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Blankenship DD, Moussessian A, Chapin E, Young DA, Wesley Patterson G, Plaut JJ, Freedman AP, Schroeder DM, Grima C, Steinbrügge G, Soderlund KM, Ray T, Richter TG, Jones-Wilson L, Wolfenbarger NS, Scanlan KM, Gerekos C, Chan K, Seker I, Haynes MS, Barr Mlinar AC, Bruzzone L, Campbell BA, Carter LM, Elachi C, Gim Y, Hérique A, Hussmann H, Kofman W, Kurth WS, Mastrogiuseppe M, McKinnon WB, Moore JM, Nimmo F, Paty C, Plettemeier D, Schmidt BE, Zolotov MY, Schenk PM, Collins S, Figueroa H, Fischman M, Tardiff E, Berkun A, Paller M, Hoffman JP, Kurum A, Sadowy GA, Wheeler KB, Decrossas E, Hussein Y, Jin C, Boldissar F, Chamberlain N, Hernandez B, Maghsoudi E, Mihaly J, Worel S, Singh V, Pak K, Tanabe J, Johnson R, Ashtijou M, Alemu T, Burke M, Custodero B, Tope MC, Hawkins D, Aaron K, Delory GT, Turin PS, Kirchner DL, Srinivasan K, Xie J, Ortloff B, Tan I, Noh T, Clark D, Duong V, Joshi S, Lee J, Merida E, Akbar R, Duan X, Fenni I, Sanchez-Barbetty M, Parashare C, Howard DC, Newman J, Cruz MG, Barabas NJ, Amirahmadi A, Palmer B, Gawande RS, Milroy G, Roberti R, Leader FE, West RD, Martin J, Venkatesh V, Adumitroaie V, Rains C, Quach C, Turner JE, O’Shea CM, Kempf SD, Ng G, Buhl DP, Urban TJ. Radar for Europa Assessment and Sounding: Ocean to Near-Surface (REASON). SPACE SCIENCE REVIEWS 2024; 220:51. [PMID: 38948073 PMCID: PMC11211191 DOI: 10.1007/s11214-024-01072-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 04/29/2024] [Indexed: 07/02/2024]
Abstract
The Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) is a dual-frequency ice-penetrating radar (9 and 60 MHz) onboard the Europa Clipper mission. REASON is designed to probe Europa from exosphere to subsurface ocean, contributing the third dimension to observations of this enigmatic world. The hypotheses REASON will test are that (1) the ice shell of Europa hosts liquid water, (2) the ice shell overlies an ocean and is subject to tidal flexing, and (3) the exosphere, near-surface, ice shell, and ocean participate in material exchange essential to the habitability of this moon. REASON will investigate processes governing this material exchange by characterizing the distribution of putative non-ice material (e.g., brines, salts) in the subsurface, searching for an ice-ocean interface, characterizing the ice shell's global structure, and constraining the amplitude of Europa's radial tidal deformations. REASON will accomplish these science objectives using a combination of radar measurement techniques including altimetry, reflectometry, sounding, interferometry, plasma characterization, and ranging. Building on a rich heritage from Earth, the moon, and Mars, REASON will be the first ice-penetrating radar to explore the outer solar system. Because these radars are untested for the icy worlds in the outer solar system, a novel approach to measurement quality assessment was developed to represent uncertainties in key properties of Europa that affect REASON performance and ensure robustness across a range of plausible parameters suggested for the icy moon. REASON will shed light on a never-before-seen dimension of Europa and - in concert with other instruments on Europa Clipper - help to investigate whether Europa is a habitable world.
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Affiliation(s)
| | - Alina Moussessian
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Elaine Chapin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Duncan A. Young
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | | | - Jeffrey J. Plaut
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Adam P. Freedman
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Dustin M. Schroeder
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305 USA
- Department of Geophysics, Stanford University, Stanford, CA 94305 USA
| | - Cyril Grima
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Gregor Steinbrügge
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Krista M. Soderlund
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Trina Ray
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Thomas G. Richter
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Laura Jones-Wilson
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | - Kirk M. Scanlan
- Geodesy & Earth Observation Division, DTU Space, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Christopher Gerekos
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Kristian Chan
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
- Department of Earth and Planetary Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78712 USA
| | - Ilgin Seker
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Mark S. Haynes
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | | | - Bruce A. Campbell
- Smithsonian Institution, Center for Earth & Planetary Studies, MRC 315, Washington, DC 20013-7012 USA
| | - Lynn M. Carter
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 USA
| | - Charles Elachi
- California Institute of Technology, Pasadena, CA 91125 USA
| | - Yonggyu Gim
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Alain Hérique
- University Grenoble Alpes, CNRS, CNES, IPAG, 38000 Grenoble, France
| | - Hauke Hussmann
- Institute of Planetary Research, German Aerospace Center, Berlin, Germany
| | - Wlodek Kofman
- University Grenoble Alpes, CNRS, CNES, IPAG, 38000 Grenoble, France
- Centrum Badan Kosmicznych Polskiej Akademii Nauk (CBK PAN), Warsaw, Poland
| | - William S. Kurth
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 USA
| | | | | | | | - Francis Nimmo
- Dept. Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064 USA
| | - Carol Paty
- Department of Earth Sciences, University of Oregon, Eugene, OR 97403 USA
| | | | - Britney E. Schmidt
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - Mikhail Y. Zolotov
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 USA
| | | | - Simon Collins
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Harry Figueroa
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Mark Fischman
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Eric Tardiff
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Andy Berkun
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Mimi Paller
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | | | - Gregory A. Sadowy
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Kevin B. Wheeler
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Emmanuel Decrossas
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Yasser Hussein
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Curtis Jin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Frank Boldissar
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Neil Chamberlain
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Brenda Hernandez
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Elham Maghsoudi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Jonathan Mihaly
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 USA
| | - Shana Worel
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Vik Singh
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Kyung Pak
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Jordan Tanabe
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Robert Johnson
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Mohammad Ashtijou
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Tafesse Alemu
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Michael Burke
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Brian Custodero
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Michael C. Tope
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - David Hawkins
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Kim Aaron
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | | | - Donald L. Kirchner
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 USA
| | - Karthik Srinivasan
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Julie Xie
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Brad Ortloff
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Ian Tan
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Tim Noh
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Duane Clark
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Vu Duong
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Shivani Joshi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Jeng Lee
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Elvis Merida
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Ruzbeh Akbar
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Xueyang Duan
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Ines Fenni
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | - Chaitali Parashare
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Duane C. Howard
- Center for Quantum Computing, Amazon Web Services, Pasadena, CA 91125 USA
| | | | - Marvin G. Cruz
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | - Ahmadreza Amirahmadi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Brendon Palmer
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Rohit S. Gawande
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Grace Milroy
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Rick Roberti
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Frank E. Leader
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Richard D. West
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Jan Martin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Vijay Venkatesh
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Virgil Adumitroaie
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Christine Rains
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Cuong Quach
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Jordi E. Turner
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 USA
| | - Colleen M. O’Shea
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 USA
| | - Scott D. Kempf
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Gregory Ng
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Dillon P. Buhl
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Timothy J. Urban
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
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2
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Sahai N, LaRowe D, Senko JM. Bioenergetics of iron snow fueling life on Europa. Proc Natl Acad Sci U S A 2024; 121:e2316452121. [PMID: 38621125 PMCID: PMC11047109 DOI: 10.1073/pnas.2316452121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 03/11/2024] [Indexed: 04/17/2024] Open
Abstract
The main sources of redox gradients supporting high-productivity life in the Europan and other icy ocean world oceans were proposed to be photolytically derived oxidants, such as reactive oxygen species (ROS) from the icy shell, and reductants (Fe(II), S(-II), CH4, H2) from bottom waters reacting with a (ultra)mafic seafloor. Important roadblocks to maintaining life, however, are that the degree of ocean mixing to combine redox species is unknown, and ROS damage biomolecules. Here, we envisage a unique solution using an acid mine drainage (AMD)-filled pit lakes analog system for the Europan ocean, which previous models predicted to be acidic. We hypothesize that surface-generated ROS oxidize dissolved Fe(II) resulting in Fe(III) (hydr)oxide precipitates, that settle to the seafloor as "iron snow." The iron snow provides a respiratory substrate for anaerobic microorganisms ("breathing iron"), and limits harmful ROS exposure since they are now neutralized at the ice-water interface. Based on this scenario, we calculated Gibbs energies and maximal biomass productivities of various anaerobic metabolisms for a range of pH, temperatures, and H2 fluxes. Productivity by iron reducers was greater for most environmental conditions considered, whereas sulfate reducers and methanogens were more favored at high pH. Participation of Fe in the metabolic redox processes is largely neglected in most models of Europan biogeochemistry. Our model overcomes important conceptual roadblocks to life in icy ocean worlds and broadens the potential metabolic diversity, thus increasing total primary productivity, the diversity and volume of habitable environmental niches and, ultimately, the probability of biosignature detection.
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Affiliation(s)
- Nita Sahai
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH44325
- Department of Geosciences, The University of Akron, Akron, OH44325
- Department of Biology, The University of Akron, Akron, OH44325
- Integrated Biosciences Program, The University of Akron, Akron, OH44325
| | - Doug LaRowe
- Department of Earth Sciences, University of Southern California, Los Angeles, CA90089
| | - John M. Senko
- Department of Geosciences, The University of Akron, Akron, OH44325
- Department of Biology, The University of Akron, Akron, OH44325
- Integrated Biosciences Program, The University of Akron, Akron, OH44325
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3
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Sieme D, Rezaei-Ghaleh N. Water dynamics in eutectic solutions of sodium chloride and magnesium sulfate: implications for life in Europa's subsurface ocean and ice shell. Phys Chem Chem Phys 2023; 26:105-115. [PMID: 38054803 DOI: 10.1039/d3cp03455k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Liquid water is essential for life as we know it and the coupling between water and biomolecular dynamics is crucial for life processes. Jupiter's moon Europa is a good candidate for searching for extraterrestrial life in our outer solar system, mainly because a liquid water salty ocean in contact with a rocky seafloor underlies its ice shell. Little, however, is known about the chemical composition of the subglacial ocean of Europa or the brine pockets within its ice shell and their impacts on water dynamics. Here, we employ 1H, 17O, 23Na and 35Cl NMR spectroscopy, especially NMR spin relaxation and diffusion methods, and investigate the mobility of water molecules and ions in eutectic solutions of magnesium sulfate and sodium chloride, two salts ubiquitously present on the surface of Europa, over a range of temperatures and pressures pertinent to Europa's subglacial ocean. The NMR data demonstrate the more pronounced effect of magnesium sulfate compared with sodium chloride on the mobility of water molecules. Even at its much lower eutectic temperature, the sodium chloride solution retains a relatively large level of water mobility. Our results highlight the higher potential of a sodium chloride-rich than magnesium sulfate-rich Europa's ocean to accommodate life and support life origination within the eutectic melts of Europa's ice shell.
