162 research outputs found

    Micro-ion Traps for Detection of (Pre)-Biotic Organic Compounds on Comets

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    Comets are currently believed to be a mixture of interstellar and nebular material. Many of the volatiles in comets are attributed to interstellar chemistry, because the same species of carbonaceous compounds are also observed in ices in interstellar molecular (ISM) clouds. Comets are thus likely to be a relatively pristine reservoir of primitive material and carbonaceous compounds in our solar system. They could be a major contributor to the delivery of prebiotic organic compounds, from which life emerged through impacts on early Earth. Mass spectrometers are very powerful tools to identify unknown chemicals, and much progress bas been made in miniaturizing mas spectrometers for space applications. Most miniatu rized mass spectrometers developed to date, however, are still relatively large, power hungry, complicated to assemble, and would have significant impact on space flight vehicle total payload and resource allocations

    Characterization of a Carbon Nanotube Field Emission Electron Gun for the VAPoR Miniaturized Pyrolysis-Time-of-Flight Mass Spectrometer

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    We are developing the VAPoR (Volatile Analysis by Pyrolysis of Regolith) instrument towards studying soil composition, volatiles, and trapped noble gases in the polar regions of the Moon. VAPOR will ingest a soil sample and conduct analysis by pyrolysis and time-of-flight mass spectrometry (ToF-MS). Here, we describe miniaturization efforts within this development, including a carbon nanotube (CNT) field emission electron gun that is under consideration for use as the electron impact ionization source for the ToF-MS

    Probing interlayer interactions and commensurate-incommensurate transition in twisted bilayer graphene through Raman spectroscopy

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    Twisted 2D layered materials have garnered a lot of attention recently as a class of 2D materials whose interlayer interactions and electronic properties are dictated by the relative rotation / twist angle between the adjacent layers. In this work, we explore a prototype of such a twisted 2D system, artificially stacked twisted bilayer graphene (TBLG), where we probe the changes in the interlayer interactions and electron-phonon scattering pathways as the twist angle is varied from 0{\deg} to 30{\deg}, using Raman spectroscopy. The long range Moir\'e potential of the superlattice gives rise to additional intravalley and intervalley scattering of the electrons in TBLG which have been investigated through their Raman signatures. The density functional theory (DFT) calculations of the electronic band structure of the TBLG superlattices was found to be in agreement with the resonant Raman excitations across the van Hove singularities in the valence and conduction bands predicted for TBLG due to hybridization of bands from the two layers. We also observe that the relative rotation between the graphene layers has a marked influence on the second order overtone and combination Raman modes signalling a commensurate-incommensurate transition in TBLG as the twist angle increases. This serves as a convenient and rapid characterization tool to determine the degree of commensurability in TBLG systems

    Detection of Organics at Mars: How Wet Chemistry Onboard SAM Helps

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    For the first time in the history of space exploration, a mission of interest to astrobiology could be able to analyze refractory organic compounds in the soil of Mars. Wet chemistry experiment allow organic components to be altered in such a way that improves there detection either by releasing the compounds from sample matricies or by changing the chemical structure to be amenable to analytical conditions. The latter is particular important when polar compounds are present. Sample Analysis at Mars (SAM), on the Curiosity rover of the Mars Science Laboratory mission, has onboard two wet chemistry experiments: derivatization and thermochemolysis. Here we report on the nature of the MTBSTFA derivatization experiment on SAM, the detection of MTBSTFA in initial SAM results, and the implications of this detection

    A review of sample analysis at mars-evolved gas analysis laboratory analog work supporting the presence of perchlorates and chlorates in gale crater, mars

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    Funding Information: The research reviewed in this paper was funded by the Mars Science Laboratory (MSL) project office. M.-P.Z. acknowledges funding from the Ministerio de Ciencia e Innovacion (ref. PID2019-104205GB-C21). The authors are grateful to the engineers and scientists of the MSL Curiosity team, who have made the mission possible and the reported data available. The authors would also like to thank the two anonymous reviewers who provided careful reviews that increased the quality of this manuscript. The authors would like to remember and recognize the contributions of Rafael Navarro-Gonzalez, a dedicated SAM and HABIT team member who passed away on 28 January 2021. Navarro-Gonzalez, who was a distinguished researcher, conducted laboratory experiments that demonstrated that chloromethanes could form through a reaction between perchlorates and organics during sample heating, which greatly advanced our understanding of perchlorates and organic detection on Mars. Data Availability Statement: SAM data are publicly available through the NASA Planetary Data System at: http://pds-geosciences.wustl.edu/missions/msl/sam.htm, which was updated in March 2021. See references for the original research articles that contain the data reviewed in this paper.Peer reviewedPublisher PD

    Asteroid Redirect Mission (ARM) Formulation Assessment and Support Team (FAST) Final Report

