication Date: 2019-07-18
    Description: The Spitzer Space Telescope, formerly known as SIRTF, is a cryogenic telescope (85 cm diameter) operating in a heliocentric orbit trailing the Earth. Its three instruments provide capabilities for spectroscopy, wide-field and small-field imaging at many wavelengths in the range 3.5-160 microns. Observations to be executed in the first two years in programs defined by the Guaranteed Time Observer (GTO) group (the authors of this presentation) consist of photometry, spectroscopy, and radiometry of many Solar System objects, including Titan and other satellites of the outer planets, Pluto, Centaurs, trans-Neptunian objects, comers, asteroids, Uranus, and Neptune. At the time of the preparation of this abstract, some preliminary observations have been made, but the final calibration and reduction of the data are still in progress. The latest results of the Solar System investigations will be presented here.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Committee on Space Research Meeting; Jul 18, 2003 - Jul 25, 2003; Paris; France
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  • 282
    Publication Date: 2019-07-18
    Description: The long-term exploration goals of NASA include developing human habitation on Mars and conducting scientific investigations on Mars and other planetary bodies. In situ resource processing is a key objective in this area We focus OR the possibility of making magnetic glasses in situ for potential applications development. The paper will focus on ongoing work at NASA Marshall Space Flight Center on making magnetic glass h m Mars soil simulants and its characterization. Analysis of the glass morphology, strength, chemistry and resulting magnetic properties will provide a fi.mdamenta1 understanding ofthe synthesized materiai that can be used for pomtiai appiications cieveiopment. In an effort to characterize the magnetic properbes of the Mars glasses, a series of tests were performed at NASA MSFC. Preliminary tests indicated that the glasses were attracted to a magnet and also had a small amount of residual magnetism. They were opaque (almost black in color). As the first step, a sample of Mars 1 glass (-lm x lmm x 5 mm length) was machined, weighed and its hysteresis curve was measured using a Vibration Sample Magnetometer 0. Next, a small furnace was designed and built and the sample was baked in a graphite (reducing agent) crucible at 800 C in an Argon atmosphere for 3 hours in the presence of a uniform, transverse (transverse to the 5mm length of the sample) magnetic field of 0.37 Tesla. The treated sample showed reddening on the outside and showed substantially increased residual magnetism. This sample was again analyzed in the VSM. The data clearly showed that some chemical change occurred during the heat treatment (color change) and that both the glasses have useful magnetic properties. Although no orientation effects of the magnetic field were considered, the data showed the following: 1. Both glass samples are primarily soft magnets and display ferromagnetic behavior (hysteresis, saturation, etc.) 2. The treated glass has improved saturation magnetism (order of magnitude increase), retentivity (factor of 6 increase) and susceptibility (order of magnitude increase) compared to the untreated glass 3. The untreated sample has higher coercivity (-50% that of Nickel) than the treated sample
    Keywords: Lunar and Planetary Science and Exploration
    Type: Materials Research Society Meeting; Nov 29, 2004 - Dec 03, 2004; Boston, MA; United States
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  • 283
    Publication Date: 2019-07-18
    Description: Jovian X-rays can be broadly classified into two categories: (1) auroral emission, which is confined to high-latitudes (approximately greater than 60 deg.) at both polar regions, and (2) dayglow emission, which originates from the sunlit low-latitude (approximately less than 50 deg.) regions of the disk (hereafter called disk emissions). Recent X-ray observations of Jupiter by chandra and XMM-Newton have shown that these two types of X-ray emission from Jupiter have different morphological, temporal, and spectral characteristics. In particular: 1) contrary to the auroral X-rays, which are concentrated in a spot in the north and in a band that runs half-way across the planet in the south, the low-latitude X-ray disk is almost uniform; 2) unlike the approximately 40 plus or minus 20-min periodic oscillations seen in the auroral X-ray emissions, the disk emissions do not show any periodic oscillations; 3) the disk emission is harder and extends to higher energies than the auroral spectrum; and 4) the disk X-ray emission show time variability similar to that seen in solar X-rays. These differences and features imply that the processes producing X-rays are different at these two latitude regions on Jupiter. We will present the details of these and other features that suggest the differences between these two classes of X-ray emissions from Jupiter, and discuss the current scenario of the production mechanism of them.
