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Dannenmann M, Klenner F, Bönigk J, Pavlista M, Napoleoni M, Hillier J, Khawaja N, Olsson-Francis K, Cable ML, Malaska MJ, Abel B, Postberg F. Toward Detecting Biosignatures of DNA, Lipids, and Metabolic Intermediates from Bacteria in Ice Grains Emitted by Enceladus and Europa. ASTROBIOLOGY 2023; 23:60-75. [PMID: 36454287 DOI: 10.1089/ast.2022.0063] [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
The reliable identification of biosignatures is key to the search for life elsewhere. On ocean worlds like Enceladus or Europa, this can be achieved by impact ionization mass spectrometers, such as the SUrface Dust Analyzer (SUDA) on board NASA's upcoming Europa Clipper mission. During spacecraft flybys, these instruments can sample ice grains formed from subsurface water and emitted by these moons. Previous laboratory analog experiments have demonstrated that SUDA-type instruments could identify amino acids, fatty acids, and peptides in ice grains and discriminate between their abiotic and biotic origins. Here, we report experiments simulating impact ionization mass spectra of ice grains containing DNA, lipids, and metabolic intermediates extracted from two bacterial cultures: Escherichia coli and Sphingopyxis alaskensis. Salty Enceladan or Europan ocean waters were simulated using matrices with different NaCl concentrations. Characteristic mass spectral signals, such as DNA nucleobases, are clearly identifiable at part-per-million-level concentrations. Mass spectra of all substances exhibit unambiguous biogenic patterns, which in some cases show significant differences between the two bacterial species. Sensitivity to the biosignatures decreases with increasing matrix salinity. The experimental parameters indicate that future impact ionization mass spectrometers will be most sensitive to the investigated biosignatures for ice grain encounter speeds of 4-6 km/s.
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Affiliation(s)
- Marie Dannenmann
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Fabian Klenner
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - Janine Bönigk
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - Miriam Pavlista
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - Maryse Napoleoni
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - Jon Hillier
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - Nozair Khawaja
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - Karen Olsson-Francis
- AstrobiologyOU, Faculty of Science, Technology, Engineering & Mathematics, The Open University, Milton Keynes, United Kingdom
| | - Morgan L Cable
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Michael J Malaska
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Bernd Abel
- Leibniz-Institute of Surface Engineering (IOM), Leipzig, Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Leipzig University, Leipzig, Germany
| | - Frank Postberg
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
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2
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MacKenzie SM, Neveu M, Davila AF, Lunine JI, Cable ML, Phillips-Lander CM, Eigenbrode JL, Waite JH, Craft KL, Hofgartner JD, McKay CP, Glein CR, Burton D, Kounaves SP, Mathies RA, Vance SD, Malaska MJ, Gold R, German CR, Soderlund KM, Willis P, Freissinet C, McEwen AS, Brucato JR, de Vera JPP, Hoehler TM, Heldmann J. Science Objectives for Flagship-Class Mission Concepts for the Search for Evidence of Life at Enceladus. ASTROBIOLOGY 2022; 22:685-712. [PMID: 35290745 PMCID: PMC9233532 DOI: 10.1089/ast.2020.2425] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 01/21/2022] [Indexed: 05/07/2023]
Abstract
Cassini revealed that Saturn's Moon Enceladus hosts a subsurface ocean that meets the accepted criteria for habitability with bio-essential elements and compounds, liquid water, and energy sources available in the environment. Whether these conditions are sufficiently abundant and collocated to support life remains unknown and cannot be determined from Cassini data. However, thanks to the plume of oceanic material emanating from Enceladus' south pole, a new mission to Enceladus could search for evidence of life without having to descend through kilometers of ice. In this article, we outline the science motivations for such a successor to Cassini, choosing the primary science goal to be determining whether Enceladus is inhabited and assuming a resource level equivalent to NASA's Flagship-class missions. We selected a set of potential biosignature measurements that are complementary and orthogonal to build a robust case for any life detection result. This result would be further informed by quantifications of the habitability of the environment through geochemical and geophysical investigations into the ocean and ice shell crust. This study demonstrates that Enceladus' plume offers an unparalleled opportunity for in situ exploration of an Ocean World and that the planetary science and astrobiology community is well equipped to take full advantage of it in the coming decades.