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Affiliation(s)
- Daniel Sieme
- Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, D-37077 Göttingen, Germany
| | - Nasrollah Rezaei-Ghaleh
- Heinrich Heine University (HHU) Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute of Physical Biology, Universitätsstrasse 1, D-40225 Düsseldorf, Germany.
- Institute of Biological Information Processing, IBI-7: Structural Biochemistry, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, D-52428 Jülich, Germany
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4
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Vance SD, Craft KL, Shock E, Schmidt BE, Lunine J, Hand KP, McKinnon WB, Spiers EM, Chivers C, Lawrence JD, Wolfenbarger N, Leonard EJ, Robinson KJ, Styczinski MJ, Persaud DM, Steinbrügge G, Zolotov MY, Quick LC, Scully JEC, Becker TM, Howell SM, Clark RN, Dombard AJ, Glein CR, Mousis O, Sephton MA, Castillo-Rogez J, Nimmo F, McEwen AS, Gudipati MS, Jun I, Jia X, Postberg F, Soderlund KM, Elder CM. Investigating Europa's Habitability with the Europa Clipper. SPACE SCIENCE REVIEWS 2023; 219:81. [PMID: 38046182 PMCID: PMC10687213 DOI: 10.1007/s11214-023-01025-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 11/03/2023] [Indexed: 12/05/2023]
Abstract
The habitability of Europa is a property within a system, which is driven by a multitude of physical and chemical processes and is defined by many interdependent parameters, so that its full characterization requires collaborative investigation. To explore Europa as an integrated system to yield a complete picture of its habitability, the Europa Clipper mission has three primary science objectives: (1) characterize the ice shell and ocean including their heterogeneity, properties, and the nature of surface-ice-ocean exchange; (2) characterize Europa's composition including any non-ice materials on the surface and in the atmosphere, and any carbon-containing compounds; and (3) characterize Europa's geology including surface features and localities of high science interest. The mission will also address several cross-cutting science topics including the search for any current or recent activity in the form of thermal anomalies and plumes, performing geodetic and radiation measurements, and assessing high-resolution, co-located observations at select sites to provide reconnaissance for a potential future landed mission. Synthesizing the mission's science measurements, as well as incorporating remote observations by Earth-based observatories, the James Webb Space Telescope, and other space-based resources, to constrain Europa's habitability, is a complex task and is guided by the mission's Habitability Assessment Board (HAB).
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Affiliation(s)
- Steven D. Vance
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Kathleen L. Craft
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD USA
| | - Everett Shock
- School of Earth & Space Exploration and School of Molecular Sciences, Arizona State University, Tempe, AZ USA
| | - Britney E. Schmidt
- Department of Astronomy and Department of Earth & Atmospheric Sciences, Cornell University, Ithaca, NY USA
| | - Jonathan Lunine
- Department of Astronomy and Department of Earth & Atmospheric Sciences, Cornell University, Ithaca, NY USA
| | - Kevin P. Hand
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - William B. McKinnon
- Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St. Louis, Saint Louis, MO USA
| | - Elizabeth M. Spiers
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
| | - Chase Chivers
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
- Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA USA
| | - Justin D. Lawrence
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
- Honeybee Robotics, Altadena, CA USA
| | - Natalie Wolfenbarger
- Institute for Geophysics, John A. and Katherine G. Jackson School of Geosciences, University of Texas at Austin, Austin, TX USA
| | - Erin J. Leonard
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | | | | | - Divya M. Persaud
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Gregor Steinbrügge
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Mikhail Y. Zolotov
- School of Earth & Space Exploration and School of Molecular Sciences, Arizona State University, Tempe, AZ USA
| | | | | | | | - Samuel M. Howell
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | | | - Andrew J. Dombard
- Dept. of Earth and Environmental Sciences, University of Illinois Chicago, Chicago, USA
| | | | - Olivier Mousis
- Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille), Marseille, France
| | - Mark A. Sephton
- Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, Imperial College London, London, United Kingdom
| | | | - Francis Nimmo
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA USA
| | - Alfred S. McEwen
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | - Murthy S. Gudipati
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Insoo Jun
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Xianzhe Jia
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI USA
| | - Frank Postberg
- Institut für Geologische Wissenschaften, Freie Universität Berlin, Berlin, Germany
| | - Krista M. Soderlund
- Institute for Geophysics, John A. and Katherine G. Jackson School of Geosciences, University of Texas at Austin, Austin, TX USA
| | - Catherine M. Elder
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
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5
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Boxberg MS, Chen Q, Plesa AC, Kowalski J. Ice Transit and Performance Analysis for Cryorobotic Subglacial Access Missions on Earth and Europa. ASTROBIOLOGY 2023; 23:1135-1152. [PMID: 36576448 DOI: 10.1089/ast.2021.0071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Ice-covered ocean worlds, such as the Jovian moon Europa, are some of the prime targets for planetary exploration due to their high astrobiological potential. While upcoming space exploration missions, such as the Europa Clipper and JUICE missions, will give us further insight into the local cryoenvironment, any conclusive life detection investigation requires the capability to penetrate and transit the icy shell and access the subglacial ocean directly. Developing robust, autonomous cryorobotic technology for such a mission constitutes an extremely demanding multistakeholder challenge and requires a concentrated interdisciplinary effort between engineers, geoscientists, and astrobiologists. An important tool with which to foster cross-disciplinary work at an early stage of mission preparation is the virtual testbed. In this article, we report on recent progress in the development of an ice transit and performance model for later integration in such a virtual testbed. We introduce a trajectory model that, for the first time, allows for the evaluation of mission-critical parameters, such as transit time and average/overall power supply. Our workflow is applied to selected, existing cryobot designs while taking into consideration different terrestrial, as well as extraterrestrial, deployment scenarios. Specific analyses presented in this study show the tradeoff minimum transit time and maximum efficiency of a cryobot and allow for quantification of different sources of uncertainty to cryobot's trajectory models.
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Affiliation(s)
- Marc S Boxberg
- Chair of Methods for Model-based Development in Computational Engineering, RWTH Aachen University, Aachen, Germany
- Computational Geoscience, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Qian Chen
- Chair of Methods for Model-based Development in Computational Engineering, RWTH Aachen University, Aachen, Germany
| | - Ana-Catalina Plesa
- Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - Julia Kowalski
- Chair of Methods for Model-based Development in Computational Engineering, RWTH Aachen University, Aachen, Germany
- Computational Geoscience, Georg-August-Universität Göttingen, Göttingen, Germany
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6
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Roberts JH, McKinnon WB, Elder CM, Tobie G, Biersteker JB, Young D, Park RS, Steinbrügge G, Nimmo F, Howell SM, Castillo-Rogez JC, Cable ML, Abrahams JN, Bland MT, Chivers C, Cochrane CJ, Dombard AJ, Ernst C, Genova A, Gerekos C, Glein C, Harris CD, Hay HCFC, Hayne PO, Hedman M, Hussmann H, Jia X, Khurana K, Kiefer WS, Kirk R, Kivelson M, Lawrence J, Leonard EJ, Lunine JI, Mazarico E, McCord TB, McEwen A, Paty C, Quick LC, Raymond CA, Retherford KD, Roth L, Rymer A, Saur J, Scanlan K, Schroeder DM, Senske DA, Shao W, Soderlund K, Spiers E, Styczinski MJ, Tortora P, Vance SD, Villarreal MN, Weiss BP, Westlake JH, Withers P, Wolfenbarger N, Buratti B, Korth H, Pappalardo RT. Exploring the Interior of Europa with the Europa Clipper. SPACE SCIENCE REVIEWS 2023; 219:46. [PMID: 37636325 PMCID: PMC10457249 DOI: 10.1007/s11214-023-00990-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 07/20/2023] [Indexed: 08/29/2023]
Abstract
The Galileo mission to Jupiter revealed that Europa is an ocean world. The Galileo magnetometer experiment in particular provided strong evidence for a salty subsurface ocean beneath the ice shell, likely in contact with the rocky core. Within the ice shell and ocean, a number of tectonic and geodynamic processes may operate today or have operated at some point in the past, including solid ice convection, diapirism, subsumption, and interstitial lake formation. The science objectives of the Europa Clipper mission include the characterization of Europa's interior; confirmation of the presence of a subsurface ocean; identification of constraints on the depth to this ocean, and on its salinity and thickness; and determination of processes of material exchange between the surface, ice shell, and ocean. Three broad categories of investigation are planned to interrogate different aspects of the subsurface structure and properties of the ice shell and ocean: magnetic induction, subsurface radar sounding, and tidal deformation. These investigations are supplemented by several auxiliary measurements. Alone, each of these investigations will reveal unique information. Together, the synergy between these investigations will expose the secrets of the Europan interior in unprecedented detail, an essential step in evaluating the habitability of this ocean world.