    Keywords: Lunar and Planetary Science and Exploration
    Type: American Geophysical Union Fall Meeting; Dec 13, 2004 - Dec 17, 2004; San Francisco, CA; United States
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  • 284
    Publication Date: 2019-07-18
    Description: Titan is unique in the solar system, the only moon that has a dense atmosphere. The major constituents of the atmosphere, nitrogen and methane, are continuously broken apart by a combination of solar UV, impinging electrons from Saturn s magnetosphere, and a steady flux of cosmic rays. The resulting molecular fragments recombine and form a variety of new species, many of which were detected for the first time by Voyager1 . The ubiquitous, surface- hiding aerosol blanket manifests the existence of still more complex compounds. In addition to hydrocarbons and nitriles, the atmosphere is known to contain CO, CO2 and externally delivered H2O. The Gas Chromatograph Mass Spectrometer (GCMS) on the Huygens Probe will measure the chemical composition of the atmosphere of Titan from 170 Km altitude (approximately 1hPa) to the surface (approximately 1500hPa) and determine the isotope ratios of the major constituents. The GCMS will also analyze gas samples from the Aerosol Collector Pyrolyser (ACP) and may be able to obtain compositional information of several surface materials. The GCMS consists of a quadrupole mass spectrometer (QP) with a secondary electron multiplier ion detector, a three-column gas chromatograph (GC) and an elaborate gas sampling system. The gas sampling system will provide atmospheric samples to the QP for nearly continuous analysis during the Probe descent and batch samples at several altitudes for GC analysis. It also contains a chemical scrubber for noble gas analysis and an enrichment cell for trace constituent enhancement. In addition to the sampling of the atmosphere periodic gas samples, derived from the pyrolysis of aerosols, will be transferred from the ACP to the GCMS for direct QP and full GCMS analysis. The QP can analyze molecular masses from 2 to 141Dalton. The nominal detection threshold is at a mixing ratio of 10E-8. Data rate is 885 bits/sec. The mass of the instrument is 17.3 kg and the energy required for operation during the descent is 110 Watt-hours.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Huygens Titan Conference; Apr 13, 2004 - Apr 17, 2004; Noordwijk; Netherlands
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  • 285
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    In:  Other Sources
    Publication Date: 2019-07-18
    Description: It is possible that at some time in the future we might recreate a habitable climate on Mars returning it to the life-bearing state it may have enjoyed early in its history. Our studies of Mars are still in a preliminary state but everything we have learned suggests that it may he possible to restore Mars to a habitable climate. Long part of the intersection of science and fiction (eg. Clarke, 1995), serious studies of planetary ecosynthesis on Mars began after the results of the Viking mission indicated that all the compounds needed for life were present on the surface of Mars is some accessible form (Averner and MacElroy, 1976; McKay et al., 1991; Fogg, 1995). Recent work has focused on the use of climate models to compute the timescales to warm Mars (McKay et al., 1991 ; McKay and Marinova, 2001). Planetary ecosynthesis on Mars has implications for the objectives and conduct of robotic and human exploration. In particular the question of forward contamination must be considered in a new way if we wish to control the introduction of life to Mars in advance of planetary ecosynthesis.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Astrobiology Conference; 28 Mar. 1 Apr. 2004; Moffett Foeld, CA; United States
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  • 286
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    In:  Other Sources
    Publication Date: 2019-07-18