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Affiliation(s)
| | - Marc Neveu
- Department of Astronomy, University of Maryland, College Park, Maryland, USA
- Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - Alfonso F. Davila
- Division of Space Science and Astrobiology, NASA Ames Research Center, Moffett Field, California, USA
| | - Jonathan I. Lunine
- Department of Astronomy, Cornell University, Ithaca, New York, USA
- Carl Sagan Institute, Cornell University, Ithaca, New York, USA
| | - Morgan L. Cable
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | | | - Jennifer L. Eigenbrode
- Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - J. Hunter Waite
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, Texas, USA
| | - Kate L. Craft
- Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA
| | - Jason D. Hofgartner
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Chris P. McKay
- Division of Space Science and Astrobiology, NASA Ames Research Center, Moffett Field, California, USA
| | - Christopher R. Glein
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, Texas, USA
| | - Dana Burton
- Department of Anthropology, George Washington University, Washington, District of Columbia, USA
| | | | - Richard A. Mathies
- Chemistry Department and Space Sciences Laboratory, University of California, Berkeley, Berkeley, California, USA
| | - Steven D. Vance
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Michael J. Malaska
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Robert Gold
- Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA
| | - Christopher R. German
- Department of Geology & Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
| | - Krista M. Soderlund
- Institute for Geophysics, Jackson School of Geosciences, The University of Texas at Austin, Austin, Texas, USA
| | - Peter Willis
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | | | - Alfred S. McEwen
- Lunar and Planetary Lab, University of Arizona, Tucson, Arizona, USA
| | | | - Jean-Pierre P. de Vera
- Space Operations and Astronaut Training, MUSC, German Aerospace Center (DLR), Cologne, Germany
| | - Tori M. Hoehler
- Division of Space Science and Astrobiology, NASA Ames Research Center, Moffett Field, California, USA
| | - Jennifer Heldmann
- Division of Space Science and Astrobiology, NASA Ames Research Center, Moffett Field, California, USA
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New Signatures of Bio-Molecular Complexity in the Hypervelocity Impact Ejecta of Icy Moon Analogues. Life (Basel) 2022; 12:life12040508. [PMID: 35454999 PMCID: PMC9026792 DOI: 10.3390/life12040508] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/07/2022] [Accepted: 03/11/2022] [Indexed: 01/05/2023] Open
Abstract
Impact delivery of prebiotic compounds to the early Earth from an impacting comet is considered to be one of the possible ways by which prebiotic molecules arrived on the Earth. Given the ubiquity of impact features observed on all planetary bodies, bolide impacts may be a common source of organics on other planetary bodies both in our own and other solar systems. Biomolecules such as amino acids have been detected on comets and are known to be synthesized due to impact-induced shock processing. Here we report the results of a set of hypervelocity impact experiments where we shocked icy mixtures of amino acids mimicking the icy surface of planetary bodies with high-speed projectiles using a two-stage light gas gun and analyzed the ejecta material after impact. Electron microscopic observations of the ejecta have shown the presence of macroscale structures with long polypeptide chains revealed from LCMS analysis. These results suggest a pathway in which impact on cometary ices containing building blocks of life can lead to the synthesis of material architectures that could have played a role in the emergence of life on the Earth and which may be applied to other planetary bodies as well.
