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Mitrofanov IG, Nikiforov SY, Djachkova MV, Lisov DI, Litvak ML, Sanin AB, Vasavada AR. Water and Chlorine in the Martian Subsurface Along the Traverse of NASA's Curiosity Rover: 1. DAN Measurement Profiles Along the Traverse. JOURNAL OF GEOPHYSICAL RESEARCH. PLANETS 2022; 127:e2022JE007327. [PMID: 36588803 PMCID: PMC9788246 DOI: 10.1029/2022je007327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 10/28/2022] [Accepted: 11/06/2022] [Indexed: 06/17/2023]
Abstract
This paper presents estimates of the water and chlorine contents in the subsurface of Gale crater based on the measurements by the Dynamic Albedo of Neutrons (DAN) instrument onboard the NASA Curiosity rover. It is Part 1 of a two-paper series. Data derived both from DAN active and passive measurements are presented in discrete surface areas (pixels) assuming a homogeneous distribution of water within the DAN sensing depth (60 cm) along the traverse of the rover. It is shown that the content of hydrogen, reported as Water Equivalent Hydrogen, varies between almost zero and a maximum of (6.1 ± 0.7) wt.%. The content of absorption equivalent chlorine varies between almost zero and (2.6 ± 0.2) wt.%. Such variations are thought to be related to the different geological processes and environmental conditions present in the strata along the traverse during the evolutionary history of Gale crater. The second paper (Part 2) studies particular properties of water and abundances of neutron absorbing elements at distinct geological regions, that the rover crossed on its way.
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Affiliation(s)
- I. G. Mitrofanov
- Space Research Institute of the Russian Academy of Sciences (IKI)MoscowRussia
| | - S. Y. Nikiforov
- Space Research Institute of the Russian Academy of Sciences (IKI)MoscowRussia
| | - M. V. Djachkova
- Space Research Institute of the Russian Academy of Sciences (IKI)MoscowRussia
| | - D. I. Lisov
- Space Research Institute of the Russian Academy of Sciences (IKI)MoscowRussia
| | - M. L. Litvak
- Space Research Institute of the Russian Academy of Sciences (IKI)MoscowRussia
| | - A. B. Sanin
- Space Research Institute of the Russian Academy of Sciences (IKI)MoscowRussia
| | - A. R. Vasavada
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
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2
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Black BA, Manga M, Ojha L, Longpré M, Karunatillake S, Hlinka L. The History of Water in Martian Magmas From Thorium Maps. GEOPHYSICAL RESEARCH LETTERS 2022; 49:e2022GL098061. [PMID: 35859852 PMCID: PMC9285613 DOI: 10.1029/2022gl098061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 05/17/2022] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
Water inventories in Martian magmas are poorly constrained. Meteorite-based estimates range widely, from 102 to >104 ppm H2O, and are likely variably influenced by degassing. Orbital measurements of H primarily reflect water cycled and stored in the regolith. Like water, Th behaves incompatibly during mantle melting, but unlike water Th is not prone to degassing and is relatively immobile during aqueous alteration at low temperature. We employ Th as a proxy for original, mantle-derived H2O in Martian magmas. We use regional maps of Th from Mars Odyssey to assess variations in magmatic water across major volcanic provinces and through time. We infer that Hesperian and Amazonian magmas had ∼100-3,000 ppm H2O, in the lower range of previous estimates. The implied cumulative outgassing since the Hesperian, equivalent to a global H2O layer ∼1-40 m deep, agrees with Mars' present-day surface and near-surface water inventory and estimates of sequestration and loss rates.
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Affiliation(s)
- Benjamin A. Black
- Department of Earth and Planetary SciencesRutgers UniversityPiscatawayNJUSA
| | - Michael Manga
- Department of Earth and Planetary SciencesUniversity of California, BerkeleyBerkeleyCAUSA
| | - Lujendra Ojha
- Department of Earth and Planetary SciencesRutgers UniversityPiscatawayNJUSA
| | - Marc‐Antoine Longpré
- School of Earth and Environmental SciencesQueens College, City University of New YorkQueensNYUSA
- Earth and Environmental SciencesThe Graduate Center, City University of New YorkNew YorkNYUSA
| | | | - Lisa Hlinka
- School of Earth and Environmental SciencesQueens College, City University of New YorkQueensNYUSA
- Earth and Environmental SciencesThe Graduate Center, City University of New YorkNew YorkNYUSA
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3
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Litvak ML, Mitrofanov IG, Sanin AB, Bakhtin B, Golovin DV, Zeitlin C. Observations of neutron radiation environment during Odyssey cruise to Mars. LIFE SCIENCES IN SPACE RESEARCH 2021; 29:53-62. [PMID: 33888288 DOI: 10.1016/j.lssr.2021.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 03/10/2021] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
In April 2001, Mars Odyssey spacecraft with the High Energy Neutron Detector (HEND) onboard was launched to Mars. HEND/Odyssey was switched on measurement mode for most of transit to Mars to monitor variations of spacecraft background and solar activity. Although HEND/Odyssey was originally designed to measure Martian neutron albedo and to search for Martian subsurface water/water ice, its measurements during cruise phase to Mars are applicable to evaluate spacecraft ambient radiation background. The biological impact of the neutron component of this radiation background should be understood, as it must be taken into account in planning future human missions to Mars. We have modeled the spacecraft neutron spectral density and compared it with HEND measurements to estimate neutron dose equivalent rates during Odyssey cruise phase, which occurred during the maximum period of solar cycle 23. We find that the Odyssey ambient neutron environment during May - September 2001 yields 10.6 ± 2.0 μSv per day in the energy range from 0 to 15 MeV, and about 29 μSv per day when extrapolated to the 0-1000 MeV energy range during solar quiet time (intervals without Solar Particle Events, SPEs). We have also extrapolated HEND/Odyssey measurements to different periods of solar cycle and find that during solar minimum (maximum of GCR flux), the neutron dose equivalent rate during cruise to Mars could be as high as 52 μSv per day with the same shielding. These values are in good agreement with results reported for a similar measurement made with an instrument aboard the Mars Science Laboratory during its cruise to Mars in 2011-2012.
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Affiliation(s)
- M L Litvak
- Space Research Institute, RAS, Moscow, 117997, Russia.
| | | | - A B Sanin
- Space Research Institute, RAS, Moscow, 117997, Russia
| | - B Bakhtin
- Space Research Institute, RAS, Moscow, 117997, Russia
| | - D V Golovin
- Space Research Institute, RAS, Moscow, 117997, Russia
| | - C Zeitlin
- Leidos, Inc., Houston, TX 77058, USA
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Rojas Vivas JA, Navarro-González R, de la Rosa J, Molina P, Sedov S, McKay CP. Radiolytic Degradation of Soil Carbon from the Mojave Desert by 60Co Gamma Rays: Implications for the Survival of Martian Organic Compounds Due to Cosmic Radiation. ASTROBIOLOGY 2021; 21:381-393. [PMID: 33351679 DOI: 10.1089/ast.2020.2257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The martian surface has been continuously exposed to galactic cosmic radiation. Since organic compounds are degraded by ionizing radiation, knowledge of their decay constants is fundamental to predicting their stability on the martian surface. In this study, we report the radiolysis constant for the destruction of soil organic compounds at a starting concentration of ∼2011 μg C/gsoil from the Mojave Desert. The soils were exposed to gamma irradiation with absorbed doses of up to 19 MGy at room temperature, representing ∼250 million years of exposure to galactic cosmic rays. The destruction of total soil organic carbon and the formation of gases were investigated by a sequential on-line analytical array coupled to gas chromatography-mass spectrometry. Soil inorganic and organic carbon were degraded exponentially with a radiolysis constant 0.3 MGy-1(30%) producing mostly carbon dioxide (93.2%), carbon monoxide (6.2%), and methane (0.6%). Using the dose rate measured by the Radiation Assessment Detector on board the Curiosity rover, we make predictions on the survival of organic compounds in the cold martian subsurface. It is estimated that soil organic compounds with initial concentrations as those found today at the Mojave Desert would have been destroyed to levels <1 ppb at 0.1 m in depth in ∼2000 Myr. Pristine organic compounds are expected to be present at a depth of ∼1.5 m. These results are relevant for the search of organic compounds in past, present, and future missions to Mars. In particular, we predict that the upcoming ExoMars will encounter pristine organic compounds at this depth.
