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  • Lunar and Planetary Science and Exploration  (2,542)
  • 11
    Publication Date: 2019-09-20
    Description: The current best estimates of Bennus gravity field will be presented, based on the independent solutions from four different teams involved on the OSIRIS-REx mission. The discovery of ejected particles about Bennu that may remain in orbit for several days or more provide a unique opportunity to probe the gravity field to higher degree and order than possible by using conventional spacecraft tracking. However, the non-gravitational forces acting on these particles must also be characterized, and their impact on solution accuracy must be assessed. This talk will present the latest results from the mission, incorporating spacecraft tracking from the lowest orbit in which the satellite will be during the mission.
    Keywords: Lunar and Planetary Science and Exploration
    Type: GSFC-E-DAA-TN68580 , European Planetary Science Congress / Division for Planetary Sciences Joint Meeting (EPSC-DPS 2019); Sep 15, 2019 - Sep 20, 2019; Geneva; Switzerland
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  • 12
    Publication Date: 2019-07-13
    Description: The Mars Science Laboratory Curiosity rover landed in Gale crater in August 2012 to study the layered sediments of lower Aeolis Mons (i.e., Mount Sharp), which have signatures of phyllosilicates, hydrated sulfates, and iron oxides in orbital visible/near-infrared observations. The observed mineralogy within the stratigraphy, from phyllosilicates in lower units to sulfates in higher units, suggests an evolution in the environments in which these secondary phases formed. Curiosity is currently investigating the sedimentary structures, geochemistry, and mineralogy of the Murray formation, the lowest exposed unit of Mount Sharp. The Murray formation is dominated by laminated lacustrine mudstone and is approx.200 m thick. Curiosity previously investigated lacustrine mudstone early in the mission at Yellowknife Bay, which represents the lowest studied stratigraphic unit. Here, we present the minerals identified in lacus-trine mudstone from Yellowknife Bay and the Murray formation. We discuss trends in mineralogy within the stratigraphy and the implications for ancient lacustrine environments, diagenesis, and sediment sources.
    Keywords: Lunar and Planetary Science and Exploration
    Type: JSC-CN-38733 , Lunar and Planetary Science Conference; 20-24 Mar. 2017; The Woodlands, TX; United States
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  • 13
    Publication Date: 2019-07-13
    Description: Comparing data from the Alpha- Particle X-Ray Spectrometer (APXS) and the Sample Analysis at Mars (SAM) instruments on MSL reveals a strong linear correlation between chlorine and oxygen, further demonstrating the presence of oxychlorine species in Gale Crater and, very likely, globally on Mars. Perchlorate was first discovered on Mars by the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument on the Phoenix lander in 2008. Current hypotheses suggest that the formation of oxychlorine species such as perchlorate or chlorate is a global process and that these species should be globally distributed on Mars [e.g. 2-4]. To date, the SAM and Chemistry and Mineralogy (CheMin) instruments on MSL have analyzed one scooped sample of aeolian material (Rocknest [RN]), and four drilled samples (John Klein [JK], Cumberland [CB], Windjana [WJ], and Confidence Hills [CH]). The APXS instrument has also investigated the same or very similar samples. Although not definitively identified, oxychlorine species have been proposed to explain releases of O2, HCl, and chlorinated hydrocarbon species detected by evolved gas analysis (EGA) with the SAM instrument. We report a strong linear correlation between wt. % Cl detected by APXS and moles O2 detected by SAM during pyrolysis, indicating the presence of oxychlorine species in Gale Crater.
    Keywords: Lunar and Planetary Science and Exploration
    Type: JSC-CN-32849 , Lunar and Planetary Science Conference; 16-20 Mar. 2015; The Woodlands, TX; United States
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  • 14
    Publication Date: 2019-07-13
    Description: One of the main goals of the Mars Science Laboratory is to determine whether the planet ever had environmental conditions able to support microbial life. Nitrogen is a fundamental element for life, and is present in structural (e.g., proteins), catalytic (e.g., enzymes and ribozymes), energy transfer (e.g., ATP) and information storage (RNA and DNA) biomolecules. Planetary models suggest that molecular nitrogen was abundant in the early Martian atmosphere, but was rapidly lost to space by photochemistry, sputtering impact erosion, and oxidized and deposited to the surface as nitrate. Nitrates are a fundamental source for nitrogen to terrestrial microorganisms. Therefore, the detection of nitrates in soils and rocks is important to assess the habitability of a Martian environment. SAM is capable of detecting nitrates by their thermal decomposition into nitric oxide, NO. Here we analyze the release of NO from soils and rocks examined by the SAM instrument at Gale crater, and discuss its origin.