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Method for detecting and quantitating capture of organic molecules in hypervelocity impacts. MethodsX 2021; 8:101239. [PMID: 34434762 PMCID: PMC8374173 DOI: 10.1016/j.mex.2021.101239] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 01/18/2021] [Indexed: 11/26/2022] Open
Abstract
Enceladus is a prime candidate in the solar system for in-depth astrobiological studies searching for habitability and life because it has a liquid water ocean with significant organic content and ongoing cryovolcanic activity. The presence of ice plumes that jet up through fissures in the ice crust covering the sub-surface ocean, enables remote sampling and in-situ analysis via a fly-by mission. However, capture and transport of organic materials to organic analyzers presents distinctive challenges as it is unknown whether, and to what extent, organic molecules imbedded in ice particles can be captured and survive hypervelocity impacts. This manuscript provides a fluorescence microscopic method to parametrically determine the amount of an organic fluorescent tracer dye, Pacific Blue™ (PB) deposited on a metallic surface. This method can be used to measure the capture and survival outcomes of terrestrial hypervelocity impact experiments where an ice projectile labeled with Pacific Blue impacts a soft metal surface. This work is an important step in the advancement of instruments like the Enceladus Organic Analyzer for detecting biosignatures in an Enceladus plume fly-by mission. An apparatus consisting of a substrate humidification shroud coupled with an epifluorescence microscope with CCD detector is developed to measure the intensity of quantitatively deposited Pacific Blue droplets under controlled humidity. Calibration curves are produced that relate the integrated fluorescence intensity of humidified PB droplets on metal foils to the number of PB molecules deposited. To demonstrate the utility of this method, our calibrations are used to analyze and quantitate organic capture and survival (up to 11% capture efficiency) following ice particle impacts at a velocity of 1.7 km/s on an aluminum substrate.
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Klenner F, Postberg F, Hillier J, Khawaja N, Cable ML, Abel B, Kempf S, Glein CR, Lunine JI, Hodyss R, Reviol R, Stolz F. Discriminating Abiotic and Biotic Fingerprints of Amino Acids and Fatty Acids in Ice Grains Relevant to Ocean Worlds. ASTROBIOLOGY 2020; 20:1168-1184. [PMID: 32493049 DOI: 10.1089/ast.2019.2188] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Identifying and distinguishing between abiotic and biotic signatures of organic molecules such as amino acids and fatty acids is key to the search for life on extraterrestrial ocean worlds. Impact ionization mass spectrometers can potentially achieve this by sampling water ice grains formed from ocean water and ejected by moons such as Enceladus and Europa, thereby exploring the habitability of their subsurface oceans in spacecraft flybys. Here, we extend previous high-sensitivity laser-based analog experiments of biomolecules in pure water to investigate the mass spectra of amino acids and fatty acids at simulated abiotic and biotic relative abundances. To account for the complex background matrix expected to emerge from a salty Enceladean ocean that has been in extensive chemical exchange with a carbonaceous rocky core, other organic and inorganic constituents are added to the biosignature mixtures. We find that both amino acids and fatty acids produce sodiated molecular peaks in salty solutions. Under the soft ionization conditions expected for low-velocity (2-6 km/s) encounters of an orbiting spacecraft with ice grains, the unfragmented molecular spectral signatures of amino acids and fatty acids accurately reflect the original relative abundances of the parent molecules within the source solution, enabling characteristic abiotic and biotic relative abundance patterns to be identified. No critical interferences with other abiotic organic compounds were observed. Detection limits of the investigated biosignatures under Enceladus-like conditions are salinity dependent (decreasing sensitivity with increasing salinity), at the μM or nM level. The survivability and ionization efficiency of large organic molecules during impact ionization appear to be significantly improved when they are protected by a frozen water matrix. We infer from our experimental results that encounter velocities of 4-6 km/s are most appropriate for impact ionization mass spectrometers to detect and discriminate between abiotic and biotic signatures.