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Affiliation(s)
| | | | - Catherine M Elder
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | | | | | - Ryan S Park
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Gregor Steinbrügge
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Francis Nimmo
- University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Samuel M Howell
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | - Morgan L Cable
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | | | | | - Corey J Cochrane
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | - Carolyn Ernst
- Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA
| | | | | | | | | | - Hamish C F C Hay
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Paul O Hayne
- University of Colorado Boulder, Boulder, CO, USA
| | | | - Hauke Hussmann
- German Aerospace Center Institute of Planetary Research, Berlin, Germany
| | | | | | - Walter S Kiefer
- Lunar and Planetary Institute, University Space Research Association, Houston, TX, USA
| | | | | | | | - Erin J Leonard
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | | | | | | | | | | | - Carol A Raymond
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Kurt D Retherford
- Sapienza University of Rome, Rome, Italy
- University of Texas at San Antonio, San Antonio, TX, USA
| | - Lorenz Roth
- KTH Royal Institute of Technology, Stockholm, Sweden
| | - Abigail Rymer
- Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA
| | | | | | | | - David A Senske
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Wencheng Shao
- University of California, Santa Cruz, Santa Cruz, CA, USA
| | | | | | - Marshall J Styczinski
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
- University of Washington, Seattle, WA, USA
| | - Paolo Tortora
- Alma Mater Studiorum - Università di Bologna, Bologna, Italy
| | - Steven D Vance
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | | | | | | | | | - Bonnie Buratti
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Haje Korth
- Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA
| | - Robert T Pappalardo
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
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7
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Weber JM, Marlin TC, Prakash M, Teece BL, Dzurilla K, Barge LM. A Review on Hypothesized Metabolic Pathways on Europa and Enceladus: Space-Flight Detection Considerations. Life (Basel) 2023; 13:1726. [PMID: 37629583 PMCID: PMC10456045 DOI: 10.3390/life13081726] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/01/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023] Open
Abstract
Enceladus and Europa, icy moons of Saturn and Jupiter, respectively, are believed to be habitable with liquid water oceans and therefore are of interest for future life detection missions and mission concepts. With the limited data from missions to these moons, many studies have sought to better constrain these conditions. With these constraints, researchers have, based on modeling and experimental studies, hypothesized a number of possible metabolisms that could exist on Europa and Enceladus if these worlds host life. The most often hypothesized metabolisms are methanogenesis for Enceladus and methane oxidation/sulfate reduction on Europa. Here, we outline, review, and compare the best estimated conditions of each moon's ocean. We then discuss the hypothetical metabolisms that have been suggested to be present on these moons, based on laboratory studies and Earth analogs. We also detail different detection methods that could be used to detect these hypothetical metabolic reactions and make recommendations for future research and considerations for future missions.
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Affiliation(s)
- Jessica M. Weber
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA (B.L.T.); (K.D.); (L.M.B.)
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8
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Boulesteix D, Buch A, Samson J, Millan M, Jomaa J, Coscia D, Moulay V, McIntosh O, Freissinet C, Stern JC, Szopa C. Influence of pH and salts on DMF-DMA derivatization for future Space Applications. Anal Chim Acta 2023; 1266:341270. [PMID: 37244655 DOI: 10.1016/j.aca.2023.341270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/24/2023] [Accepted: 04/23/2023] [Indexed: 05/29/2023]
Abstract
For gas chromatography - mass spectrometry (GC-MS) analyses performed in situ, pH and salts (e.g., chlorides, sulfates) may enhance or inhibit the detection of targeted molecules of interest for astrobiology (e.g. amino acids, fatty acids, nucleobases). Obviously, salts influence the ionic strength of the solutions, the pH value, and the salting effect. But the presence of salts may also produce complexes or mask ions in the sample (masking effect on hydroxide ion, ammonia, etc.). For future space missions, wet chemistry will be conducted before GC-MS analyses to detect the full organic content of a sample. The defined organic targets for space GC-MS instrument requirements are generally strongly polar or refractory organic compounds, such as amino acids playing a role in the protein production and metabolism regulations for life on Earth, nucleobases essential for DNA and RNA formation and mutation, and fatty acids that composed most of the eukaryote and prokaryote membranes on Earth and resist to environmental stress long enough to still be observed on Mars or ocean worlds in geological well-preserved records. The wet-chemistry chemical treatment consists of reacting an organic reagent with the sample to extract and volatilize polar or refractory organic molecules (i.e. dimethylformamide dimethyl acetal (DMF-DMA) in this study). DMF-DMA derivatizes functional groups with labile H in organics, without modifying their chiral conformation. The influence of pH and salt concentration of extraterrestrial materials on the DMF-DMA derivatization remains understudied. In this research, we studied the influence of different salts and pHs on the derivatization of organic molecules of astrobiological interest with DMF-DMA, such as amino acids, carboxylic acids, and nucleobases. Results show that salts and pH influence the derivatization yield, and that their effect depend on the nature of the organics and the salts studied. Second, monovalent salts lead to a higher or similar organic recovery compared to divalent salts regardless of pH below 8. However, a pH above 8 inhibits the DMF-DMA derivatization influencing the carboxylic acid function to become an anionic group without labile H. Overall, considering the negative effect of the salts on the detection of organic molecules, future space missions may have to consider a desalting step prior to derivatization and GC-MS analyses.
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Affiliation(s)
- D Boulesteix
- Laboratoire Génie des Procédés et Matériaux, CentraleSupélec, University Paris-Saclay, 8-10 Rue Joliot-Curie, 91190, Gif-sur-Yvette, France.
| | - A Buch
- Laboratoire Génie des Procédés et Matériaux, CentraleSupélec, University Paris-Saclay, 8-10 Rue Joliot-Curie, 91190, Gif-sur-Yvette, France.
| | - J Samson
- Laboratoire Génie des Procédés et Matériaux, CentraleSupélec, University Paris-Saclay, 8-10 Rue Joliot-Curie, 91190, Gif-sur-Yvette, France
| | - M Millan
- LATMOS/IPSL, UVSQ University Paris-Saclay, Sorbonne University, CNRS, 11 Bd d'Alembert, 78280, Guyancourt, France
| | - J Jomaa
- Planetary Environments Laboratory (Code 699), NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA; School of Medicine, Wayne State University, 42 W. Warren Ave, Detroit, MI, 48202, USA
| | - D Coscia
- LATMOS/IPSL, UVSQ University Paris-Saclay, Sorbonne University, CNRS, 11 Bd d'Alembert, 78280, Guyancourt, France
| | - V Moulay
- LATMOS/IPSL, UVSQ University Paris-Saclay, Sorbonne University, CNRS, 11 Bd d'Alembert, 78280, Guyancourt, France
| | - O McIntosh
- LATMOS/IPSL, UVSQ University Paris-Saclay, Sorbonne University, CNRS, 11 Bd d'Alembert, 78280, Guyancourt, France
| | - C Freissinet
- LATMOS/IPSL, UVSQ University Paris-Saclay, Sorbonne University, CNRS, 11 Bd d'Alembert, 78280, Guyancourt, France
| | - J C Stern
- Space Science Exploration Division (Code 690), NASA, Goddard Space Flight Center, Greenbelt, MD, 20771, USA
| | - C Szopa
- LATMOS/IPSL, UVSQ University Paris-Saclay, Sorbonne University, CNRS, 11 Bd d'Alembert, 78280, Guyancourt, France
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9
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Trinh KT, Bierson CJ, O'Rourke JG. Slow evolution of Europa's interior: metamorphic ocean origin, delayed metallic core formation, and limited seafloor volcanism. SCIENCE ADVANCES 2023; 9:eadf3955. [PMID: 37327336 DOI: 10.1126/sciadv.adf3955] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 05/11/2023] [Indexed: 06/18/2023]
Abstract
Europa's ocean lies atop an interior made of metal and silicates. On the basis of gravity data from the Galileo mission, many argued that Europa's interior, like Earth, is differentiated into a metallic core and a mantle composed of anhydrous silicates. Some studies further assumed that Europa differentiated while (or soon after) it accreted, also like Earth. However, Europa probably formed at much colder temperatures, meaning that Europa plausibly ended accretion as a mixture containing water-ice and/or hydrated silicates. Here, we use numerical models to describe the thermal evolution of Europa's interior assuming low initial temperatures (~200 to 300 kelvin). We find that silicate dehydration can produce Europa's current ocean and icy shell. Rocks below the seafloor may remain cool and hydrated today. Europa's metallic core, if it exists, may have formed billions of years after accretion. Ultimately, we expect the chemistry of Europa's ocean to reflect protracted heating of the interior.
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Affiliation(s)
- Kevin T Trinh
- School of Earth and Space Exploration, Arizona State University, AZ 85287, USA
| | - Carver J Bierson
- School of Earth and Space Exploration, Arizona State University, AZ 85287, USA
| | - Joseph G O'Rourke
- School of Earth and Space Exploration, Arizona State University, AZ 85287, USA
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10
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Castillo‐Rogez J, Weiss B, Beddingfield C, Biersteker J, Cartwright R, Goode A, Melwani Daswani M, Neveu M. Compositions and Interior Structures of the Large Moons of Uranus and Implications for Future Spacecraft Observations. JOURNAL OF GEOPHYSICAL RESEARCH. PLANETS 2023; 128:e2022JE007432. [PMID: 37034459 PMCID: PMC10078161 DOI: 10.1029/2022je007432] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 11/29/2022] [Accepted: 12/02/2022] [Indexed: 06/19/2023]
Abstract
The five large moons of Uranus are important targets for future spacecraft missions. To motivate and inform the exploration of these moons, we model their internal evolution, present-day physical structures, and geochemical and geophysical signatures that may be measured by spacecraft. We predict that if the moons preserved liquid until present, it is likely in the form of residual oceans less than 30 km thick in Ariel, Umbriel, and less than 50 km in Titania, and Oberon. The preservation of liquid strongly depends on material properties and, potentially, on dynamical circumstances that are presently unknown. Miranda is unlikely to host liquid at present unless it experienced tidal heating a few tens of million years ago. We find that since the thin residual layers may be hypersaline, their induced magnetic fields could be detectable by future spacecraft-based magnetometers. However, if the ocean is maintained primarily by ammonia, and thus well below the water freezing point, then its electrical conductivity may be too small to be detectable by spacecraft. Lastly, our calculated tidal Love number (k 2) and dissipation factor (Q) are consistent with the Q/k 2 values previously inferred from dynamical evolution models. In particular, we find that the low Q/k 2 estimated for Titania supports the hypothesis that Titania currently holds an ocean.
