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1. Diverse Organic-Mineral Associations in Jezero Crater, Mars

Author: Sunanda Sharma, Ryan D. Roppel, Ashley E. Murphy, Luther W. Beegle, Rohit Bhartia, Andrew Steele, Joseph Razzell Hollis, Sandra Siljeström, Francis M. McCubbin, Sanford A. Asher, William J. Abbey, Abigail C. Allwood, Eve L. Berger, Benjamin L. Bleefeld, Aaron S. Burton, Sergei V. Bykov, Emily L. Cardarelli, Pamela G. Conrad, Andrea Corpolongo, Andrew D. Czaja, Lauren P. DeFlores, Kenneth Edgett, Kenneth A. Farley, Teresa Fornaro, Allison C. Fox, Marc D. Fries, David Harker, Keyron Hickman-Lewis, Joshua Huggett, Samara Imbeah, Ryan S. Jakubek, Linda C. Kah, Carina Lee, Yang Liu, Angela Magee, Michelle Minitti, Kelsey R. Moore, Alyssa Pascuzzo, Carolina Rodriguez Sanchez-Vahamonde, Eva L. Scheller, Svetlana Shkolyar, Kathryn M. Stack, Kim Steadman, Michael Tuite, Kyle Uckert, Alyssa Werynski, Roger C. Wiens, Amy J. Williams, Katherine Winchell, Megan R. Kennedy, and Anastasia Yanchilina
Subjects: Lunar and Planetary Science and Exploration, Geosciences (General)
Abstract: The presence and distribution of preserved organic matter on the surface of Mars can provide key information about the Martian carbon cycle and the potential of the planet to host life throughout its history. Several types of organic molecules have been previously detected in Martian meteorites1 and at Gale crater, Mars. Evaluating the diversity and detectability of organic matter elsewhere on Mars is important for understanding the extent and diversity of Martian surface processes and the potential availability of carbon sources1,5,6. Here we report the detection of Raman and fluorescence spectra consistent with several species of aromatic organic molecules in the Máaz and Séítah formations within the Crater Floor sequences of Jezero crater, Mars. We report specific fluorescence-mineral associations consistent with many classes of organic molecules occurring in different spatial patterns within these compositionally distinct formations, potentially indicating different fates of carbon across environments. Our findings suggest there may be a diversity of aromatic molecules prevalent on the Martian surface, and these materials persist despite exposure to surface conditions. These potential organic molecules are largely found within minerals linked to aqueous processes, indicating that these processes may have had a key role in organic synthesis, transport or preservation.
Published: 2023
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2. Perseverance’s Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) Investigation

Author: Rohit Bhartia, Luther W Beegle, Lauren DeFlores, William J Abbey, Joseph Razzell Hollis, Kyle Uckert, Brian Monacelli, Kenneth S Edgett, Megan R Kennedy, Margarite Sylvia, David Aldrich, Mark S Anderson, Sanford A Asher, Zachary J Bailey, Kerry Boyd, Aaron S Burton, Michael Caffrey, Michael J Calaway, Robert J Calvet, Bruce A Cameron, Michael A Caplinger, Brandi Carrier, Natalie Chen, Amy C Chen, Matthew J Clark, Samuel M Clegg, Pamela G Conrad, Moogega Cooper, Kristine N Davis, Bethany L Ehlmann, Linda J Facto, Marc D Fries, Daniel H Garrison, Denine Gasway, F Tony Ghaemi, Trevor G Graff, Kevin P Hand, Cathleen Harris, Jeffrey D Hein, Nicholas Heinz, Harrison Herzog, Eric B Hochberg, Andrew Houck, William F Hug, Elsa H Jensen, Linda Christine Kah, John A Kennedy, Robert Krylo, Johnathan Lam, Mark A Lindeman, Justin McGlown, John Michel, Ed Miller, Zachary Mills, Michelle E Minitti, Fai Mok, James D Moore, Kenneth H Nealson, Anthony Nelson, Raymond Newell, Brian E Nixon, Daniel A Nordman, Danielle L Nuding, Sonny M Orellana, Michael T Pauken, Glen Peterson, Randy Pollock, Heather Quinn, Claire Quinto, Michael A Ravine, Ray D Reid, Joe Riendeau, Amy J Ross, Joshua Sackos, Jacob A Schaffner, Mark A Schwochert, Molly O Shelton, Rufus Simon, Caroline L Smith, Pablo Sobron, Kimberly B Steadman, Andrew Steele, Dave Thiessen, Vinh D Tran, Tony Tsai, Michael Tuite, Eric Tung, Rami A Wehbe, Rachael Weinberg, Ryan H Weiner, Roger C Weins, Kenneth Williford, Chris Wollonciej, Yen-Hung Wu, R Aileen Yingst, and Jason A Zan
Subjects: Lunar And Planetary Science And Exploration
Abstract: The Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) is a robotic arm-mounted instrument on NASA’s Perseverance rover. SHERLOC has two primary boresights. The Spectroscopy boresight generates spatially resolved chemical maps using fluorescence and Raman spectroscopy coupled to microscopic images (10.1 μm/pixel). The second boresight is a Wide Angle Topographic Sensor for Operations and eNgineering (WATSON); a copy of the Mars Science Laboratory (MSL) Mars Hand Lens Imager (MAHLI) that obtains color images from microscopic scales (∼13 μm/pixel) to infinity. SHERLOC Spectroscopy focuses a 40 μs pulsed deep UV neon-copper laser (248.6 nm), to a ∼100 μm spot on a target at a working distance of ∼48 mm. Fluorescence emissions from organics, and Raman scattered photons from organics and minerals, are spectrally resolved with a single diffractive grating spectrograph with a spectral range of 250 to ∼370 nm. Because the fluorescence and Raman regions are naturally separated with deep UV excitation (<250 nm), the Raman region ∼ 800 – 4000 cm−1 (250 to 273 nm) and the fluorescence region (274 to ∼370 nm) are acquired simultaneously without time gating or additional mechanisms. SHERLOC science begins by using an Autofocus Context Imager (ACI) to obtain target focus and acquire 10.1 μm/pixel greyscale images. Chemical maps of organic and mineral signatures are acquired by the orchestration of an internal scanning mirror that moves the focused laser spot across discrete points on the target surface where spectra are captured on the spectrometer detector. ACI images and chemical maps (< 100 μm/mapping pixel) will enable the first Mars in situ view of the spatial distribution and interaction between organics, minerals, and chemicals important to the assessment of potential biogenicity (containing CHNOPS). Single robotic arm placement chemical maps can cover areas up to 7x7 mm in area and, with the < 10 min acquisition time per map, larger mosaics are possible with arm movements. This microscopic view of the organic geochemistry of a target at the Perseverance field site, when combined with the other instruments, such as Mastcam-Z, PIXL, and SuperCam, will enable unprecedented analysis of geological materials for both scientific research and determination of which samples to collect and cache for Mars sample return.
Published: 2021
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3. Seasonal Variations in Atmospheric Composition as Measured in Gale Crater, Mars

Author: Melissa G. Trainer, Michael H. Wong, Timothy H. Mcconnochie, Heather B. Franz, Sushil K. Atreya, Pamela G. Conrad, Franck Lefèvre, Paul R. Mahaffy, Charles A. Malespin, Heidi L. K. Manning, Javier Martín‐Torres, Germán M. Martínez, Christopher P. Mckay, Rafael Navarro‐González, Álvaro Vicente‐Retortillo, Christopher R. Webster, and María‐Paz Zorzano
Subjects: Lunar And Planetary Science And Exploration
Abstract: The Sample Analysis at Mars (SAM) instrument onboard the Mars Science Laboratory Curiosity rover measures the chemical composition of major atmospheric species (CO2, N2, 40Ar,O2, and CO) through a dedicated atmospheric inlet. We report here measurements of volume mixing ratios in Gale Crater using the SAM quadrupole mass spectrometer, obtained over a period of nearly 5 years (3 Mars years) from landing. The observation period spans the northern summer of MY31 and solar longitude (L(sub S)) of 175° through spring of MY 34, L(sub S) = 12°. This work expands upon prior reports of the mixing ratios measured by SAM QMS in the first 105 sols of the mission. The SAM QMS atmospheric measurements were taken periodically, with a cumulative coverage of four or five experiments per season on Mars. Major observations include the seasonal cycle of CO2, N2, and Ar, which lags approximately 20–40° of L(sub S) behind the pressure cycle driven by CO2 condensation and sublimation from the winter poles. This seasonal cycle indicates that transport occurs on faster timescales than mixing. The mixing ratio of O2 shows significant seasonal and interannual variability, suggesting an unknown atmospheric or surface process at work. The O2 measurements are compared to several parameters, including dust optical depth and trace CH4 measurements by Curiosity. We derive annual mean volume mixing ratios for the atmosphere in Gale Crater: CO2 = 0.951 (±0.003), N2 = 0.0259 (±0.0006), 40Ar = 0.0194 (±0.0004), O2 = 1.61 (±0.09) x 10(exp ‐3), and CO = 5.8 (±0.8) x 10(exp ‐4).
Published: 2019
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4. The Scientific Need for a Dedicated Interplanetary Dust Instrument at Mars

Author: L. D. Graham, Philip A. Bland, Apostolos A. Christou, J. S. New, Michael E. Zolensky, L. C. Welzenbach, J. Rojas, K. Fisher, Anna L. Butterworth, M. J. Genge, J. W. Ashley, Emmanuel Dartois, Matteo Crismani, Andrew Steele, Diego Janches, George J. Flynn, I. L. ten Kate, John M. C. Plane, Luther W. Beegle, Rohit Bhartia, Marc Fries, Mihaly Horanyi, J. Duprat, Pamela G. Conrad, Mark V. Sykes, Cécile Engrand, William J. Cooke, Aaron S. Burton, Mark A. Sephton, Zack Gainsforth, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: Interplanetary dust cloud, 13. Climate action, [SDU]Sciences of the Universe [physics], Mars Exploration Program, Astrobiology
Abstract: International audience; Interplanetary dust is a scientifically important constituent of the Solar System that consists of material shed by asteroids, comets, and other airless bodies. As used here, the term “dust” includes interplanetary dust particles and micrometeoroids. Dust has been studied by missions such as Mariner, Pioneer, and Voyager in both interplanetary space and in the vicinity of most of the planets.To date, however, no dedicated interplanetary dust instrument has yet been employed for detailed analysis of the dust environment of Mars. Partial data on dust flux has been provided by the 1965 Mariner IV flyby, the MAVEN orbiter, and other missions, but a complete understanding of interplanetary dust abundance, composition, debris hazard, annual flux variation, and origins is lacking. These data are critical for understanding the effects of dust upon the martian system, including the carbonaceous input into the regolith of Mars and its moons, the chemical input into the martian atmosphere, potential effects upon remote sensing data, the hypothesized existence of a Phobos dust ring, and possible annual variations from meteor shower infall. These effects have direct ramifications for interpretation of Mars/Phobos/Deimos mission science and analysis of returned samples from those worlds. To remediate this shortfall, the authors recommend that a dedicated interplanetary dust analysis instrument should be included in the instrument package for an upcoming martian orbiter in the near term. Such an interplanetary dust analysis instrument should collect data over a time period of several martian years in order to generate a statistically robust data set on interplanetary dust concentration and flux over a wide range of mass, and to discern temporal variation over multiple martian years.
Published: 2021

5. Initial SAM calibration gas experiments on Mars: Quadrupole mass spectrometer results and implications

Author: E. Raaen, Michael H. Wong, Charles Malespin, Pamela G. Conrad, Richard H. Becker, Mehdi Benna, B. D. Prats, Sushil K. Atreya, Caroline Freissinet, Heidi L. K. Manning, Melissa G. Trainer, Jennifer L. Eigenbrode, Heather B. Franz, and Paul R. Mahaffy
Subjects: Martian, Materials science, 010504 meteorology & atmospheric sciences, Analytical chemistry, Astronomy and Astrophysics, Mars Exploration Program, Mass spectrometry, 01 natural sciences, Calibration gas, Astrobiology, Atmosphere, Space and Planetary Science, 0103 physical sciences, Sample Analysis at Mars, Calibration, 010303 astronomy & astrophysics, Quadrupole mass analyzer, 0105 earth and related environmental sciences
Abstract: The Sample Analysis at Mars (SAM) instrument suite of the Mars Science Laboratory (MSL) Curiosity rover is equipped to analyze both martian atmospheric gases and volatiles released by pyrolysis of solid surface materials, with target measurements including chemical and isotopic composition (Mahaffy et al., 2012). To facilitate assessment of instrument performance and validation of results obtained on Mars, SAM houses a calibration cell containing CO2, Ar, N2, Xe, and several fluorinated hydrocarbon compounds (Franz et al., 2014; Mahaffy et al., 2012). This report describes the first two experiments utilizing this calibration cell on Mars and gives results from analysis of data acquired with the SAM Quadrupole Mass Spectrometer (QMS). These data support the accuracy of isotope ratios obtained with the QMS (Conrad et al., 2016; Mahaffy et al., 2013) and provide ground-truth for reassessment of analytical constants required for atmospheric measurements, which were reported in previous contributions (Franz et al., 2015, 2014). The most significant implication of the QMS data involves reinterpretation of pre-launch contamination previously believed to affect only CO abundance measurements (Franz et al., 2015) to affect N2 abundances, as well. The corresponding adjustment to the N2 calibration constant presented here brings the atmospheric volume mixing ratios for Ar and N2 retrieved by SAM into closer agreement with those reported by the Viking mission (Owen et al., 1977; Oyama and Berdahl, 1977).
Published: 2017

6. Abiotic Input of Fixed Nitrogen by Bolide Impacts to Gale Crater During the Hesperian: Insights From the Mars Science Laboratory