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Affiliation(s)
- Fabian Klenner
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
- Institute of Earth Sciences, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | - Frank Postberg
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
- Institute of Earth Sciences, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | - Jon Hillier
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - Nozair Khawaja
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
- Institute of Earth Sciences, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | - Morgan L Cable
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Bernd Abel
- Leibniz-Institute of Surface Engineering, Leipzig, Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Universität Leipzig, Leipzig, Germany
| | - Sascha Kempf
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado, USA
| | - Christopher R Glein
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, Texas, USA
| | - Jonathan I Lunine
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
- Department of Astronomy and Carl Sagan Institute, Cornell University, Ithaca, New York, USA
| | - Robert Hodyss
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - René Reviol
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
- Institute of Earth Sciences, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | - Ferdinand Stolz
- Leibniz-Institute of Surface Engineering, Leipzig, Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Universität Leipzig, Leipzig, Germany
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6
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Organic Molecules: Is It Possible to Distinguish Aromatics from Aliphatics Collected by Space Missions in High-Speed Impacts? SCI 2020. [DOI: 10.3390/sci2030056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
A prime site of astrobiological interest within the Solar System is the interior ocean of Enceladus. This ocean has already been shown to contain organic molecules, and is thought to have the conditions necessary for more complex organic biomolecules to emerge and potentially even life itself. This sub-surface ocean has been accessed by Cassini, an unmanned spacecraft that interacted with the water plumes ejected naturally from Enceladus. The encounter speed with these plumes and their contents, was between 5 and 15 km s−1. Encounters at such speeds allow analysis of vapourised material from submicron-sized particles within the plume, but sampling micron-sized particles remains an open question. The latter particles can impact metal targets exposed on the exterior of future spacecraft, producing impact craters lined with impactor residue, which can then be analysed. Although there is considerable literature on how mineral grains behave in such high-speed impacts, and also on the relationship between the crater residue and the original grain composition, far less is known regarding the behaviour of organic particles. Here we consider a deceptively simple yet fundamental scientific question: for impacts at speeds of around 5−6 kms−1 would the impactor residue alone be sufficient to enable us to recognise the signature conferred by organic particles? Furthermore, would it be possible to identify the organic molecules involved, or at least distinguish between aromatic and aliphatic chemical structures? For polystyrene (aromatic-rich) and polymethylmethacrylate (solely aliphatic) latex particles impinging at around 5 km s−1 onto metal targets, we find that sufficient residue is retained at the impact site to permit identification of a carbon-rich projectile, but not of the particular molecules involved, nor is it currently possible to discriminate between aromatic-rich and solely aliphatic particles. This suggests that an alternative analytical method to simple impacts on metal targets is required to enable successful collection of organic samples in a fly-by Enceladus mission, or, alternatively, a lower encounter speed is required.
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7
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Organic Molecules: Is It Possible to Distinguish Aromatics from Aliphatics Collected by Space Missions in High-Speed Impacts? SCI 2020. [DOI: 10.3390/sci2020041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A prime site of astrobiological interest within the Solar System is the interior ocean of Enceladus. This ocean has already been shown to contain organic molecules, and is thought to have the conditions necessary for more complex organic biomolecules to emerge and potentially even life itself. This sub-surface ocean has been accessed by Cassini, an unmanned spacecraft that interacted with the water plumes ejected naturally from Enceladus. The encounter speed with these plumes and their contents, was between 5 and 15 km s−1. Encounters at such speeds allow analysis of vapourised material from submicron-sized particles within the plume, but sampling micron-sized particles remains an open question. The latter particles can impact metal targets exposed on the exterior of future spacecraft, producing impact craters lined with impactor residue, which can then be analysed. Although there is considerable literature on how mineral grains behave in such high-speed impacts, and also on the relationship between the crater residue and the original grain composition, far less is known regarding the behaviour of organic particles. Here we consider a deceptively simple yet fundamental scientific question: for impacts at speeds of around 5–6 kms−1 would the impactor residue alone be sufficient to enable us to recognise the signature conferred by organic particles? Furthermore, would it be possible to identify the organic molecules involved, or at least distinguish between aromatic and aliphatic chemical structures? For polystyrene (aromatic-rich) and poly(methyl methacrylate) (solely aliphatic) latex particles impinging at around 5 km s−1 onto metal targets, we find that sufficient residue is retained at the impact site to permit identification of a carbon-rich projectile, but not of the particular molecules involved, nor is it currently possible to discriminate between aromatic-rich and solely aliphatic particles. This suggests that an alternative analytical method to simple impacts on metal targets is required to enable successful collection of organic samples in a fly-by Enceladus mission, or, alternatively, a lower encounter speed is required.