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Affiliation(s)
- José Alfredo Rojas Vivas
- Posgrado en Ciencias de la Tierra, Universidad Nacional Autónoma de México, Circuito de la investigación S/N, Ciudad Universitaria, Ciudad de México, Mexico
- Laboratorio de Química de Plasmas y Estudios Planetarios, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior S/N, Ciudad Universitaria, Ciudad de México, Mexico
| | - Rafael Navarro-González
- Laboratorio de Química de Plasmas y Estudios Planetarios, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior S/N, Ciudad Universitaria, Ciudad de México, Mexico
| | - José de la Rosa
- Laboratorio de Química de Plasmas y Estudios Planetarios, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior S/N, Ciudad Universitaria, Ciudad de México, Mexico
| | - Paola Molina
- Laboratorio de Química de Plasmas y Estudios Planetarios, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior S/N, Ciudad Universitaria, Ciudad de México, Mexico
| | - Sergey Sedov
- Departamento de Ciencias Ambientales y del Suelo, Instituto de Geología, Universidad Nacional Autónoma de México, Circuito de la investigación S/N, Ciudad Universitaria, Ciudad de México, Mexico
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Orosei R, Ding C, Fa W, Giannopoulos A, Hérique A, Kofman W, Lauro SE, Li C, Pettinelli E, Su Y, Xing S, Xu Y. The Global Search for Liquid Water on Mars from Orbit: Current and Future Perspectives. Life (Basel) 2020; 10:life10080120. [PMID: 32722008 PMCID: PMC7460233 DOI: 10.3390/life10080120] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/17/2020] [Accepted: 07/20/2020] [Indexed: 12/02/2022] Open
Abstract
Due to its significance in astrobiology, assessing the amount and state of liquid water present on Mars today has become one of the drivers of its exploration. Subglacial water was identified by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) aboard the European Space Agency spacecraft Mars Express through the analysis of echoes, coming from a depth of about 1.5 km, which were stronger than surface echoes. The cause of this anomalous characteristic is the high relative permittivity of water-bearing materials, resulting in a high reflection coefficient. A determining factor in the occurrence of such strong echoes is the low attenuation of the MARSIS radar pulse in cold water ice, the main constituent of the Martian polar caps. The present analysis clarifies that the conditions causing exceptionally strong subsurface echoes occur solely in the Martian polar caps, and that the detection of subsurface water under a predominantly rocky surface layer using radar sounding will require thorough electromagnetic modeling, complicated by the lack of knowledge of many subsurface physical parameters. Higher-frequency radar sounders such as SHARAD cannot penetrate deep enough to detect basal echoes over the thickest part of the polar caps. Alternative methods such as rover-borne Ground Penetrating Radar and time-domain electromagnetic sounding are not capable of providing global coverage. MARSIS observations over the Martian polar caps have been limited by the need to downlink data before on-board processing, but their number will increase in coming years. The Chinese mission to Mars that is to be launched in 2020, Tianwen-1, will carry a subsurface sounding radar operating at frequencies that are close to those of MARSIS, and the expected signal-to-noise ratio of subsurface detection will likely be sufficient for identifying anomalously bright subsurface reflectors. The search for subsurface water through radar sounding is thus far from being concluded.
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Affiliation(s)
- Roberto Orosei
- Istituto di Radioastronomia, Istituto Nazionale di Astrofisica, Via Piero Gobetti 101, 40129 Bologna, Italy
- Correspondence:
| | - Chunyu Ding
- School of Atmosphere Sciences, Sun Yat-sen University, 2 Daxue Road, Xiangzhou District, Zhuhai City 519000, China;
| | - Wenzhe Fa
- Institute of Remote Sensing and Geographical Information System, School of Earth and Space Sciences, Peking University, Beijing 100871, China;
| | - Antonios Giannopoulos
- School of Engineering, The University of Edinburgh, Alexander Graham Bell Building, Thomas Bayes Road, Edinburgh EH9 3FG, UK;
| | - Alain Hérique
- Université Grenoble Alpes, CNRS, CNES, IPAG, 38000 Grenoble, France; (A.H.); (W.K.)
| | - Wlodek Kofman
- Université Grenoble Alpes, CNRS, CNES, IPAG, 38000 Grenoble, France; (A.H.); (W.K.)
- Centrum Badan Kosmicznych Polskiej Akademii Nauk (CBK PAN), Bartycka 18A, 00-716 Warsaw, Poland
| | - Sebastian E. Lauro
- Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy; (S.E.L.); (E.P.)
| | - Chunlai Li
- Key Laboratory of Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100101, China; (C.L.); (Y.S.)
- University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Elena Pettinelli
- Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy; (S.E.L.); (E.P.)
| | - Yan Su
- Key Laboratory of Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100101, China; (C.L.); (Y.S.)
- University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Shuguo Xing
- Piesat Information Technology Co., Ltd, Beijing 100195, China;
| | - Yi Xu
- State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau;
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6
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Shotwell RF, Hays LE, Beaty DW, Goreva Y, Kieft TL, Mellon MT, Moridis G, Peterson LD, Spycher N. Can an Off-Nominal Landing by an MMRTG-Powered Spacecraft Induce a Special Region on Mars When No Ice Is Present? ASTROBIOLOGY 2019; 19:1315-1338. [PMID: 31657948 DOI: 10.1089/ast.2017.1688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This work aims at addressing whether a catastrophic failure of an entry, descent, and landing event of a Multimission Radioisotope Thermoelectric Generator-based lander could embed the heat sources into the martian subsurface and create a local environment that (1) would temporarily satisfy the conditions for a martian Special Region and (2) could establish a transport mechanism through which introduced terrestrial organisms could be mobilized to naturally occurring Special Regions elsewhere on Mars. Two models were run, a primary model by researchers at the Lawrence Berkeley National Laboratory and a secondary model by researchers at the Jet Propulsion Laboratory, both of which were based on selected starting conditions for various surface composition cases that establish the worst-case scenario, including geological data collected by the Mars Science Laboratory at Gale Crater. The summary outputs of both modeling efforts showed similar results: that the introduction of the modeled heat source could temporarily create the conditions established for a Special Region, but that there would be no transport mechanism by which an introduced terrestrial microbe, even if it was active during the temporarily induced Special Region conditions, could be transported to a naturally occurring Special Region of Mars.
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Affiliation(s)
- Robert F Shotwell
- Jet Propulsion Laboratory/California Institute of Technology, Pasadena, California
| | - Lindsay E Hays
- Jet Propulsion Laboratory/California Institute of Technology, Pasadena, California
| | - David W Beaty
- Jet Propulsion Laboratory/California Institute of Technology, Pasadena, California
| | - Yulia Goreva
- Jet Propulsion Laboratory/California Institute of Technology, Pasadena, California
| | - Thomas L Kieft
- Biology Department, New Mexico Tech, Socorro, New Mexico
| | - Michael T Mellon
- The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland
| | - George Moridis
- Lawrence Berkeley National Laboratory, Berkeley, California
| | - Lee D Peterson
- Jet Propulsion Laboratory/California Institute of Technology, Pasadena, California
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7
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Cabrol NA. The Coevolution of Life and Environment on Mars: An Ecosystem Perspective on the Robotic Exploration of Biosignatures. ASTROBIOLOGY 2018; 18:1-27. [PMID: 29252008 PMCID: PMC5779243 DOI: 10.1089/ast.2017.1756] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 11/27/2017] [Indexed: 05/09/2023]
Abstract
Earth's biological and environmental evolution are intertwined and inseparable. This coevolution has become a fundamental concept in astrobiology and is key to the search for life beyond our planet. In the case of Mars, whether a coevolution took place is unknown, but analyzing the factors at play shows the uniqueness of each planetary experiment regardless of similarities. Early Earth and early Mars shared traits. However, biological processes on Mars, if any, would have had to proceed within the distinctive context of an irreversible atmospheric collapse, greater climate variability, and specific planetary characteristics. In that, Mars is an important test bed for comparing the effects of a unique set of spatiotemporal changes on an Earth-like, yet different, planet. Many questions remain unanswered about Mars' early environment. Nevertheless, existing data sets provide a foundation for an intellectual framework where notional coevolution models can be explored. In this framework, the focus is shifted from planetary-scale habitability to the prospect of habitats, microbial ecotones, pathways to biological dispersal, biomass repositories, and their meaning for exploration. Critically, as we search for biosignatures, this focus demonstrates the importance of starting to think of early Mars as a biosphere and vigorously integrating an ecosystem approach to landing site selection and exploration. Key Words: Astrobiology-Biosignatures-Coevolution of Earth and life-Mars. Astrobiology 18, 1-27.