Author: Patrice Coll, Jennifer C. Stern, Daniel P. Glavin, Christopher P. McKay, Heather B. Franz, Paul R. Mahaffy, Jennifer L. Eigenbrode, P. Douglas Archer, Rafael Navarro-González, Arnaud Buch, Benny Prats, Michel Cabane, María Paz Zorzano-Mier, Charles Malespin, Caroline Freissinet, Ashwin Vasavada, Douglas W. Ming, J. V. Hogancamp, Richard V. Morris, José Antonio Rodríguez-Manfredi, Karina F. Navarro, Amy McAdam, Brad Sutter, F. Javier Martin-Torres, Sushil K. Atreya, François Raulin, Melissa G. Trainer, Pamela G. Conrad, Cyril Szopa, Universidad Nacional Autónoma de México, Consejo Nacional de Ciencia y Tecnología (México), Instituto de Ciencias Nucleares [Mexico], Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), NASA Ames Research Center (ARC), NASA Goddard Space Flight Center (GSFC), Jacobs Technology ESCG, NASA Johnson Space Center (JSC), NASA, Laboratoire de Génie des Procédés et Matériaux - EA 4038 (LGPM), CentraleSupélec, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Computer Science, Electrical and Space Engineering [Luleå], Luleå University of Technology (LUT), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Universidad Nacional Autónoma de México (UNAM), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and California Institute of Technology (CALTECH)-NASA
Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Noachian, chemistry.chemical_element, 01 natural sciences, Nitrogen, Atmosphere, chemistry.chemical_compound, Geophysics, chemistry, Nitrate, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Bolide, Environmental chemistry, Carbon dioxide, Earth and Planetary Sciences (miscellaneous), Nitrogen fixation, Hesperian, 0105 earth and related environmental sciences
Abstract: Molecular hydrogen (H2) from volcanic emissions is suggested to warm the Martian surface when carbon dioxide (CO2) levels dropped from the Noachian (4100 to 3700 Myr) to the Hesperian (3700 to 3000 Myr). Its presence is expected to shift the conversion of molecular nitrogen (N2) into different forms of fixed nitrogen (N). Here we present experimental data and theoretical calculations that investigate the efficiency of nitrogen fixation by bolide impacts in CO2‐N2 atmospheres with or without H2. Surprisingly, nitric oxide (NO) was produced more efficiently in 20% H2 in spite of being a reducing agent and not likely to increase the rate of nitrogen oxidation. Nevertheless, its presence led to a faster cooling of the shock wave raising the freeze‐out temperature of NO resulting in an enhanced yield. We estimate that the nitrogen fixation rate by bolide impacts varied from 7 × 10−4 to 2 × 10−3 g N·Myr−1·cm−2 and could imply fluvial concentration to explain the nitrogen (1.4 ± 0.7 g N·Myr−1·cm−2) detected as nitrite (NO2 −) and nitrate (NO3 −) by Curiosity at Yellowknife Bay. One possible explanation is that the nitrogen detected in the lacustrine sediments at Gale was deposited entirely on the crater's surface and was subsequently dissolved and transported by superficial and ground waters to the lake during favorable wet climatic conditions. The nitrogen content sharply decreases in younger sediments of the Murray formation suggesting a decline of H2 in the atmosphere and the rise of oxidizing conditions causing a shortage in the supply to putative microbial life., We acknowledge the NASA Mars Science Laboratory Program, Centre National d'Études Spatiales, the Universidad Nacional Autónoma de México (PAPIIT IN109416, IN111619, and PAPIME PE103216), and the Consejo Nacional de Ciencia y Tecnología de México (CONACyT 220626) for their support.
Published: 2019

7. Seasonal variations in atmospheric composition as measured in Gale Crater, Mars

Author: H. L. K. Manning, Paul R. Mahaffy, Rafael Navarro-González, Franck Lefèvre, Heather B. Franz, Chris Webster, Pamela G. Conrad, Álvaro Vicente-Retortillo, Melissa G. Trainer, Sushil K. Atreya, Timothy H. McConnochie, Christopher P. McKay, Michael H. Wong, Javier Martin-Torres, German Martinez, Charles Malespin, María Paz Zorzano, NASA Goddard Space Flight Center (GSFC), Department of Climate and Space Sciences and Engineering (CLaSP), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Carnegie Institution for Science [Washington], PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Misericordia University, Department of Computer Science, Electrical and Space Engineering [Luleå], Luleå University of Technology (LUT), Instituto Andaluz de Ciencias de la Tierra (IACT), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Universidad de Granada (UGR), Lunar and Planetary Institute [Houston] (LPI), NASA Ames Research Center (ARC), Instituto de Ciencias Nucleares [Mexico], Universidad Nacional Autónoma de México (UNAM), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), National Aeronautics and Space Administration (US), Universidad Nacional Autónoma de México, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Zorzano, M. P. [0000-0002-4492-9650], Navarro González, R. [0000-0002-6078-7621], Martín Torres, J. [0000-0001-6479-2236], and Vicente Retortillo, A. [0000-0002-4553-7624]
Subjects: Engineering, 010504 meteorology & atmospheric sciences, Sample analysis at Mars, Library science, 01 natural sciences, Atmospheric composition, Mars atmosphere, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Atmospheric Composition, 0105 earth and related environmental sciences, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Mars seasonal cycle, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, Gale crater, Mars Exploration Program, Atmosphere of Mars, Curiosity rover, Planetary Data System, CRISM, Geophysics, Mars science laboratory, 13. Climate action, Space and Planetary Science, Sample Analysis at Mars, business
Abstract: The Sample Analysis at Mars (SAM) instrument onboard the Mars Science Laboratory Curiosity rover measures the chemical composition of major atmospheric species (CO2, N2, 40Ar, O2, and CO) through a dedicated atmospheric inlet. We report here measurements of volume mixing ratios in Gale Crater using the SAM quadrupole mass spectrometer, obtained over a period of nearly 5 years (3 Mars years) from landing. The observation period spans the northern summer of MY 31 and solar longitude (LS) of 175° through spring of MY 34, LS = 12°. This work expands upon prior reports of the mixing ratios measured by SAM QMS in the first 105 sols of the mission. The SAM QMS atmospheric measurements were taken periodically, with a cumulative coverage of four or five experiments per season on Mars. Major observations include the seasonal cycle of CO2, N2, and Ar, which lags approximately 20¿40° of LS behind the pressure cycle driven by CO2 condensation and sublimation from the winter poles. This seasonal cycle indicates that transport occurs on faster timescales than mixing. The mixing ratio of O2 shows significant seasonal and interannual variability, suggesting an unknown atmospheric or surface process at work. The O2 measurements are compared to several parameters, including dust optical depth and trace CH4 measurements by Curiosity. We derive annual mean volume mixing ratios for the atmosphere in Gale Crater: CO2 = 0.951 (±0.003), N2 = 0.0259 (±0.0006), 40Ar = 0.0194 (±0.0004), O2 = 1.61 (±0.09) x 10-3, and CO = 5.8 (±0.8) x 10-4. ©2019. The Authors., All MSL data used in this manuscript (REMS and SAM) are freely available on NASA's Planetary Data System (PDS) Geosciences Node, from within 6 months after receipt on Earth (http://pds‐geosciences.wustl.edu/missions/msl/). The mixing ratios developed and presented in this paper are available at a publicly available archive (dataverse.org: doi.org/10.7910/DVN/CVUOWW) as cited within the manuscript. The successful operation of the Curiosity rover and the SAM instrument on Mars is due to the hard work and dedication of hundreds of scientists, engineers, and managers over more than a decade. Essential contributions to the successful operation of SAM on Mars and the acquisition of SAM data were provided by the SAM development, operations, and test bed teams. The authors gratefully thank the SAM and MSL teams that have contributed in numerous ways to obtain the data that enabled this scientific work. We also thank NASA for the support of the development of SAM, SAM data analysis, and the continued support of the Mars Science Laboratory mission. The contribution of F. Lefèvre was supported by the Programme National de Planétologie (PNP). R. Navarro‐Gonzalez acknowledges support from the Universidad Nacional Autónoma de México (PAPIIT IN111619). LPI is operated by USRA under a cooperative agreement with the Science Mission Directorate of the National Aeronautics and Space Administration. We thank members of the SAM and larger MSL team for insightful discussions and support. In particular, we thank R. Becker and R. O. Pepin for careful review of data analysis and interpretation. We thank M. D. Smith for discussion of CRISM CO measurements. We thank A. Brunner, M. Johnson, and M. Lefavor for their development of customized data analysis tools used here and in other SAM publications.
Published: 2019

8. In situ measurement of atmospheric krypton and xenon on Mars with Mars Science Laboratory

Author: Susanne P. Schwenzer, Caroline Freissinet, Melissa G. Trainer, A. A. Pavlov, John H. Jones, Pamela G. Conrad, Michael H. Wong, Sushil K. Atreya, Roger C. Wiens, Robert O. Pepin, H. L. K. Manning, Paul R. Mahaffy, Charles Malespin, T. C. Owen, and Heather B. Franz
Subjects: Martian, 010504 meteorology & atmospheric sciences, Krypton, chemistry.chemical_element, Noble gas, Atmosphere of Mars, Mars Exploration Program, 01 natural sciences, Astrobiology, Geophysics, Xenon, chemistry, Meteorite, Space and Planetary Science, Geochemistry and Petrology, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Isotopes of xenon, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract: Mars Science Laboratory's Sample Analysis at Mars (SAM) investigation has measured all of the stable isotopes of the heavy noble gases krypton and xenon in the martian atmosphere, in situ, from the Curiosity Rover at Gale Crater, Mars. Previous knowledge of martian atmospheric krypton and xenon isotope ratios has been based upon a combination of the Viking mission's krypton and xenon detections and measurements of noble gas isotope ratios in martian meteorites. However, the meteorite measurements reveal an impure mixture of atmospheric, mantle, and spallation contributions. The xenon and krypton isotopic measurements reported here include the complete set of stable isotopes, unmeasured by Viking. The new results generally agree with Mars meteorite measurements but also provide a unique opportunity to identify various non-atmospheric heavy noble gas components in the meteorites. Kr isotopic measurements define a solar-like atmospheric composition, but deviating from the solar wind pattern at 80Kr and 82Kr in a manner consistent with contributions originating from neutron capture in Br. The Xe measurements suggest an intriguing possibility that isotopes lighter than 132Xe have been enriched to varying degrees by spallation and neutron capture products degassed to the atmosphere from the regolith, and a model is constructed to explore this possibility. Such a spallation component, however, is not apparent in atmospheric Xe trapped in the glassy phases of martian meteorites.
Published: 2016

9. A cometary origin for martian atmospheric methane

Author: Marc Fries, Paul B. Niles, M. Matney, Andrew Steele, J. L. Eigenbrode, I. L. ten Kate, William J. Cooke, D. Archer, Pamela G. Conrad, Allan H. Treiman, Apostolos A. Christou, and Mark V. Sykes
Subjects: Martian, Geochemistry and Petrology, Atmospheric methane, Environmental Chemistry, Environmental science, Geology, Astrobiology
Published: 2015

10. Organic synthesis on Mars by electrochemical reduction of CO2

Author: Juan Diego Rodriguez Blanco, Erik H. Hauri, J. L. Eigenbrode, Andrew Steele, Marc Fries, Francis M. McCubbin, Liane G. Benning, Karyn L. Rogers, Pamela G. Conrad, A. Needham, J. H. Wang, R. Wirth, Sandra Siljeström, D. Kilcoyne, and A. Schreiber
Subjects: Martian, Total organic carbon, Multidisciplinary, 010504 meteorology & atmospheric sciences, Mars Exploration Program, Pyroxene, 010502 geochemistry & geophysics, 01 natural sciences, Astrobiology, chemistry.chemical_compound, Igneous rock, Meteorite, chemistry, Organic synthesis, 0105 earth and related environmental sciences, Melt inclusions
Abstract: The sources and nature of organic carbon on Mars have been a subject of intense research. Steele et al. (2012) showed that 10 martian meteorites contain macromolecular carbon phases contained within pyroxene- and olivine-hosted melt inclusions. Here, we show that martian meteorites Tissint, Nakhla, and NWA 1950 have an inventory of organic carbon species associated with fluid-mineral reactions that are remarkably consistent with those detected by the Mars Science Laboratory (MSL) mission. We advance the hypothesis that interactions among spinel-group minerals, sulfides, and a brine enable the electrochemical reduction of aqueous CO2 to organic molecules. Although documented here in martian samples, a similar process likely occurs wherever igneous rocks containing spinel-group minerals and/or sulfides encounter brines.
Published: 2018

11. Organic matter preserved in 3-billion-year-old mudstones at Gale crater, Mars

Author: Patrice Coll, Arnaud Buch, Paul R. Mahaffy, Pamela G. Conrad, John P. Grotzinger, Heather B. Franz, Sanjeev Gupta, Caroline Freissinet, Daniel P. Glavin, Brad Sutter, Maeva Millan, Dawn Y. Sumner, Andrew Steele, P. D. Archer, Joel A. Hurowitz, Amy McAdam, Jennifer L. Eigenbrode, Rafael Navarro-González, Cyril Szopa, Charles Malespin, D. W. Ming, Roger E. Summons, NASA Goddard Space Flight Center (GSFC), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Geophysical Laboratory [Carnegie Institution], Carnegie Institution for Science [Washington], PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Georgetown University [Washington] (GU), Instituto de Ciencias Nucleares [Mexico], Universidad Nacional Autónoma de México (UNAM), Jacobs Technology ESCG, Astromaterials Research and Exploration Science (ARES), NASA Johnson Space Center (JSC), NASA-NASA, Stony Brook University [SUNY] (SBU), State University of New York (SUNY), Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Department of Earth Science and Engineering [Imperial College London], Imperial College London, Department of Earth and Planetary Sciences [Davis], University of California [Davis] (UC Davis), University of California-University of California, Laboratoire de Génie des Procédés et Matériaux - EA 4038 (LGPM), CentraleSupélec, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), NASA Goddard Space Flight Center ( GSFC ), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] ( EAPS ), Massachusetts Institute of Technology ( MIT ), IMPEC - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales ( LATMOS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Georgetown University [Washington] ( GU ), Universidad Nacional Autónoma de México ( UNAM ), Astromaterials Research and Exploration Science ( ARES ), NASA Johnson Space Center ( JSC ), Stony Brook University [The State University of New York] ( SBU ), California Institute of Technology ( CALTECH ), Department of Earth Science and Engineering [London], University of California [Davis] ( UC Davis ), Laboratoire de Génie des Procédés et Matériaux - EA 4038 ( LGPM ), Laboratoire inter-universitaire des systèmes atmosphèriques ( LISA ), Centre National de la Recherche Scientifique ( CNRS ) -Université Paris-Est Créteil Val-de-Marne - Paris 12 ( UPEC UP12 ) -Université Paris Diderot - Paris 7 ( UPD7 ) -Institut national des sciences de l'Univers ( INSU - CNRS ), Carnegie Institution for Science, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), Department of Earth and Planetary Sciences [Univ California Davis] (EPS - UC Davis), University of California (UC)-University of California (UC), Laboratoire de Génie des Procédés et Matériaux (LGPM), CentraleSupélec-Université Paris-Saclay, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Science and Technology Facilities Council (STFC)
Subjects: 010504 meteorology & atmospheric sciences, Evolved gas analysis, General Science & Technology, chemistry.chemical_element, 01 natural sciences, Astrobiology, PHASES, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, 0103 physical sciences, Organic matter, 010303 astronomy & astrophysics, [ SDU.ASTR ] Sciences of the Universe [physics]/Astrophysics [astro-ph], 0105 earth and related environmental sciences, Total organic carbon, Martian, chemistry.chemical_classification, Science & Technology, Multidisciplinary, [ SDU.STU.PL ] Sciences of the Universe [physics]/Earth Sciences/Planetology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], PYROLYSIS, Mars Exploration Program, 15. Life on land, Multidisciplinary Sciences, chemistry, 13. Climate action, Sample Analysis at Mars, Science & Technology - Other Topics, Environmental science, Carbon, Pyrolysis
Abstract: Measuring martian organics and methane The Curiosity rover has been sampling on Mars for the past 5 years (see the Perspective by ten Kate). Eigenbrode et al. used two instruments in the SAM (Sample Analysis at Mars) suite to catch traces of complex organics preserved in 3-billion-year-old sediments. Heating the sediments released an array of organics and volatiles reminiscent of organic-rich sedimentary rock found on Earth. Most methane on Earth is produced by biological sources, but numerous abiotic processes have been proposed to explain martian methane. Webster et al. report atmospheric measurements of methane covering 3 martian years and found that the background level varies with the local seasons. The seasonal variation provides an important clue for determining the origin of martian methane. Science , this issue p. 1096 , p. 1093 ; see also p. 1068
Published: 2018