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8
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Organic Molecules: Is It Possible To Distinguish Aromatics From Aliphatics Collected By Space Missions in High-Speed Impacts. SCI 2020. [DOI: 10.3390/sci2010012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A prime site of astrobiological interest within the Solar System is the interior ocean of Enceladus. This ocean has already been shown to contain organic molecules, and is thought to have the conditions necessary for more complex organic biomolecules to emerge and potentially even life itself. This sub-surface ocean has been accessed by Cassini, an unmanned spacecraft that interacted with the water plumes ejected naturally from Enceladus. The encounter speed with these plumes and their contents, was 5 km s−1 and above. Encounters at such speeds allow analysis of vapourised material from submicron-sized particles within the plume, but sampling micron-sized particles remains an open question. The latter particles can impact metal targets exposed on the exterior of future spacecraft, producing impact craters lined with impactor residue, which can then be analysed. Although there is considerable literature on how mineral grains behave in such high-speed impacts, and also on the relationship between the crater residue and the original grain composition, far less is known regarding the behaviour of organic particles. Here we consider a deceptively simple yet fundamental scientific question: for impacts at speeds of around 5−6 kms−1 would the impactor residue alone be sufficient to enable us to recognise the signature conferred by organic particles? Furthermore, would it be possible to identify the organic molecules involved, or at least distinguish between aromatic and aliphatic chemical structures? For polystyrene (aromatic-rich) and poly(methyl methacrylate) (solely aliphatic) latex particles impinging at around 5 km s-1 onto metal targets, we find that sufficient residue is retained at the impact site to permit identification of a carbon-rich projectile, but not of the particular molecules involved, nor is it currently possible to discriminate between aromatic-rich and solely aliphatic particles. This suggests that an alternative analytical method to simple impacts on metal targets is required to enable successful collection of organic samples in a fly-by Enceladus mission, or, alternatively, a lower encounter speed is required.
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9
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New JS, Mathies RA, Price MC, Cole MJ, Golozar M, Spathis V, Burchell MJ, Butterworth AL. Characterizing organic particle impacts on inert metal surfaces: Foundations for capturing organic molecules during hypervelocity transits of Enceladus plumes. METEORITICS & PLANETARY SCIENCE 2020; 55:465-479. [PMID: 32362737 PMCID: PMC7188319 DOI: 10.1111/maps.13448] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/08/2020] [Indexed: 05/23/2023]
Abstract
The presence and accessibility of a sub-ice-surface saline ocean at Enceladus, together with geothermal activity and a rocky core, make it a compelling location to conduct further, in-depth, astrobiological investigations to probe for organic molecules indicative of extraterrestrial life. Cryovolcanic plumes in the south polar region of Enceladus enable the use of remote in situ sampling and analysis techniques. However, efficient plume sampling and the transportation of captured organic materials to an organic analyzer present unique challenges for an Enceladus mission. A systematic study, accelerating organic ice-particle simulants into soft inert metal targets at velocities ranging 0.5-3.0 km s-1, was carried out using a light gas gun to explore the efficacy of a plume capture instrument. Capture efficiency varied for different metal targets as a function of impact velocity and particle size. Importantly, organic chemical compounds remained chemically intact in particles captured at speeds up to ~2 km s-1. Calibration plots relating the velocity, crater, and particle diameter were established to facilitate future ice-particle impact experiments where the size of individual ice particles is unknown.