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Affiliation(s)
| | - Benjamin Weiss
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
- Department of Earth, Atmospheric and Planetary SciencesMassachusetts Institute of Technology (MIT)CambridgeMAUSA
| | - Chloe Beddingfield
- SETI InstituteMountain ViewCAUSA
- NASA Ames Research CenterMountain ViewCAUSA
| | - John Biersteker
- Department of Earth, Atmospheric and Planetary SciencesMassachusetts Institute of Technology (MIT)CambridgeMAUSA
| | | | - Allison Goode
- Department of Earth, Atmospheric and Planetary SciencesMassachusetts Institute of Technology (MIT)CambridgeMAUSA
| | | | - Marc Neveu
- University of MarylandCollege ParkMDUSA
- NASA Goddard Space Flight CenterGreenbeltMDUSA
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11
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Wolfenbarger NS, Buffo JJ, Soderlund KM, Blankenship DD. Ice Shell Structure and Composition of Ocean Worlds: Insights from Accreted Ice on Earth. ASTROBIOLOGY 2022; 22:937-961. [PMID: 35787145 DOI: 10.1089/ast.2021.0044] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Accreted ice retains and preserves traces of the ocean from which it formed. In this work, we study two classes of accreted ice found on Earth-frazil ice, which forms through crystallization within a supercooled water column, and congelation ice, which forms through directional freezing at an existing interface-and discuss where each might be found in the ice shells of ocean worlds. We focus our study on terrestrial ice formed in low temperature gradient environments (e.g., beneath ice shelves), consistent with conditions expected at the ice-ocean interfaces of Europa and Enceladus, and we highlight the juxtaposition of compositional trends in relation to ice formed in higher temperature gradient environments (e.g., at the ocean surface). Observations from Antarctic sub-ice-shelf congelation ice and marine ice show that the purity of frazil ice can be nearly two orders of magnitude higher than congelation ice formed in the same low temperature gradient environment (∼0.1% vs. ∼10% of the ocean salinity). In addition, where congelation ice can maintain a planar ice-water interface on a microstructural scale, the efficiency of salt rejection is enhanced (∼1% of the ocean salinity) and lattice soluble impurities such as chloride are preferentially incorporated. We conclude that an ice shell that forms by gradual thickening as its interior cools would be composed of congelation ice, whereas frazil ice will accumulate where the ice shell thins on local (rifts and basal fractures) or regional (latitudinal gradients) scales through the operation of an "ice pump."
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Affiliation(s)
| | - Jacob J Buffo
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Krista M Soderlund
- Institute for Geophysics, University of Texas at Austin, Austin, Texas, USA
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12
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Buffo JJ, Brown EK, Pontefract A, Schmidt BE, Klempay B, Lawrence J, Bowman J, Grantham M, Glass JB, Plattner T, Chivers C, Doran P. The Bioburden and Ionic Composition of Hypersaline Lake Ices: Novel Habitats on Earth and Their Astrobiological Implications. ASTROBIOLOGY 2022; 22:962-980. [PMID: 35671513 DOI: 10.1089/ast.2021.0078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We present thermophysical, biological, and chemical observations of ice and brine samples from five compositionally diverse hypersaline lakes in British Columbia's interior plateau. Possessing a spectrum of magnesium, sodium, sulfate, carbonate, and chloride salts, these low-temperature high-salinity lakes are analogs for planetary ice-brine environments, including the ice shells of Europa and Enceladus and ice-brine systems on Mars. As such, understanding the thermodynamics and biogeochemistry of these systems can provide insights into the evolution, habitability, and detectability of high-priority astrobiology targets. We show that biomass is typically concentrated in a layer near the base of the ice cover, but that chemical and biological impurities are present throughout the ice. Coupling bioburden, ionic concentration, and seasonal temperature measurements, we demonstrate that impurity entrainment in the ice is directly correlated to ice formation rate and parent fluid composition. We highlight unique phenomena, including brine supercooling, salt hydrate precipitation, and internal brine layers in the ice cover, important processes to be considered for planetary ice-brine environments. These systems can be leveraged to constrain the distribution, longevity, and habitability of low-temperature solar system brines-relevant to interpreting spacecraft data and planning future missions in the lens of both planetary exploration and planetary protection.
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Affiliation(s)
- Jacob J Buffo
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Emma K Brown
- School of Earth and Space Exploration, Arizona State University, Pheonix, AZ, USA
| | | | | | | | - Justin Lawrence
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Jeff Bowman
- Scripps Institution of Oceanography, La Jolla, CA, USA
| | - Meg Grantham
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Jennifer B Glass
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Taylor Plattner
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Chase Chivers
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Peter Doran
- Department of Geology and Geophysics, Louisiung State University, Baton Rouge, LA, USA
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13
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Kang W, Mittal T, Bire S, Campin JM, Marshall J. How does salinity shape ocean circulation and ice geometry on Enceladus and other icy satellites? SCIENCE ADVANCES 2022; 8:eabm4665. [PMID: 35857831 PMCID: PMC9299536 DOI: 10.1126/sciadv.abm4665] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Accepted: 06/06/2022] [Indexed: 05/28/2023]
Abstract
Of profound astrobiological interest, Enceladus appears to have a global saline subsurface ocean, indicating water-rock reaction at present or in the past, an important mechanism in the moon's potential habitability. Here, we investigate how salinity and the partition of heat production between the silicate core and the ice shell affect ocean dynamics and the associated heat transport-a key factor determining equilibrium ice shell geometry. Assuming steady-state conditions, we show that the meridional overturning circulation of the ocean, driven by heat and salt exchange with the poleward-thinning ice shell, has opposing signs at very low and very high salinities. Regardless of these differing circulations, heat and fresh water converge toward the equator, where the ice is thick, acting to homogenize thickness variations. Among scenarios explored here, the pronounced ice thickness variations observed on Enceladus are most consistent with heating that is predominantly in the ice shell and a salinity of intermediate range.
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14
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Instrumentation for Detecting Sulphur Isotopes as Biosignatures on Europa and Ganymede by Forthcoming Missions. UNIVERSE 2022. [DOI: 10.3390/universe8070357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
There has been remarkable progress in identifying a certain type of biosignature, both from the point of view of the payloads of forthcoming missions, and from the point of view of biogeochemistry. This progress has been due to the evolution of miniaturized mass spectrometry that can be used, under certain circumstances and for certain samples, to distinguish between putatively abiotic and biotic sulphur isotopes. These specific types of biosignatures are discussed in the context of Europa and Ganymede. Such instruments are sufficiently precise to differentiate between abiotic and biotic signatures. We reflect on new possibilities that will be available during this decade for exploring the nearest ocean worlds: Europa and Ganymede. We review arguments that point out the presence of intriguing sulphur patches on Europa’s icy surface that were discovered by the Galileo mission. These patches lead to a “sulphur dilemma”, which suggests not to focus future measurements exclusively on organics. We comment on the possibility of measurements of sulphur isotopes, as one kind of biosignature, to be complemented with additional biosignatures, in order to fully test biogenicity. These suggestions are intended to point out the best use of the available spacecrafts’ payloads during the planning of the forthcoming Jovian missions.
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15
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Nguyen K, Kumar P. Morphological Phenotypes, Cell Division, and Gene Expression of Escherichia coli under High Concentration of Sodium Sulfate. Microorganisms 2022; 10:microorganisms10020274. [PMID: 35208727 PMCID: PMC8875244 DOI: 10.3390/microorganisms10020274] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/13/2022] [Accepted: 01/14/2022] [Indexed: 01/10/2023] Open
Abstract
Sodium and sulfate ions are among the suggested abundant ions on Europa, a moon of Jupiter. In order to investigate the potential habitability of Europa, we study the effects of sodium sulfate (Na2SO4) on a non-halophilic bacterium by subjecting Escherichia coli (E. coli) to a wide range of Na2SO4 concentrations (0–1.0 m). We discover that, as the concentration of sodium sulfate increases, the biomass doubling time increases and the cell growth is completely inhibited at 1.0 m Na2SO4. Furthermore, we find that E. coli exhibits three distinct morphological phenotypes—(i) shortened, (ii) normal, and (iii) elongated/filamented cells at 0.6 m and 0.8 m Na2SO4. We have examined the expression of different genes involved in sodium and sulfate transport (nhaA, nhaB, cysZ, sbp), osmotically driven transport of water (aqpZ), sulfate metabolism (cysN), fatty acid production (fabA), and a global transcriptional regulator (osmZ). Our results suggest that the expression of these genes is not affected significantly at high concentrations of sodium sulfate in the exponential growth phase. Using our experimental data and the existing data in the literature, we show that the osmotic pressure difference may play a major role in determining the growth inhibition of E. coli and B. subtilis at high concentrations of salt.
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16
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Abstract
Ground-based telescopes and space exploration have provided outstanding observations of the complexity of icy planetary surfaces. This work presents our review of the varying nature of carbon dioxide (CO2) and carbon monoxide (CO) ices from the cold traps on the Moon to Pluto in the Kuiper Belt. This review is organized into five parts. First, we review the mineral physics (e.g., rheology) relevant to these environments. Next, we review the radiation-induced chemical processes and the current interpretation of spectral signatures. The third section discusses the nature and distribution of CO2 in the giant planetary systems of Jupiter and Saturn, which are much better understood than the satellites of Uranus and Neptune, discussed in the subsequent section. The final sections focus on Pluto in comparison to Triton, having mainly CO, and a brief overview of cometary materials. We find that CO2 ices exist on many of these icy bodies by way of magnetospheric influence, while intermixing into solid ices with CH4 (methane) and N2 (nitrogen) out to Triton and Pluto. Such radiative mechanisms or intermixing can provide a wide diversity of icy surfaces, though we conclude where further experimental research of these ices is still needed.