12. Instruments and strategies for detecting extraterrestrial life

Author: Pamela G. Conrad
Published: 2018

13. Transient liquid water and water activity at Gale crater on Mars

Author: Craig Hardgrove, O. Kemppinen, David T. Vaniman, F. Javier Martín-Torres, Patricia Valentin-Serrano, Alfred S. McEwen, Morten Madsen, Pamela G. Conrad, Charles S. Cockell, Rafael Navarro-González, Edgard G. Rivera-Valentin, Michael A. Mischna, Ari-Matti Harri, Vincent Chevrier, Gilles Berger, María Paz Zorzano, Insoo Jun, Maria Genzer, Jesús Martínez-Frías, Tim McConnochie, Nilton O. Renno, Walter Goetz, James J. Wray, Dawn Y. Sumner, and Ashwin R. Vasavada
Subjects: Water on Mars, Water activity, Liquid water, General Earth and Planetary Sciences, Gale crater, Humidity, Mars Exploration Program, Transient (oscillation), Curiosity rover, Geology, Astrobiology
Abstract: Liquid water on equatorial Mars is inconsistent with large-scale climatic conditions. Humidity and temperature measurements by the Curiosity rover support the formation of subsurface liquid brines by hydration of perchlorates during the night.
Published: 2015

14. Large sulfur isotope fractionations in Martian sediments at Gale crater

Author: Rebecca E. Plummer, Heather B. Franz, Andrew Steele, C. A. Knudson, Pamela G. Conrad, Roger E. Summons, J. W. Dottin, Paul R. Mahaffy, John P. Grotzinger, R. V. Morris, Rafael Navarro-González, Susanne P. Schwenzer, Kenneth A. Farley, Scott M. McLennan, Christopher H. House, Daniel L. Eldridge, Amy McAdam, D. T. Vaniman, Caroline Freissinet, Joel A. Hurowitz, Sarah Stewart Johnson, P. D. Archer, E. B. Rampe, Brad Sutter, J. C. Stern, Woodward W. Fischer, S. K. Atreya, D. W. Ming, Daniel P. Glavin, J. L. Eigenbrode, and A. A. Pavlov
Subjects: event.disaster_type, Martian, 010504 meteorology & atmospheric sciences, Crustal recycling, chemistry.chemical_element, Mars Exploration Program, 010502 geochemistry & geophysics, 01 natural sciences, Sulfur, Equilibrium fractionation, Astrobiology, Volcanic Gases, chemistry, Meteorite, Meteorology & Atmospheric Sciences, General Earth and Planetary Sciences, event, Composition of Mars, Geology, 0105 earth and related environmental sciences
Abstract: © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. Variability in the sulfur isotopic composition in sediments can reflect atmospheric, geologic and biological processes. Evidence for ancient fluvio-lacustrine environments at Gale crater on Mars and a lack of efficient crustal recycling mechanisms on the planet suggests a surface environment that was once warm enough to allow the presence of liquid water, at least for discrete periods of time, and implies a greenhouse effect that may have been influenced by sulfur-bearing volcanic gases. Here we report in situ analyses of the sulfur isotopic compositions of SO2volatilized from ten sediment samples acquired by NASA's Curiosity rover along a 13 km traverse of Gale crater. We find large variations in sulfur isotopic composition that exceed those measured for Martian meteorites and show both depletion and enrichment in34S. Measured values of Δ34S range from - 47 ± 14‰ to 28 ± 7‰, similar to the range typical of terrestrial environments. Although limited geochronological constraints on the stratigraphy traversed by Curiosity are available, we propose that the observed sulfur isotopic signatures at Gale crater can be explained by equilibrium fractionation between sulfate and sulfide in an impact-driven hydrothermal system and atmospheric processing of sulfur-bearing gases during transient warm periods.
Published: 2017

15. Chemistry, mineralogy, and grain properties at Namib and High dunes, Bagnold dune field, Gale crater, Mars: A synthesis of Curiosity rover observations

Author: Victoria E. Hamilton, Albert S. Yen, Pamela G. Conrad, R. Gellert, D. W. Ming, Ashwin R. Vasavada, Mathieu G.A. Lapotre, Scott K. Rowland, Abigail A. Fraeman, Roger C. Wiens, David F. Blake, Kenneth S. Edgett, Jeffrey R. Johnson, C. D. O'Connell-Cooper, P.-Y. Meslin, D. T. Vaniman, Danika Wellington, Ryan C. Sullivan, Michelle E. Minitti, Kirsten L. Siebach, Nathaniel Stein, Agnes Cousin, Sylvestre Maurice, Robert T. Downs, Nathan T. Bridges, Cherie N. Achilles, Stephen Kuhn, Craig Hardgrove, Lucy M. Thompson, Travis Gabriel, Paul R. Mahaffy, M. L. Litvak, Susanne Schröder, R. V. Morris, J. M. Morookian, Raymond E. Arvidson, Bethany L. Ehlmann, Patrick Pinet, Brad Sutter, M. McHenry, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Services communs OMP (UMS 831)
Subjects: 010504 meteorology & atmospheric sciences, Namib, 01 natural sciences, Planetary Sciences: Solar System Objects, Earth and Planetary Sciences (miscellaneous), 010303 astronomy & astrophysics, Research Articles, Martian, grain size, Mars Science Laboratory, Investigations of the Bagnold Dune Field, Gale crater, Mars Exploration Program, Mineralogy, Physical Properties of Materials, Grain size, Planetary Mineralogy and Petrology, Chemistry, Geophysics, volatiles, Aeolian processes, Erosion and Weathering, dust, Geology, Composition, Research Article, Dunes, Surface Materials and Properties, Bedform, Mars, engineering.material, Planetary Geochemistry, amorphous phase, Geochemistry and Petrology, 0103 physical sciences, Rover, Plagioclase, MSL, Planetary Sciences: Solid Surface Planets, Mineralogy and Petrology, 0105 earth and related environmental sciences, Olivine, Mars soils, Bagnold, Geochemistry, sand dunes, Curiosity, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Rocknest, engineering
Abstract: The Mars Science Laboratory Curiosity rover performed coordinated measurements to examine the textures and compositions of aeolian sands in the active Bagnold dune field. The Bagnold sands are rounded to subrounded, very fine to medium sized (~45–500 μm) with ≥6 distinct grain colors. In contrast to sands examined by Curiosity in a dust‐covered, inactive bedform called Rocknest and soils at other landing sites, Bagnold sands are darker, less red, better sorted, have fewer silt‐sized or smaller grains, and show no evidence for cohesion. Nevertheless, Bagnold mineralogy and Rocknest mineralogy are similar with plagioclase, olivine, and pyroxenes in similar proportions comprising >90% of crystalline phases, along with a substantial amorphous component (35% ± 15%). Yet Bagnold and Rocknest bulk chemistry differ. Bagnold sands are Si enriched relative to other soils at Gale crater, and H2O, S, and Cl are lower relative to all previously measured Martian soils and most Gale crater rocks. Mg, Ni, Fe, and Mn are enriched in the coarse‐sieved fraction of Bagnold sands, corroborated by visible/near‐infrared spectra that suggest enrichment of olivine. Collectively, patterns in major element chemistry and volatile release data indicate two distinctive volatile reservoirs in Martian soils: (1) amorphous components in the sand‐sized fraction (represented by Bagnold) that are Si‐enriched, hydroxylated alteration products and/or H2O‐ or OH‐bearing impact or volcanic glasses and (2) amorphous components in the fine fraction (, Key Points Because of ongoing aeolian activity, the Bagnold dunes consist of well‐sorted sands and lack the finer grains typical of Martian soilsDune sands are chemically distinct with elevated Si, Mg, and Ni and lower H2O, S, and Cl relative to all previously measured Martian finesTwo distinct, water‐/OH‐bearing amorphous components are identified: Fe‐, S‐, and Cl‐rich material in dust and Si‐rich material in the sands
Published: 2017

16. Analytical techniques for retrieval of atmospheric composition with the quadrupole mass spectrometer of the Sample Analysis at Mars instrument suite on Mars Science Laboratory

Author: Paul R. Mahaffy, Melissa G. Trainer, Laurie A. Leshin, J. Thomas Nolan, Michael H. Wong, Mehdi Benna, Pamela G. Conrad, Christopher P. McKay, Heidi L. K. Manning, Sushil K. Atreya, Heather B. Franz, Charles Malespin, Jennifer C. Stern, E. Raaen, and Dan Harpold
Subjects: Atmosphere, Martian, Atmosphere of Earth, Spectrometer, Space and Planetary Science, Sample Analysis at Mars, Environmental science, Astronomy and Astrophysics, Mars Exploration Program, Atmosphere of Mars, Quadrupole mass analyzer, Astrobiology, Remote sensing
Abstract: The Sample Analysis at Mars (SAM) instrument suite is the largest scientific payload on the Mars Science Laboratory (MSL) Curiosity rover, which landed in Mars׳ Gale Crater in August 2012. As a miniature geochemical laboratory, SAM is well-equipped to address multiple aspects of MSL׳s primary science goal, characterizing the potential past or present habitability of Gale Crater. Atmospheric measurements support this goal through compositional investigations relevant to martian climate evolution. SAM instruments include a quadrupole mass spectrometer, a tunable laser spectrometer, and a gas chromatograph that are used to analyze martian atmospheric gases as well as volatiles released by pyrolysis of solid surface materials ( Mahaffy et al., 2012 ). This report presents analytical methods for retrieving the chemical and isotopic composition of Mars׳ atmosphere from measurements obtained with SAM׳s quadrupole mass spectrometer. It provides empirical calibration constants for computing volume mixing ratios of the most abundant atmospheric species and analytical functions to correct for instrument artifacts and to characterize measurement uncertainties. Finally, we discuss differences in volume mixing ratios of the martian atmosphere as determined by SAM ( Mahaffy et al., 2013 ) and Viking ( Owen et al., 1977 , Oyama and Berdahl, 1977 ) from an analytical perspective. Although the focus of this paper is atmospheric observations, much of the material concerning corrections for instrumental effects also applies to reduction of data acquired with SAM from analysis of solid samples.
Published: 2014

17. Isotopes of nitrogen on Mars: Atmospheric measurements by Curiosity's mass spectrometer

Author: Paul Mahaffy, Richard H. Becker, Heidi L. K. Manning, Charles Malespin, Christopher P. McKay, Rafael Navarro-González, Melissa G. Trainer, Bruce M. Jakosky, Jennifer C. Stern, Heather B. Franz, Sushil K. Atreya, Pamela G. Conrad, Michael H. Wong, Tobias Owen, Andrew Steele, John H. Jones, and Robert O. Pepin
Subjects: Physics, Martian, Analytical chemistry, chemistry.chemical_element, Mars Exploration Program, Mass spectrometry, Nitrogen, Isotopes of nitrogen, Astrobiology, Geophysics, chemistry, Meteorite, Sample Analysis at Mars, General Earth and Planetary Sciences, Quadrupole mass analyzer, Regular Articles
Abstract: [1] The Sample Analysis at Mars (SAM) instrument suite on the Mars Science Laboratory (MSL) measured a Mars atmospheric14N/15N ratio of 173 ± 11 on sol 341 of the mission, agreeing with Viking's measurement of 168 ± 17. The MSL/SAM value was based on Quadrupole Mass Spectrometer measurements of an enriched atmospheric sample, with CO2 and H2O removed. Doubly ionized nitrogen data at m/z 14 and 14.5 had the highest signal/background ratio, with results confirmed by m/z 28 and 29 data. Gases in SNC meteorite glasses have been interpreted as mixtures containing a Martian atmospheric component, based partly on distinctive14N/15N and40Ar/14N ratios. Recent MSL/SAM measurements of the40Ar/14N ratio (0.51 ± 0.01) are incompatible with the Viking ratio (0.35 ± 0.08). The meteorite mixing line is more consistent with the atmospheric composition measured by Viking than by MSL.
Published: 2013

18. Mars methane detection and variability at Gale crater

Author: Susanne P. Schwenzer, Christopher R. Webster, Tobias Owen, Mark T. Lemmon, Javier Martin-Torres, Sushil K. Atreya, Michael A. Mischna, John Bridges, P. Douglas Archer, G. Flesch, Patrice Coll, Kenneth A. Farley, Ralf Gellert, Alexander A. Pavlov, Daniel P. Glavin, Christopher P. McKay, Andrew Steele, Jennifer L. Eigenbrode, Paul R. Mahaffy, Timothy H. McConnochie, Rafael Navarro-González, John E. Moores, Charles Malespin, Pamela G. Conrad, Brad Sutter, Caroline Freissinet, María Paz Zorzano, Lance E. Christensen, and Pierre-Yves Meslin
Subjects: Multidisciplinary, Spectrometer, Atmospheric methane, Mars, methane detection, Mars Exploration Program, Atmosphere of Mars, Gale crater, Methane, Astrobiology, chemistry.chemical_compound, Interplanetary dust cloud, Curiosity, chemistry, Carbonaceous chondrite, Sample Analysis at Mars, Environmental science
Abstract: Of water and methane on Mars The Curiosity rover has been collecting data for the past 2 years, since its delivery to Mars (see the Perspective by Zahnle). Many studies now suggest that many millions of years ago, Mars was warmer and wetter than it is today. But those conditions required an atmosphere that seems to have vanished. Using the Curiosity rover, Mahaffy et al. measured the ratio of deuterium to hydrogen in clays that were formed 3.0 to 3.7 billion years ago. Hydrogen escapes more readily than deuterium, so this ratio offers a snapshot measure of the ancient atmosphere that can help constrain when and how it disappeared. Most methane on Earth has a biological origin, so planetary scientists have keenly pursued its detection in the martian atmosphere as well. Now, Webster et al. have precisely confirmed the presence of methane in the martian atmosphere with the instruments aboard the Curiosity rover at Gale crater. Science , this issue p. 412 , p. 415 ; see also p. 370
Published: 2015