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    The Asteroid Redirect Mission (ARM) Formulation Assessment and Support Team (FAST) was a two-month effort, chartered by NASA, to provide timely inputs for mission requirement formulation in support of the Asteroid Redirect Robotic Mission (ARRM) Requirements Closure Technical Interchange Meeting held December 15-16, 2015, to assist in developing an initial list of potential mission investigations, and to provide input on potential hosted payloads and partnerships. The FAST explored several aspects of potential science benefits and knowledge gain from the ARM. Expertise from the science, engineering, and technology communities was represented in exploring lines of inquiry related to key characteristics of the ARRM reference target asteroid (2008 EV5) for engineering design purposes. Specific areas of interest included target origin, spatial distribution and size of boulders, surface geotechnical properties, boulder physical properties, and considerations for boulder handling, crew safety, and containment. In order to increase knowledge gain potential from the mission, opportunities for partnerships and accompanying payloads were also investigated. Potential investigations could be conducted to reduce mission risks and increase knowledge return in the areas of science, planetary defense, asteroid resources and in-situ resource utilization, and capability and technology demonstrations. This report represents the FAST"TM"s final product for the ARM

    Volatile Analysis by Pyrolysis of Regolith for Planetary Resource Exploration

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    The extraction and identification of volatile resources that could be utilized by humans including water, oxygen, noble gases, and hydrocarbons on the Moon, Mars, and small planetary bodies will be critical for future long-term human exploration of these objects. Vacuum pyrolysis at elevated temperatures has been shown to be an efficient way to release volatiles trapped inside solid samples. In order to maximize the extraction of volatiles, including oxygen and noble gases from the breakdown of minerals, a pyrolysis temperature of 1400 C or higher is required, which greatly exceeds the maximum temperatures of current state-of-the-art flight pyrolysis instruments. Here we report on the recent optimization and field testing results of a high temperature pyrolysis oven and sample manipulation system coupled to a mass spectrometer instrument called Volatile Analysis by Pyrolysis of Regolith (VAPoR). VAPoR is capable of heating solid samples under vacuum to temperatures above 1300 C and determining the composition of volatiles released as a function of temperature

    Sulfur-bearing phases detected by evolved gas analysis of the Rocknest aeolian deposit, Gale Crater, Mars

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    The Sample Analysis at Mars (SAM) instrument suite detected SO_2, H_(2)S, OCS, and CS_2 from ~450 to 800°C during evolved gas analysis (EGA) of materials from the Rocknest aeolian deposit in Gale Crater, Mars. This was the first detection of evolved sulfur species from a Martian surface sample during in situ EGA. SO_2 (~3–22 µmol) is consistent with the thermal decomposition of Fe sulfates or Ca sulfites, or evolution/desorption from sulfur-bearing amorphous phases. Reactions between reduced sulfur phases such as sulfides and evolved O_2 or H_(2)O in the SAM oven are another candidate SO_2 source. H_(2)S (~41–109 nmol) is consistent with interactions of H_(2)O, H_2 and/or HCl with reduced sulfur phases and/or SO2 in the SAM oven. OCS (~1–5 nmol) and CS2 (~0.2–1 nmol) are likely derived from reactions between carbon-bearing compounds and reduced sulfur. Sulfates and sulfites indicate some aqueous interactions, although not necessarily at the Rocknest site; Fe sulfates imply interaction with acid solutions whereas Ca sulfites can form from acidic to near-neutral solutions. Sulfides in the Rocknest materials suggest input from materials originally deposited in a reducing environment or from detrital sulfides from an igneous source. The presence of sulfides also suggests that the materials have not been extensively altered by oxidative aqueous weathering. The possibility of both reduced and oxidized sulfur compounds in the deposit indicates a nonequilibrium assemblage. Understanding the sulfur mineralogy in Rocknest materials, which exhibit chemical similarities to basaltic fines analyzed elsewhere on Mars, can provide insight in to the origin and alteration history of Martian surface materials

    PADME (Phobos And Deimos and Mars Environment): A Proposed NASA Discovery Mission to Investigate the Two Moons of Mars

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    After 40 years of solar system exploration by spacecraft, the origin of Mars's satellites, remains vexingly unknown. There are three prevailing hypotheses concerning their origin: H1: They are captured small bodies from the outer main belt or beyond; H2: They are reaccreted Mars impact ejecta; H3: They are remnants of Mars' formation. There are many variants of these hypotheses, but as stated, these three capture the key ideas and constraints on their nature. So far, data and modeling have not allowed any one of these hypotheses to be verified or excluded. Each one of these hypotheses has important implications for the evolution of the solar system, the formation and evolution of planets and satellites, and the delivery of water and organics to Early Mars and Early Earth. Determining the origin of Phobos and Deimos is identified by the NASA and the NRC Decadal Survey as the most important science goal at these bodies

    The Sample Analysis at Mars Investigation and Instrument Suite

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    The Sample Analysis at Mars (SAM) investigation of the Mars Science Laboratory(MSL) addresses the chemical and isotopic composition of the atmosphere and volatilesextracted from solid samples. The SAM investigation is designed to contribute substantiallyto the mission goal of quantitatively assessing the habitability of Mars as an essentialstep in the search for past or present life on Mars. SAM is a 40 kg instrument suite locatedin the interior of MSLs Curiosity rover. The SAM instruments are a quadrupole massspectrometer, a tunable laser spectrometer, and a 6-column gas chromatograph all coupledthrough solid and gas processing systems to provide complementary information on thesame samples. The SAM suite is able to measure a suite of light isotopes and to analyzevolatiles directly from the atmosphere or thermally released from solid samples. In additionto measurements of simple inorganic compounds and noble gases SAM will conducta sensitive search for organic compounds with either thermal or chemical extraction fromsieved samples delivered by the sample processing system on the Curiosity rovers roboticarm
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