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8
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Mickol RL, Kral TA. Low Pressure Tolerance by Methanogens in an Aqueous Environment: Implications for Subsurface Life on Mars. ORIGINS LIFE EVOL B 2017; 47:511-532. [PMID: 27663448 DOI: 10.1007/s11084-016-9519-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/05/2016] [Indexed: 11/26/2022]
Abstract
The low pressure at the surface of Mars (average: 6 mbar) is one potentially biocidal factor that any extant life on the planet would need to endure. Near subsurface life, while shielded from ultraviolet radiation, would also be exposed to this low pressure environment, as the atmospheric gas-phase pressure increases very gradually with depth. Few studies have focused on low pressure as inhibitory to the growth or survival of organisms. However, recent work has uncovered a potential constraint to bacterial growth below 25 mbar. The study reported here tested the survivability of four methanogen species (Methanothermobacter wolfeii, Methanosarcina barkeri, Methanobacterium formicicum, Methanococcus maripaludis) under low pressure conditions approaching average martian surface pressure (6 mbar - 143 mbar) in an aqueous environment. Each of the four species survived exposure of varying length (3 days - 21 days) at pressures down to 6 mbar. This research is an important stepping-stone to determining if methanogens can actively metabolize/grow under these low pressures. Additionally, the recently discovered recurring slope lineae suggest that liquid water columns may connect the surface to deeper levels in the subsurface. If that is the case, any organism being transported in the water column would encounter the changing pressures during the transport.
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Affiliation(s)
- R L Mickol
- Arkansas Center for Space and Planetary Sciences, University of Arkansas, Stone House North, 332 N. Arkansas Ave, Fayetteville, AR, 72701, USA.
| | - T A Kral
- Arkansas Center for Space and Planetary Sciences, University of Arkansas, Stone House North, 332 N. Arkansas Ave, Fayetteville, AR, 72701, USA
- Department of Biological Sciences, Science and Engineering 601, University of Arkansas, Fayetteville, AR, 72701, USA
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9
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Abstract
Theory and direct observation indicate that micro-organisms exist in liquid veins in ice and permafrost, provided the temperature is above the eutectic for H2O and soluble impurities present. Microbes can exist and metabolize in glacial ice and permafrost on Earth, Mars, and Europa. One can search directly (with fluorescence microscopy at liquid veins in Vostok ice core samples) or with a biologging instrument (for microbial fluorescence in a borehole in terrestrial or martian permafrost or ice). The viability lifetime against DNA destruction of bacterial spores can be measured with analytical techniques that identify calcium dipicolinate, which is unique to spores.
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10
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Guo J, Zeitlin C, Wimmer-Schweingruber R, Hassler DM, Köhler J, Ehresmann B, Böttcher S, Böhm E, Brinza DE. Measurements of the neutral particle spectra on Mars by MSL/RAD from 2015-11-15 to 2016-01-15. LIFE SCIENCES IN SPACE RESEARCH 2017; 14:12-17. [PMID: 28887938 DOI: 10.1016/j.lssr.2017.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 06/13/2017] [Accepted: 06/15/2017] [Indexed: 06/07/2023]
Abstract
The Radiation Assessment Detector (RAD), onboard the Mars Science Laboratory (MSL) rover Curiosity, has been measuring the energetic charged and neutral particles and the radiation dose rate on the surface of Mars since the landing of the rover in August 2012. In contrast to charged particles, neutral particles (neutrons and γ-rays) are measured indirectly: the energy deposition spectra produced by neutral particles are complex convolutions of the incident particle spectra with the detector response functions. An inversion technique has been developed and applied to jointly unfold the deposited energy spectra measured in two scintillators of different types (CsI for high γ detection efficiency, and plastic for neutrons) to obtain the neutron and γ-ray spectra. This result is important for determining the biological impact of the Martian surface radiation contributed by neutrons, which interact with materials differently from the charged particles. These first in-situ measurements on Mars provide (1) an important reference for assessing the radiation-associated health risks for future manned missions to the red planet and (2) an experimental input for validating the particle transport codes used to model the radiation environments within spacecraft or on the surface of planets. Here we present neutral particle spectra as well as the corresponding dose and dose equivalent rates derived from RAD measurement during a period (November 15, 2015 to January 15, 2016) for which the surface particle spectra have been simulated via different transport models.
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Affiliation(s)
- Jingnan Guo
- Christian-Albrechts-Universität zu Kiel, Kiel, Germany.
| | - Cary Zeitlin
- Leidos, NASA Johnson Space Center, Houston, Texas, USA
| | | | - Donald M Hassler
- Southwest Research Institute, Space Science and Engineering Division, Boulder, CO, USA; Institut dAstrophysique Spatiale, Orsay, France
| | - Jan Köhler
- Thales Electronic Systems GmbH, Kiel, Germany
| | - Bent Ehresmann
- Southwest Research Institute, Space Science and Engineering Division, Boulder, CO, USA
| | | | - Eckart Böhm
- Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - David E Brinza
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
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11
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Mitrofanov IG, Litvak ML, Nikiforov SY, Jun I, Bobrovnitsky YI, Golovin DV, Grebennikov AS, Fedosov FS, Kozyrev AS, Lisov DI, Malakhov AV, Mokrousov MI, Sanin AB, Shvetsov VN, Timoshenko GN, Tomilina TM, Tret'yakov VI, Vostrukhin AA. The ADRON-RM Instrument Onboard the ExoMars Rover. ASTROBIOLOGY 2017; 17:585-594. [PMID: 28731818 DOI: 10.1089/ast.2016.1566] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This overview presents the physical principles, design, measurement capabilities, and summary of planned operations of the autonomous detector of radiation of neutrons onboard rover at Mars (ADRON-RM) on the surface of Mars. ADRON-RM is a Russian project selected for the joint European Space Agency-Roscosmos ExoMars 2020 landing mission. A compact passive neutron spectrometer, ADRON-RM, was designed to study the abundance and distribution of water and neutron absorption elements (such as Cl, Fe, and others) in the martian subsurface along the path of the ExoMars rover. Key Words: Mars exploration-Surface-Neutron Spectroscopy-Water. Astrobiology 17, 585-594.
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Affiliation(s)
- I G Mitrofanov
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - M L Litvak
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - S Y Nikiforov
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - I Jun
- 2 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California
| | - Y I Bobrovnitsky
- 3 A.A. Blagonravov Institute of Mechanical Engineering , Russian Academy of Sciences, Moscow, Russia
| | - D V Golovin
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - A S Grebennikov
- 3 A.A. Blagonravov Institute of Mechanical Engineering , Russian Academy of Sciences, Moscow, Russia
| | - F S Fedosov
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - A S Kozyrev
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - D I Lisov
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - A V Malakhov
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - M I Mokrousov
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - A B Sanin
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - V N Shvetsov
- 4 Joint Institute of Nuclear Research , Dubna, Russia
| | | | - T M Tomilina
- 3 A.A. Blagonravov Institute of Mechanical Engineering , Russian Academy of Sciences, Moscow, Russia
| | - V I Tret'yakov
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - A A Vostrukhin
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
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12
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Fischer E, Martínez GM, Rennó NO. Formation and Persistence of Brine on Mars: Experimental Simulations throughout the Diurnal Cycle at the Phoenix Landing Site. ASTROBIOLOGY 2016; 16:937-948. [PMID: 27912028 PMCID: PMC5178027 DOI: 10.1089/ast.2016.1525] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 08/30/2016] [Indexed: 05/28/2023]
Abstract
In the last few years, water ice and salts capable of melting this ice and producing liquid saline water (brine) have been detected on Mars. Moreover, indirect evidence for brine has been found in multiple areas of the planet. Here, we simulate full diurnal cycles of temperature and atmospheric water vapor content at the Phoenix landing site for the first time and show experimentally that, in spite of the low Mars-like chamber temperature, brine forms minutes after the ground temperature exceeds the eutectic temperature of salts in contact with water ice. Moreover, we show that the brine stays liquid for most of the diurnal cycle when enough water ice is available to compensate for evaporation. This is predicted to occur seasonally in areas of the polar region where the temperature exceeds the eutectic value and frost or snow is deposited on saline soils, or where water ice and salts coexist in the shallow subsurface. This is important because the existence of liquid water is a key requirement for habitability. Key Words: Mars-Ice-Perchlorates-Brine-Water-Raman spectroscopy. Astrobiology 16, 937-948.