19. Evidence for perchlorates and the origin of chlorinated hydrocarbons detected by SAM at the Rocknest aeolian deposit in Gale Crater

Author: Jennifer L. Eigenbrode, Paul R. Mahaffy, Arnaud Buch, Rafael Navarro-González, Michel Cabane, Roger E. Summons, Pamela G. Conrad, Samuel Teinturier, Douglas W. Ming, David Coscia, Alexander A. Pavlov, Heather B. Franz, William B. Brinckerhoff, Caroline Freissinet, Jason P. Dworkin, Andrew Steele, Cyril Szopa, John P. Grotzinger, Daniel P. Glavin, Christopher P. McKay, Brad Sutter, Mildred G. Martin, A. E. Brunner, P. Douglas Archer, Sushil K. Atreya, Laurie A. Leshin, Kristen E. Miller, and Patrice Coll
Subjects: 010504 meteorology & atmospheric sciences, Mineralogy, 01 natural sciences, Astrobiology, Perchlorate, chemistry.chemical_compound, Geochemistry and Petrology, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Benzene, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, chemistry.chemical_classification, Chloromethane, Gale crater, Geophysics, Hydrocarbon, chemistry, 13. Climate action, Space and Planetary Science, Chlorobenzene, Rocknest, Environmental chemistry, Sample Analysis at Mars, Aeolian processes, Pyrolysis, Geology
Abstract: [1] A single scoop of the Rocknest aeolian deposit was sieved (
Published: 2013

20. Light and variable ^(37)Cl/^(35)Cl ratios in rocks from Gale Crater, Mars: Possible signature of perchlorate

Author: P. Martin, Charles Malespin, Paul R. Mahaffy, P. D. Archer, Alberto G. Fairén, Kenneth A. Farley, S. K. Atreya, Daniel P. Glavin, D. W. Ming, Caroline Freissinet, Pamela G. Conrad, J. L. Eigenbrode, Brad Sutter, Rafael Navarro-González, and Heather B. Franz
Subjects: 010504 meteorology & atmospheric sciences, Isotope, Analytical chemistry, Mineralogy, Fractionation, 010502 geochemistry & geophysics, 01 natural sciences, Chemical reaction, Chloride, Atmosphere, Perchlorate, chemistry.chemical_compound, Geophysics, Deposition (aerosol physics), chemistry, Space and Planetary Science, Geochemistry and Petrology, Rocknest, Earth and Planetary Sciences (miscellaneous), medicine, Geology, 0105 earth and related environmental sciences, medicine.drug
Abstract: Cl isotope ratios measured on HCl thermally evolved from as-yet-unknown phases in sedimentary rocks and sand in Gale Crater provide unexpected insights to the Martian surficial Cl cycle. The seven samples yield δ^(37)Cl values ranging from −1±25‰ to −51±5‰. Five analyses from two samples of the Sheepbed mudstone (Yellowknife Bay study area) are analytically indistinguishable with a mean δ^(37)Cl of −11±7‰ (1σ). In contrast, four mudstones/sandstones from the Kimberley and Pahrump study areas also yielded indistinguishable ratios, but with a mean δ^(37)Cl of −43±6‰. The Rocknest sand deposit gave a highly uncertain δ^(37)Cl value of −7±44‰. These light and highly variable δ^(37)Cl values are unique among known solar system materials. Two endmember models are offered to account for these observations, and in both, perchlorate, with its extreme ability to fractionate Cl isotopes, is critical. In the first model, SAM is detecting HCl from an oxychlorine compound (e.g., perchlorate) produced from volcanic gas emissions by atmospheric chemical reactions. Similar reactions in Earth's atmosphere may be responsible for the isotopically lightest known Cl outside of this study, in perchlorate from the Atacama Desert. Some of the Gale Crater δ^(37)Cl values are more negative than those in Atacama perchlorate, but because reaction mechanisms and associated fractionation factors are unknown, it is impossible to assess whether this difference is prohibitive. If the negative δ^(37)Cl signal is produced in this fashion, the isotopic variability among samples could arise either from variations in the relative size of the reactant chloride and product perchlorate reservoirs, or from variations in the fraction of perchlorate reduced back to chloride after deposition. Such reduction strongly enriches ^(37)Cl in the residual perchlorate. Perchlorate reduction alone offers an alternative endmember model that can explain the observed data if SAM measured HCl derived from chloride. In this model isotopically normal perchlorate produced by an unspecified mechanism is reduced to chloride. Depending on the relative size of the reduced reservoir, the integrated product chloride can vary in isotopic composition from −70‰ in the first increment all the way to the starting composition if the perchlorate is fully reduced. Thus, variable degrees of perchlorate reduction can produce chloride with the appropriate δ^(37)Cl range. Combination of the two endmember models, in which the perchlorate subject to post-deposition reduction is isotopically negative from atmospheric reactions, is also possible. Determination of the phase hosting the Cl measured by SAM, an oxychlorine compound or chloride, is critical for selecting between these models, and for developing implications of the results for the Mars surficial Cl cycle. At present it is not possible to conclusively establish which phase is responsible (possibly both), but limited evidence favors the conclusion that the measured Cl derives mostly from an oxychlorine compound.
Published: 2016

21. STRATIGRAPHIC DEPENDENCE OF CHLORINE ISOTOPE VALUES IN GALE CRATER

Author: Brad Sutter, Kenneth A. Farley, Rafael Navarro-González, P. Doug Archer, Heather B. Franz, Pamela G. Conrad, Sushil K. Atreya, Paul R. Mahaffy, and P. Martin
Subjects: Geochemistry, Isotopes of chlorine, Gale crater, Geology, Astrobiology
Published: 2016

22. MICRO RAMAN SPECTROSCOPY OF FLUID INCLUSIONS IN CHERTS: EXTENDING LIFE DETECTION STRATEGIES TO GEOCHRONOLOGY

Author: Pamela G. Conrad, D. M. Bower, Marc Fries, and Andrew Steele
Subjects: Geochronology, Geochemistry, Mineralogy, Fluid inclusions, Life detection, Geology, Micro raman spectroscopy
Published: 2016

23. DISCOVERING THE ORIGINS OF CARBONACEOUS MATERIALS IN SILICEOUS DEPOSITS: MICRO RAMAN SPECTROSCOPIC CHARACTERIZATION OF QUARTZ FABRICS IN CHERTS

Author: Pamela G. Conrad, Marc Fries, Andrew Steele, and D. M. Bower
Subjects: Materials science, Micro raman, Metallurgy, Mineralogy, Quartz, Characterization (materials science)
Published: 2016

24. A Reduced Organic Carbon Component in Martian Basalts

Author: L. Kater, Hans E. F. Amundsen, R. Bowden, Edward P. Vicenzi, Pamela G. Conrad, Francis M. McCubbin, Steven B. Shirey, Allan H. Treiman, Sandra Siljeström, Richard N. Zare, Nabil Z. Boctor, Marc Fries, Mihaela Glamoclija, Maegan K. Spencer, Christopher D. K. Herd, Andrew Steele, Matthew R. Hammond, Marilyn L. Fogel, A. J. T. Jull, Emma S. Bullock, Amy L. Morrow, and Bjorn O. Mysen
Subjects: Total organic carbon, Martian, Basalt, Multidisciplinary, Extraterrestrial Environment, Chemistry, Silicates, Mars, chemistry.chemical_element, Mineralogy, Oxides, Meteoroids, Mars Exploration Program, Spectrum Analysis, Raman, Carbon, Astrobiology, Carbon cycle, Meteorite, Sample Analysis at Mars, Organic Chemicals, Polycyclic Aromatic Hydrocarbons, Crystallization, Oxidation-Reduction
Abstract: Abiotic Martian Organics Understanding the sources and the formation mechanisms of organic carbon compounds on Mars has implications for our understanding of the martian carbon cycle. Steele et al. (p. 212 , published online 24 May) present measurements of organic material in 11 martian meteorites, including the Tissint meteorite, which fell in the Moroccan desert in July 2011. Ten of the meteorites contain complex hydrocarbons encased within igneous minerals. The results imply that the organics formed as the magma melt crystallized and are thus of abiotic origin.
Published: 2012

25. The Mars Science Laboratory Organic Check Material

Author: Jennifer L. Eigenbrode, Joel Johnson, Claus T. Mogensen, Pamela G. Conrad, Daniel P. Glavin, John Canham, Therese Errigo, Paul R. Mahaffy, Dan Harpold, and Max O. Von der Heydt
Subjects: Martian, Repeated sampling, business.industry, Sample (material), Astronomy and Astrophysics, Mars Exploration Program, Curiosity rover, Exploration of Mars, Porous ceramics, Space and Planetary Science, Sample Analysis at Mars, Environmental science, Process engineering, business, Remote sensing
Abstract: Mars Science Laboratory’s Curiosity rover carries a set of five external verification standards in hermetically sealed containers that can be sampled as would be a Martian rock, by drilling and then portioning into the solid sample inlet of the Sample Analysis at Mars (SAM) suite. Each organic check material (OCM) canister contains a porous ceramic solid, which has been doped with a fluorinated hydrocarbon marker that can be detected by SAM. The purpose of the OCM is to serve as a verification tool for the organic cleanliness of those parts of the sample chain that cannot be cleaned other than by dilution, i.e., repeated sampling of Martian rock. SAM possesses internal calibrants for verification of both its performance and its internal cleanliness, and the OCM is not used for that purpose. Each OCM unit is designed for one use only, and the choice to do so will be made by the project science group (PSG).
Published: 2012

26. Crystal structure and Raman spectrum of hydroxyl-bastnasite-(Ce), CeCO3(OH)

Author: Hexiong Yang, Pamela G. Conrad, Robert T. Downs, and Robert F. Dembowski
Subjects: Diffraction, Bastnäsite, Crystallography, symbols.namesake, Geophysics, Geochemistry and Petrology, Chemistry, Group (periodic table), symbols, Crystal structure, Isostructural, Raman spectroscopy, Ion
Abstract: Hydroxyl-bastnasite-(Ce), ideally CeCO 3 (OH), had been regarded isostructural with bastnasite-(Ce), CeCO 3 F, the dominant member of the bastnasite family that produces ~70% of the world’s supply of rare-earth elements. Using single-crystal X-ray diffraction and Raman spectroscopy, our structural analysis on hydroxyl-bastnasite-(Ce) shows that the previous assumption is incorrect. The crystal structure of hydroxyl-bastnasite-(Ce) possesses P 6 symmetry with unit-cell parameters a = 12.4112(2), c = 9.8511(3) A, and V = 1314.2(1) A 3 , in contrast to the space group P 62 c and a ≈ 7.10, c ≈ 9.76 A, and V ≈ 430 A 3 for bastnasite-(Ce). Moreover, there are 6, 3, and 5 symmetrically-distinct CO 3 groups, Ce cations, and (OH/F) ions, respectively, in hydroxyl-bastnasite-(Ce), but 1, 1, and 2 in bastnasite-(Ce). The two structures, nevertheless, are similarly characterized by the layers of CO 3 groups alternating with the Ce-(OH/F) layers along the c direction. The Raman spectrum of hydroxyl-bastnasite-(Ce) is dominated by three strong bands at 1080, 1087, and 1098 cm −1 in the CO 3 symmetrical stretching region, along with at least four bands in the OH stretching region. Our study further suggests that natural hydroxyl-bastnasite-(Nd) is most likely isotypic with hydroxyl-bastnasite-(Ce), rather than with bastnasite-(Ce), as previously proposed.
Published: 2008

27. Textural and mineralogical biosignatures in an unusual microbialite from Death Valley, California

Author: Susanne Douglas, Pamela G. Conrad, Isik Kanik, William Abbey, and Randall E. Mielke
Subjects: Calcite, Gypsum, Mineral, Geochemistry, Astronomy and Astrophysics, Context (language use), Mars Exploration Program, engineering.material, Texture (geology), Abiogenic petroleum origin, chemistry.chemical_compound, chemistry, Space and Planetary Science, Biosignature, engineering, Geology
Abstract: For in situ astrobiological studies of Mars or other planets, we must employ strategies that will enable us to verify whether our approach and prototype instruments are actually capable of distinguishing life from non-life. This must be done against a background of rigorously conducted scientific characterization of the environment or sample types being considered for measurement by the instruments under development. In this study we show how a combination of mineralogical and textural features can be considered a biosignature in an early Mars analogue environment, Death Valley, California. We propose that it is a combination of features in context of the geologic matrix which allows determination of biogenicity to be made. Polymineralic microbialites (organosedimentary formations constructed by microorganisms) from a spring pool at Badwater, within Death Valley National Park, are composed of alternating biogenic and abiogenic minerals in a distinct triplet sequence related to wet and dry seasons. A microbial community, occurring as a black biofilm, produced paired layers of two different mineral types: manganese oxyhydroxides and calcite. These biogenic layers are separated from the next pair by a gypsum layer and appear to be laid down in the wet season, with the gypsum (a mineral positively identified on Mars) precipitating in the dry part of the year, abiogenically (i.e., not dependent on microbial metabolic activity for its deposition). In addition, textural features (smaller grain size and less geometric morphology) unique to the biogenic vs the abiogenic layers, were consistently observed so that texture served as a biosignature in this environment.
Published: 2008