    Description: During the last 8 years the US has successfully sent 2 major spacecraft to Mars 1z?der= planet. The Mars Global Surveyor spacecraft (IGS), which started operating at Mars in Sept 1977 and Mars Odyssey spacecraft that started operating in Jan 2002, are both operational and collecting data, including 1.5 meter pixel imagery, them spectrometry, magnetometry, altimeter/radiometry, gamma ray and neutron counts. imaging spectrometry, and gravity. The two orbiters are conceptually similar to Earth orbiting spacecraft in that their primary purpose is to observe, monitor, and measure a variety of parameters about the planet and report any changes that might be occurring on the surfaces and in the atmosphere. As a result we now have detailed physical descriptions of the shape, topography, magnetism. surface roughness, thermal inertia, atmospheric pressure and temperature, the distribution of hydrogen in the top meter of the crust, models for the planetary interior based upon data, and an image set that portrays much of the history of the past 3 billion years. understand how the planet came to be this way.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Catholic University Seminar; Jan 21, 2004; Washington, DC; United States
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  • 287
    Publication Date: 2019-07-18
    Description: A range of analytical techniques and protocols that might be applied b in situ investigations of martian fines, ices, and rock samples are evaluated by analysis of organic molecules m Mars analogues. These simulants 6om terrestrial (i.e. tephra from Hawaii) or extraterrestrial (meteoritic) samples are examined by pyrolysis gas chromatograph mass spectrometry (GCMS), organic extraction followed by chemical derivatization GCMS, and laser desorption mass spectrometry (LDMS). The combination of techniques imparts analysis breadth since each technique provides a unique analysis capability for Certain classes of organic molecules.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Astrobiology Science Conference; Mar 28, 2004 - Apr 01, 2004; Moffet Field, CA; United States
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  • 288
    Publication Date: 2019-07-18
    Description: We report on new observations of the orbital position of Phobos, and use them to obtain a new and improved estimate of the rate of secular acceleration in longitude due to tidal dissipation within Mars. Phobos is the inner-most natural satellite of Mars, and one of the few natural satellites in the solar system with orbital period shorter than the rotation period of its primary. As a result, any departure from a perfect elastic response by Mars in the tides raised on it by Phobos will cause a transfer of angular momentum from the orbit of Phobos to the spin of Mars. Since its discovery in 1877, Phobos has completed over 145,500 orbits, and has one of the best studied orbits in the solar system, with over 6000 earth-based astrometric observations, and over 300 spacecraft observations. As early as 1945, Sharpless noted that there is a secular acceleration in mean longitude, with rate (1.88 + 0.25) 10(exp -3) degrees per square year. In preparation for the 1989 Russian spacecraft mission to Phobos, considerable work was done compiling past observations, and refining the orbital model. All of the published estimates from that era are in good agreement. A typical solution (Jacobson et al., 1989) yields (1.249 + 0.018) 10(exp -3) degrees per square year. The MOLA instrument on MGS is a laser altimeter, and was designed to measure the topography of Mars. However, it has also been used to make observations of the position of Phobos. In 1998, a direct range measurement was made, which indicated that Phobos was slightly ahead of the predicted position. The MOLA detector views the surface of Mars in a narrow field of view, at 1064 nanometer wavelength, and can detect shadows cast by Phobos on the surface of Mars. We have found 15 such serendipitous shadow transit events over the interval from xx to xx, and all of them show Phobos to be ahead of schedule, and getting progressively farther ahead of the predicted position. In contrast, the cross-track positions are quite close to the predicted values. Assuming that the along-track discrepancy is small enough that we can linearize the corrections, we model the mean orbital longitude as a quadratic function of time, and solve for corrections to the constant, linear, and quadratic terms. The time span of the recent observations is insufficient to properly resolve this issue alone, but when the 127 years of prior observations are added, we find a solution which reduces misfit to the new observations considerably, and makes no significant change to the fit to earlier observations. Our estimate for the secular acceleration term is (1.367 + 0.006) degrees per square year. The corresponding rate of energy dissipation is 3.34 MW. From a geophysical perspective, a more interesting parameter than the secular acceleration itself is the tidal lag angle, or tidal quality factor Q, for Mars. Unfortunately, the limiting error source in that determination is remaining uncertainty in the tidal Love numbers at harmonic degrees 2,3, and even 4. Until those parameters are better constrained, improvement in the orbital model of Phobos will not provide corresponding benefits for understanding the interior of Mars.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Fall AGU Meeting; Dec 13, 2004 - Dec 17, 2004; San Francisco, CA; United States