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Affiliation(s)
- E Fischer
- Department of Climate and Space Sciences and Engineering, University of Michigan , Ann Arbor, Michigan
| | - G M Martínez
- Department of Climate and Space Sciences and Engineering, University of Michigan , Ann Arbor, Michigan
| | - N O Rennó
- Department of Climate and Space Sciences and Engineering, University of Michigan , Ann Arbor, Michigan
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Lasne J, Noblet A, Szopa C, Navarro-González R, Cabane M, Poch O, Stalport F, François P, Atreya SK, Coll P. Oxidants at the Surface of Mars: A Review in Light of Recent Exploration Results. ASTROBIOLOGY 2016; 16:977-996. [PMID: 27925795 DOI: 10.1089/ast.2016.1502] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In 1976, the Viking landers carried out the most comprehensive search for organics and microbial life in the martian regolith. Their results indicate that Mars' surface is lifeless and, surprisingly, depleted in organics at part-per-billion levels. Several biology experiments on the Viking landers gave controversial results that have since been explained by the presence of oxidizing agents on the surface of Mars. These oxidants may degrade abiotic or biological organics, resulting in their nondetection in the regolith. As several exploration missions currently focus on the detection of organics on Mars (or will do so in the near future), knowledge of the oxidative state of the surface is fundamental. It will allow for determination of the capability of organics to survive on a geological timescale, the most favorable places to seek them, and the best methods to process the samples collected at the surface. With this aim, we review the main oxidants assumed to be present on Mars, their possible formation pathways, and those laboratory studies in which their reactivity with organics under Mars-like conditions has been evaluated. Among the oxidants assumed to be present on Mars, only four have been detected so far: perchlorate ions (ClO4-) in salts, hydrogen peroxide (H2O2) in the atmosphere, and clays and metal oxides composing surface minerals. Clays have been suggested as catalysts for the oxidation of organics but are treated as oxidants in the following to keep the structure of this article straightforward. This work provides an insight into the oxidizing potential of the surface of Mars and an estimate of the stability of organic matter in an oxidizing environment. Key Words: Mars surface-Astrobiology-Oxidant-Chemical reactions. Astrobiology 16, 977-996.
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Affiliation(s)
- J Lasne
- 1 LISA, Universités Paris-Est Créteil and Paris Diderot, Institut Pierre Simon Laplace , CNRS UMR 7583, Créteil, France
| | - A Noblet
- 1 LISA, Universités Paris-Est Créteil and Paris Diderot, Institut Pierre Simon Laplace , CNRS UMR 7583, Créteil, France
| | - C Szopa
- 2 LATMOS, UPMC Université Paris 06, Université Versailles St Quentin , CNRS, Guyancourt, France
| | - R Navarro-González
- 3 Laboratorio de Química de Plasmas y Estudios Planetarios, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México , Ciudad de México, México
| | - M Cabane
- 2 LATMOS, UPMC Université Paris 06, Université Versailles St Quentin , CNRS, Guyancourt, France
| | - O Poch
- 1 LISA, Universités Paris-Est Créteil and Paris Diderot, Institut Pierre Simon Laplace , CNRS UMR 7583, Créteil, France
- 4 NCCR PlanetS, Physikalisches Institut, Universität Bern , Bern, Switzerland
| | - F Stalport
- 1 LISA, Universités Paris-Est Créteil and Paris Diderot, Institut Pierre Simon Laplace , CNRS UMR 7583, Créteil, France
| | - P François
- 1 LISA, Universités Paris-Est Créteil and Paris Diderot, Institut Pierre Simon Laplace , CNRS UMR 7583, Créteil, France
- 5 IC2MP, Equipe Eau Géochimie Santé, Université de Poitiers , CNRS UMR 7285, Poitiers, France
| | - S K Atreya
- 6 Department of Climate and Space Sciences, University of Michigan , Ann Arbor, Michigan, USA
| | - P Coll
- 1 LISA, Universités Paris-Est Créteil and Paris Diderot, Institut Pierre Simon Laplace , CNRS UMR 7583, Créteil, France
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14
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Baker VR, Hamilton CW, Burr DM, Gulick VC, Komatsu G, Luo W, Rice JW, Rodriguez J. Fluvial geomorphology on Earth-like planetary surfaces: A review. GEOMORPHOLOGY (AMSTERDAM, NETHERLANDS) 2015; 245:149-182. [PMID: 29176917 PMCID: PMC5701759 DOI: 10.1016/j.geomorph.2015.05.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Morphological evidence for ancient channelized flows (fluvial and fluvial-like landforms) exists on the surfaces of all of the inner planets and on some of the satellites of the Solar System. In some cases, the relevant fluid flows are related to a planetary evolution that involves the global cycling of a volatile component (water for Earth and Mars; methane for Saturn's moon Titan). In other cases, as on Mercury, Venus, Earth's moon, and Jupiter's moon Io, the flows were of highly fluid lava. The discovery, in 1972, of what are now known to be fluvial channels and valleys on Mars sparked a major controversy over the role of water in shaping the surface of that planet. The recognition of the fluvial character of these features has opened unresolved fundamental questions about the geological history of water on Mars, including the presence of an ancient ocean and the operation of a hydrological cycle during the earliest phases of planetary history. Other fundamental questions posed by fluvial and fluvial-like features on planetary bodies include the possible erosive action of large-scale outpourings of very fluid lavas, such as those that may have produced the remarkable canali forms on Venus; the ability of exotic fluids, such as methane, to create fluvial-like landforms, as observed on Saturn's moon, Titan; and the nature of sedimentation and erosion under different conditions of planetary surface gravity. Planetary fluvial geomorphology also illustrates fundamental epistemological and methodological issues, including the role of analogy in geomorphological/geological inquiry.
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Affiliation(s)
- Victor R. Baker
- Department of Hydrology and Water Resources, University of Arizona, Tucson, AZ 85721, USA
- Lunar and Planetary Laboratory, Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Christopher W. Hamilton
- Lunar and Planetary Laboratory, Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Devon M. Burr
- Earth and Planetary Sciences Department, University of Tennessee-Knoxville, Knoxville, TN 37996-1410, USA
| | - Virginia C. Gulick
- SETI Institute, Mountain View, CA 94043, USA
- NASA Ames Research Center, MS 239-20, Moffett Field, CA 94035, USA
| | - Goro Komatsu
- International Research School of Planetary Sciences, Università d’Annunzio, Viale Pindaro 42, 65127 Pescara, Italy
| | - Wei Luo
- Department of Geography, Northern Illinois University, DeKalb, IL 60115, USA
| | | | - J.A.P. Rodriguez
- NASA Ames Research Center, MS 239-20, Moffett Field, CA 94035, USA
- Planetary Science Institute, Tucson, AZ 85719, USA
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15
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Peplowski PN, Bazell D, Evans LG, Goldsten JO, Lawrence DJ, Nittler LR. Hydrogen and major element concentrations on 433 Eros: Evidence for an L- or LL-chondrite-like surface composition. METEORITICS & PLANETARY SCIENCE 2015; 50:353-367. [PMID: 27917034 PMCID: PMC5114864 DOI: 10.1111/maps.12434] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 12/21/2014] [Indexed: 06/02/2023]
Abstract
A reanalysis of NEAR X-ray/gamma-ray spectrometer (XGRS) data provides robust evidence that the elemental composition of the near-Earth asteroid 433 Eros is consistent with the L and LL ordinary chondrites. These results facilitated the use of the gamma-ray measurements to produce the first in situ measurement of hydrogen concentrations on an asteroid. The measured value, 1100-700+1600 ppm, is consistent with hydrogen concentrations measured in L and LL chondrite meteorite falls. Gamma-ray derived abundances of hydrogen and potassium show no evidence for depletion of volatiles relative to ordinary chondrites, suggesting that the sulfur depletion observed in X-ray data is a surficial effect, consistent with a space-weathering origin. The newfound agreement between the X-ray, gamma-ray, and spectral data suggests that the NEAR landing site, a ponded regolith deposit, has an elemental composition that is indistinguishable from the mean surface. This observation argues against a pond formation process that segregates metals from silicates, and instead suggests that the differences observed in reflectance spectra between the ponds and bulk Eros are due to grain size differences resulting from granular sorting of ponded material.
