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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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Sasaki S, Yamagishi A, Yoshimura Y, Enya K, Miyakawa A, Ohno S, Fujita K, Usui T, Limaye S. In situ bio/chemical characterization of Venus cloud particles using Life-signature Detection Microscope for Venus (Venus LDM). Can J Microbiol 2022; 68:413-425. [PMID: 35235433 DOI: 10.1139/cjm-2021-0140] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Much of the information about the size and shape of aerosols forming haze and the cloud layer of Venus is obtained from indirect inferences from nephelometers on probes and from analysis of the variation of polarization with the phase angle and the glory feature from images of Venus. Microscopic imaging of Venus' aerosols has been advocated recently. Direct measurements from a fluorescence microscope can provide information on the morphology, density, and biochemical characteristics of the particles; thus, the fluorescence microscope is attractive for the in situ particle characterization of Venus' cloud layer. Fluorescence imaging of Venus' cloud particles presents several challenges due to the sulfuric acid composition and the corrosive effects. In this article, we identify the challenges and describe our approach to overcoming them for a fluorescence microscope based on an in situ bio/chemical and physical characterization instrument for use in the clouds of Venus from a suitable aerial platform. We report that a pH adjustment using alkali was effective for obtaining fluorescence images, and that fluorescence attenuation was observed after the adjustment, even when the acidophile suspension in the concentrated sulfuric acid was used as a sample.
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Affiliation(s)
- Satoshi Sasaki
- Tokyo University of Technology, 13097, Hachioji, Japan, 192-0914;
| | - Akihiko Yamagishi
- Tokyo University of Pharmacy and Life Sciences, 13115, Hachioji, Tokyo, Japan;
| | | | - Keigo Enya
- JAXA, 13557, Sagamihara, Kanagawa, Japan;
| | - Atsuo Miyakawa
- Tokyo University of Pharmacy and Life Sciences, 13115, Hachioji, Tokyo, Japan;
| | - Sohsuke Ohno
- Chiba Institute of Technology, 12829, Chiba, Chiba, Japan;
| | | | | | - Sanjay Limaye
- University of Wisconsin-Madison, 5228, Madison, Wisconsin, United States;
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Kotsyurbenko OR, Cordova JA, Belov AA, Cheptsov VS, Kölbl D, Khrunyk YY, Kryuchkova MO, Milojevic T, Mogul R, Sasaki S, Słowik GP, Snytnikov V, Vorobyova EA. Exobiology of the Venusian Clouds: New Insights into Habitability through Terrestrial Models and Methods of Detection. ASTROBIOLOGY 2021; 21:1186-1205. [PMID: 34255549 PMCID: PMC9545807 DOI: 10.1089/ast.2020.2296] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 04/16/2021] [Indexed: 06/13/2023]
Abstract
The search for life beyond Earth has focused on Mars and the icy moons Europa and Enceladus, all of which are considered a safe haven for life due to evidence of current or past water. The surface of Venus, on the other hand, has extreme conditions that make it a nonhabitable environment to life as we know it. This is in contrast, however, to its cloud layer, which, while still an extreme environment, may prove to be a safe haven for some extreme forms of life similar to extremophiles on Earth. We consider the venusian clouds a habitable environment based on the presence of (1) a solvent for biochemical reactions, (2) appropriate physicochemical conditions, (3) available energy, and (4) biologically relevant elements. The diversity of extreme microbial ecosystems on Earth has allowed us to identify terrestrial chemolithoautotrophic microorganisms that may be analogs to putative venusian organisms. Here, we hypothesize and describe biological processes that may be performed by such organisms in the venusian clouds. To detect putative venusian organisms, we describe potential biosignature detection methods, which include metal-microbial interactions and optical methods. Finally, we describe currently available technology that can potentially be used for modeling and simulation experiments.
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Affiliation(s)
- Oleg R. Kotsyurbenko
- Yugra State University, The Institute of Oil and Gas, School of Ecology, Khanty-Mansiysk, Russian Federation
- Network of Researchers on the Chemical Evolution of Life, Leeds, UK
| | - Jaime A. Cordova
- Laboratory of Genetics, University of Wisconsin, Madison, Wisconsin, USA
| | - Andrey A. Belov
- Network of Researchers on the Chemical Evolution of Life, Leeds, UK
- Moscow State University, Faculty of Soil Science, Moscow, Russian Federation
| | - Vladimir S. Cheptsov
- Network of Researchers on the Chemical Evolution of Life, Leeds, UK
- Moscow State University, Faculty of Soil Science, Moscow, Russian Federation
- Space Research Institute, Russian Academy of Sciences, Moscow, Russian Federation
| | - Denise Kölbl
- Space Biochemistry Group, Department of Biophysical Chemistry, University of Vienna, Vienna, Austria
| | - Yuliya Y. Khrunyk
- Department of Heat Treatment and Physics of Metal, Ural Federal University, Ekaterinburg, Russian Federation
- M.N. Mikheev Institute of Metal Physics of the Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russian Federation
| | - Margarita O. Kryuchkova
- Network of Researchers on the Chemical Evolution of Life, Leeds, UK
- Moscow State University, Faculty of Soil Science, Moscow, Russian Federation
| | - Tetyana Milojevic
- Space Biochemistry Group, Department of Biophysical Chemistry, University of Vienna, Vienna, Austria
| | - Rakesh Mogul
- Chemistry and Biochemistry Department, California State Polytechnic University, Pomona, California, USA
| | - Satoshi Sasaki
- School of Biosciences and Biotechnology/School of Health Sciences, Tokyo University of Technology, Hachioji, Tokyo, Japan
| | - Grzegorz P. Słowik
- Institute of Materials and Biomedical Engineering, Faculty of Mechanical Engineering, University of Zielona Góra, Zielona Góra, Poland
| | - Valery Snytnikov
- Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russian Federation
- Novosibirsk State University, Novosibirsk, Russian Federation
| | - Elena A. Vorobyova
- Network of Researchers on the Chemical Evolution of Life, Leeds, UK
- Moscow State University, Faculty of Soil Science, Moscow, Russian Federation
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