28. Deposition, exhumation, and paleoclimate of an ancient lake deposit, Gale crater, Mars

Author: Scott M. McLennan, Michelle E. Minitti, J. L. Griffes, Nicolas Mangold, Pamela G. Conrad, P.G. Mahaffy, Joel A. Hurowitz, R. Gellert, W.F. Fischer, Sanjeev Gupta, David T. Vaniman, Douglas W. Ming, Fred Calef, Dorothy Z. Oehler, Rebecca M. E. Williams, Marie J. McBride, Melissa S. Rice, David F. Blake, Michael A. Mischna, H. E. Newsom, John P. Grotzinger, Kirsten L. Siebach, Ralph E. Milliken, Marisa C. Palucis, Kenneth S. Edgett, T. J. Parker, Michael P. Lamb, Sharon A. Wilson, John A. Grant, Dawn Y. Sumner, Gilles Dromart, Lauren A. Edgar, Kevin W. Lewis, Ryan C. Ewing, Ashwin R. Vasavada, Linda C. Kah, William E. Dietrich, R. A. Yingst, Gary Kocurek, Raymond E. Arvidson, Joy A. Crisp, David M. Rubin, Diana L. Blaney, Michael C. Malin, K. Stack, Roger C. Wiens, Juergen Schieber, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)
Subjects: Multidisciplinary, 010504 meteorology & atmospheric sciences, Ancient lake, Water on Mars, Outcrop, General Science & Technology, Climate, Geochemistry, Fluvial, Mars, Paleontology, Mars Exploration Program, Exhumation, 01 natural sciences, Lakes, Impact crater, 13. Climate action, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Erosion, Sedimentary rock, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract: Ancient lake system at Gale crater Since 2012, the Curiosity rover has been diligently studying rocky outcrops on Mars, looking for clues about past water, climate, and habitability. Grotzinger et al. describe the analysis of a huge section of sedimentary rocks near Gale crater, where Mount Sharp now stands (see the Perspective by Chan). The features within these sediments are reminiscent of delta, stream, and lake deposits on Earth. Although individual lakes were probably transient, it is likely that there was enough water to fill in low-lying depressions such as impact craters for up to 10,000 years. Wind-driven erosion removed many of these deposits, creating Mount Sharp. Science , this issue p. 10.1126/science.aac7575 , see also p. 167
Published: 2015

29. Organic molecules in the Sheepbed Mudstone, Gale Crater, Mars

Author: Paul R. Mahaffy, Pascaline Francois, Pamela G. Conrad, Michel Cabane, Daniel P. Glavin, D. J. Des Marais, María Paz Zorzano, John P. Grotzinger, C. A. Malespin, Arnaud Buch, Rafael Navarro-González, Douglas W. Ming, Roger E. Summons, Caroline Freissinet, A. E. Brunner, Steven W. Squyres, Dawn Y. Sumner, M. G. Martin, P. D. Archer, Andrew Steele, Alberto G. Fairén, Cyril Szopa, Sushil K. Atreya, S. Kashyap, Brad Sutter, I. L. ten Kate, Jennifer L. Eigenbrode, Patrice Coll, Laurie A. Leshin, H. B. Franz, William B. Brinckerhoff, Kristen E. Miller, Jennifer C. Stern, F. J. Martin-Torres, Amy McAdam, B. D. Prats, Jason P. Dworkin, Alexander A. Pavlov, Petrology, Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Miller, Kristen, Summons, Roger E, NASA Goddard Space Flight Center (GSFC), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Center for Research and Exploration in Space Science and Technology [GSFC] (CRESST), Laboratoire de Génie des Procédés et Matériaux - EA 4038 (LGPM), CentraleSupélec, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), NASA Johnson Space Center (JSC), NASA, Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), NASA Ames Research Center (ARC), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Astronomy [Ithaca], Cornell University [New York], Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Department of Earth Sciences [Utrecht], Utrecht University [Utrecht], Rensselaer Polytechnic Institute (RPI), Goddard Earth Sciences and Technology and Research (GESTAR), NASA-Universities Space Research Association (USRA), Department of Chemistry [CUA], Catholic University of America, Department of Computer Science, Electrical and Space Engineering [Luleå], Luleå University of Technology (LUT), Instituto Andaluz de Ciencias de la Tierra (IACT), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Universidad de Granada = University of Granada (UGR), Astromaterials Research and Exploration Science (ARES), NASA-NASA, Instituto de Ciencias Nucleares [Mexico], Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), Geophysical Laboratory [Carnegie Institution], Carnegie Institution for Science, Department of Earth and Planetary Science [UC Berkeley] (EPS), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), NASAFrench Space Agency (CNES), IMPEC - LATMOS, Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Cornell University, Universities Space Research Association (USRA)-NASA, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Universidad de Granada (UGR), Universidad Nacional Autónoma de México (UNAM), Carnegie Institution for Science [Washington], University of California [Berkeley], University of California-University of California, Universidad de Granada (UGR)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Universidad de Granada (UGR)
Subjects: organic molecules, 010504 meteorology & atmospheric sciences, oxychlorine, Curiosity rover, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mars, Erosion and weathering, 01 natural sciences, Astrobiology, chemistry.chemical_compound, Interplanetary dust cloud, Volcanism, Geochemistry and Petrology, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), MSL, 010303 astronomy & astrophysics, Research Articles, 0105 earth and related environmental sciences, Martian, Surface materials and properties, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Mars Science Laboratory, Geology, Mars Exploration Program, Regolith, Gale Crater, Diagenesis, Geophysics, SAM, Geochemistry, Meteorite, chemistry, 13. Climate action, Chlorobenzene, Space and Planetary Science, Oxychlorine, Sample Analysis at Mars, chlorobenzene, Organic molecules, Astronomical and Space Sciences, Composition
Abstract: The Sample Analysis at Mars (SAM) instrument on board the Mars Science Laboratory Curiosity rover is designed to conduct inorganic and organic chemical analyses of the atmosphere and the surface regolith and rocks to help evaluate the past and present habitability potential of Mars at Gale Crater. Central to this task is the development of an inventory of any organic molecules present to elucidate processes associated with their origin, diagenesis, concentration, and long-term preservation. This will guide the future search for biosignatures. Here we report the definitive identification of chlorobenzene (150–300 parts per billion by weight (ppbw)) and C2 to C4 dichloroalkanes (up to 70 ppbw) with the SAM gas chromatograph mass spectrometer (GCMS) and detection of chlorobenzene in the direct evolved gas analysis (EGA) mode, in multiple portions of the fines from the Cumberland drill hole in the Sheepbed mudstone at Yellowknife Bay. When combined with GCMS and EGA data from multiple scooped and drilled samples, blank runs, and supporting laboratory analog studies, the elevated levels of chlorobenzene and the dichloroalkanes cannot be solely explained by instrument background sources known to be present in SAM. We conclude that these chlorinated hydrocarbons are the reaction products of Martian chlorine and organic carbon derived from Martian sources (e.g., igneous, hydrothermal, atmospheric, or biological) or exogenous sources such as meteorites, comets, or interplanetary dust particles. Key Points First in situ evidence of nonterrestrial organics in Martian surface sediments Chlorinated hydrocarbons identified in the Sheepbed mudstone by SAM Organics preserved in sample exposed to ionizing radiation and oxidative condition
Published: 2015

30. The imprint of atmospheric evolution in the D/H of Hesperian clay minerals on Mars

Author: Pamela G. Conrad, Daniel P. Glavin, Rafael Navarro-González, Paul R. Mahaffy, A. A. Pavlov, Amy McAdam, Shawn Domagal-Goldman, Jennifer C. Stern, Melissa G. Trainer, A. E. Brunner, J. L. Eigenbrode, Sushil K. Atreya, Christopher R. Webster, H. B. Franz, D. W. Ming, Kenneth H. Williford, John P. Grotzinger, G. Flesch, Charles Malespin, Caroline Freissinet, James J. Wray, Lance E. Christensen, Andrew Steele, T. C. Owen, L. A. Leshin, Paul B. Niles, and John H. Jones
Subjects: Martian, Multidisciplinary, Hydrogen, MSL-Radiation, chemistry.chemical_element, Mars, Atmosphere of Mars, Mars Exploration Program, Gale crater, Astrobiology, chemistry, Impact crater, Sample Analysis at Mars, D/H ratio, Hesperian, Clay minerals, Geology
Abstract: Of water and methane on Mars The Curiosity rover has been collecting data for the past 2 years, since its delivery to Mars (see the Perspective by Zahnle). Many studies now suggest that many millions of years ago, Mars was warmer and wetter than it is today. But those conditions required an atmosphere that seems to have vanished. Using the Curiosity rover, Mahaffy et al. measured the ratio of deuterium to hydrogen in clays that were formed 3.0 to 3.7 billion years ago. Hydrogen escapes more readily than deuterium, so this ratio offers a snapshot measure of the ancient atmosphere that can help constrain when and how it disappeared. Most methane on Earth has a biological origin, so planetary scientists have keenly pursued its detection in the martian atmosphere as well. Now, Webster et al. have precisely confirmed the presence of methane in the martian atmosphere with the instruments aboard the Curiosity rover at Gale crater. Science , this issue p. 412 , p. 415 ; see also p. 370
Published: 2015

31. Planetary science. Scratching the surface of martian habitability

Author: Pamela G, Conrad
Subjects: Physical Phenomena, Chemical Phenomena, Extraterrestrial Environment, Exobiology, Mars, Spacecraft
Published: 2014