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Affiliation(s)
| | - David Bazell
- The Johns Hopkins University Applied Physics LaboratoryLaurelMaryland20723USA
| | - Larry G. Evans
- Computer Sciences CorporationLanham‐SeabrookMaryland20706USA
| | - John O. Goldsten
- The Johns Hopkins University Applied Physics LaboratoryLaurelMaryland20723USA
| | - David J. Lawrence
- The Johns Hopkins University Applied Physics LaboratoryLaurelMaryland20723USA
| | - Larry R. Nittler
- Department of Terrestrial MagnetismCarnegie Institution of WashingtonWashingtonDistrict of Columbia20015USA
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Rummel JD, Beaty DW, Jones MA, Bakermans C, Barlow NG, Boston PJ, Chevrier VF, Clark BC, de Vera JPP, Gough RV, Hallsworth JE, Head JW, Hipkin VJ, Kieft TL, McEwen AS, Mellon MT, Mikucki JA, Nicholson WL, Omelon CR, Peterson R, Roden EE, Sherwood Lollar B, Tanaka KL, Viola D, Wray JJ. A new analysis of Mars "Special Regions": findings of the second MEPAG Special Regions Science Analysis Group (SR-SAG2). ASTROBIOLOGY 2014; 14:887-968. [PMID: 25401393 DOI: 10.1089/ast.2014.1227] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A committee of the Mars Exploration Program Analysis Group (MEPAG) has reviewed and updated the description of Special Regions on Mars as places where terrestrial organisms might replicate (per the COSPAR Planetary Protection Policy). This review and update was conducted by an international team (SR-SAG2) drawn from both the biological science and Mars exploration communities, focused on understanding when and where Special Regions could occur. The study applied recently available data about martian environments and about terrestrial organisms, building on a previous analysis of Mars Special Regions (2006) undertaken by a similar team. Since then, a new body of highly relevant information has been generated from the Mars Reconnaissance Orbiter (launched in 2005) and Phoenix (2007) and data from Mars Express and the twin Mars Exploration Rovers (all 2003). Results have also been gleaned from the Mars Science Laboratory (launched in 2011). In addition to Mars data, there is a considerable body of new data regarding the known environmental limits to life on Earth-including the potential for terrestrial microbial life to survive and replicate under martian environmental conditions. The SR-SAG2 analysis has included an examination of new Mars models relevant to natural environmental variation in water activity and temperature; a review and reconsideration of the current parameters used to define Special Regions; and updated maps and descriptions of the martian environments recommended for treatment as "Uncertain" or "Special" as natural features or those potentially formed by the influence of future landed spacecraft. Significant changes in our knowledge of the capabilities of terrestrial organisms and the existence of possibly habitable martian environments have led to a new appreciation of where Mars Special Regions may be identified and protected. The SR-SAG also considered the impact of Special Regions on potential future human missions to Mars, both as locations of potential resources and as places that should not be inadvertently contaminated by human activity.
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Affiliation(s)
- John D Rummel
- 1 Department of Biology, East Carolina University , Greenville, North Carolina, USA
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17
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Ponomarenko SA, Surin NM, Borshchev OV, Luponosov YN, Akimov DY, Alexandrov IS, Burenkov AA, Kovalenko AG, Stekhanov VN, Kleymyuk EA, Gritsenko OT, Cherkaev GV, Kechek'yan AS, Serenko OA, Muzafarov AM. Nanostructured organosilicon luminophores and their application in highly efficient plastic scintillators. Sci Rep 2014; 4:6549. [PMID: 25293808 PMCID: PMC4189022 DOI: 10.1038/srep06549] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 09/17/2014] [Indexed: 11/09/2022] Open
Abstract
Organic luminophores are widely used in various optoelectronic devices, which serve for photonics, nuclear and particle physics, quantum electronics, medical diagnostics and many other fields of science and technology. Improving their spectral-luminescent characteristics for particular technical requirements of the devices is a challenging task. Here we show a new concept to universal solution of this problem by creation of nanostructured organosilicon luminophores (NOLs), which are a particular type of dendritic molecular antennas. They combine the best properties of organic luminophores and inorganic quantum dots: high absorption cross-section, excellent photoluminescence quantum yield, fast luminescence decay time and good processability. A NOL consists of two types of covalently bonded via silicon atoms organic luminophores with efficient Förster energy transfer between them. Using NOLs in plastic scintillators, widely utilized for radiation detection and in elementary particles discoveries, led to a breakthrough in their efficiency, which combines both high light output and fast decay time. Moreover, for the first time plastic scintillators, which emit light in the desired wavelength region ranging from 370 to 700 nm, have been created. We anticipate further applications of NOLs as working elements of pulsed dye lasers in photonics, optoelectronics and as fluorescent labels in biology and medical diagnostics.
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Affiliation(s)
- Sergei A Ponomarenko
- 1] Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya st. 70, Moscow 117393, Russian Federation [2] Chemistry Department, Moscow State University, Leninskie Gory 1-3, Moscow 119991, Russian Federation [3]
| | - Nikolay M Surin
- 1] Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya st. 70, Moscow 117393, Russian Federation [2]
| | - Oleg V Borshchev
- Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya st. 70, Moscow 117393, Russian Federation
| | - Yuriy N Luponosov
- Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya st. 70, Moscow 117393, Russian Federation
| | - Dmitry Y Akimov
- State Scientific Centre of Russian Federation Institute for Theoretical and Experimental Physics (ITEP), Bolshaya Cheremushkinskaya st. 25, Moscow 117218, Russian Federation
| | - Ivan S Alexandrov
- 1] State Scientific Centre of Russian Federation Institute for Theoretical and Experimental Physics (ITEP), Bolshaya Cheremushkinskaya st. 25, Moscow 117218, Russian Federation [2] National Research Nuclear University "MEPhI" (Moscow Engineering Physics Institute), Moscow 115409, Russian Federation
| | - Alexander A Burenkov
- 1] State Scientific Centre of Russian Federation Institute for Theoretical and Experimental Physics (ITEP), Bolshaya Cheremushkinskaya st. 25, Moscow 117218, Russian Federation [2] National Research Nuclear University "MEPhI" (Moscow Engineering Physics Institute), Moscow 115409, Russian Federation
| | - Alexey G Kovalenko
- 1] State Scientific Centre of Russian Federation Institute for Theoretical and Experimental Physics (ITEP), Bolshaya Cheremushkinskaya st. 25, Moscow 117218, Russian Federation [2] National Research Nuclear University "MEPhI" (Moscow Engineering Physics Institute), Moscow 115409, Russian Federation
| | - Viktor N Stekhanov
- 1] State Scientific Centre of Russian Federation Institute for Theoretical and Experimental Physics (ITEP), Bolshaya Cheremushkinskaya st. 25, Moscow 117218, Russian Federation [2] National Research Nuclear University "MEPhI" (Moscow Engineering Physics Institute), Moscow 115409, Russian Federation
| | - Elena A Kleymyuk
- Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya st. 70, Moscow 117393, Russian Federation
| | - Oleg T Gritsenko
- Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya st. 70, Moscow 117393, Russian Federation
| | - Georgiy V Cherkaev
- Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya st. 70, Moscow 117393, Russian Federation
| | - Alexander S Kechek'yan
- Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya st. 70, Moscow 117393, Russian Federation
| | - Olga A Serenko
- 1] Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya st. 70, Moscow 117393, Russian Federation [2] Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova St. 28, Moscow 119991, Russian Federtion
| | - Aziz M Muzafarov
- 1] Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya st. 70, Moscow 117393, Russian Federation [2] Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova St. 28, Moscow 119991, Russian Federtion
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Models of formation and activity of spring mounds in the mechertate-chrita-sidi el hani system, eastern Tunisia: implications for the habitability of Mars. Life (Basel) 2014; 4:386-432. [PMID: 25370379 PMCID: PMC4206853 DOI: 10.3390/life4030386] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 07/25/2014] [Accepted: 07/28/2014] [Indexed: 11/29/2022] Open
Abstract
Spring mounds on Earth and on Mars could represent optimal niches of life development. If life ever occurred on Mars, ancient spring deposits would be excellent localities to search for morphological or chemical remnants of an ancient biosphere. In this work, we investigate models of formation and activity of well-exposed spring mounds in the Mechertate-Chrita-Sidi El Hani (MCSH) system, eastern Tunisia. We then use these models to explore possible spring mound formation on Mars. In the MCSH system, the genesis of the spring mounds is a direct consequence of groundwater upwelling, triggered by tectonics and/or hydraulics. As they are oriented preferentially along faults, they can be considered as fault spring mounds, implying a tectonic influence in their formation process. However, the hydraulic pressure generated by the convergence of aquifers towards the surface of the system also allows consideration of an origin as artesian spring mounds. In the case of the MCSH system, our geologic data presented here show that both models are valid, and we propose a combined hydro-tectonic model as the likely formation mechanism of artesian-fault spring mounds. During their evolution from the embryonic (early) to the islet (“island”) stages, spring mounds are also shaped by eolian accumulations and induration processes. Similarly, spring mounds have been suggested to be relatively common in certain provinces on the Martian surface, but their mode of formation is still a matter of debate. We propose that the tectonic, hydraulic, and combined hydro-tectonic models describing the spring mounds at MCSH could be relevant as Martian analogs because: (i) the Martian subsurface may be over pressured, potentially expelling mineral-enriched waters as spring mounds on the surface; (ii) the Martian subsurface may be fractured, causing alignment of the spring mounds in preferential orientations; and (iii) indurated eolian sedimentation and erosional remnants are common features on Mars. The spring mounds further bear diagnostic mineralogic and magnetic properties, in comparison with their immediate surroundings. Consequently, remote sensing techniques can be very useful to identify similar spring mounds on Mars. The mechanisms (tectonic and/or hydraulic) of formation and evolution of spring mounds at the MCSH system are suitable for the proliferation and protection of life respectively. Similarly, life or its resulting biomarkers on Mars may have been protected or preserved under the spring mounds.