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Affiliation(s)
- J. S. New
- Space Sciences LaboratoryUniversity of CaliforniaBerkeley7 Gauss WayBerkeleyCalifornia94720USA
- School of Physical SciencesUniversity of KentCanterburyKentCT2 7NHUK
| | - R. A. Mathies
- Space Sciences LaboratoryUniversity of CaliforniaBerkeley7 Gauss WayBerkeleyCalifornia94720USA
- Department of ChemistryUniversity of CaliforniaBerkeleyCalifornia94720USA
| | - M. C. Price
- School of Physical SciencesUniversity of KentCanterburyKentCT2 7NHUK
| | - M. J. Cole
- School of Physical SciencesUniversity of KentCanterburyKentCT2 7NHUK
| | - M. Golozar
- Space Sciences LaboratoryUniversity of CaliforniaBerkeley7 Gauss WayBerkeleyCalifornia94720USA
- Department of ChemistryUniversity of CaliforniaBerkeleyCalifornia94720USA
| | - V. Spathis
- School of Physical SciencesUniversity of KentCanterburyKentCT2 7NHUK
| | - M. J. Burchell
- School of Physical SciencesUniversity of KentCanterburyKentCT2 7NHUK
| | - A. L. Butterworth
- Space Sciences LaboratoryUniversity of CaliforniaBerkeley7 Gauss WayBerkeleyCalifornia94720USA
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10
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Organic Molecules: Is It Possible to Distinguish Aromatics from Aliphatics Collected by Space Missions in High Speed Impacts? SCI 2019. [DOI: 10.3390/sci1020053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
A prime site of astrobiological interest within the Solar System is the interior ocean of Enceladus. This ocean has already been shown to contain organic molecules and is thought to have the conditions necessary for more complex organic biomolecules to emerge and potentially even life itself. This sub-surface ocean has been accessed by Cassini, an unmanned spacecraft that interacted with the water plumes ejected naturally from Enceladus. The encounter speed with these plumes and their contents was 5 km s−1 and above. Encounters at such speeds allow analysis of vaporised material from submicron-sized particles within the plume, but sampling micron-sized particles remains an open question. The latter particles can impact metal targets exposed on the exterior of future spacecraft, producing impact craters lined with impactor residue, which can then be analysed. Although there is considerable literature on how mineral grains behave in such high-speed impacts, and also on the relationship between the crater residue and the original grain composition, far less is known regarding the behaviour of organic particles. Here we consider a deceptively simple yet fundamental scientific question: for impacts at speeds of around 5–6 kms−1 would the impactor residue alone be sufficient to enable us to recognise the signature conferred by organic particles? Furthermore, would it be possible to identify the organic molecules involved, or at least distinguish between aromatic and aliphatic chemical structures? For polystyrene (aromatic-rich) and poly (methyl methacrylate) (solely aliphatic) latex particles impinging at around 5 km s−1 onto metal targets, we found that sufficient residue is retained at the impact site to permit identification of a carbon-rich projectile, but not of the particular molecules involved, nor is it currently possible to discriminate between aromatic-rich and solely aliphatic particles. This suggests that an alternative analytical method to simple impacts on metal targets is required to enable successful collection of organic samples in a fly-by Enceladus mission.
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11
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Neveu M, Hays LE, Voytek MA, New MH, Schulte MD. The Ladder of Life Detection. ASTROBIOLOGY 2018; 18:1375-1402. [PMID: 29862836 PMCID: PMC6211372 DOI: 10.1089/ast.2017.1773] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 03/23/2018] [Indexed: 05/04/2023]
Abstract
We describe the history and features of the Ladder of Life Detection, a tool intended to guide the design of investigations to detect microbial life within the practical constraints of robotic space missions. To build the Ladder, we have drawn from lessons learned from previous attempts at detecting life and derived criteria for a measurement (or suite of measurements) to constitute convincing evidence for indigenous life. We summarize features of life as we know it, how specific they are to life, and how they can be measured, and sort these features in a general sense based on their likelihood of indicating life. Because indigenous life is the hypothesis of last resort in interpreting life-detection measurements, we propose a small but expandable set of decision rules determining whether the abiotic hypothesis is disproved. In light of these rules, we evaluate past and upcoming attempts at life detection. The Ladder of Life Detection is not intended to endorse specific biosignatures or instruments for life-detection measurements, and is by no means a definitive, final product. It is intended as a starting point to stimulate discussion, debate, and further research on the characteristics of life, what constitutes a biosignature, and the means to measure them.
