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Organic Products of Fatty Acid and Magnesium Sulfate Mixtures after Gamma Radiolysis: Implications for Missions to Europa

Year: 2024
Type: article
Abstract: If ocean-derived materials are present at Europa's surface, they would represent accessible records of ocean chemistry and habitability, but such materials would be further processed by Europa's harsh radiation environment. In this study, saturated fatty acids were precipitated onto a Europa-relevant hydrated magnesium sulfate and exposed to gamma radiation doses up to 2 MGy at -196°C. Alkane chains, with carbon numbers one less than those of the starting fatty acids, were the most abundant radiolysis products in solvent and thermal extracts analyzed by gas chromatography mass spectrometry. Detections of monounsaturated fatty acids and combined radiolysis products were attributed to the experiment's Europa-like parameters. Additionally, elevated concentrations of shorter-chain saturated fatty acids suggest that gamma radiation induced charge remote fragmentation of the alkyl chains of some starting fatty acids under these experimental conditions. Quantitation of fatty acid concentrations in the irradiated samples enabled the calculation of a radiolysis constant that indicated exposure to a 5 MGy dose of gamma radiation would have resulted in a ∼90% loss of the initial fatty acid population. The samples were further studied by Raman spectroscopy and laser desorption and ionization mass spectrometry, which characterized the distribution of fatty acids and their radiolysis products on sulfate surfaces. The substantial loss of starting fatty acids typically seen with increasing radiation dose, along with the remarkable diversity of radiolysis products identified, suggests that the detection of fatty acids in irradiated sulfate deposits on Europa will be challenged by rapid destruction of any initial fatty acid populations and scrambling of their residual signals by a myriad of organic radiolysis products. If missions to Europa encounter sulfate deposits, targeting minimally irradiated units may still enable the detection of surviving fatty acid signatures that could inform about Europa's subsurface chemistry and habitability.
Source: Astrobiology
DOI: 10.1089/ast.2024.0047
Authors: James M.T. Lewis, Dina M. Bower, Alexander A. Pavlov, Xiang Li, Sarinah Z. Wahl, Jennifer L. Eigenbrode, Amy C. McAdam
Language: English
Open Access status: hybrid
Award: IGF::OT::IGF CRESST IITHE GODDARD CENTER FOR RESEARCH AND EXPLORATION IN SPACE SCIENCE AND TECHNOLOGY (CRESST) II WILL CARRY OUT OBSERVATIONAL EXPERIMENTAL AND THEORETICAL RESEARCH IN SUPPORT OF NASA STRATEGIC SCIENCE MISSION OBJECTIVES RELATING TO:A.THE SOLAR SYSTEM STARS GALAXIES AND THE UNIVERSE AT LARGE;B.THE INFORMATIONAL AND COMPUTATIONAL SCIENCES RELATED TO THE UNIQUE NEEDS OF DATA SYSTEMS REQUIRED TO INTERPRET DATA FROM THE SPACE SCIENCES; ANDC.THE DEVELOPMENT OF THE TECHNOLOGY REQUIRED TO ACHIEVE THESE SCIENTIFIC CHALLENGES.THIS COOPERATIVE AGREEMENT WILL ALLOW FOR SUBSTANTIAL PROGRAMMATIC INVOLVEMENT IN THE FORM OF COLLABORATION BETWEEN GSFC AND THE CRESST II AS WELL AS JOINT DEVELOPMENT OF RESEARCH OBJECTIVES.THE GOAL IS TO ESTABLISH A FOCUSED PARTNERSHIP THAT:A.BRINGS TOGETHER GSFC AND EXTERNAL SCIENTISTS TO IMPLEMENT THE NASA STRATEGIC GOAL IN SPACE SCIENCE;B.BUILDS ON THE CAPABILITIES AND STRENGTHS OF PARTICIPATING ORGANIZATION IN SPACE SCIENCE;C.PROVIDES ORGANIZATION AND STAFFING FLEXIBILITY TO ADAPT TO EVOLVING RESEARCH PROGRAM NEEDS;D.INCREASES THE INVOLVEMENT OF MINORITY AND WOMEN SCIENTISTS IN SPACE SCIENCE RESEARCH; ANDE.FACILITATES ACCESS TO STUDENT TALENT AND PROVIDES OPPORTUNITIES FOR THEIR PARTICIPATION IN NASA PROGRAMS.A BROAD AND VIGOROUS SPACE RESEARCH PROGRAM IN NASA IS VITAL FOR THE ADVANCEMENT OF KNOWLEDGE. SCIENTISTS AT NASA IN COLLABORATION WITH OUTSIDE SCIENTISTS PLAY A KEY ROLE IN CONCEIVING NEW SPACE MISSIONS PROVIDING MISSION REQUIREMENTS AND ACHIEVING RESEARCH OBJECTIVES AIMED AT UNDERSTANDING THE ORIGINS STRUCTURE AND EVOLUTION OF SYSTEMS IN THE UNIVERSE AND EXPLORING THE SOLAR SYSTEM.THE CRESST II WILL FOCUS PRIMARILY ON SCIENTIFIC RESEARCH. IT IS EXPECTED TO STRENGTHEN COOPERATIVE RELATIONSHIPS BETWEEN THE RECIPIENT AND GOVERNMENT SCIENTISTS IN THE GODDARD SCIENCES AND EXPLORATION DIRECTORATE (SED) AND WILL PROVIDE A VEHICLE TO INCREASE THE INVOLVEMENT OF THE EXTERNAL SCIENCE COMMUNITY IN THE PURSUIT OF NASA GOALS.THE CRESST II WILL CONDUCT RESEARCH COLLABORATIVELY WITH ORGANIZATIONAL ELEMENTS WITHIN THE GODDARD SED (CODE 600). RESEARCH MAY INVOLVE ANALYSIS OF DATA FROM OPERATING AND PAST MISSIONS AND MODELING AND DESIGN OF MISSIONS PLANNED OR UNDER DEVELOPMENT. FUTURE RESEARCH ACTIVITIES WILL EVOLVE AS A FUNCTION OF PRIORITIES BUDGETS FUNDING OPPORTUNITIES AND SUCCESS OF PROPOSAL SUBMISSIONS.
OpenAlex ID: W4404724335
FWCI: 0.572
Cites: 88
Cited by: 3
Related to: 10