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Fischer E, Martínez GM, Elliott HM, Rennó NO. Experimental evidence for the formation of liquid saline water on Mars. GEOPHYSICAL RESEARCH LETTERS 2014; 41:4456-4462. [PMID: 25821267 PMCID: PMC4373172 DOI: 10.1002/grl.51829] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 06/11/2014] [Indexed: 05/09/2023]
Abstract
UNLABELLED Evidence for deliquescence of perchlorate salts has been discovered in the Martian polar region while possible brine flows have been observed in the equatorial region. This appears to contradict the idea that bulk deliquescence is too slow to occur during the short periods of the Martian diurnal cycle during which conditions are favorable for it. We conduct laboratory experiments to study the formation of liquid brines at Mars environmental conditions. We find that when water vapor is the only source of water, bulk deliquescence of perchlorates is not rapid enough to occur during the short periods of the day during which the temperature is above the salts' eutectic value, and the humidity is above the salts' deliquescence value. However, when the salts are in contact with water ice, liquid brine forms in minutes, indicating that aqueous solutions could form temporarily where salts and ice coexist on the Martian surface and in the shallow subsurface. KEY POINTS The formation of brines at Martian conditions was studied experimentallyBulk deliquescence from water vapor is too slow to occur diurnally on MarsBrines form in minutes when salts are placed in direct contact with ice.
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Affiliation(s)
- Erik Fischer
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan Ann Arbor, Michigan, USA
| | - Germán M Martínez
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan Ann Arbor, Michigan, USA
| | - Harvey M Elliott
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan Ann Arbor, Michigan, USA
| | - Nilton O Rennó
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan Ann Arbor, Michigan, USA
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20
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Fischer E, Martínez GM, Elliott HM, Rennó NO. Experimental evidence for the formation of liquid saline water on Mars. GEOPHYSICAL RESEARCH LETTERS 2014. [PMID: 25821267 DOI: 10.1002/2014gl060302] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
UNLABELLED Evidence for deliquescence of perchlorate salts has been discovered in the Martian polar region while possible brine flows have been observed in the equatorial region. This appears to contradict the idea that bulk deliquescence is too slow to occur during the short periods of the Martian diurnal cycle during which conditions are favorable for it. We conduct laboratory experiments to study the formation of liquid brines at Mars environmental conditions. We find that when water vapor is the only source of water, bulk deliquescence of perchlorates is not rapid enough to occur during the short periods of the day during which the temperature is above the salts' eutectic value, and the humidity is above the salts' deliquescence value. However, when the salts are in contact with water ice, liquid brine forms in minutes, indicating that aqueous solutions could form temporarily where salts and ice coexist on the Martian surface and in the shallow subsurface. KEY POINTS The formation of brines at Martian conditions was studied experimentallyBulk deliquescence from water vapor is too slow to occur diurnally on MarsBrines form in minutes when salts are placed in direct contact with ice.
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Affiliation(s)
- Erik Fischer
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan Ann Arbor, Michigan, USA
| | - Germán M Martínez
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan Ann Arbor, Michigan, USA
| | - Harvey M Elliott
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan Ann Arbor, Michigan, USA
| | - Nilton O Rennó
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan Ann Arbor, Michigan, USA
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Heldmann JL, Schurmeier L, McKay C, Davila A, Stoker C, Marinova M, Wilhelm MB. Midlatitude ice-rich ground on mars as a target in the search for evidence of life and for in situ resource utilization on human missions. ASTROBIOLOGY 2014; 14:102-118. [PMID: 24506507 DOI: 10.1089/ast.2013.1103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Midlatitude ground ice on Mars is of significant scientific interest for understanding the history and evolution of ice stability on Mars and is relevant for human exploration as a possible in situ resource. For both science and exploration, assessing the astrobiological potential of the ice is important in terms of (1) understanding the potential for life on Mars and (2) evaluating the presence of possible biohazards in advance of human exploration. In the present study, we review the evidence for midlatitude ground ice on Mars, discuss the possible explanations for its occurrence, and assess its potential habitability. During the course of study, we systematically analyzed remote-sensing data sets to determine whether a viable landing site exists in the northern midlatitudes to enable a robotic mission that conducts in situ characterization and searches for evidence of life in the ice. We classified each site according to (1) presence of polygons as a proxy for subsurface ice, (2) presence and abundance of rough topographic obstacles (e.g., large cracks, cliffs, uneven topography), (3) rock density, (4) presence and abundance of large boulders, and (5) presence of craters. We found that a suitable landing site exists within Amazonis Planitia near ground ice that was recently excavated by a meteorite impact.
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Affiliation(s)
- J L Heldmann
- 1 NASA Ames Research Center , Division of Space Sciences and Astrobiology, Moffett Field, California
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22
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Lawrence DJ, Peplowski PN, Prettyman TH, Feldman WC, Bazell D, Mittlefehldt DW, Reedy RC, Yamashita N. Constraints on Vesta's elemental composition: Fast neutron measurements by Dawn's gamma ray and neutron detector. METEORITICS & PLANETARY SCIENCE 2013; 48:2271-2288. [PMID: 26074718 PMCID: PMC4461122 DOI: 10.1111/maps.12187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 07/11/2013] [Indexed: 06/04/2023]
Abstract
Surface composition information from Vesta is reported using fast neutron data collected by the gamma ray and neutron detector on the Dawn spacecraft. After correcting for variations due to hydrogen, fast neutrons show a compositional dynamic range and spatial variability that is consistent with variations in average atomic mass from howardite, eucrite, and diogenite (HED) meteorites. These data provide additional compositional evidence that Vesta is the parent body to HED meteorites. A subset of fast neutron data having lower statistical precision show spatial variations that are consistent with a 400 ppm variability in hydrogen concentrations across Vesta and supports the idea that Vesta's hydrogen is due to long-term delivery of carbonaceous chondrite material.
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Affiliation(s)
- David J Lawrence
- The Johns Hopkins University Applied Physics LaboratoryLaurel, Maryland, USA
| | - Patrick N Peplowski
- The Johns Hopkins University Applied Physics LaboratoryLaurel, Maryland, USA
| | | | | | - David Bazell
- The Johns Hopkins University Applied Physics LaboratoryLaurel, Maryland, USA
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23
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Prettyman TH, Mittlefehldt DW, Yamashita N, Lawrence DJ, Beck AW, Feldman WC, McCoy TJ, McSween HY, Toplis MJ, Titus TN, Tricarico P, Reedy RC, Hendricks JS, Forni O, Le Corre L, Li JY, Mizzon H, Reddy V, Raymond CA, Russell CT. Elemental mapping by Dawn reveals exogenic H in Vesta's regolith. Science 2012; 338:242-6. [PMID: 22997135 DOI: 10.1126/science.1225354] [Citation(s) in RCA: 186] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Using Dawn's Gamma Ray and Neutron Detector, we tested models of Vesta's evolution based on studies of howardite, eucrite, and diogenite (HED) meteorites. Global Fe/O and Fe/Si ratios are consistent with HED compositions. Neutron measurements confirm that a thick, diogenitic lower crust is exposed in the Rheasilvia basin, which is consistent with global magmatic differentiation. Vesta's regolith contains substantial amounts of hydrogen. The highest hydrogen concentrations coincide with older, low-albedo regions near the equator, where water ice is unstable. The young, Rheasilvia basin contains the lowest concentrations. These observations are consistent with gradual accumulation of hydrogen by infall of carbonaceous chondrites--observed as clasts in some howardites--and subsequent removal or burial of this material by large impacts.