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17
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Cochrane CJ, Vance SD, Nordheim TA, Styczinski MJ, Masters A, Regoli LH. In Search of Subsurface Oceans Within the Uranian Moons. JOURNAL OF GEOPHYSICAL RESEARCH. PLANETS 2021. [PMID: 35859709 DOI: 10.1029/2020je006418] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The Galileo mission to Jupiter discovered magnetic signatures associated with hidden subsurface oceans at the moons Europa and Callisto using the phenomenon of magnetic induction. These induced magnetic fields originate from electrically conductive layers within the moons and are driven by Jupiter's strong time-varying magnetic field. The ice giants and their moons are also ideal laboratories for magnetic induction studies. Both Uranus and Neptune have a strongly tilted magnetic axis with respect to their spin axis, creating a dynamic and strongly variable magnetic field environment at the orbits of their major moons. Although Voyager 2 visited the ice giants in the 1980s, it did not pass close enough to any of the moons to detect magnetic induction signatures. However, Voyager 2 revealed that some of these moons exhibit surface features that hint at recent geologically activity, possibly associated with subsurface oceans. Future missions to the ice giants may therefore be capable of discovering subsurface oceans, thereby adding to the family of known "ocean worlds" in our Solar System. Here, we assess magnetic induction as a technique for investigating subsurface oceans within the major moons of Uranus. Furthermore, we establish the ability to distinguish induction responses created by different interior characteristics that tie into the induction response: ocean thickness, conductivity and depth, and ionospheric conductance. The results reported here demonstrate the possibility of single-pass ocean detection and constrained characterization within the moons of Miranda, Ariel, and Umbriel, and provide guidance for magnetometer selection and trajectory design for future missions to Uranus.
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Affiliation(s)
- C J Cochrane
- Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA
| | - S D Vance
- Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA
| | - T A Nordheim
- Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA
| | | | | | - L H Regoli
- Applied Physics Laboratory John Hopkins University Baltimore MD USA
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18
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Thompson SP, Kennedy H, Butler BM, Day SJ, Safi E, Evans A. Laboratory exploration of mineral precipitates from Europa's subsurface ocean. J Appl Crystallogr 2021; 54:1455-1479. [PMID: 34667451 PMCID: PMC8493616 DOI: 10.1107/s1600576721008554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 08/17/2021] [Indexed: 11/10/2022] Open
Abstract
The precipitation of hydrated phases from a chondrite-like Na-Mg-Ca-SO4-Cl solution is studied using in situ synchrotron X-ray powder diffraction, under rapid- (360 K h-1, T = 250-80 K, t = 3 h) and ultra-slow-freezing (0.3 K day-1, T = 273-245 K, t = 242 days) conditions. The precipitation sequence under slow cooling initially follows the predictions of equilibrium thermodynamics models. However, after ∼50 days at 245 K, the formation of the highly hydrated sulfate phase Na2Mg(SO4)2·16H2O, a relatively recent discovery in the Na2Mg(SO4)2-H2O system, was observed. Rapid freezing, on the other hand, produced an assemblage of multiple phases which formed within a very short timescale (≤4 min, ΔT = 2 K) and, although remaining present throughout, varied in their relative proportions with decreasing temperature. Mirabilite and meridianiite were the major phases, with pentahydrite, epsomite, hydrohalite, gypsum, blödite, konyaite and loweite also observed. Na2Mg(SO4)2·16H2O was again found to be present and increased in proportion relative to other phases as the temperature decreased. The results are discussed in relation to possible implications for life on Europa and application to other icy ocean worlds.
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Affiliation(s)
- Stephen P. Thompson
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Hilary Kennedy
- School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey LL59 5AB, United Kingdom
| | - Benjamin M. Butler
- Environmental and Biochemical Sciences, The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, United Kingdom
| | - Sarah J. Day
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Emmal Safi
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
- Astrophysics Group, Lennard-Jones Laboratories, Keele University, Keele, Staffordshire ST5 5BG, United Kingdom
| | - Aneurin Evans
- Astrophysics Group, Lennard-Jones Laboratories, Keele University, Keele, Staffordshire ST5 5BG, United Kingdom
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Melwani Daswani M, Vance SD, Mayne MJ, Glein CR. A Metamorphic Origin for Europa's Ocean. GEOPHYSICAL RESEARCH LETTERS 2021; 48:e2021GL094143. [PMID: 35865189 PMCID: PMC9286408 DOI: 10.1029/2021gl094143] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/26/2021] [Accepted: 08/04/2021] [Indexed: 05/28/2023]
Abstract
Europa likely contains an iron-rich metal core. For it to have formed, temperatures within Europa reached ≳ 1250 K. Going up to that temperature, accreted chondritic minerals - for example, carbonates and phyllosilicates - would partially devolatilize. Here, we compute the amounts and compositions of exsolved volatiles. We find that volatiles released from the interior would have carried solutes, redox-sensitive species, and could have generated a carbonic ocean in excess of Europa's present-day hydrosphere, and potentially an early CO 2 atmosphere. No late delivery of cometary water was necessary. Contrasting with prior work, CO 2 could be the most abundant solute in the ocean, followed by Ca 2 + , SO 4 2 - , and HCO 3 - . However, gypsum precipitation going from the seafloor to the ice shell decreases the dissolved S/Cl ratio, such that Cl > S at the shallowest depths, consistent with recently inferred endogenous chlorides at Europa's surface. Gypsum would form a 3-10 km thick sedimentary layer at the seafloor.
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Affiliation(s)
| | - Steven D. Vance
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Matthew J. Mayne
- Department of Earth SciencesStellenbosch UniversityStellenboschSouth Africa
| | - Christopher R. Glein
- Space Science and Engineering DivisionSouthwest Research InstituteSan AntonioTXUSA
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20
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Complex Brines and Their Implications for Habitability. Life (Basel) 2021; 11:life11080847. [PMID: 34440591 PMCID: PMC8398403 DOI: 10.3390/life11080847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/09/2021] [Accepted: 08/11/2021] [Indexed: 11/16/2022] Open
Abstract
There is evidence that life on Earth originated in cold saline waters around scorching hydrothermal vents, and that similar conditions might exist or have existed on Mars, Europa, Ganymede, Enceladus, and other worlds. Could potentially habitable complex brines with extremely low freezing temperatures exist in the shallow subsurface of these frigid worlds? Earth, Mars, and carbonaceous chondrites have similar bulk elemental abundances, but while the Earth is depleted in the most volatile elements, the Icy Worlds of the outer solar system are expected to be rich in them. The cooling of ionic solutions containing substances that likely exist in the Icy Worlds could form complex brines with the lowest eutectic temperature possible for the compounds available in them. Indeed, here, we show observational and theoretical evidence that even elements present in trace amounts in nature are concentrated by freeze–thaw cycles, and therefore contribute significantly to the formation of brine reservoirs that remain liquid throughout the year in some of the coldest places on Earth. This is interesting because the eutectic temperature of water–ammonia solutions can be as low as ~160 K, and significant fractions of the mass of the Icy Worlds are estimated to be water substance and ammonia. Thus, briny solutions with eutectic temperature of at least ~160 K could have formed where, historically, temperature have oscillated above and below ~160 K. We conclude that complex brines must exist in the shallow subsurface of Mars and the Icy Worlds, and that liquid saline water should be present where ice has existed, the temperature is above ~160 K, and evaporation and sublimation have been inhibited.
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21
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Scully JEC, Schenk PM, Castillo-Rogez JC, Buczkowski DL, Williams DA, Pasckert JH, Duarte KD, Romero VN, Quick LC, Sori MM, Landis ME, Raymond CA, Neesemann A, Schmidt BE, Sizemore HG, Russell CT. The varied sources of faculae-forming brines in Ceres' Occator crater emplaced via hydrothermal brine effusion. Nat Commun 2020; 11:3680. [PMID: 32778642 PMCID: PMC7417532 DOI: 10.1038/s41467-020-15973-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 04/06/2020] [Indexed: 11/23/2022] Open
Abstract
Before acquiring highest-resolution data of Ceres, questions remained about the emplacement mechanism and source of Occator crater's bright faculae. Here we report that brine effusion emplaced the faculae in a brine-limited, impact-induced hydrothermal system. Impact-derived fracturing enabled brines to reach the surface. The central faculae, Cerealia and Pasola Facula, postdate the central pit, and were primarily sourced from an impact-induced melt chamber, with some contribution from a deeper, pre-existing brine reservoir. Vinalia Faculae, in the crater floor, were sourced from the laterally extensive deep reservoir only. Vinalia Faculae are comparatively thinner and display greater ballistic emplacement than the central faculae because the deep reservoir brines took a longer path to the surface and contained more gas than the shallower impact-induced melt chamber brines. Impact-derived fractures providing conduits, and mixing of impact-induced melt with deeper endogenic brines, could also allow oceanic material to reach the surfaces of other large icy bodies.
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Affiliation(s)
- J E C Scully
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.