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  • 289
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    In:  CASI
    Publication Date: 2019-07-20
    Description: Geological mapping and topical studies, primarily in the southern Acidalia Planitia/Cydonia Mensae region of Mars is presented. The overall objective was to understand geologic processes and crustal history in the northern lowland in order to assess the probability that an ocean once existed in this region. The major deliverable is a block of 6 1:500,000 scale geologic maps that will be published in 2004 as a single map at 1:1,000,000 scale along with extensive descriptive and interpretive text. A major issue addressed by the mapping was the relative ages of the extensive plains of Acidalia Planitia and the knobs and mesas of Cydonia Mensae. The mapping results clearly favor a younger age for the plains. Topical studies included a preliminary analysis of the very abundant small domes and cones to assess the possibility that their origins could be determined by detailed mapping and remote-sensing analysis. We also tested the validity of putative shorelines by using GIs to co-register full-resolution MOLA altimetry data and Viking images with these shorelines plotted on them. Of the 3 proposed shorelines in this area, one is probably valid, one is definitely not valid, and the third is apparently 2 shorelines closely spaced in elevation. Publications supported entirely or in part by this grant are included.
    Keywords: Lunar and Planetary Science and Exploration
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  • 290
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    In:  CASI
    Publication Date: 2019-07-13
    Description: The NASA supported project 'Modeling of Cometary Atmospheres' has been quite successful in broadening our understanding of the cometary environment. We list peer reviewed publications and conference presentation that have been made as a result of studies performed under this project. Following the list we present details of a selection of the results.
    Keywords: Lunar and Planetary Science and Exploration
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  • 291
    Publication Date: 2019-07-13
    Description: A systems analysis has been conducted for a Neptune-Triton Exploration Mission in which aerocapture is used to capture a spacecraft at Neptune. Aerocapture uses aerodynamic drag instead of propulsion to decelerate from the interplanetary approach trajectory to a captured orbit during a single pass through the atmosphere. After capture, propulsion is used to move the spacecraft from the initial captured orbit to the desired science orbit. A preliminary assessment identified that a spacecraft with a lift to drag ratio of 0.8 was required for aerocapture. Performance analyses of the 0.8 L/D vehicle were performed using a high fidelity flight simulation within a Monte Carlo executive to determine mission success statistics. The simulation was the Program to Optimize Simulated Trajectories (POST) modified to include Neptune specific atmospheric and planet models, spacecraft aerodynamic characteristics, and interplanetary trajectory models. To these were added autonomous guidance and pseudo flight controller models. The Monte Carlo analyses incorporated approach trajectory delivery errors, aerodynamic characteristics uncertainties, and atmospheric density variations. Monte Carlo analyses were performed for a reference set of uncertainties and sets of uncertainties modified to produce increased and reduced atmospheric variability. For the reference uncertainties, the 0.8 L/D flatbottom ellipsled vehicle achieves 100% successful capture and has a 99.87 probability of attaining the science orbit with a 360 m/s V budget for apoapsis and periapsis adjustment. Monte Carlo analyses were also performed for a guidance system that modulates both bank angle and angle of attack with the reference set of uncertainties. An alpha and bank modulation guidance system reduces the 99.87 percentile DELTA V 173 m/s (48%) to 187 m/s for the reference set of uncertainties.