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Affiliation(s)
- Thomas H Prettyman
- Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719-2395, USA.
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Mitrofanov I, Litvak M, Sanin A, Malakhov A, Golovin D, Boynton W, Droege G, Chin G, Evans L, Harshman K, Fedosov F, Garvin J, Kozyrev A, McClanahan T, Milikh G, Mokrousov M, Starr R, Sagdeev R, Shevchenko V, Shvetsov V, Tret'yakov V, Trombka J, Varenikov A, Vostrukhin A. Testing polar spots of water-rich permafrost on the Moon: LEND observations onboard LRO. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011je003956] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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25
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Maurice S, Feldman W, Diez B, Gasnault O, Lawrence DJ, Pathare A, Prettyman T. Mars Odyssey neutron data: 1. Data processing and models of water-equivalent-hydrogen distribution. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011je003810] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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26
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Rao MN, Nyquist LE, Bogard DD, Garrison DH, Sutton SR, Michel R, Reedy RC, Leya I. Isotopic evidence for a Martian regolith component in shergottite meteorites. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010je003764] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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27
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Abstract
Ionizing radiation is a ubiquitous feature of the Cosmos, from exogenous cosmic rays (CR) to the intrinsic mineral radioactivity of a habitable world, and its influences on the emergence and persistence of life are wide-ranging and profound. Much attention has already been focused on the deleterious effects of ionizing radiation on organisms and the complex molecules of life, but ionizing radiation also performs many crucial functions in the generation of habitable planetary environments and the origins of life. This review surveys the role of CR and mineral radioactivity in star formation, generation of biogenic elements, and the synthesis of organic molecules and driving of prebiotic chemistry. Another major theme is the multiple layers of shielding of planetary surfaces from the flux of cosmic radiation and the various effects on a biosphere of violent but rare astrophysical events such as supernovae and gamma-ray bursts. The influences of CR can also be duplicitous, such as limiting the survival of surface life on Mars while potentially supporting a subsurface biosphere in the ocean of Europa. This review highlights the common thread that ionizing radiation forms between the disparate component disciplines of astrobiology.
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Affiliation(s)
- Lewis R Dartnell
- UCL Institute for Origins, University College London, London, UK.
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28
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Hausrath EM, Brantley SL. Basalt and olivine dissolution under cold, salty, and acidic conditions: What can we learn about recent aqueous weathering on Mars? ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2010je003610] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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29
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Caruso AN. The physics of solid-state neutron detector materials and geometries. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:443201. [PMID: 21403341 DOI: 10.1088/0953-8984/22/44/443201] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Detection of neutrons, at high total efficiency, with greater resolution in kinetic energy, time and/or real-space position, is fundamental to the advance of subfields within nuclear medicine, high-energy physics, non-proliferation of special nuclear materials, astrophysics, structural biology and chemistry, magnetism and nuclear energy. Clever indirect-conversion geometries, interaction/transport calculations and modern processing methods for silicon and gallium arsenide allow for the realization of moderate- to high-efficiency neutron detectors as a result of low defect concentrations, tuned reaction product ranges, enhanced effective omnidirectional cross sections and reduced electron-hole pair recombination from more physically abrupt and electronically engineered interfaces. Conversely, semiconductors with high neutron cross sections and unique transduction mechanisms capable of achieving very high total efficiency are gaining greater recognition despite the relative immaturity of their growth, lithographic processing and electronic structure understanding. This review focuses on advances and challenges in charged-particle-based device geometries, materials and associated mechanisms for direct and indirect transduction of thermal to fast neutrons within the context of application. Calorimetry- and radioluminescence-based intermediate processes in the solid state are not included.
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Affiliation(s)
- A N Caruso
- Department of Physics, University of Missouri-Kansas City, Kansas City, MO 64110, USA.
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30
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Nunes DC, Smrekar SE, Safaeinili A, Holt J, Phillips RJ, Seu R, Campbell B. Examination of gully sites on Mars with the shallow radar. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009je003509] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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31
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Searls ML, Mellon MT, Cull S, Hansen CJ, Sizemore HG. Seasonal defrosting of the Phoenix landing site. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009je003438] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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32
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Davila AF, Skidmore M, Fairén AG, Cockell C, Schulze-Makuch D. New priorities in the robotic exploration of Mars: the case for in situ search for extant life. ASTROBIOLOGY 2010; 10:705-710. [PMID: 20929400 DOI: 10.1089/ast.2010.0538] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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33
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Clifford SM, Lasue J, Heggy E, Boisson J, McGovern P, Max MD. Depth of the Martian cryosphere: Revised estimates and implications for the existence and detection of subpermafrost groundwater. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009je003462] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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34
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Stoker CR, Zent A, Catling DC, Douglas S, Marshall JR, Archer D, Clark B, Kounaves SP, Lemmon MT, Quinn R, Renno N, Smith PH, Young SM. Habitability of the Phoenix landing site. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009je003421] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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35
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Abstract
Evidence of past liquid water on the surface of Mars suggests that this world once had habitable conditions and leads to the question of life. If there was life on Mars, it would be interesting to determine if it represented a separate origin from life on Earth. To determine the biochemistry and genetics of life on Mars requires that we have access to an organism or the biological remains of one-possibly preserved in ancient permafrost. A way to determine if organic material found on Mars represents the remains of an alien biological system could be based on the observation that biological systems select certain organic molecules over others that are chemically similar (e.g., chirality in amino acids).
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36
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Lawrence DJ, Elphic RC, Feldman WC, Funsten HO, Prettyman TH. Performance of orbital neutron instruments for spatially resolved hydrogen measurements of airless planetary bodies. ASTROBIOLOGY 2010; 10:183-200. [PMID: 20298147 PMCID: PMC2956572 DOI: 10.1089/ast.2009.0401] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 12/28/2009] [Indexed: 05/29/2023]
Abstract
Orbital neutron spectroscopy has become a standard technique for measuring planetary surface compositions from orbit. While this technique has led to important discoveries, such as the deposits of hydrogen at the Moon and Mars, a limitation is its poor spatial resolution. For omni-directional neutron sensors, spatial resolutions are 1-1.5 times the spacecraft's altitude above the planetary surface (or 40-600 km for typical orbital altitudes). Neutron sensors with enhanced spatial resolution have been proposed, and one with a collimated field of view is scheduled to fly on a mission to measure lunar polar hydrogen. No quantitative studies or analyses have been published that evaluate in detail the detection and sensitivity limits of spatially resolved neutron measurements. Here, we describe two complementary techniques for evaluating the hydrogen sensitivity of spatially resolved neutron sensors: an analytic, closed-form expression that has been validated with Lunar Prospector neutron data, and a three-dimensional modeling technique. The analytic technique, called the Spatially resolved Neutron Analytic Sensitivity Approximation (SNASA), provides a straightforward method to evaluate spatially resolved neutron data from existing instruments as well as to plan for future mission scenarios. We conclude that the existing detector--the Lunar Exploration Neutron Detector (LEND)--scheduled to launch on the Lunar Reconnaissance Orbiter will have hydrogen sensitivities that are over an order of magnitude poorer than previously estimated. We further conclude that a sensor with a geometric factor of approximately 100 cm(2) Sr (compared to the LEND geometric factor of approximately 10.9 cm(2) Sr) could make substantially improved measurements of the lunar polar hydrogen spatial distribution.
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Affiliation(s)
- David J Lawrence
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA.