| | - P M Schenk
- Lunar and Planetary Institute, Houston, TX, USA
| | - J C Castillo-Rogez
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - D L Buczkowski
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - D A Williams
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | - J H Pasckert
- Institute für Planetologie, University of Münster, Münster, Germany
| | - K D Duarte
- Georgia Institute of Technology, Atlanta, GA, USA
| | - V N Romero
- Georgia Institute of Technology, Atlanta, GA, USA
| | - L C Quick
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - M M Sori
- Lunar and Planetary Laboratory, Tucson, AZ, USA
| | - M E Landis
- Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, CO, USA
| | - C A Raymond
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - A Neesemann
- Free University of Berlin, 14195, Berlin, Germany
| | - B E Schmidt
- Georgia Institute of Technology, Atlanta, GA, USA
| | | | - C T Russell
- University of California, Los Angeles, CA, USA
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23
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Martin‐Cuadrado A, Senel E, Martínez‐García M, Cifuentes A, Santos F, Almansa C, Moreno‐Paz M, Blanco Y, García‐Villadangos M, Cura MÁG, Sanz‐Montero ME, Rodríguez‐Aranda JP, Rosselló‐Móra R, Antón J, Parro V. Prokaryotic and viral community of the sulfate‐rich crust from Peñahueca ephemeral lake, an astrobiology analogue. Environ Microbiol 2019; 21:3577-3600. [DOI: 10.1111/1462-2920.14680] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 05/09/2019] [Accepted: 05/11/2019] [Indexed: 11/29/2022]
Affiliation(s)
| | - Ece Senel
- Department of Physiology, Genetics and MicrobiologyUniversity of Alicante Alicante Spain
- Department of BiologyGraduate School of Sciences, Eskisehir Technical University Yunusemre Campus, Eskisehir 26470 Turkey
| | - Manuel Martínez‐García
- Department of Physiology, Genetics and MicrobiologyUniversity of Alicante Alicante Spain
| | - Ana Cifuentes
- Department of Ecology and Marine Resources, Marine Microbiology GroupMediterranean Institute for Advanced Studies (IMEDEA, CSIC‐UIB) Esporles Spain
| | - Fernando Santos
- Department of Physiology, Genetics and MicrobiologyUniversity of Alicante Alicante Spain
| | - Cristina Almansa
- Research Technical Services (SSTTI), Microscopy UnitUniversity of Alicante Alicante Spain
| | - Mercedes Moreno‐Paz
- Department of Molecular EvolutionCentro de Astrobiología (INTA‐CSIC) Madrid Spain
| | - Yolanda Blanco
- Department of Molecular EvolutionCentro de Astrobiología (INTA‐CSIC) Madrid Spain
| | | | | | | | | | - Ramon Rosselló‐Móra
- Department of BiologyGraduate School of Sciences, Eskisehir Technical University Yunusemre Campus, Eskisehir 26470 Turkey
| | - Josefa Antón
- Department of Physiology, Genetics and MicrobiologyUniversity of Alicante Alicante Spain
| | - Víctor Parro
- Department of Molecular EvolutionCentro de Astrobiología (INTA‐CSIC) Madrid Spain
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Ward LM, Stamenković V, Hand K, Fischer WW. Follow the Oxygen: Comparative Histories of Planetary Oxygenation and Opportunities for Aerobic Life. ASTROBIOLOGY 2019; 19:811-824. [PMID: 31188035 DOI: 10.1089/ast.2017.1779] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Aerobic respiration-the reduction of molecular oxygen (O2) coupled to the oxidation of reduced compounds such as organic carbon, ferrous iron, reduced sulfur compounds, or molecular hydrogen while conserving energy to drive cellular processes-is the most widespread and bioenergetically favorable metabolism on Earth today. Aerobic respiration is essential for the development of complex multicellular life; thus the presence of abundant O2 is an important metric for planetary habitability. O2 on Earth is supplied by oxygenic photosynthesis, but it is becoming more widely understood that abiotic processes may supply meaningful amounts of O2 on other worlds. The modern atmosphere and rock record of Mars suggest a history of relatively high O2 as a result of photochemical processes, potentially overlapping with the range of O2 concentrations used by biology. Europa may have accumulated high O2 concentrations in its subsurface ocean due to the radiolysis of water ice at its surface. Recent modeling efforts suggest that coexisting water and O2 may be common on exoplanets, with confirmation from measurements of exoplanet atmospheres potentially coming soon. In all these cases, O2 accumulates through abiotic processes-independent of water-oxidizing photosynthesis. We hypothesize that abiogenic O2 may enhance the habitability of some planetary environments, allowing highly energetic aerobic respiration and potentially even the development of complex multicellular life which depends on it, without the need to first evolve oxygenic photosynthesis. This hypothesis is testable with further exploration and life-detection efforts on O2-rich worlds such as Mars and Europa, and comparison to O2-poor worlds such as Enceladus. This hypothesis further suggests a new dimension to planetary habitability: "Follow the Oxygen," in which environments with opportunities for energy-rich metabolisms such as aerobic respiration are preferentially targeted for investigation and life detection.
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Affiliation(s)
- Lewis M Ward
- 1 Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California
| | - Vlada Stamenković
- 2 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | - Kevin Hand
- 2 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | - Woodward W Fischer
- 1 Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California
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25
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Trumbo SK, Brown ME, Hand KP. Sodium chloride on the surface of Europa. SCIENCE ADVANCES 2019; 5:eaaw7123. [PMID: 31206026 PMCID: PMC6561749 DOI: 10.1126/sciadv.aaw7123] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 05/03/2019] [Indexed: 06/01/2023]
Abstract
The potential habitability of Europa's subsurface ocean depends on its chemical composition, which may be reflected in that of Europa's geologically young surface. Investigations using Galileo Near-Infrared Mapping Spectrometer data led to the prevailing view that Europa's endogenous units are rich in sulfate salts. However, recent ground-based infrared observations have suggested that, while regions experiencing sulfur radiolysis may contain sulfate salts, Europa's more pristine endogenous material may reflect a chloride-dominated composition. Chlorides have no identifying spectral features at infrared wavelengths, but develop distinct visible-wavelength absorptions under irradiation, like that experienced on the surface of Europa. Using spectra obtained with the Hubble Space Telescope, we present the detection of a 450-nm absorption indicative of irradiated sodium chloride on the surface. The feature correlates with geologically disrupted chaos terrain, suggesting an interior source. The presence of endogenous sodium chloride on the surface of Europa has important implications for our understanding of its subsurface chemistry.
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Affiliation(s)
- Samantha K Trumbo
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Michael E Brown
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Kevin P Hand
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
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26
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Vance SD, Barge LM, Cardoso SSS, Cartwright JHE. Self-Assembling Ice Membranes on Europa: Brinicle Properties, Field Examples, and Possible Energetic Systems in Icy Ocean Worlds. ASTROBIOLOGY 2019; 19:685-695. [PMID: 30964322 DOI: 10.1089/ast.2018.1826] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Brinicles are self-assembling tubular ice membrane structures, centimeters to meters in length, found beneath sea ice in the polar regions of Earth. We discuss how the properties of brinicles make them of possible importance for chemistry in cold environments-including that of life's emergence-and we consider their formation in icy ocean worlds. We argue that the non-ice composition of the ice on Europa and Enceladus will vary spatially due to thermodynamic and mechanical properties that serve to separate and fractionate brines and solid materials. The specifics of the composition and dynamics of both the ice and the ocean in these worlds remain poorly constrained. We demonstrate through calculations using FREZCHEM that sulfate likely fractionates out of accreting ice in Europa and Enceladus, and thus that an exogenous origin of sulfate observed on Europa's surface need not preclude additional endogenous sulfate in Europa's ocean. We suggest that, like hydrothermal vents on Earth, brinicles in icy ocean worlds constitute ideal places where ecosystems of organisms might be found.
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Affiliation(s)
- Steven D Vance
- 1 NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Laura M Barge
- 1 NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Silvana S S Cardoso
- 2 Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Julyan H E Cartwright
- 3 Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, Granada, Spain
- 4 Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, Granada, Spain
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27
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Survival of Radioresistant Bacteria on Europa’s Surface after Pulse Ejection of Subsurface Ocean Water. GEOSCIENCES 2018. [DOI: 10.3390/geosciences9010009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We briefly present preliminary results of our study of the radioresistant bacteria in a low temperature and pressure and high-radiation environment and hypothesize the ability of microorganisms to survive extraterrestrial high-radiation environments, such as the icy surface of Jupiter’s moon, Europa. In this study, samples containing a strain of Deinococcus radiodurans VKM B-1422T embedded into a simulated version of Europa’s ice were put under extreme environmental (−130 °C, 0.01 mbar) and radiation conditions using a specially designed experimental vacuum chamber. The samples were irradiated with 5, 10, 50, and 100 kGy doses and subsequently studied for residual viable cells. We estimate the limit of the accumulated dose that viable cells in those conditions could withstand at 50 kGy. Combining our numerical modelling of the accumulated dose in ice with observations of water eruption events on Europa, we hypothesize that in the case of such events, it is possible that putative extraterrestrial organisms might retain viability in a dormant state for up to 10,000 years, and could be sampled and studied by future probe missions.
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28
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Shkolyar S, Farmer JD. Biosignature Preservation Potential in Playa Evaporites: Impacts of Diagenesis and Implications for Mars Exploration. ASTROBIOLOGY 2018; 18:1460-1478. [PMID: 30124326 DOI: 10.1089/ast.2018.1849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Assessing biosignature preservation potential (BPP) in ancient habitable environments on Mars is a top NASA priority. We address this goal through the study of Miocene-Pliocene evaporites of the Verde Formation (central Arizona). We assessed the effects of diagenesis on BPP, integrating outcrop-scale observations with six lab analyses: thin-section petrography, X-ray diffraction, Raman spectroscopy, total organic carbon (TOC), electron probe microanalysis (EPMA), and visible to near-infrared (VNIR) reflectance spectroscopy. We recognized five facies and their diagenetic pathways. Two facies included mudstones which contain clusters of displacive growth gypsum (DGG). Early DGG was altered during diagenesis by dissolution forming crystal cavities and later underwent recrystallization, cation substitution, and sulfate dehydration. Another facies was identified by lenticular beds dominated by halite and late diagenetic thenardite (Na2SO4). These pods are overlain by a sequence of interbedded gray and red mudstones which record cyclic oxidation and Fe-oxide cementation. During the Pleistocene, a lacustrine environment developed, accompanied by magnesite cementation of playa mudstones. TOC analyses were used as a proxy for inferring the BPP in each facies. The highest BPP was associated with both red and gray mudstone facies. This study provides a taphonomic framework for playa environments on Earth that record the impacts of diagenesis on BPP, with potential applications to Mars sample return (MSR) missions.
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Affiliation(s)
- Svetlana Shkolyar
- School of Earth and Space Exploration, Arizona State University , Tempe, Arizona
| | - Jack D Farmer
- School of Earth and Space Exploration, Arizona State University , Tempe, Arizona
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29
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Carrozzo FG, De Sanctis MC, Raponi A, Ammannito E, Castillo-Rogez J, Ehlmann BL, Marchi S, Stein N, Ciarniello M, Tosi F, Capaccioni F, Capria MT, Fonte S, Formisano M, Frigeri A, Giardino M, Longobardo A, Magni G, Palomba E, Zambon F, Raymond CA, Russell CT. Nature, formation, and distribution of carbonates on Ceres. SCIENCE ADVANCES 2018; 4:e1701645. [PMID: 29546235 PMCID: PMC5851657 DOI: 10.1126/sciadv.1701645] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 01/23/2018] [Indexed: 06/08/2023]
Abstract
Different carbonates have been detected on Ceres, and their abundance and spatial distribution have been mapped using a visible and infrared mapping spectrometer (VIR), the Dawn imaging spectrometer. Carbonates are abundant and ubiquitous across the surface, but variations in the strength and position of infrared spectral absorptions indicate variations in the composition and amount of these minerals. Mg-Ca carbonates are detected all over the surface, but localized areas show Na carbonates, such as natrite (Na2CO3) and hydrated Na carbonates (for example, Na2CO3·H2O). Their geological settings and accessory NH4-bearing phases suggest the upwelling, excavation, and exposure of salts formed from Na-CO3-NH4-Cl brine solutions at multiple locations across the planet. The presence of the hydrated carbonates indicates that their formation/exposure on Ceres' surface is geologically recent and dehydration to the anhydrous form (Na2CO3) is ongoing, implying a still-evolving body.