    Keywords: Lunar and Planetary Science and Exploration
    Type: AIAA Paper 2004-4955 , AIAA Atmospheric Flight Mechanics Conference and Exhibit; Aug 16, 2004 - Aug 19, 2004; Providence, RI; United States
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  • 292
    Publication Date: 2019-07-13
    Description: Because of communication limits, planetary rovers must operate autonomously during consequent durations. The ability to plan under uncertainty is one of the main components of autonomy. Previous approaches to planning under uncertainty in NASA applications are not able to address the challenges of future missions, because of several apparent limits. On another side, decision theory provides a solid principle framework for reasoning about uncertainty and rewards. Unfortunately, there are several obstacles to a direct application of decision-theoretic techniques to the rover domain. This paper focuses on the issues of structure and concurrency, and continuous state variables. We describes two techniques currently under development that address specifically these issues and allow scaling-up decision theoretic solution techniques to planetary rover planning problems involving a small number of goals.
    Keywords: Lunar and Planetary Science and Exploration
    Type: AAAI-04 Workshop on Learning and Planning in MARK V Processing; Jul 26, 2004; San Jose, CA; United States
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  • 293
    Publication Date: 2019-07-13
    Description: The objective of the proposal was to construct global magnetospheric models of Jupiter for the use of Jovian magnetospheric community. In the four years of the grant period we were able to achieve all of the stated science objectives. The work has resulted in: 1) A new structural model of Jovian current sheet; 2) Global thickness map of the current sheet; 3) Magnetic field models of the current sheet; 4) The global model of Jupiter's magnetospheric field including hinging and delay of the current sheet, sweepback of the magnetic field and the shielding field of the magnetopause. To accomplish our work, we assembled an exhaustive magnetic field data base from all of the spacecraft that have visited Jupiter (Pioneers 10 and 11, Voyagers 1 and 2, Ulysses and Galileo). The data were rotated into system III and JSM coordinates. We used the data at resolutions of 1 minute (for studies of the structure of the current sheet) and 10 minutes (for building the global model).
    Keywords: Lunar and Planetary Science and Exploration
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  • 294
    Publication Date: 2019-07-13
    Description: For altitudes below 80 km, Mars Global Reference Atmospheric Model (Mars-GRAM 2001) is based on output climatology from NASA Ames Mars General Circulation Model (MGCM). At COSPAR 2002, results were presented of validation tests of Mars-GRAM versus data from Mars Global Surveyor Thermal Emission Spectrometer (TES) and Radio Science (RS) experiment. Further validation tests are presented comparing Mars- GRAM densities with those from the European Mars Climate Database (MCD), and comparing densities from both Mars-GRAM and MCD against TES observations. Throughout most of the height and latitude range of TES data (040 km and 70s to 70N), good agreement is found between atmospheric densities from Mars-GRAM and MCD. However, at the season and latitude zone for Mars Phoenix arrival and landing (Ls = 65 to 80 degrees and latitude 65 to 75N), Mars-GRAM densities are about 30 to 45 percent higher than MCD densities near 40 km altitude. Further evaluation is warranted concerning potential impact of these model differences on planning for Phoenix entry and descent. Three planned features for Mars-GRAM update are also discussed: (1) new MGCM and Thermospheric General Circulation Model data sets to be used as a revised basis for Mars-GRAM mean atmosphere, (2) a new feature to represent planetary-scale traveling waves for upper altitude density variations (such as found during Mars Odyssey aerobraking), and (3) a new model for effects of high resolution topographic slope on winds near the surface (0 to 4.5 km above MOLA topography level). Mars-GRAM slope winds will be computed from a diagnostic (algebraic) relationship based on Ye, Segal, and Pielke (1990). This approach differs from mesoscale models (such as MRAMS and Mars MM5), which use prognostic, full-physics solutions of the time- and space-dependent differential equations of motion. As such, slope winds in Mars-GRAM will be consistent with its "engineering-level" approach, and will be extremely fast and easy to evaluate, compared with mesoscale model solutions. Mars-GRAM slope winds are not being suggested as a replacement for sophisticated, full-physics Mars mesoscale models, but may have value, particularly for preliminary screening of large numbers of candidate landing sites for future Mars missions, such as Phoenix and Mars Science Laboratory. Test output is presented from Mars-GRAM slope winds in the area of Gusev Crater and Valles Marineris.