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Affiliation(s)
- Marc Neveu
- NASA Postdoctoral Management Program Fellow, Universities Space Research Association, Columbia, Maryland
- NASA Headquarters, Washington, DC
| | - Lindsay E. Hays
- NASA Headquarters, Washington, DC
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
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12
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Mathies RA, Razu ME, Kim J, Stockton AM, Turin P, Butterworth A. Feasibility of Detecting Bioorganic Compounds in Enceladus Plumes with the Enceladus Organic Analyzer. ASTROBIOLOGY 2017; 17:902-912. [PMID: 28915087 PMCID: PMC5610425 DOI: 10.1089/ast.2017.1660] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Enceladus presents an excellent opportunity to detect organic molecules that are relevant for habitability as well as bioorganic molecules that provide evidence for extraterrestrial life because Enceladus' plume is composed of material from the subsurface ocean that has a high habitability potential and significant organic content. A primary challenge is to send instruments to Enceladus that can efficiently sample organic molecules in the plume and analyze for the most relevant molecules with the necessary detection limits. To this end, we present the scientific feasibility and engineering design of the Enceladus Organic Analyzer (EOA) that uses a microfluidic capillary electrophoresis system to provide sensitive detection of a wide range of relevant organic molecules, including amines, amino acids, and carboxylic acids, with ppm plume-detection limits (100 pM limits of detection). Importantly, the design of a capture plate that effectively gathers plume ice particles at encounter velocities from 200 m/s to 5 km/s is described, and the ice particle impact is modeled to demonstrate that material will be efficiently captured without organic decomposition. While the EOA can also operate on a landed mission, the relative technical ease of a fly-by mission to Enceladus, the possibility to nondestructively capture pristine samples from deep within the Enceladus ocean, plus the high sensitivity of the EOA instrument for molecules of bioorganic relevance for life detection argue for the inclusion of EOA on Enceladus missions. Key Words: Lab-on-a-chip-Organic biomarkers-Life detection-Planetary exploration. Astrobiology 17, 902-912.
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Affiliation(s)
- Richard A. Mathies
- Department of Chemistry, University of California at Berkeley, Berkeley, California
| | - Md Enayet Razu
- Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas
| | - Jungkyu Kim
- Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas
| | - Amanda M. Stockton
- Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia
| | - Paul Turin
- Berkeley Space Sciences Lab, University of California at Berkeley, Berkeley, California
| | - Anna Butterworth
- Berkeley Space Sciences Lab, University of California at Berkeley, Berkeley, California
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13
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Nadeau J, Lindensmith C, Deming JW, Fernandez VI, Stocker R. Microbial Morphology and Motility as Biosignatures for Outer Planet Missions. ASTROBIOLOGY 2016; 16:755-774. [PMID: 27552160 PMCID: PMC5069736 DOI: 10.1089/ast.2015.1376] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 06/13/2016] [Indexed: 05/23/2023]
Abstract
Meaningful motion is an unambiguous biosignature, but because life in the Solar System is most likely to be microbial, the question is whether such motion may be detected effectively on the micrometer scale. Recent results on microbial motility in various Earth environments have provided insight into the physics and biology that determine whether and how microorganisms as small as bacteria and archaea swim, under which conditions, and at which speeds. These discoveries have not yet been reviewed in an astrobiological context. This paper discusses these findings in the context of Earth analog environments and environments expected to be encountered in the outer Solar System, particularly the jovian and saturnian moons. We also review the imaging technologies capable of recording motility of submicrometer-sized organisms and discuss how an instrument would interface with several types of sample-collection strategies. Key Words: In situ measurement-Biosignatures-Microbiology-Europa-Ice. Astrobiology 16, 755-774.