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Affiliation(s)
- Filippo Giacomo Carrozzo
- Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | | | - Andrea Raponi
- Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | | | - Julie Castillo-Rogez
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Bethany L. Ehlmann
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Simone Marchi
- Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
- Southwest Research Institute, 1050 Walnut Street, Boulder, CO 80302, USA
| | - Nathaniel Stein
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Mauro Ciarniello
- Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | - Federico Tosi
- Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | - Fabrizio Capaccioni
- Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | - Maria Teresa Capria
- Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | - Sergio Fonte
- Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | - Michelangelo Formisano
- Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | - Alessandro Frigeri
- Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | - Marco Giardino
- Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | - Andrea Longobardo
- Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | - Gianfranco Magni
- Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | - Ernesto Palomba
- Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | - Francesca Zambon
- Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | - Carol A. Raymond
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Christopher T. Russell
- Earth Planetary and Space Sciences, University of California, Los Angeles, CA 90095, USA
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30
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Combe JP, McCord TB, Tosi F, Ammannito E, Carrozzo FG, De Sanctis MC, Raponi A, Byrne S, Landis ME, Hughson KHG, Raymond CA, Russell CT. Detection of local H2O exposed at the surface of Ceres. Science 2016; 353:353/6303/aaf3010. [PMID: 27701085 DOI: 10.1126/science.aaf3010] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 06/22/2016] [Indexed: 01/10/2023]
Abstract
The surface of dwarf planet Ceres contains hydroxyl-rich materials. Theories predict a water ice-rich mantle, and water vapor emissions have been observed, yet no water (H2O) has been previously identified. The Visible and InfraRed (VIR) mapping spectrometer onboard the Dawn spacecraft has now detected water absorption features within a low-illumination, highly reflective zone in Oxo, a 10-kilometer, geologically fresh crater, on five occasions over a period of 1 month. Candidate materials are H2O ice and mineral hydrates. Exposed H2O ice would become optically undetectable within tens of years under current Ceres temperatures; consequently, only a relatively recent exposure or formation of H2O would explain Dawn's findings. Some mineral hydrates are stable on geological time scales, but their formation would imply extended contact with ice or liquid H2O.
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Affiliation(s)
- Jean-Philippe Combe
- Bear Fight Institute, 22 Fiddler's Road, P.O. Box 667, Winthrop, WA 98862, USA.
| | - Thomas B McCord
- Bear Fight Institute, 22 Fiddler's Road, P.O. Box 667, Winthrop, WA 98862, USA
| | - Federico Tosi
- Istituto di Astrofisica e Planetologia Spaziali-Istituto Nazionale di Astrofisica, Rome, Italy
| | - Eleonora Ammannito
- Istituto di Astrofisica e Planetologia Spaziali-Istituto Nazionale di Astrofisica, Rome, Italy. Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA, USA
| | | | | | - Andrea Raponi
- Istituto di Astrofisica e Planetologia Spaziali-Istituto Nazionale di Astrofisica, Rome, Italy
| | - Shane Byrne
- Lunar and Planetary Laboratory, Tucson, AZ, USA
| | | | - Kynan H G Hughson
- Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA, USA
| | | | - Christopher T Russell
- Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA, USA
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Ainslie MA, Leighton TG. Sonar equations for planetary exploration. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2016; 140:1400. [PMID: 27586766 DOI: 10.1121/1.4960786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The set of formulations commonly known as "the sonar equations" have for many decades been used to quantify the performance of sonar systems in terms of their ability to detect and localize objects submerged in seawater. The efficacy of the sonar equations, with individual terms evaluated in decibels, is well established in Earth's oceans. The sonar equations have been used in the past for missions to other planets and moons in the solar system, for which they are shown to be less suitable. While it would be preferable to undertake high-fidelity acoustical calculations to support planning, execution, and interpretation of acoustic data from planetary probes, to avoid possible errors for planned missions to such extraterrestrial bodies in future, doing so requires awareness of the pitfalls pointed out in this paper. There is a need to reexamine the assumptions, practices, and calibrations that work well for Earth to ensure that the sonar equations can be accurately applied in combination with the decibel to extraterrestrial scenarios. Examples are given for icy oceans such as exist on Europa and Ganymede, Titan's hydrocarbon lakes, and for the gaseous atmospheres of (for example) Jupiter and Venus.
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Affiliation(s)
- Michael A Ainslie
- Netherlands Organisation for Applied Scientific Research (TNO), P.O. Box 96864, 2509 JG, The Hague, The Netherlands
| | - Timothy G Leighton
- Institute of Sound and Vibration Research, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
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Bezacier L, Journaux B, Perrillat JP, Cardon H, Hanfland M, Daniel I. Equations of state of ice VI and ice VII at high pressure and high temperature. J Chem Phys 2014; 141:104505. [DOI: 10.1063/1.4894421] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Lucile Bezacier
- European Synchrotron Radiation Facility, 6 rue Jules Horowitz, 38000 Grenoble, France
| | - Baptiste Journaux
- Laboratoire de Géologie de Lyon, UMR 5276 CNRS, Ecole Normale Supérieure de Lyon – Université Claude Bernard Lyon 1, 2 rue Raphael Dubois, 69622 Villeurbanne Cedex, France
| | - Jean-Philippe Perrillat
- Laboratoire de Géologie de Lyon, UMR 5276 CNRS, Ecole Normale Supérieure de Lyon – Université Claude Bernard Lyon 1, 2 rue Raphael Dubois, 69622 Villeurbanne Cedex, France
| | - Hervé Cardon
- Laboratoire de Géologie de Lyon, UMR 5276 CNRS, Ecole Normale Supérieure de Lyon – Université Claude Bernard Lyon 1, 2 rue Raphael Dubois, 69622 Villeurbanne Cedex, France
| | - Michael Hanfland
- European Synchrotron Radiation Facility, 6 rue Jules Horowitz, 38000 Grenoble, France
| | - Isabelle Daniel
- Laboratoire de Géologie de Lyon, UMR 5276 CNRS, Ecole Normale Supérieure de Lyon – Université Claude Bernard Lyon 1, 2 rue Raphael Dubois, 69622 Villeurbanne Cedex, France
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Pappalardo RT, Vance S, Bagenal F, Bills BG, Blaney DL, Blankenship DD, Brinckerhoff WB, Connerney JEP, Hand KP, Hoehler TM, Leisner JS, Kurth WS, McGrath MA, Mellon MT, Moore JM, Patterson GW, Prockter LM, Senske DA, Schmidt BE, Shock EL, Smith DE, Soderlund KM. Science potential from a Europa lander. ASTROBIOLOGY 2013; 13:740-773. [PMID: 23924246 DOI: 10.1089/ast.2013.1003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The prospect of a future soft landing on the surface of Europa is enticing, as it would create science opportunities that could not be achieved through flyby or orbital remote sensing, with direct relevance to Europa's potential habitability. Here, we summarize the science of a Europa lander concept, as developed by our NASA-commissioned Science Definition Team. The science concept concentrates on observations that can best be achieved by in situ examination of Europa from its surface. We discuss the suggested science objectives and investigations for a Europa lander mission, along with a model planning payload of instruments that could address these objectives. The highest priority is active sampling of Europa's non-ice material from at least two different depths (0.5-2 cm and 5-10 cm) to understand its detailed composition and chemistry and the specific nature of salts, any organic materials, and other contaminants. A secondary focus is geophysical prospecting of Europa, through seismology and magnetometry, to probe the satellite's ice shell and ocean. Finally, the surface geology can be characterized in situ at a human scale. A Europa lander could take advantage of the complex radiation environment of the satellite, landing where modeling suggests that radiation is about an order of magnitude less intense than in other regions. However, to choose a landing site that is safe and would yield the maximum science return, thorough reconnaissance of Europa would be required prior to selecting a scientifically optimized landing site.
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Affiliation(s)
- R T Pappalardo
- Planetary Sciences Section, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.
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Muñoz-Iglesias V, Bonales LJ, Prieto-Ballesteros O. pH and salinity evolution of Europa's brines: Raman spectroscopy study of fractional precipitation at 1 and 300 bar. ASTROBIOLOGY 2013; 13:693-702. [PMID: 23944292 DOI: 10.1089/ast.2012.0900] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Several lines of evidence indicate the existence of salty liquid water below the icy surface of the satellite Europa. Depending on the chemical composition of the original interior brines, minerals that precipitate will be varied as will be the resulting physicochemical parameters of the evolving solutions such as pH and salinity. These parameters are determinants apropos to the study of the possible habitability of the satellite. In this work, experiments of fractional precipitation by cooling of several brines with different chemical composition (acid, alkaline, and neutral) were performed at 1 and 300 bar. The gradual decrease in temperature leads to mineral precipitation and changes in salinity and pH values. During the experiment, Raman spectroscopy was used to analyze quantitatively the variation of the salt concentration in the aqueous solutions. The obtained laboratory data indicate the manner in which cryomagma differentiation might occur on Europa. These endogenous processes of differentiation require planetary energy, which seems to have been plentiful during Europa's geological history. Ultimately, the dissipation of part of that energy is translated to a higher complexity of the cryopetrology in Europa's crust. From the results, we conclude that fractional differentiation processes of briny cryomagmas produce several types of igneous salty mineral suites on icy moons.