    Keywords: Lunar and Planetary Science and Exploration
    Type: 35th COSPAR Scientific Assembly Meeting; Jul 18, 2004 - Jul 25, 2004; Paris; France
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  • 295
    Publication Date: 2019-07-13
    Description: A study was performed in conjunction with the In Space Technology Investment Area of NASA's Marshall Space Flight Center to investigate potential applications of solar sails to Mars missions. While solar sails have been proposed as possible candidates for several missions, including Geostorm and a Polar Observer mission, Mars has often been overlooked as a potential destination. It was found that solar sails may have potential in Mars observation missions with smaller payloads. Sail aerocapture maneuvers also show an improvement in payload delivery capability. This study has shown that solar sail spacecraft rival chemical interplanetary probes to Mars and may have applications in future Mars exploration.
    Keywords: Lunar and Planetary Science and Exploration
    Type: JPC 2004 Conference; Jul 11, 2004 - Jul 14, 2004; Fort Lauderdale, FL; United States
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  • 296
    Publication Date: 2019-07-13
    Description: There are eight destinations in the solar System with sufficient atmosphere for aerocapture to be a viable aeroassist option - Venus, Earth, Mars, Jupiter, Saturn and its moon Titan, Uranus, and Neptune. Engineering-level atmospheric models for four of these targets (Earth, Mars, Titan, and Neptune) have been developed for NASA to support systems analysis studies of potential future aerocapture missions. Development of a similar atmospheric model for Venus has recently commenced. An important capability of all of these models is their ability to simulate quasi-random density perturbations for Monte Carlo analyses in developing guidance, navigation and control algorithm, and for thermal systems design. Similarities and differences among these atmospheric models are presented, with emphasis on the recently developed Neptune model and on planned characteristics of the Venus model. Example applications for aerocapture are also presented and illustrated. Recent updates to the Titan atmospheric model are discussed, in anticipation of applications for trajectory and atmospheric reconstruct of Huygens Probe entry at Titan.
    Keywords: Lunar and Planetary Science and Exploration
    Type: 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference; Jul 11, 2004 - Jul 14, 2004; Fort Lauderdale, FL; United States
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  • 297
    Publication Date: 2019-07-13
    Description: The Mars Science Laboratory (MSL) Project is an aggressive mission launching in 2009 to deliver a new generation of rover safely to the surface of Mars and conduct comprehensive in situ investigations using a new generation of instruments. This system will be designed to land with precision and be capable of operating over a large percentage on the surface of Mars. It will have capabilities that will support NASA's scientific goals into the next decade of exphation. The MSL Technology program is developing a wide-range of technologies needed for this Mission and potentially other space missions. The MSL Technology Program reports to both the MSL Project and the Mars Technology Program (MTP). The dual reporting process creates a challenging management situation, but ensures the new technology meets both the specific MSL requirements and the broader Mars Program requirements. MTP is a NASA-wide technology development program managed by the Jet Propulsion Laboratory (JPL) and is divided into a Focused Program and a Base Program. The Focused Technology Program addresses technologies that are specific and critical to near-term missions, while the Base Technology Program addresses those technologies that are applicable to multiple missions and which can be characterized as longer term, higher risk, and high payoff technologies. The MSL Technology Program is under the Focused Program and is tightly coupled to MSL's mission milestones and deliverables. The technology budget is separate from the flight Project budget, but the technology s requirements and the development process are tightly coordinated with the Project. The Technology Program combines proven management techniques of flight projects with commercial and academic technology management strategies, to create a technology management program that meets the near-term requirements of MSL and the long-term requirements of MTP. This paper examines the initiation of 2002 MSL Technology program. Some of the areas discussed in this paper include technology definition, task selection, technology management, and technology assessment.