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Affiliation(s)
- Jay Nadeau
- 1 GALCIT, California Institute of Technology , Pasadena, California
| | - Chris Lindensmith
- 2 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California
| | - Jody W Deming
- 3 Department of Biological Oceanography, University of Washington , Seattle, Washington
| | - Vicente I Fernandez
- 4 Department of Civil and Environmental Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts
| | - Roman Stocker
- 4 Department of Civil and Environmental Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts
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14
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Montgomery W, Bromiley GD, Sephton MA. The nature of organic records in impact excavated rocks on Mars. Sci Rep 2016; 6:30947. [PMID: 27492071 PMCID: PMC4974657 DOI: 10.1038/srep30947] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 07/11/2016] [Indexed: 11/09/2022] Open
Abstract
Impact ejected rocks are targets for life detection missions to Mars. The Martian subsurface is more favourable to organic preservation than the surface owing to an attenuation of radiation and physical separation from oxidising materials with increasing depth. Impact events bring materials to the surface where they may be accessed without complicated drilling procedures. On Earth, different assemblages of organic matter types are derived from varying depositional environments. Here we assess whether these different types of organic materials can survive impact events without corruption. We subjected four terrestrial organic matter types to elevated pressures and temperatures in piston-cylinder experiments followed by chemical characterisation using whole-rock pyrolysis-gas chromatography-mass spectrometry. Our data reveal that long chain hydrocarbon-dominated organic matter (types I and II; mainly microbial or algal) are unresistant to pressure whereas aromatic hydrocarbon-dominated organic matter types (types III and IV; mainly land plant, metamorphosed or degraded, displaying some superficial chemical similarities to abiotic meteoritic organic matter) are relatively resistant. This suggests that the impact excavated record of potential biology on Mars will be unavoidably biased, with microbial organic matter underrepresented while metamorphosed, degraded or abiotic meteoritic organic matter types will be selectively preserved.
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Affiliation(s)
- W Montgomery
- Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, Imperial College London, SW7 2AZ, UK
| | - G D Bromiley
- School of GeoSciences, University of Edinburgh, Grant Institute, West Main Road, Edinburgh EH9 3JW, UK
| | - M A Sephton
- Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, Imperial College London, SW7 2AZ, UK
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15
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Matthewman R, Court RW, Crawford IA, Jones AP, Joy KH, Sephton MA. The Moon as a recorder of organic evolution in the early solar system: a lunar regolith analog study. ASTROBIOLOGY 2015; 15:154-168. [PMID: 25615648 PMCID: PMC4322787 DOI: 10.1089/ast.2014.1217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 12/06/2014] [Indexed: 06/04/2023]
Abstract
The organic record of Earth older than ∼3.8 Ga has been effectively erased. Some insight is provided to us by meteorites as well as remote and direct observations of asteroids and comets left over from the formation of the Solar System. These primitive objects provide a record of early chemical evolution and a sample of material that has been delivered to Earth's surface throughout the past 4.5 billion years. Yet an effective chronicle of organic evolution on all Solar System objects, including that on planetary surfaces, is more difficult to find. Fortunately, early Earth would not have been the only recipient of organic matter-containing objects in the early Solar System. For example, a recently proposed model suggests the possibility that volatiles, including organic material, remain archived in buried paleoregolith deposits intercalated with lava flows on the Moon. Where asteroids and comets allow the study of processes before planet formation, the lunar record could extend that chronicle to early biological evolution on the planets. In this study, we use selected free and polymeric organic materials to assess the hypothesis that organic matter can survive the effects of heating in the lunar regolith by overlying lava flows. Results indicate that the presence of lunar regolith simulant appears to promote polymerization and, therefore, preservation of organic matter. Once polymerized, the mineral-hosted newly formed organic network is relatively protected from further thermal degradation. Our findings reveal the thermal conditions under which preservation of organic matter on the Moon is viable.
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Affiliation(s)
- Richard Matthewman
- Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, South Kensington Campus, Imperial College London, London, UK
| | - Richard W. Court
- Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, South Kensington Campus, Imperial College London, London, UK
| | - Ian A. Crawford
- Department of Earth and Planetary Sciences, Birkbeck College, University of London, London, UK
| | - Adrian P. Jones
- Department of Earth Sciences, University College London, London, UK
| | - Katherine H. Joy
- School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, UK
| | - Mark A. Sephton
- Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, South Kensington Campus, Imperial College London, London, UK
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