32. Volatile and Organic Compositions of Sedimentary Rocks in Yellowknife Bay, Gale Crater, Mars

Author: M. A. Meyer, Mark I. Richardson, Robert C. Anderson, Marisa C. Palucis, Sara Navarro Lopez, Rodney C. Ewing, Sanjeev Gupta, Caroline Freissinet, Edward M. Stolper, James F. Bell, M. A. Ravine, I. G. Mitrofanov, Thomas F. Bristow, Dawn Y. Sumner, Joel A. Hurowitz, Robert M. Haberle, Claire E. Newman, Andrew Steele, Muriel Saccoccio, Leslie Keely, E. Pallier, Jason P. Dworkin, Claude Geffroy, Mary A. Voytek, Michael Caplinger, Fred Goesmann, Yann Parot, Maria-Paz Zorzano Mier, A. B. Sanin, S. W. Squyres, Javier Caride Rodriguez, J. L. Griffes, Julio José Romeral-Planello, Jason Feldman, Katherine L. French, V. Sautter, Nicolas Mangold, David L. Bish, Vivian Lafaille, Michael D. Smith, François Raulin, V. Prokhorov, Gilles Berger, S. Slavney, Heather B. Franz, S. Johnstone, Susanne P. Schwenzer, Felipe Gómez, Harri Haukka, Francis A. Cucinotta, J. Hudgins, T. Cleghorn, Pascaline Francois, Alain Lepinette Malvitte, Shuai Li, Paul R. Mahaffy, K. M. Robertson, Bruce M. Jakosky, J. Guo, Juergen Schieber, Rafael Navarro-González, G. J. Flesch, Scott M. McLennan, Jennifer G. Blank, M. Carmosino, Kenneth A. Farley, Yves Langevin, P. D. Archer, A. E. Brunner, M. D. Dyar, S. Le Mouélic, V. Hipkin, Sara Alejandra Sans Fuentes, Kenneth S. Edgett, Sabrina Feldman, Gale Paulsen, Paul Herrera, Alberto G. Fairén, Kirsten L. Siebach, Jan-Peter Muller, M. J. Schoppers, Eldar Noe Dobrea, Nina Lanza, Marc Gailhanou, Genevieve Marchand, Sönke Burmeister, Craig Hardgrove, Justin N. Maki, Ari-Matti Harri, Michael C. Malin, M. J. Wolff, Roger E. Summons, H. Blau, Jacqueline Cameron, Jeff A. Berger, Didier Keymeulen, Agnes Cousin, Guillermo M. Muñoz Caro, Eric Lyness, Cedric Pilorget, Michael B. Baker, Christopher S. Edwards, M. L. Litvak, Brian M. Duston, Rebecca M. E. Williams, T. Nolan, Robert T. Downs, V. E. Hamilton, Walter Goetz, Pamela G. Conrad, J. Baroukh, Nathan T. Bridges, Meenakshi Wadhwa, Roger C. Wiens, Samuel M. Clegg, Philippe Sarrazin, L. Bleacher, Eric Lorigny, Mike Toplis, Michael H. Wong, Timothy H. McConnochie, Ian Mcewan, Kiran Patel, Mary Beth Wilhelm, John P. Grotzinger, Jeffrey E. Moersch, Michael A. Wilson, Mark Paton, I. Plante, Eric Lewin, Franck Poitrasson, Tori M. Hoehler, P. Guillemot, Mackenzie Day, David F. Blake, José Antonio Rodríguez Manfredi, G. W. Lugmair, Robert F. Wimmer-Schweingruber, Dorothy Z. Oehler, Samuel Teinturier, Bent Ehresmann, Jérémie Lasue, K. E. Herkenhoff, Daniel C. Berman, Scott VanBommel, Jeffrey R. Johnson, Emily M. McCullough, A. A. Fraeman, Ezat Heydari, Penelope L. King, K. M. Stack, Diana L. Blaney, A. Salamon, John G. Spray, L. Posiolova, Jeff Hollingsworth, David Choi, Kevin W. Lewis, B. D. Prats, Tonci Balic-Zunic, Mehdi Benna, H. M. Elliott, Jesús Martínez-Frías, R. Mueller-Mellin, William V. Boynton, Lance E. Christensen, Richard Leveille, John A. Grant, David E. Harker, J. M. Morookian, Caleb I. Fassett, S. Jacob, Donald Fay, R. Perez, Horton E. Newsom, Morten Madsen, M. G. Trainer, G. Israel, B. E. Nixon, Claude d’Uston, John E. Moores, Olivier Gasnault, Daniel J. Krysak, Vladislav Tretyakov, G. M. Perrett, Andrew D. Aubrey, L. E. Kirkland, F. Stalport, B. L. Barraclough, Alain Cros, Stephan Böttcher, Michel Cabane, William B. Brinckerhoff, Jack D. Farmer, James J. Wray, P. Y. Meslin, Arnaud Buch, Allan H. Treiman, S. C. R. Rafkin, B. C. Clark, Noureddine Melikechi, R. Jackson, Luther W. Beegle, Angela Lundberg, Bethany L. Ehlmann, William E. Dietrich, Karl Iagnemma, K. Supulver, Radu Popa, R. Zimdar, Melissa Floyd, Wesley T. Huntress, Paul B. Niles, D. M. Delapp, C. N.. Achilles, Darrell Drake, T. Nelson, Alain Gaboriaud, Verónica Peinado-Gonzalez, Edward P. Vicenzi, T. Boucher, Jennifer L. Eigenbrode, C. Tate, David J. Des Marais, F. Javier Martin-Torres, Antoine Charpentier, Chris Webster, Mildred P. Martin, Robert M. Sucharski, Lucy M. Thompson, Cyril Szopa, D. Halleaux, Antonio Molina Jurado, Richard V. Morris, Andrey Vostrukhin, Peter C. Thomas, Ara V. Nefian, Pablo Sobron Sanchez, Manuel de la Torre Juárez, B. Elliott, Hannu Savijärvi, J. Bentz, Sergey Nikiforov, S. Gordon, Shaunna M. Morrison, Jean-Luc Lacour, Günter Reitz, M. E. Newcombe, David E. Brinza, C. Yana, Gary Kocurek, L. J. Lipkaman, C. M. Garcia, Maria Genzer, Fred Calef, A. Godber, Stubbe F. Hviid, C. Donny, T. Van Beek, Ruslan O. Kuzmin, Alexander Hayes, T. S. Olson, George D. Cody, J. Martín-Soler, N. Karpushkina, John Bridges, Mercedes Jiménez, M. Lefavor, Sylvestre Maurice, H. L. K. Manning, Ralph E. Milliken, Susanne Schröder, N. Spanovich, L. J. Edwards, A. Koefoed, Roser Urqui-O'Callaghan, Eduardo Sebastian Martinez, Cary Zeitlin, Noël Stewart, David T. Vaniman, E. A. Breves, Laurent Favot, A. Varenikov, Gérard Manhès, R. B. Williams, David Martin, Steven J. Rowland, E. Boehm, Adrian P. Jones, Alexis Paillet, R. Francis, Sushil K. Atreya, Mariek E. Schmidt, David Baratoux, N. I. Boyd, Qiu-Mei Lee, I. L. ten Kate, Bernard Hallet, K. Stoiber, Vivian Z. Sun, M. R. Kennedy, Gillian M. Krezoski, Mark A. Bullock, T. Stein, Michelle E. Minitti, I. Pradler, Susan L. S. Stipp, Scott Davis, Robert O. Pepin, B. L. Ehlmann, Janne Kauhanen, Dmitry Golovin, Steve J. Chipera, Raymond E. Arvidson, Javier Gómez-Elvira, L. C. Kah, Melissa S. Rice, Isaias Carrasco Blazquez, Cécile Fabre, John J. Simmonds, Joy A. Crisp, Jens Frydenvang, Florence Tan, Julia DeMarines, S. P. Gorevan, Elizabeth B. Rampe, E. McCartney, Lauren DeFlores, K. Harshman, D. N. Harpold, J. Van Beek, Luis Mora-Sotomayor, Douglas W. Ming, Kristen E. Miller, John Campbell, Amy McAdam, L. Saper, Robert Sullivan, Lorenzo Fluckiger, Kjartan M. Kinch, Arik Posner, H. Bower, A. A. Pavlov, D. Scholes, Insoo Jun, Brigitte Gondet, Patrice Coll, Burt Baker, Donald M. Hassler, Ralf Gellert, Laurie A. Leshin, T. Siili, Gilles Dromart, Lauren A. Edgar, Ryan B. Anderson, Robert Dingler, Leon Radziemski, Jean-Baptiste Sirven, G. Weigle, Cynthia K. Little, A. Mezzacappa, Olivier Forni, A. S. Kozyrev, Edward A. Cloutis, Ashwin Vasavada, A. Behar, François Robert, D. M. Rubin, Alexey Malakhov, E. Jensen, T. C. Owen, Sebastien Hettrich, Miguel Ramos, B. Sutter, Melinda A. Kahre, Patrick Pinet, John H. Jones, Claude Brunet, B. Pavri, Nilton O. Renno, Evgeny Atlaskin, Laurent Peret, Maxim Mokrousov, David Lees, J. J. B. Avalos, Jennifer C. Stern, Ann Ollila, Josefina Torres Redondo, Miles J. Johnson, M. A. D. P. Hernandez, Daniel P. Glavin, Albert S. Yen, Christophe Agard, Jouni Polkko, Christopher P. McKay, J. Peterson, Oliver Botta, Mark T. Lemmon, Marion Nachon, K. M. Bean, Bruce A. Cantor, Jan Köhler, M. Fitzgibbon, Carlos Armiens-Aparicio, Jorge Pla-Garcia, Henrik Kahanpää, Frances Westall, Walter Schmidt, M.-H. Kim, Kenneth G. Miller, Sharon A. Wilson, S. McNair, O. Kortmann, David Grinspoon, E. M. Lee, S. Indyk, Osku Kemppinen, E. Raaen, Michael Mischna, R. S. Sletten, James B. Garvin, John M. Ward, R. L. Tokar, Paulo M. Vasconcelos, Charles Malespin, T. J. Parker, Aaron J. Sengstacken, S. Bender, Jean-Pierre Williams, F. Fedosov, Patrick Mauchien, Audrey Dupont, R. A. Yingst, David Coscia, David A. Cremers, Danika Wellington, Kenneth H. Nealson, J. K. Jensen, Martin R. Fisk, J. Joseph, Amy J. Williams, W. Brunner, NASA Johnson Space Center (JSC), NASA, NASA Goddard Space Flight Center (GSFC), Center for Research and Exploration in Space Science and Technology [GSFC] (CRESST), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Guelph], University of Guelph, Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, ASU School of Earth and Space Exploration (SESE), Arizona State University [Tempe] (ASU), Laboratoire de Génie des Procédés et Matériaux - EA 4038 (LGPM), CentraleSupélec, Space Science and Astrobiology Division at Ames, NASA Ames Research Center (ARC), Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Astronomy [Ithaca], Cornell University [New York], Center for Earth and Planetary Studies [Washington] (CEPS), Smithsonian National Air and Space Museum, Smithsonian Institution-Smithsonian Institution, Department of Earth Science and Technology [Imperial College London], Imperial College London, United States Geological Survey [Reston] (USGS), Department of Geosciences [Stony Brook], Stony Brook University [SUNY] (SBU), State University of New York (SUNY)-State University of New York (SUNY), Rensselaer Polytechnic Institute (RPI), Princeton University, State University of New York (SUNY), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Department of Earth and Planetary Sciences [Knoxville], The University of Tennessee [Knoxville], Instituto de Ciencias Nucleares [Mexico], Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), Geophysical Laboratory [Carnegie Institution], Carnegie Institution for Science, Department of Earth and Planetary Science [UC Berkeley] (EPS), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), NOAA Earth System Research Laboratory (ESRL), National Oceanic and Atmospheric Administration (NOAA), Lunar and Planetary Institute [Houston] (LPI), Planetary Science Institute [Tucson] (PSI), School of Earth and Atmospheric Sciences [Atlanta], Georgia Institute of Technology [Atlanta], Aalto University, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Applied Research Associates, Inc. (ARA), Center for Meteorite Studies [Tempe], Ashima Research, ATOS Origin, Australian National University (ANU), Bay Area Environmental Research Institute (BAER), Big Head Endian LLC, Brock University [Canada], Brown University, Canadian Space Agency (CSA), Capgemini Consulting [Paris], Carnegie Mellon University [Pittsburgh] (CMU), Catholic University of America, Institut des Matériaux, de Microélectronique et des Nanosciences de Provence (IM2NP), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Centre de biophysique moléculaire (CBM), Université d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Chesapeake Energy Corporation, Service de la Corrosion et du Comportement des Matériaux dans leur Environnement (SCCME), Département de Physico-Chimie (DPC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire d'Interaction Laser Matière (LILM), Concordia College, Moorhead, CS-Systèmes d'Information [Toulouse] (CS-SI), Delaware State University (DSU), Denver Museum of Nature and Science, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Finnish Meteorological Institute (FMI), GeoRessources, Institut national des sciences de l'Univers (INSU - CNRS)-Centre de recherches sur la géologie des matières premières minérales et énergétiques (CREGU)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Global Science and Technology, Inc., Honeybee Robotics Ltd, Indiana University [Bloomington], Indiana University System, Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Institut des Sciences de la Terre (ISTerre), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Jackson State University (JSU), Jacobs Technology ESCG, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Minéralogie et Cosmochimie du Muséum (LMCM), Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Los Alamos National Laboratory (LANL), Space Remote Sensing Group (ISR-2), Malin Space Science Systems (MSSS), Depertment of Polymer Chemistry, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, DLR Institute of Planetary Research, German Aerospace Center (DLR), NASA Headquarters, Oregon State University (OSU), Search for Extraterrestrial Intelligence Institute (SETI), Smithsonian Institution, Department of Space Studies [Boulder], Southwest Research Institute [Boulder] (SwRI), Space Research Institute of the Russian Academy of Sciences (IKI), Russian Academy of Sciences [Moscow] (RAS), TechSource Inc., Texas A&M University [College Station], The Open University [Milton Keynes] (OU), University of Arizona, Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office [Exeter], Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Niels Bohr Institute [Copenhagen] (NBI), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), Institute for Astronomy [Honolulu], University of Hawai‘i [Mānoa] (UHM), California Institute of Technology (CALTECH)-NASA, Universidad Nacional Autónoma de México (UNAM), Carnegie Institution for Science [Washington], University of California [Berkeley], University of California-University of California, Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Université d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Centre de recherches sur la géologie des matières premières minérales et énergétiques (CREGU)-Institut national des sciences de l'Univers (INSU - CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), NWO-NSO: The role of perchlorates in the preservation of organic compounds on Mars, Petrology, Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN), and Kruch, Catherine
Subjects: Geologic Sediments, 010504 meteorology & atmospheric sciences, Extraterrestrial Environment, Curiosity rover, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mineralogy, [SDU.ASTR.EP] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mars, Sulfides, 01 natural sciences, organic compositions, Bassanite, 0103 physical sciences, Exobiology, [SDU.ASTR.SR] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Hydrocarbons, Chlorinated, MSL, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Total organic carbon, Martian, mudstone samples, Volatile Organic Compounds, Multidisciplinary, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Water, Mars Exploration Program, Carbon Dioxide, Oxygen, Bays, 13. Climate action, Rocknest, Sample Analysis at Mars, Sedimentary rock, Pyrolysis
Abstract: H 2 O, CO 2 , SO 2 , O 2 , H 2 , H 2 S, HCl, chlorinated hydrocarbons, NO, and other trace gases were evolved during pyrolysis of two mudstone samples acquired by the Curiosity rover at Yellowknife Bay within Gale crater, Mars. H 2 O/OH-bearing phases included 2:1 phyllosilicate(s), bassanite, akaganeite, and amorphous materials. Thermal decomposition of carbonates and combustion of organic materials are candidate sources for the CO 2 . Concurrent evolution of O 2 and chlorinated hydrocarbons suggests the presence of oxychlorine phase(s). Sulfides are likely sources for sulfur-bearing species. Higher abundances of chlorinated hydrocarbons in the mudstone compared with Rocknest windblown materials previously analyzed by Curiosity suggest that indigenous martian or meteoritic organic carbon sources may be preserved in the mudstone; however, the carbon source for the chlorinated hydrocarbons is not definitively of martian origin.
Published: 2014

33. A Non-Earthcentric Approach to Life Detection

Author: Pamela G. Conrad and Kenneth H. Nealson
Subjects: Extraterrestrial Environment, Earth, Planet, business.industry, Origin of Life, Biology, Machine learning, computer.software_genre, Agricultural and Biological Sciences (miscellaneous), Field (computer science), Chemical evolution, Life, Space and Planetary Science, Exobiology, Artificial intelligence, business, Temporal scales, Life detection, computer, Remote sensing
Abstract: The ultimate goal of a comprehensive life detection strategy is never to miss life when we encounter it. To accomplish this goal, we must define life in universal, that is, non-Earthcentric, measurable terms. Next, we must understand the nature of biosignatures observed from the measured parameters of life. And finally, we must have a clear idea of the end-member states for the search--what does life, past life, or no life look like (in terms of the measured parameters) at multiple spatial and temporal scales? If we can approach these problems both in the laboratory and in the field on Earth, then we have a chance of being able to detect life elsewhere in our solar system. What are the required limits of detection at each of those scales? What spatial, spectral, and temporal resolutions are necessary to detect life? These questions are actively being investigated in our group, and in this report, we present our strategy and approach to non-Earthcentric life detection.
Published: 2001

34. The crystal structure of 'Tetragonal Almandine-Pyrope Phase' (TAPP): A reexamination

Author: Larry W. Finger and Pamela G. Conrad
Subjects: biology, Chemistry, Crystal structure, biology.organism_classification, Sial, law.invention, Pyrope, Almandine, Crystal, Tetragonal crystal system, Crystallography, Geophysics, Geochemistry and Petrology, law, Phase (matter), Crystallization
Abstract: X-ray intensities for the “tetragonal almandine-pyrope phase” (TAPP), *(FeMg) VIII (AlMgFe) 4 [IV (SiAl)O 4 ] 3 where * refers to a capped tetrahedral site, reported by Harris et al. (1997) were recollected using the identical crystal, and the crystal structure was refined from these new data. The basic structure of the previous report is confirmed; however, some of the details regarding cation occupancies are revised. The chemical composition of this phase corresponds to a high-pressure origin; however, significant questions remain regarding the crystallization pressure of this phase.
Published: 2000

35. A new pyroxene structure at high pressure; single-crystal X-ray and Raman study of the Pbcn-P21cn phase transition in protopyroxene

Author: Charles T. Prewit, Larry W. Finger, Robert M. Hazen, Pamela G. Conrad, and Hexiong Yang
Subjects: Phase transition, Crystal structure, Silicate, chemistry.chemical_compound, symbols.namesake, Crystallography, Geophysics, chemistry, Octahedron, Geochemistry and Petrology, Phase (matter), symbols, Raman spectroscopy, Anisotropy, Single crystal
Abstract: The crystal structure of (Mg (sub 1.54) Li (sub 0.23) Sc (sub 0.23) )Si 2 O 6 protopyroxene has been studied with single-crystal X-ray diffraction at pressures to 9.98 GPa and Raman spectroscopy to 10.4 GPa. A first-order displacive phase transformation from the Pbcn space group to P2 1 cn was observed between 2.03 and 2.50 GPa, which is characterized by a discontinuous decrease in a, c, and V by 1.1, 2.4, and 2.6%, respectively, and an increase in b by 0.9%, along with appearance of intensities of some Okl reflections with knot =2n. This is the first substantiated example of protopyroxene having the symmetry predicted by Thompson (1970). Evidence for the phase transition from Raman spectroscopy is also presented. The prominent structural changes associated with the Pbcn-to-P2 1 cn transformation involve the abrupt splitting of one type of O-rotated silicate chain in low-pressure protopyroxene into S-rotated A and O-rotated B chains in high-pressure protopyroxene, coupled with a marked decrease in the O3-O3-O3 angles and a re-configuration of O atoms around the M2 site. The kinking angle of the silicate chain in the low-pressure phase at 2.03 GPa is 165.9 degrees , whereas the angles are 147.9 degrees and 153.9 degrees for the A and B chains, respectively, in high-pressure phase at 2.50 GPa. Strikingly, the two types of silicate chains in the P2 1 cn structure alternate along the b axis in a tetrahedral layer parallel to (100). Such a mixed arrangement of two differently rotated silicate chains in a tetrahedral layer has not been observed in any other pyroxene structure. Compression anisotropy of the protopyroxene structure is affected by the phase transition. The relative linear compressibilities (beta a :beta b :beta c ) are 1.00:1.72:0.99 for low-pressure protopyroxene, but are 1.00:1.28:1.65 for high-pressure protopyroxene. The bulk moduli of low- and high-pressure phases are 130(3) and 111(1) GPa, respectively. This study concludes that the Pbcn-to-P2 1 cn phase transition results from the differential compression between SiO 4 tetrahedra and MO 6 octahedra.
Published: 1999