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Tani A, Hasegawa N, Norizawa K, Yada T, Ikeya M. Radiation-induced radicals in hydrated magnesium sulfate. RADIAT MEAS 2012. [DOI: 10.1016/j.radmeas.2012.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Dalton JB, Shirley JH, Kamp LW. Europa's icy bright plains and dark linea: Exogenic and endogenic contributions to composition and surface properties. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011je003909] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Pasek MA, Greenberg R. Acidification of Europa's subsurface ocean as a consequence of oxidant delivery. ASTROBIOLOGY 2012; 12:151-159. [PMID: 22283235 DOI: 10.1089/ast.2011.0666] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Oxidants are formed at the surface of Europa and may be delivered to the subsurface ocean, possibly in great quantities. Whether these substances would be available for biological metabolism is uncertain, because they may react with sulfides and other compounds to generate sulfuric and other acids. If this process has been active on Europa for much of its age, then not only would it rob the ocean of life-supporting oxidants but the subsurface ocean could have a pH of ~2.6, which is so acidic as to present an environmental challenge for life, unless organisms consume or sequester the oxidants fast enough to ameliorate the acidification.
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Affiliation(s)
- Matthew A Pasek
- Department of Geology, University of South Florida, Tampa, Florida 33620, USA.
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Cassidy TA, Johnson RE, Geissler PE, Leblanc F. Simulation of NaDemission near Europa during eclipse. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007je002955] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Billings L, Cameron V, Claire M, Dick GJ, Domagal-Goldman SD, Javaux EJ, Johnson OJ, Laws C, Race MS, Rask J, Rummel JD, Schelble RT, Vance S. The astrobiology primer: an outline of general knowledge--version 1, 2006. ASTROBIOLOGY 2006; 6:735-813. [PMID: 17067259 DOI: 10.1089/ast.2006.6.735] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The Astrobiology Primer has been created as a reference tool for those who are interested in the interdisciplinary field of astrobiology. The field incorporates many diverse research endeavors, but it is our hope that this slim volume will present the reader with all he or she needs to know to become involved and to understand, at least at a fundamental level, the state of the art. Each section includes a brief overview of a topic and a short list of readable and important literature for those interested in deeper knowledge. Because of the great diversity of material, each section was written by a different author with a different expertise. Contributors, authors, and editors are listed at the beginning, along with a list of those chapters and sections for which they were responsible. We are deeply indebted to the NASA Astrobiology Institute (NAI), in particular to Estelle Dodson, David Morrison, Ed Goolish, Krisstina Wilmoth, and Rose Grymes for their continued enthusiasm and support. The Primer came about in large part because of NAI support for graduate student research, collaboration, and inclusion as well as direct funding. We have entitled the Primer version 1 in hope that it will be only the first in a series, whose future volumes will be produced every 3-5 years. This way we can insure that the Primer keeps up with the current state of research. We hope that it will be a great resource for anyone trying to stay abreast of an ever-changing field.
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Hand KP, Chyba CF, Carlson RW, Cooper JF. Clathrate hydrates of oxidants in the ice shell of Europa. ASTROBIOLOGY 2006; 6:463-82. [PMID: 16805702 DOI: 10.1089/ast.2006.6.463] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Europa's icy surface is radiolytically modified by high-energy electrons and ions, and photolytically modified by solar ultraviolet photons. Observations from the Galileo Near Infrared Mapping Spectrometer, ground-based telescopes, the International Ultraviolet Explorer, and the Hubble Space Telescope, along with laboratory experiment results, indicate that the production of oxidants, such as H2O2, O2, CO2, and SO2, is a consequence of the surface radiolytic chemistry. Once created, some of the products may be entrained deeper into the ice shell through impact gardening or other resurfacing processes. The temperature and pressure environments of regions within the europan hydrosphere are expected to permit the formation of mixed clathrate compounds. The formation of carbon dioxide and sulfur dioxide clathrates has been examined in some detail. Here we add to this analysis by considering oxidants produced radiolytically on the surface of Europa. Our results indicate that the bulk ice shell could have a approximately 1.7-7.6% by number contamination of oxidants resulting from radiolysis at the surface. Oxidant-hosting clathrates would consequently make up approximately 12-53% of the ice shell by number relative to ice, if oxidants were entrained throughout. We examine, in brief, the consequences of such contamination on bulk ice shell thickness and find that clathrate formation could lead to substantially thinner ice shells on Europa than otherwise expected. Finally, we propose that double occupancy of clathrate cages by O2 molecules could serve as an explanation for the observation of condensed-phase O2 on Europa. Clathrate-sealed, gas-filled bubbles in the near surface ice could also provide an effective trapping mechanism, though they cannot explain the 5771 A (O2)2 absorption.
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Affiliation(s)
- Kevin P Hand
- Department of Geological & Environmental Sciences, Stanford University, Stanford, California 94305, USA.
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Zolotov MY. A model for low-temperature biogeochemistry of sulfur, carbon, and iron on Europa. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003je002194] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Dalton JB, Mogul R, Kagawa HK, Chan SL, Jamieson CS. Near-infrared detection of potential evidence for microscopic organisms on Europa. ASTROBIOLOGY 2003; 3:505-529. [PMID: 14678661 DOI: 10.1089/153110703322610618] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The possibility of an ocean within the icy shell of Jupiter's moon Europa has established that world as a primary candidate in the search for extraterrestrial life within our Solar System. This paper evaluates the potential to detect evidence for microbial life by comparing laboratory studies of terrestrial microorganisms with measurements from the Galileo Near Infrared Imaging Spectrometer (NIMS). If the interior of Europa at one time harbored life, some evidence may remain in the surface materials. Examination of laboratory spectra of terrestrial extremophiles measured at cryogenic temperatures reveals distorted, asymmetric nearinfrared absorption features due to water of hydration. The band centers, widths, and shapes of these features closely match those observed in the Europa spectra. These features are strongest in reddish-brown, disrupted terrains such as linea and chaos regions. Narrow spectral features due to amide bonds in the microbe proteins provide a means of constraining the abundances of such materials using the NIMS data. The NIMS data of disrupted terrains exhibit distorted, asymmetric near-infrared absorption features consistent with the presence of water ice, sulfuric acid octahydrate, hydrated salts, and possibly as much as 0.2 mg cm(-3) of carbonaceous material that could be of biological origin. However, inherent noise in the observations and limitations of spectral sampling must be taken into account when discussing these findings.
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Affiliation(s)
- J Brad Dalton
- SETI Institute, NASA Ames Research Center, Mountain View, Moffitt Field, California 94035-1000, USA.
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Marion GM, Fritsen CH, Eicken H, Payne MC. The search for life on Europa: limiting environmental factors, potential habitats, and Earth analogues. ASTROBIOLOGY 2003; 3:785-811. [PMID: 14987483 DOI: 10.1089/153110703322736105] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The putative ocean of Europa has focused considerable attention on the potential habitats for life on Europa. By generally clement Earth standards, these Europan habitats are likely to be extreme environments. The objectives of this paper were to examine: (1) the limits for biological activity on Earth with respect to temperature, salinity, acidity, desiccation, radiation, pressure, and time; (2) potential habitats for life on Europa; and (3) Earth analogues and their limitations for Europa. Based on empirical evidence, the limits for biological activity on Earth are: (1) the temperature range is from 253 to 394 K; (2) the salinity range is a(H2O) = 0.6-1.0; (3) the desiccation range is from 60% to 100% relative humidity; (4) the acidity range is from pH 0 to 13; (5) microbes such as Deinococcus are roughly 4,000 times more resistant to ionizing radiation than humans; (6) the range for hydrostatic pressure is from 0 to 1,100 bars; and (7) the maximum time for organisms to survive in the dormant state may be as long as 250 million years. The potential habitats for life on Europa are the ice layer, the brine ocean, and the seafloor environment. The dual stresses of lethal radiation and low temperatures on or near the icy surface of Europa preclude the possibility of biological activity anywhere near the surface. Only at the base of the ice layer could one expect to find the suitable temperatures and liquid water that are necessary for life. An ice layer turnover time of 10 million years is probably rapid enough for preserving in the surface ice layers dormant life forms originating from the ocean. Model simulations demonstrate that hypothetical oceans could exist on Europa that are too cold for biological activity (T < 253 K). These simulations also demonstrate that salinities are high, which would restrict life to extreme halophiles. An acidic ocean (if present) could also potentially limit life. Pressure, per se, is unlikely to directly limit life on Europa. But indirectly, pressure plays an important role in controlling the chemical environments for life. Deep ocean basins such as the Mariana Trench are good analogues for the cold, high-pressure ocean of Europa. Many of the best terrestrial analogues for potential Europan habitats are in the Arctic and Antarctica. The six factors likely to be most important in defining the environments for life on Europa and the focus for future work are liquid water, energy, nutrients, low temperatures, salinity, and high pressures.
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McKinnon WB, Zolensky ME. Sulfate content of Europa's ocean and shell: evolutionary considerations and some geological and astrobiological implications. ASTROBIOLOGY 2003; 3:879-897. [PMID: 14987488 DOI: 10.1089/153110703322736150] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Recent models for the origin of Jupiter indicate that the Galilean satellites were mostly derived from largely unprocessed solar nebula solids and planetesimals. In the jovian subnebula the solids that built Europa were first heated and then cooled, but the major effect was most likely partial or total devolatilization, and less likely to have been wholesale thermochemical reprocessing of rock + metal compositions (e.g., oxidation of Fe and hydration of silicates). Ocean formation and substantial alteration of interior rock by accreted water and ice would occur during and after accretion, but none of the formation models predicts or implies accretion of sulfates. Europa's primordial ocean was most likely sulfidic. After accretion and later radiogenic and tidal heating, the primordial ocean would have interacted hydrothermally with subjacent rock. It has been hypothesized that sulfides could be converted to sulfates if sufficient hydrogen was lost to space, but pressure effects and the impermeability of serpentinite imply that extraction of sulfate from thoroughly altered Europa-rock would have been inefficient (if indeed Mg sulfates formed at all). Permissive physical limits on the extent of alteration limit the sulfate concentration of Europa's evolved ocean to 10% by weight MgSO(4) or equivalent. Later oxidation of the deep interior of Europa may have also occurred because of water released by the breakdown of hydrated silicates, ultimately yielding S magma and/or SO(2) gas. Geological and astrobiological implications are considered.
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Affiliation(s)
- William B McKinnon
- Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University, St. Louis, Missouri 63130, USA.
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