    Keywords: Lunar and Planetary Science and Exploration
    Type: 2004 IEEE Aerospace Conference; Mar 06, 2004 - Mar 13, 2004; Big Sky, MT; United States
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  • 298
    Publication Date: 2019-07-13
    Description: In January, 2004, two NASA rovers, named Spirit and Opportunity, successfully landed on Mars, starting an unprecedented exploration of the Martian surface. Power and thermal concerns constrained the duration of this mission, leading to an aggressive plan for commanding both rovers every day. As part of the process for generating these command loads, the MAPGEN tool provides engineers and scientists an intelligent activity planning tool that allows them to more effectively generate complex plans that maximize the science return each day. The key to'the effectiveness of the MAPGEN tool is an underlying artificial intelligence plan and constraint reasoning engine. In this paper we outline the design and functionality of the MAEPGEN tool and focus on some of the key capabilities it offers to the MER mission engineers.
    Keywords: Lunar and Planetary Science and Exploration
    Type: 4th International Workshop on Planning and Scheduling for Space; Jun 23, 2004 - Jun 25, 2004; Darmstadt; Germany
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  • 299
    Publication Date: 2019-07-13
    Description: Commercially available polymer thin fdms with thickness of 15 microns or less were evaluated for potential application as the gas envelope material of balloons and other inflated vehicles. Films on this thickness scale are of interest for Earth and Mars ballooning as well as many gossamer space structures. Due to the uniqueness of these missions relative to typical uses of these materials, application-specific materials properties measurements were made. We evaluated numerous polymer chemistries, plus a few variations within one chemistry. The data show that there are often trade-offs among the different materials, such as with polyesters and polyimides having greater stiffness (modulus) but lower tear propagation resistance than polyethylene. Sections of polyethylene films can be joined by heat sealing, while adhesives and their accompanying mass penalty must be used with polyesters and polyimides. When the analysis temperature is reduced to 190 K, polyethylenes display dramatically increased stiffness and yield point, while the increase for other materials is more modest. The data also show that manufacturing processes can significantly affect film properties. To emphasize the need for application-specific properties assessment, we discuss two recent applications using these materials.
    Keywords: Lunar and Planetary Science and Exploration
    Type: 5th AIAA Gossamer Spacecraft Forum; Apr 19, 2004 - Apr 22, 2004; Palm Springs, CA; United States
    Format: application/pdf
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  • 300
    Publication Date: 2019-07-13
    Description: Large, fresh-appearing alluvial fans (typically greater than 10 km long) have been identified during a systematic search of 100 m/pixel low-sun daylight THEMIS IR imaging in deep late-Noachian or early-Hesperian craters. Our study of these fans was augmented with MOLA-derived topography and high-resolution MOC and THEMIS VIS images where available. The influence of alluvial fan deposition on the topography of crater floors has been recognized in previous topographic studies. Recent Mars Odyssey-era studies have also identified and described in detail a fluvial delta or fan of approximately the same age as the alluvial fans of this study. Our results, at the time of this writing, indicate that these fans are only found in less than 5% of all craters greater than or equal to 70 kilometers in diameter within a large study region. In every case the fan-containing craters were restricted to a latitude belt between 20 degrees S and 30 degrees S. All of which had significant topographic relief and appeared morphologically younger than typical mid-Noachian craters in the size range. However, large fans were not found in the most pristine (and presumably youngest) craters in this size range. Most Martian fans have morphologies consistent with terrestrial debris-flow-dominated fans.
    Keywords: Lunar and Planetary Science and Exploration
    Type: Lunar and Planetary Science Conference; Mar 12, 2004 - Mar 20, 2004; Houston, TX; United States
    Format: application/pdf
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