36. The high-pressure, single-crystal elasticity of pyrope, grossular, and andradite

Author: Russell J. Hemley, Pamela G. Conrad, Ho-kwang Mao, and Chang-Sheng Zha
Subjects: Grossular, biology, Extrapolation, Mineralogy, Thermodynamics, biology.organism_classification, Pyrope, Geophysics, Geochemistry and Petrology, Andradite, Brillouin scattering, visual_art, visual_art.visual_art_medium, Elasticity (economics), Single crystal, Elastic modulus, Geology
Abstract: High-pressure Brillouin scattering experiments were conducted on three natural, singlecrystal garnets with near end-member compositions: pyrope (Mg3Al2Si3O12), grossular (Ca3Al2Si3O12), and andradite (Ca3Fe 31 2Si3O12). Acoustic velocities of the samples were measured from the samples at pressures to 10 GPa in a diamond-anvil cell with a methanolethanol-water pressure medium. Elastic stiffness constants ( Cij) and their pressure dependencies (]Cij/]P) were calculated, as were aggregate elastic moduli (KS and G) and their respective pressure derivatives. The Cauchy relations changed with pressure for both grossular and andradite, suggesting that assuming these are constant is not valid for extrapolation to high pressures for these and possibly other minerals. The variation in ]KS /dP and ]G/]P was sensitive to composition and required a complex mixing model for extrapolation of end-member elasticity values from garnets of intermediate compositions.
Published: 1999

37. Scratching the surface of martian habitability

Author: Pamela G. Conrad
Subjects: Earth analog, Mars rover, Martian, Multidisciplinary, Planetary habitability, Planetary surface, Planet, Habitability, Mars Exploration Program, Astrobiology
Abstract: Earth and Mars, though formed at the same time from the same materials, look very different today. Early in their histories they evolved through some of the same processes, but at some point their evolutionary paths diverged, sending them in perhaps irrevocably different directions. Knowledge of the factors that contributed to such different outcomes will help to determine how planets become habitable and how common habitable planets may be. The Mars surface environment is harsh today, but in situ measurements of ancient sedimentary rock by Mars Science Laboratory reveal chemical and mineralogical evidence of past conditions that might have been more favorable for life to exist. But chemistry is only part of what is required to make an environment habitable. Physical conditions constrain the chemical reactions that underlie life processes; the chemical and physical characteristics that make planets habitable are thus entangled.
Published: 2014

38. Primordial argon isotope fractionation in the atmosphere of Mars measured by the SAM instrument on

Author: Sushil K, Atreya, Melissa G, Trainer, Heather B, Franz, Michael H, Wong, Heidi L K, Manning, Charles A, Malespin, Paul R, Mahaffy, Pamela G, Conrad, Anna E, Brunner, Laurie A, Leshin, John H, Jones, Christopher R, Webster, Tobias C, Owen, Robert O, Pepin, and R, Navarro-González
Subjects: habitability, Mars, solar system, planetary atmospheres, argon isotopes, atmospheric loss, Regular Articles
Abstract: [1] The quadrupole mass spectrometer of the Sample Analysis at Mars (SAM) instrument on Curiosity rover has made the first high-precision measurement of the nonradiogenic argon isotope ratio in the atmosphere of Mars. The resulting value of 36Ar/38Ar = 4.2 ± 0.1 is highly significant for it provides excellent evidence that “Mars” meteorites are indeed of Martian origin, and it points to a significant loss of argon of at least 50% and perhaps as high as 85–95% from the atmosphere of Mars in the past 4 billion years. Taken together with the isotopic fractionations in N, C, H, and O measured by SAM, these results imply a substantial loss of atmosphere from Mars in the posthydrodynamic escape phase.
Published: 2013

39. Mars Science Laboratory Mission and Science Investigation

Author: Robert Barry, Pamela G. Conrad, Maxim Litvak, Louise Jandura, M. A. Meyer, Charles J. Baker, John J. Simmonds, Matthew P. Golombek, I. G. Mitrofanov, Joy A. Crisp, David T. Vaniman, Michael C. Malin, Justin N. Maki, Donald M. Hassler, Richard V. Welch, Roger C. Wiens, Robert C. Anderson, Javier Gómez-Elvira, Ralf Gellert, David F. Blake, John B. Gilbert, John P. Grotzinger, Kenneth S. Edgett, Bobak Ferdowski, Ashwin R. Vasavada, and Paul R. Mahaffy
Subjects: Space and Planetary Science, Rocknest, Martian surface, Sample Analysis at Mars, Mars landing, Astronomy and Astrophysics, Mars Exploration Program, Exploration of Mars, Radiation assessment detector, Geology, Gas analyzer, Remote sensing
Abstract: Scheduled to land in August of 2012, the Mars Science Laboratory (MSL) Mission was initiated to explore the habitability of Mars. This includes both modern environments as well as ancient environments recorded by the stratigraphic rock record preserved at the Gale crater landing site. The Curiosity rover has a designed lifetime of at least one Mars year (∼23 months), and drive capability of at least 20 km. Curiosity’s science payload was specifically assembled to assess habitability and includes a gas chromatograph-mass spectrometer and gas analyzer that will search for organic carbon in rocks, regolith fines, and the atmosphere (SAM instrument); an x-ray diffractometer that will determine mineralogical diversity (CheMin instrument); focusable cameras that can image landscapes and rock/regolith textures in natural color (MAHLI, MARDI, and Mastcam instruments); an alpha-particle x-ray spectrometer for in situ determination of rock and soil chemistry (APXS instrument); a laser-induced breakdown spectrometer to remotely sense the chemical composition of rocks and minerals (ChemCam instrument); an active neutron spectrometer designed to search for water in rocks/regolith (DAN instrument); a weather station to measure modern-day environmental variables (REMS instrument); and a sensor designed for continuous monitoring of background solar and cosmic radiation (RAD instrument). The various payload elements will work together to detect and study potential sampling targets with remote and in situ measurements; to acquire samples of rock, soil, and atmosphere and analyze them in onboard analytical instruments; and to observe the environment around the rover. The 155-km diameter Gale crater was chosen as Curiosity’s field site based on several attributes: an interior mountain of ancient flat-lying strata extending almost 5 km above the elevation of the landing site; the lower few hundred meters of the mountain show a progression with relative age from clay-bearing to sulfate-bearing strata, separated by an unconformity from overlying likely anhydrous strata; the landing ellipse is characterized by a mixture of alluvial fan and high thermal inertia/high albedo stratified deposits; and a number of stratigraphically/geomorphically distinct fluvial features. Samples of the crater wall and rim rock, and more recent to currently active surface materials also may be studied. Gale has a well-defined regional context and strong evidence for a progression through multiple potentially habitable environments. These environments are represented by a stratigraphic record of extraordinary extent, and insure preservation of a rich record of the environmental history of early Mars. The interior mountain of Gale Crater has been informally designated at Mount Sharp, in honor of the pioneering planetary scientist Robert Sharp. The major subsystems of the MSL Project consist of a single rover (with science payload), a Multi-Mission Radioisotope Thermoelectric Generator, an Earth-Mars cruise stage, an entry, descent, and landing system, a launch vehicle, and the mission operations and ground data systems. The primary communication path for downlink is relay through the Mars Reconnaissance Orbiter. The primary path for uplink to the rover is Direct-from-Earth. The secondary paths for downlink are Direct-to-Earth and relay through the Mars Odyssey orbiter. Curiosity is a scaled version of the 6-wheel drive, 4-wheel steering, rocker bogie system from the Mars Exploration Rovers (MER) Spirit and Opportunity and the Mars Pathfinder Sojourner. Like Spirit and Opportunity, Curiosity offers three primary modes of navigation: blind-drive, visual odometry, and visual odometry with hazard avoidance. Creation of terrain maps based on HiRISE (High Resolution Imaging Science Experiment) and other remote sensing data were used to conduct simulated driving with Curiosity in these various modes, and allowed selection of the Gale crater landing site which requires climbing the base of a mountain to achieve its primary science goals. The Sample Acquisition, Processing, and Handling (SA/SPaH) subsystem is responsible for the acquisition of rock and soil samples from the Martian surface and the processing of these samples into fine particles that are then distributed to the analytical science instruments. The SA/SPaH subsystem is also responsible for the placement of the two contact instruments (APXS, MAHLI) on rock and soil targets. SA/SPaH consists of a robotic arm and turret-mounted devices on the end of the arm, which include a drill, brush, soil scoop, sample processing device, and the mechanical and electrical interfaces to the two contact science instruments. SA/SPaH also includes drill bit boxes, the organic check material, and an observation tray, which are all mounted on the front of the rover, and inlet cover mechanisms that are placed over the SAM and CheMin solid sample inlet tubes on the rover top deck.
Published: 2012

40. Precision Subsampling System for Planetary Exploration

Author: Jack Craft, Kris Zacny, William B. Brinckerhoff, Gale Paulsen, I. L. ten Kate, Pamela G. Conrad, and B. Mellerowicz
Subjects: Scientific instrument, Engineering, Lead (geology), business.industry, Habitability, Mars Exploration Program, Sample collection, Breadboard, business, Planetary exploration, Remote sensing, Characterization (materials science)
Abstract: We present details of a Precision Subsampling System (PSS) developed for surface exploration of Mars and other planetary bodies. The PSS combines a fine-scale solid powder extraction tool with sample collection, manipulation, and instrument analysis subsystems in a highly compact package. The system offers future landed missions the ability to selectively analyze heterogeneous surface sample composition on millimeter scales. Analysis of subsamples by mass spectrometry and other tools would then permit characterization of highly-localized chemical and mineralogical phases that could be key indicators of past or present habitability on Mars. Systematic measurements along a finely laminated sedimentary sequence would also lead to a greater understanding of surface formation processes. Following subsystem design and test, our breadboard PSS will undergo full end-to-end characterization at Mars ambient pressures using analog rock samples and integrated prototype spaceflight analytical instruments.
Published: 2012

41. The Mars Science Laboratory Organic Check Material

Author: Pamela G. Conrad, Jennifer L. Eigenbrode, Max O. Von der Heydt, Claus T. Mogensen, John Canham, Dan N. Harpold, Joel Johnson, Therese Errigo, Daniel P. Glavin, and Paul R. Mahaffy
Published: 2012

42. The Sample Analysis at Mars Investigation and Instrument Suite

Author: David Martin, Michel Cabane, Tobias Owen, John H. Jones, Ryan M. Miller, Greg Flesch, Florence Tan, James J. Wray, L. Bleacher, Didier Keymeulen, Cyril Szopa, E. Raaen, Douglas W. Ming, Paul R. Mahaffy, Robert A. Chalmers, Douglas L. Hawk, Curt Baffes, Laurie A. Leshin, Pamela G. Conrad, Oren E. Sheinman, Jennifer L. Eigenbrode, Robert Kline-Schoder, Paul Sorensen, D. Sheppard, Mark Cascia, Gregory Frazier, Daniel P. Glavin, Richard V. Morris, Arnaud Buch, Christopher P. McKay, Rafael Navarro-González, Charles Malespin, Patrice Coll, Rodger Farley, Christopher S. Johnson, Chris Webster, Cindy Gundersen, Bruce M. Jakosky, Daniel Carignan, Paula Everson, Heather B. Franz, Jason Feldman, Steve Woodward, Ray Garcia, Andrea Jones, Eric Lyness, Ken Arnett, Samuel Teinturier, Melissa G. Trainer, Mehdi Benna, Alexander A. Pavlov, E. Mumm, Steven W. Squyres, Marvin Noriega, James W. Kellogg, Jesse Lewis, Oliver Botta, David Coscia, H. L. K. Manning, John Maurer, Charles Edmonson, Steven Feng, Caroline Freissinet, Siamak Forouhar, Andrew Steele, Robert Arvey, Jason P. Dworkin, Douglas McLennan, Stephen Gorevan, Jennifer C. Stern, François Raulin, James Smith, Patrick R. Jordan, Sushil K. Atreya, Robert Sternberg, B. D. Prats, Therese Errigo, Bruce P. Block, T. Nolan, Michael Barciniak, D. N. Harpold, Vincent Holmes, William B. Brinckerhoff, Amy McAdam, Steve Battel, NASA Goddard Space Flight Center (GSFC), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, NASA Johnson Space Center (JSC), NASA, AMU Engineering, Inc., Geophysical Laboratory [Carnegie Institution], Carnegie Institution for Science [Washington], School of Earth and Atmospheric Sciences [Atlanta], Georgia Institute of Technology [Atlanta], Swiss Space Office Bern (SSO), Department of Earth and Environmental Sciences [Troy, NY], Rensselaer Polytechnic Institute (RPI), Institute for Astronomy [Honolulu], University of Hawai‘i [Mānoa] (UHM), Battel Engineering, Inc., Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Concordia College, Moorhead, Department of Astronomy [Ithaca], Cornell University [New York], Laboratorio de Química de Plasmas y Estudios Planetarios [Mexico], Instituto de Ciencias Nucleares [Mexico], Universidad Nacional Autónoma de México (UNAM)-Universidad Nacional Autónoma de México (UNAM), NASA Ames Research Center (ARC), Ecole Centrale Paris, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Space Physics Research Laboratory [Ann Arbor] (SPRL), IMPEC - LATMOS, Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Cornell University, Carnegie Institution for Science, Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM)-Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), NASA Goddard Space Flight Center ( GSFC ), Jet Propulsion Laboratory ( JPL ), NASA-California Institute of Technology ( CALTECH ), Laboratoire Atmosphères, Milieux, Observations Spatiales ( LATMOS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire inter-universitaire des systèmes atmosphèriques ( LISA ), Centre National de la Recherche Scientifique ( CNRS ) -Université Paris-Est Créteil Val-de-Marne - Paris 12 ( UPEC UP12 ) -Université Paris Diderot - Paris 7 ( UPD7 ) -Institut national des sciences de l'Univers ( INSU - CNRS ), Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] ( AOSS ), NASA Johnson Space Center ( JSC ), Swiss Space Office Bern ( SSO ), Department of Earth and Environmental Sciences [Troy], Rensselaer Polytechnic Institute ( RPI ), University of Hawaii at Manoa ( UHM ), Laboratory for Atmospheric and Space Physics [Boulder] ( LASP ), University of Colorado Boulder [Boulder], Universidad Nacional Autónoma de México ( UNAM ) -Universidad Nacional Autónoma de México ( UNAM ), NASA Ames Research Center ( ARC ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), and Space Physics Research Laboratory [Ann Arbor] ( SPRL )
Subjects: Volatiles, [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], 010504 meteorology & atmospheric sciences, Gas chromatography mass spectrometry, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Habitability, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mars, Life on Mars, 01 natural sciences, Astrobiology, Laboratory, Atmosphere, Isotopes, 0103 physical sciences, Organic compounds, 010303 astronomy & astrophysics, Quadrupole mass analyzer, 0105 earth and related environmental sciences, Spectrometer, [ SDU.ASTR.IM ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Astronomy and Astrophysics, Mars Exploration Program, Curiosity Rover, Gale crater, [ SDU.ASTR.EP ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Noble gases, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], [ PHYS.ASTR.EP ] Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 13. Climate action, Space and Planetary Science, Rocknest, Sample Analysis at Mars, Measuring instrument, Environmental science, Evolved gas analysis, [ PHYS.ASTR.IM ] Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM]
Abstract: International audience; The Sample Analysis at Mars (SAM) investigation of the Mars Science Laboratory (MSL) addresses the chemical and isotopic composition of the atmosphere and volatiles extracted from solid samples. The SAM investigation is designed to contribute substantially to the mission goal of quantitatively assessing the habitability of Mars as an essential step in the search for past or present life on Mars. SAM is a 40 kg instrument suite located in the interior of MSL's Curiosity rover. The SAM instruments are a quadrupole mass spectrometer, a tunable laser spectrometer, and a 6-column gas chromatograph all coupled through solid and gas processing systems to provide complementary information on the same samples. The SAM suite is able to measure a suite of light isotopes and to analyze volatiles directly from the atmosphere or thermally released from solid samples. In addition to measurements of simple inorganic compounds and noble gases SAM will conduct a sensitive search for organic compounds with either thermal or chemical extraction from sieved samples delivered by the sample processing system on the Curiosity rover's robotic arm.
Published: 2012