    Keywords: Lunar and Planetary Science and Exploration
    Type: JSC-CN-30382 , Lunar and Planetary Science Conference; 17-21 Mar. 2014; The Woodlands, TX; United States
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  • 15
    Publication Date: 2019-07-13
    Description: To prepare for the exploration of Mars by humans, as outlined in the new national vision for Space Exploration (VSE), the Mars Exploration Program Analysis Group (MEPAG), chartered by NASA's Mars Exploration Program (MEP), formed a Human Exploration of Mars Science Analysis Group (HEM-SAG), in March 2007. HEM-SAG was chartered to develop the scientific goals and objectives for the human exploration of Mars based on the Mars Scientific Goals, Objectives, Investigations, and Priorities.1 The HEM-SAG is one of several humans to Mars scientific, engineering and mission architecture studies chartered in 2007 to support NASA s plans for the human exploration of Mars. The HEM-SAG is composed of about 30 Mars scientists representing the disciplines of Mars biology, climate/atmosphere, geology and geophysics from the U.S., Canada, England, France, Italy and Spain. MEPAG selected Drs. James B. Garvin (NASA Goddard Space Flight Center) and Joel S. Levine (NASA Langley Research Center) to serve as HEMSAG co-chairs. The HEM-SAG team conducted 20 telecons and convened three face-to-face meetings from March through October 2007. The management of MEP and MEPAG were briefed on the HEM-SAG interim findings in May. The HEM-SAG final report was presented on-line to the full MEPAG membership and was presented at the MEPAG meeting on February 20-21, 2008. This presentation will outline the HEM-SAG biology and climate/atmosphere goals and objectives. A companion paper will outline the HEM-SAG geology and geophysics goals and objectives.
    Keywords: Lunar and Planetary Science and Exploration
    Type: 39th Lunar and Planetary Sciences Conference; 10-14 Mar. 2008; Houston, TX; United States
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  • 16
    Publication Date: 2019-07-13
    Description: The Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments on the Mars Science Laboratory (MSL) analysed several subsamples of 〈150 m fines from five sites at Gale Crater. Three were in Yellowknife Bay: the Rocknest aeolian bedform ("RN") and drilled Sheepbed mudstone from sites John Klein ("JK") and Cumberland ("CB"). One was drilled from the Windjana ("WJ") site on a sandstone of the Kimberly formation investigated on route to Mount Sharp. Another was drilled from the Confidence Hills ("CH") site on a sandstone of the Murray Formation at the base of Mt. Sharp (Pahrump Hills). Outcrops are sedimentary rocks that are largely of fluvial or lacustrine origin, with minor aeolian deposits.. SAM's evolved gas analysis (EGA) mass spectrometry detected H2O, CO2, O2, H2, SO2, H2S, HCl, NO, and other trace gases, including organic fragments. The identity and evolution temperature (T) of evolved gases can support CheMin mineral detection and place constraints on trace volatile-bearing phases or phases difficult to characterize with XRD (e.g., X-ray amorphous phases). They can also give constraints on sample organic chemistry. Here, we discuss trends in major evolved volatiles from SAM EGA analyses to date.
    Keywords: Lunar and Planetary Science and Exploration
    Type: JSC-CN-32774 , Lunar and Planetary Science Conference; 16-20 Mar. 2015; The Woodlands, TX; United States
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  • 17
    Publication Date: 2019-07-13
    Description: NASA's Dawn spacecraft entered orbit around asteroid (4) Vesta in July 2011 for a yearlong mapping orbit. The surface of Vesta as imaged by the Dawn Framing Camera (FC) revealed a surface that is unlike any asteroid we have visited so far with a spacecraft. Albedo and color variations on Vesta are the most diverse in the asteroid belt with a majority of these linked to distinct compositional units on the asteroid s surface. FC discovered dark material on Vesta. These low albedo surface features were first observed during Rotational Characterization 3 phase at a resolution of approx. 487 m/pixel. Here we explore the composition and possible meteoritical analogs for the dark material on Vesta.