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37
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Sizemore HG, Mellon MT, Searls ML, Lemmon MT, Zent AP, Heet TL, Arvidson RE, Blaney DL, Keller HU. In situ analysis of ice table depth variations in the vicinity of small rocks at the Phoenix landing site. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009je003414] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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38
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Nelli SM, Murphy JR, Feldman WC, Schaeffer JR. Characterization of the nighttime low-latitude water ice deposits in the NASA Ames Mars General Circulation Model 2.1 under present-day atmospheric conditions. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008je003289] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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39
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Edwards CS, Bandfield JL, Christensen PR, Fergason RL. Global distribution of bedrock exposures on Mars using THEMIS high-resolution thermal inertia. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009je003363] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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40
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Byrne S, Dundas CM, Kennedy MR, Mellon MT, McEwen AS, Cull SC, Daubar IJ, Shean DE, Seelos KD, Murchie SL, Cantor BA, Arvidson RE, Edgett KS, Reufer A, Thomas N, Harrison TN, Posiolova LV, Seelos FP. Distribution of mid-latitude ground ice on Mars from new impact craters. Science 2009; 325:1674-6. [PMID: 19779195 DOI: 10.1126/science.1175307] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
New impact craters at five sites in the martian mid-latitudes excavated material from depths of decimeters that has a brightness and color indicative of water ice. Near-infrared spectra of the largest example confirm this composition, and repeated imaging showed fading over several months, as expected for sublimating ice. Thermal models of one site show that millimeters of sublimation occurred during this fading period, indicating clean ice rather than ice in soil pores. Our derived ice-table depths are consistent with models using higher long-term average atmospheric water vapor content than present values. Craters at most of these sites may have excavated completely through this clean ice, probing the ice table to previously unsampled depths of meters and revealing substantial heterogeneity in the vertical distribution of the ice itself.
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Affiliation(s)
- Shane Byrne
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA.
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41
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Kadish SJ, Barlow NG, Head JW. Latitude dependence of Martian pedestal craters: Evidence for a sublimation-driven formation mechanism. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008je003318] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Seth J. Kadish
- Department of Geological Sciences; Brown University; Providence Rhode Island USA
| | - Nadine G. Barlow
- Department of Physics and Astronomy; Northern Arizona University; Flagstaff Arizona USA
| | - James W. Head
- Department of Geological Sciences; Brown University; Providence Rhode Island USA
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42
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Prettyman TH, Feldman WC, Titus TN. Characterization of Mars' seasonal caps using neutron spectroscopy. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008je003275] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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43
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Smith PH, Tamppari LK, Arvidson RE, Bass D, Blaney D, Boynton WV, Carswell A, Catling DC, Clark BC, Duck T, Dejong E, Fisher D, Goetz W, Gunnlaugsson HP, Hecht MH, Hipkin V, Hoffman J, Hviid SF, Keller HU, Kounaves SP, Lange CF, Lemmon MT, Madsen MB, Markiewicz WJ, Marshall J, McKay CP, Mellon MT, Ming DW, Morris RV, Pike WT, Renno N, Staufer U, Stoker C, Taylor P, Whiteway JA, Zent AP. H2O at the Phoenix landing site. Science 2009; 325:58-61. [PMID: 19574383 DOI: 10.1126/science.1172339] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Phoenix mission investigated patterned ground and weather in the northern arctic region of Mars for 5 months starting 25 May 2008 (solar longitude between 76.5 degrees and 148 degrees ). A shallow ice table was uncovered by the robotic arm in the center and edge of a nearby polygon at depths of 5 to 18 centimeters. In late summer, snowfall and frost blanketed the surface at night; H(2)O ice and vapor constantly interacted with the soil. The soil was alkaline (pH = 7.7) and contained CaCO(3), aqueous minerals, and salts up to several weight percent in the indurated surface soil. Their formation likely required the presence of water.
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Affiliation(s)
- P H Smith
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA.
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44
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Baldridge AM, Christensen PR. A laboratory technique for thermal emission measurement of hydrated minerals. APPLIED SPECTROSCOPY 2009; 63:678-688. [PMID: 19531295 DOI: 10.1366/000370209788559665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Laboratory emission spectra are measured at Arizona State University's Mars Space Flight Facility for comparison to remotely sensed data from Earth and Mars. Such emission spectroscopy using an interferometric spectrometer measures the energy of the sample, including reflected and emitted background sources. The detector is uncooled at ambient temperature, which produces a very low signal when measuring the energy from a sample that has a temperature close to its own. In order to increase the energy difference between the sample and the detector, thereby increasing the signal received by the detector, samples are typically heated to between 60 and 80 degrees C for several hours prior to measurement. While this method is acceptable for most rock and mineral samples, some hydrous minerals dehydrate quickly at low relative humidity and temperatures above room temperature. This change is evident in both the physical appearance of the mineral and in the position and shape of its spectral absorptions. One solution to this problem is to heat samples to lower temperatures (e.g., 40 degrees C) for only a short time period. However, this approach results in a low signal from the sample and does not always avoid dehydration. For this reason, we have developed a technique for measuring and calibrating emission spectra of hydrated minerals that involves cooling samples to well below the temperature of the detector, which avoids dehydration, while creating a large delta temperature and a strong signal from the sample. Our method allows for accurate library spectra, with discrete, pronounced spectral features (high spectral contrast), of hydrated minerals that can be used for comparison to planetary surfaces.
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Affiliation(s)
- A M Baldridge
- Jet Propulsion Laboratory, Pasadena, California 91109, USA.
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45
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Zent AP, Hecht MH, Cobos DR, Campbell GS, Campbell CS, Cardell G, Foote MC, Wood SE, Mehta M. Thermal and Electrical Conductivity Probe (TECP) for Phoenix. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2007je003052] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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46
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47
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Lee C, Lawson WG, Richardson MI, Heavens NG, Kleinböhl A, Banfield D, McCleese DJ, Zurek R, Kass D, Schofield JT, Leovy CB, Taylor FW, Toigo AD. Thermal Tides in the Martian Middle Atmosphere as Seen by the Mars Climate Sounder. JOURNAL OF GEOPHYSICAL RESEARCH 2009. [PMID: 27630378 DOI: 10.1029/2008je003302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The first systematic observations of the middle atmosphere of Mars (35km-80km) with the Mars Climate Sounder (MCS) show dramatic patterns of diurnal thermal variation, evident in retrievals of temperature and water ice opacity. At the time of writing, the dataset of MCS limb retrievals is sufficient for spectral analysis within a limited range of latitudes and seasons. This analysis shows that these thermal variations are almost exclusively associated with a diurnal thermal tide. Using a Martian General Circulation Model to extend our analysis we show that the diurnal thermal tide dominates these patterns for all latitudes and all seasons.
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Affiliation(s)
- C Lee
- Division of Geological and Planetary Sciences, California Institute of Technology
| | - W G Lawson
- Division of Geological and Planetary Sciences, California Institute of Technology
| | - M I Richardson
- Division of Geological and Planetary Sciences, California Institute of Technology
| | - N G Heavens
- Division of Geological and Planetary Sciences, California Institute of Technology
| | - A Kleinböhl
- Jet Propulsion Laboratory, California Institute of Technology
| | - D Banfield
- Department of Astronomy, Cornell University
| | - D J McCleese
- Jet Propulsion Laboratory, California Institute of Technology
| | - R Zurek
- Jet Propulsion Laboratory, California Institute of Technology
| | - D Kass
- Jet Propulsion Laboratory, California Institute of Technology
| | - J T Schofield
- Jet Propulsion Laboratory, California Institute of Technology
| | - C B Leovy
- Department of Atmospheric Sciences, University of Washington
| | - F W Taylor
- Department of Physics, University of Oxford
| | - A D Toigo
- Department of Astronomy, Cornell University
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48
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Levy J, Head J, Marchant D. Thermal contraction crack polygons on Mars: Classification, distribution, and climate implications from HiRISE observations. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008je003273] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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49
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Pham LBS, Karatekin O, Dehant V. Effects of meteorite impacts on the atmospheric evolution of Mars. ASTROBIOLOGY 2009; 9:45-54. [PMID: 19317624 DOI: 10.1089/ast.2008.0242] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Early in its history, Mars probably had a denser atmosphere with sufficient greenhouse gases to sustain the presence of stable liquid water at the surface. Impacts by asteroids and comets would have played a significant role in the evolution of the martian atmosphere, not only by causing atmospheric erosion but also by delivering material and volatiles to the planet. We investigate the atmospheric loss and the delivery of volatiles with an analytical model that takes into account the impact simulation results and the flux of impactors given in the literature. The atmospheric loss and the delivery of volatiles are calculated to obtain the atmospheric pressure evolution. Our results suggest that the impacts alone cannot satisfactorily explain the loss of significant atmospheric mass since the Late Noachian (approximately 3.7-4 Ga). A period with intense bombardment of meteorites could have increased the atmospheric loss; but to explain the loss of a speculative massive atmosphere in the Late Noachian, other factors of atmospheric erosion and replenishment also need to be taken into account.
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50
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Fergason RL, Christensen PR. Formation and erosion of layered materials: Geologic and dust cycle history of eastern Arabia Terra, Mars. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007je002973] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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