43. The Sample Analysis at Mars Investigation and Instrument Suite

Author: Paul R. Mahaffy, Christopher R. Webster, Michel Cabane, Pamela G. Conrad, Patrice Coll, Sushil K. Atreya, Robert Arvey, Michael Barciniak, Mehdi Benna, Lora Bleacher, William B. Brinckerhoff, Jennifer L. Eigenbrode, Daniel Carignan, Mark Cascia, Robert A. Chalmers, Jason P. Dworkin, Therese Errigo, Paula Everson, Heather Franz, Rodger Farley, Steven Feng, Gregory Frazier, Caroline Freissinet, Daniel P. Glavin, Daniel N. Harpold, Douglas Hawk, Vincent Holmes, Christopher S. Johnson, Andrea Jones, Patrick Jordan, James Kellogg, Jesse Lewis, Eric Lyness, Charles A. Malespin, David K. Martin, John Maurer, Amy C. McAdam, Douglas McLennan, Thomas J. Nolan, Marvin Noriega, Alexander A. Pavlov, Benito Prats, Eric Raaen, Oren Sheinman, David Sheppard, James Smith, Jennifer C. Stern, Florence Tan, Melissa Trainer, Douglas W. Ming, Richard V. Morris, John Jones, Cindy Gundersen, Andrew Steele, James Wray, Oliver Botta, Laurie A. Leshin, Tobias Owen, Steve Battel, Bruce M. Jakosky, Heidi Manning, Steven Squyres, Rafael Navarro-González, Christopher P. McKay, Francois Raulin, Robert Sternberg, Arnaud Buch, Paul Sorensen, Robert Kline-Schoder, David Coscia, Cyril Szopa, Samuel Teinturier, Curt Baffes, Jason Feldman, Greg Flesch, Siamak Forouhar, Ray Garcia, Didier Keymeulen, Steve Woodward, Bruce P. Block, Ken Arnett, Ryan Miller, Charles Edmonson, Stephen Gorevan, and Erik Mumm
Subjects: 010504 meteorology & atmospheric sciences, 0103 physical sciences, 010303 astronomy & astrophysics, 01 natural sciences, 0105 earth and related environmental sciences
Published: 2012

44. Precision Subsampling System for Mars and Beyond

Author: T. Hernstig, Bolek Mellerowicz, Tullis C. Onstott, E. Mumm, Pamela G. Conrad, I. L. ten Kate, William B. Brinckerhoff, Paul R. Mahaffy, John Wilson, C. M. Corrigan, E. J. Romani, H. B. Franz, and Kris Zacny
Subjects: Planet, Sampling (statistics), Mars Exploration Program, Geology, Space exploration, Remote sensing
Published: 2010

45. Classification of organic and biological materials with deep ultraviolet excitation

Author: Kenneth H. Nealson, William Abbey, Willam F. Hug, Ray D. Reid, K. Sijapati, Rohit Bhartia, Arthur L. Lane, A. I. Tsapin, Pamela G. Conrad, and Everett C. Salas
Subjects: Principal Component Analysis, medicine.diagnostic_test, Chemistry, Ultraviolet Rays, Analytical chemistry, chemistry.chemical_element, medicine.disease_cause, Mass spectrometry, Nitrogen, Fluorescence, Wavelength, Biopolymers, Spectrometry, Fluorescence, Spectrophotometry, medicine, Spectrophotometry, Ultraviolet, Emission spectrum, Organic Chemicals, Instrumentation, Spectroscopy, Ultraviolet, Excitation, Algorithms
Abstract: We show that native fluorescence can be used to differentiate classes or groups of organic molecules and biological materials when excitation occurs at specific excitation wavelengths in the deep ultraviolet (UV) region. Native fluorescence excitation–emission maps (EEMs) of pure organic materials, microbiological samples, and environmental background materials were compared using excitation wavelengths between 200–400 nm with emission wavelengths from 270 to 500 nm. These samples included polycyclic aromatic hydrocarbons (PAHs), nitrogen- and sulfur-bearing organic heterocycles, bacterial spores, and bacterial vegetative whole cells (both Gram positive and Gram negative). Each sample was categorized into ten distinct groups based on fluorescence properties. Emission spectra at each of 40 excitation wavelengths were analyzed using principal component analysis (PCA). Optimum excitation wavelengths for differentiating groups were determined using two metrics. We show that deep UV excitation at 235 (±2) nm optimally separates all organic and biological groups within our dataset with >90% confidence. For the specific case of separation of bacterial spores from all other samples in the database, excitation at wavelengths less than 250 nm provides maximum separation with >6σ confidence.
Published: 2008

46. Mitigation of the impact of terrestrial contamination on organic measurements from the Mars Science Laboratory

Author: Therese Errigo, Pamela G. Conrad, John Canham, Ira Katz, Paul R. Mahaffy, and Inge Loes ten Kate
Subjects: Geologic Sediments, Spectrometer, Atmosphere, Polymers, Mars, Mars Exploration Program, Biological potential, Contamination, Containment of Biohazards, Exploration of Mars, Agricultural and Biological Sciences (miscellaneous), Gas Chromatography-Mass Spectrometry, Astrobiology, Organic molecules, Space and Planetary Science, Sample Analysis at Mars, Environmental science, Organic Chemicals, Volatilization, Laboratories, Remote sensing
Abstract: The objective of the 2009 Mars Science Laboratory (MSL), which is planned to follow the Mars Exploration Rovers and the Phoenix lander to the surface of Mars, is to explore and assess quantitatively a site on Mars as a potential habitat for present or past life. Specific goals include an assessment of the past or present biological potential of the target environment and a characterization of its geology and geochemistry. Included in the 10 investigations of the MSL rover is the Sample Analysis at Mars (SAM) instrument suite, which is designed to obtain trace organic measurements, measure water and other volatiles, and measure several light isotopes with experiment sequences designed for both atmospheric and solid-phase samples. SAM integrates a gas chromatograph, a mass spectrometer, and a tunable laser spectrometer supported by sample manipulation tools both within and external to the suite. The sub-part-per-billion sensitivity of the suite for trace species, particularly organic molecules, along with a mobile platform that will contain many kilograms of organic materials, presents a considerable challenge due to the potential for terrestrial contamination to mask the signal of martian organics. We describe the effort presently underway to understand and mitigate, wherever possible within the resource constraints of the mission, terrestrial contamination in MSL and SAM measurements.
Published: 2008

47. Water and surface contamination monitoring using deep UV laser induced native fluorescence and Raman spectroscopy

Author: Ray D. Reid, Pamela G. Conrad, K. Sijapati, A. I. Tsapin, William F. Hug, Rohit Bhartia, and Arthur L. Lane
Subjects: Detection limit, Chemistry, Resonance Raman spectroscopy, Analytical chemistry, Laser, Fluorescence, law.invention, symbols.namesake, Capillary electrophoresis, law, Chemical specificity, symbols, Luminescence, Raman spectroscopy
Abstract: Reagentless water and surface sensors employing laser induced native fluorescence (LINF) and resonance Raman spectroscopy (RRS) in the deep UV are making significant progress in detecting chemical and biological targets and differentiating them against a wide range of background materials. Methods for optimizing sensor performance for specific target and backgrounds materials will be discussed in relationship to closed industrial environments and open natural environments. Limits of detection and chemical specificity will be discussed for high and low spectral resolution systems for a wide range of compounds and composite particles such as spores and cells. Detection and identification of single spores at working distance of several meters is illustrated. A range of sensors will be described along with their physical and performance specifications including sample, sipper and immersion sensors for water and fixed point and scanner systems for surfaces. In addition, the use of UV LINF and RRS for detection in capillary electrophoresis and liquid chromatography will be described with limits of detection in the range of a few nmol L-1.
Published: 2006

48. Biochemical detection and identification false alarm rate dependence on wavelength using laser induced native fluorescence

Author: Rohit Bhartia, Arthur L. Lane, K. Sijapati, Pamela G. Conrad, Everett C. Salas, W. F. Hug, and R. D. Reid
Subjects: Chemistry, business.industry, Laser, medicine.disease_cause, Biochemical detection, Fluorescence, law.invention, Wavelength, Optics, law, medicine, Optoelectronics, Bacterial spore, Absorption (electromagnetic radiation), business, Laser-induced fluorescence, Ultraviolet
Abstract: Most organic and many inorganic materials absorb strongly in specific wavelength ranges in the deep UV between about 220nm and 300nm. Excitation within these absorption bands results in native fluorescence emission. Each compound or composite material, such as a bacterial spore, has a unique excitation-emission fingerprint that can be used to provide information about the material. The sensitivity and specificity with which these materials can be detected and identified depends on the excitation wavelength and the number and location of observation wavelengths. We will present data on our deep ultraviolet Targeted Ultraviolet Chemical Sensors that demonstrate the sensitivity and specificity of the sensors. In particular, we will demonstrate the ability to quantitatively differentiate a wide range of biochemical agent targets against a wide range of background materials. We will describe the relationship between spectral resolution and specificity in target identification, as well as simple, fast, algorithms to identify materials. Hand-held, battery operated instruments using a deep UV laser and multi-band detection have been developed and deployed on missions to the Antarctic, the Arctic, and the deep ocean with the capability of detecting a single bacterial spore and to differentiate a wide range of organic and biological compounds.
Published: 2006

49. Status of miniature integrated UV resonance fluorescence and Raman sensors for detection and identification of biochemical warfare agents

Author: Pamela G. Conrad, Arthur L. Lane, Rohit Bhartia, K. Sijapati, Alexandre Taspin, Ray D. Reid, and William F. Hug
Subjects: Chemistry, Analytical chemistry, medicine.disease_cause, Laser, Fluorescence, law.invention, symbols.namesake, Wavelength, Resonance fluorescence, law, medicine, symbols, Luminescence, Absorption (electromagnetic radiation), Raman spectroscopy, Ultraviolet
Abstract: Laser induced native fluorescence (LINF) is the most sensitive method of detection of biological material including microorganisms, virus', and cellular residues. LINF is also a sensitive method of detection for many non-biological materials as well. The specificity with which these materials can be classified depends on the excitation wavelength and the number and location of observation wavelengths. Higher levels of specificity can be obtained using Raman spectroscopy but a much lower levels of sensitivity. Raman spectroscopy has traditionally been employed in the IR to avoid fluorescence. Fluorescence rarely occurs at wavelength below about 270nm. Therefore, when excitation occurs at a wavelength below 250nm, no fluorescence background occurs within the Raman fingerprint region for biological materials. When excitation occurs within electronic resonance bands of the biological target materials, Raman signal enhancement over one million typically occurs. Raman sensitivity within several hundred times fluorescence are possible in the deep UV where most biological materials have strong absorption. Since the Raman and fluorescence emissions occur at different wavelength, both spectra can be observed simultaneously, thereby providing a sensor with unique sensitivity and specificity capability. We will present data on our integrated, deep ultraviolet, LINF/Raman instruments that are being developed for several applications including life detection on Mars as well as biochemical warfare agents on Earth. We will demonstrate the ability to discriminate organic materials based on LINF alone. Together with UV resonance Raman, higher levels of specificity will be demonstrated. In addition, these instruments are being developed as on-line chemical sensors for industrial and municipal waste streams and product quality applications.
Published: 2005

50. Direct Observation of Microbial Inhibition of Calcite Dissolution

Author: Pamela G. Conrad and Andreas Luttge
Subjects: Shewanella, Mineralogy, Applied Microbiology and Biotechnology, law.invention, Corrosion, Calcium Carbonate, Crystal, chemistry.chemical_compound, law, Crystallization, Shewanella oneidensis, Dissolution, Calcite, Ecology, biology, Chemistry, Cleavage (crystal), biology.organism_classification, Geomicrobiology, Calcium carbonate, Interferometry, Chemical engineering, Biofilms, Water Microbiology, Food Science, Biotechnology
Abstract: Vertical scanning interferometry (VSI) provides a method for quantification of surface topography at the angstrom to nanometer level. Time-dependent VSI measurements can be used to study the surface-normal retreat across crystal and other solid surfaces during dissolution or corrosion processes. Therefore, VSI can be used to directly and nondestructively measure mineral dissolution rates with high precision. We have used this method to compare the abiotic dissolution behavior of a representative calcite (CaCO 3 ) cleavage face with that observed upon addition of an environmental microbe, Shewanella oneidensis MR-1, to the crystal surface. From our direct observations, we have concluded that the presence of the microbes results in a significant inhibition of the rate of calcite dissolution. This inhibition appears to be a 2nd-order effect that is related to the formation of etch pits. The opening of etch pits was greatly inhibited in the presence of added bacteria, suggesting that the bacterial cells exert their effect by inhibiting the formation of etch pits at high-energy sites at the crystal surface caused by lattice defects, e.g., screw or point dislocations. The experimental methodology thus provides a nondestructive, directly quantifiable, and easily visualized view of the interactions of microbes and minerals during weathering (or corrosion) processes or during mineral precipitation.
Published: 2004

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