    Keywords: Lunar and Planetary Science and Exploration
    Type: JSC-CN-26602 , 75th Annual Meeting of the Meteorical Society; 12-17 Aug. 2012; Cairns; Australia
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  • 18
    Publication Date: 2019-07-13
    Description: Variability in the sulfur isotopic composition in sediments can reflect atmospheric, geologic and biological processes. Evidence for ancient fluvio-lacustrine environments at Gale crater on Mars and a lack of efficient crustal recycling mechanisms on the planet suggests a surface environment that was once warm enough to allow the presence of liquid water, at least for discrete periods of time, and implies a greenhouse effect that may have been influenced by sulfur-bearing volcanic gases. Here we report in situ analyses of the sulfur isotopic compositions of SO2 volatilized from ten sediment samples acquired by NASA's Curiosity rover along a 13 km traverse of Gale crater. We find large variations in sulfur isotopic composition that exceed those measured for Martian meteorites and show both depletion and enrichment in S-34. Measured values of S-34 range from -47 +/- 14% to 28 +/- 7%, similar to the range typical of terrestrial environments. Although limited geochronological constraints on the stratigraphy traversed by Curiosity are available, we propose that the observed sulfur isotopic signatures at Gale crater can be explained by equilibrium fractionation between sulfate and sulfide in an impact-driven hydrothermal system and atmospheric processing of sulfur-bearing gases during transient warm periods.
    Keywords: Lunar and Planetary Science and Exploration
    Type: GSFC-E-DAA-TN53781 , Nature Geoscience (ISSN 1752-0894) (e-ISSN 1752-0908); 10; 9; 658–662
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  • 19
    Publication Date: 2019-07-20
    Description: The Sample Analysis at Mars (SAM) instrument on the Mars Science Laboratory (MSL) rover Curiosity has analyzed 3 scooped samples and 15 drilled samples since landing in 2012. Oxychlorine compounds (perchlorate/chlorate) were detected in the first 9 drilled samples but have not been detected in the last 6, starting with the Oudam sample in the Hartmanns Valley member of the Murray formation (Table 1). Scooped samples have all contained detectable oxychlorine. These results suggest that oxychlorine formation and preservation spans the geologic record on Mars but has not been uniform spatially or temporally.
    Keywords: Lunar and Planetary Science and Exploration
    Type: JSC-E-DAA-TN64978 , Lunar and Planetary Science Conference (LPSC 2019); 18–22 Mar. 2019; The Woodlands, TX; United States
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  • 20
    Publication Date: 2019-07-19
    Description: The Mars Science Laboratory Curiosity rover landed in Gale crater in August 2012 to assess the habitability of sedimentary deposits that show orbital evidence for diverse ancient aqueous environments. Gale crater contains a 5 km high mound of layered sedimentary rocks in its center, informally named Mount Sharp. The lowermost rocks of Mount Sharp contain minerals that are consistent with a dramatic climate change during Mars' early history. During the rover's traverse across the Gale crater plains to the base of Mount Sharp, Curiosity discovered sedimentary rocks consistent with a fluviolacustrine sequence. Curiosity studied ancient lacustrine deposits at Yellowknife Bay on the plains of Gale crater and continues to study ancient lacustrine deposits in the Murray formation, the lowermost unit of Mount Sharp. These investigations include drilling into the mudstone and delivering the sieved less than 150 micrometers fraction to the CheMin XRD/XRF instrument inside the rover. Rietveld refinement of XRD patterns measured by CheMin generates mineral abundances with a detection limit of 1-2 wt.% and refined unit-cell parameters of minerals present in abundances greater than approximately 5 wt.%. FULLPAT analyses of CheMin XRD patterns provide the abundance of X-ray amorphous materials and constrain the identity of these phases (e.g., opal-A vs. opal-CT). At the time of writing, CheMin has analyzed 14 samples, seven of which were drilled from lacustrine deposits. The mineralogy from CheMin, combined with in-situ geochemical measurements and sedimentological observations, suggest an evolution in the lake waters through time, including changes in pH and salinity and transitions between oxic and anoxic conditions. In addition to a geochemically dynamic lake environment, the igneous minerals discovered in the lake sediments indicate changes in source region through time, with input from mafic and silicic igneous sources. The Murray formation is predominantly comprised of lacustrine mudstone and is 150-200 m thick, suggesting long history of lake environments in Gale crater. Curiosity has traversed through the lowermost approximately 30 m of the Murray formation, and each additional sample provides clues about the climate on early Mars.
    Keywords: Lunar and Planetary Science and Exploration
    Type: JSC-CN-37441 , Geological Society of America Meeting (GSA 2016); 25-28 Sep. 2016; Denver, CO; United States
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