From habitability to life on Mars

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Cover FROM HABITABILITY TO LIFE ON MARS Copyright List of Contributors Foreword Color Plate 1 Color Plate 2 1. Habitability as a Tool in Astrobiological Exploration Overview Introduction Defining Habitability Follow the Water Follow the Bioessential Elements Follow the Energy Sources Exploring the Extremes of Life Niche-Based Multivariate Approach to Habitability Conclusions References Further Reading 2. An Origin of Life on Mars? Overview Introduction Liquid Water Carbon Chemistry Water on Mars The Timing of Aquatic Habitats Possible Sources of Organic Molecules on Mars Where are the Martian Organic Molecules? Several Possible Ways to Start Life on Mars The Odds for an Origin of Life Conclusion References 3. Remote Detection of Phyllosilicates on Mars and Implications for Climate and Habitability Overview Presence of Phyllosilicates and Poorly Crystalline Aluminosilicates on Mars Remote Detection of Phyllosilicates and Related Materials at Mars Detection of Phyllosilicates and SRO Materials on Mars Using VNIR Spectra Detection of Phyllosilicates and SRO Materials on Mars in TIR Spectra Si-O Stretching Vibrations Si-O Bending Vibrations Detection of Phyllosilicates and SRO Materials on Mars by Rovers Detection of Phyllosilicates and SRO Materials in Martian Meteorites Characterization of Phyllosilicates and SRO Materials on Mars Global Observations of Phyllosilicates, SRO Phases and Aqueous Alteration on Mars Regional Characterization of Phyllosilicates and Aqueous Alteration on Mars The Phyllosilicate-Rich Mawrth Vallis Region in Eastern Chryse Planitia The Clay-Bearing Region West and South of Isidis Planitia Discussion of Phyllosilicates and Climate on Mars Discussion of Phyllosilicates and Habitability on Mars Summary of Phyllosilicates and SRO Materials on Mars Acknowledgments References 4. Martian Habitability as Inferred From Landed Mission Observations Introduction Summary of Landed Missions Needs and Challenges for Habitability and Life Indicators of Habitability From Landed Missions Phoenix: Northern Latitude Soils and Water Ice Overview Perchlorates and Other Salts Low Water Activity Environment Curiosity: Fluvial-Deltaic-Lacustrine Deposits in Gale Crater Overview Prolonged Surface Water Varying Redox Conditions Organic Carbon in Mudstones Detection of Nitrate Alteration by Ground Water Evolution of Water Availability Opportunity: Burns Formation Sandstones Overview From Playa Muds to Sandstones Acidic Conditions Spirit: Aqueous Activity in the Columbia Hills Overview Sulfate-Rich Sands Silica-Rich Deposits Opportunity: Fracture-Related Aqueous Processes on Endeavour Crater’s Rim Overview Matijevic Formation and the Espérance Fracture Sulfates and Manganese Oxides on the Island Rocks Smectites, Hematite, and Sulfates in Marathon Valley Outlook for Habitability and Life on Mars Overview Sustained Water Chemical Energy Essential Elements Favorable Environmental Conditions Hazards to Habitability Overall Assessment References Further Reading 5. Archean Lakes as Analogues for Habitable Martian Paleoenvironments Introduction Archean Lakes Fortescue Group Regional Geologic Setting Sedimentary Environments Fluvial Facies Near Shore Lake Facies Desiccation Cracks Tepee Structures Symmetrical Ripple Cross-Stratification Edgewise Conglomerate and Stone Rosettes Fenestrae Ooids Near-shore Stromatolites Shallow Water Lake Facies Soft Sediment Deformation Event Beds Shallow Water Stromatolites Deep Water Lake Facies Biosignature Preservation Microbialites Microfossils Chemical and Isotopic Biosignatures Biosignatures That Are Notably Absent Lessons for Martian Paleolake Exploration References Further Reading 6. Evolution of Altiplanic Lakes at the Pleistocene/Holocene Transition: A Window Into Early Mars Declining Habitability, Cha ... Overview Introduction Environmental Setting Volcanic/Hydrothermal Activity Stratigraphic Record Geosignatures Chemical and Isotopic Signatures Changes in Lake Habitat and Biosignatures Conclusion References Further Reading 7. Siliceous Hot Spring Deposits: Why They Remain Key Astrobiological Targets Introduction Hot Spring Deposits as Astrobiology Targets Detection of Siliceous Hydrothermal Hot Spring Deposits on Mars Mars Hot Spring Deposits at Nili Patera Opaline Silica Deposits at Columbia Hills The Likelihood of Finding More Hot Spring Deposits on Mars Geochemical Considerations Competing Hypotheses for the Origin of Silica-Rich Deposits on Mars Site Selection Considerations Relevant to the Return to Mars References Further Reading 8. Habitability and Biomarker Preservation in the Martian Near-Surface Radiation Environment Introduction The Ionizing Radiation Environment on Mars Radiation Effects on Living Cells Radiation Chemistry of Water Biological Impact of Various Forms of Radiation The Maximum Dormancy Limit on Mars Conclusions Appendix A: Mathematical Expressions Normal Bethe-Bloch Formula Electron Bethe-Bloch Formula References Further Reading 9. UV and Life Adaptation Potential on Early Mars: Lessons From Extreme Terrestrial Analogs Overview Background A Polyextreme Environment Adaptation and Its Limits Conclusion Acknowledgments References Further Reading 10. Are Recurring Slope Lineae Habitable? Overview Introduction and Background RSL in the Southern Middle Latitudes RSL in Equatorial and Northern Middle Latitudes Color Observations CRISM Detection of Hydrated Salts RSL Association With Small Gullies and Slumps How Do RSL Form? Melting of Shallow Ice Groundwater Models Deliquescence Dry RSL Models Hybrid Models Implications for Habitability Should Candidate RSL Be Treated Like Special Regions? Future Study of RSL Acknowledgments References 11. The NASA Mars 2020 Rover Mission and the Search for Extraterrestrial Life Introduction Background and Previous Missions Mission Objectives Mission Overview and Comparison to MSL Science Payload and In Situ Investigations Mastcam-Z RIMFAX SuperCam PIXL SHERLOC MEDA MOXIE Returned Sample Science Sampling and Caching System Sample-Related Requirements Design of the Sampling and Caching System Sample Caching and Potential Return Extant Life and Planetary Protection Landing Site Selection Mars 2020 and the Search for Life Beyond Earth Mars 2020 and In Situ Astrobiology Martian Biosignatures Astrobiologic Considerations for MSR Some Thoughts on Returned Sample Science Acknowledgments References 12. Searching for Traces of Life With the ExoMars Rover Overview What Is ExoMars? Possible Life on Mars: When and Where? Biosignatures: Which and How Reliable? Morphological Biosignatures Chemical Biosignatures Importance of Geological Context for Boosting Biosignature Confidence ExoMars Biosignature Targeting The Need for Subsurface Exploration Results From Previous Missions Degradation of Organic Matter Access to Molecular Biosignatures The ExoMars Rover and Its Pasteur Payload From Panoramic to Molecular Scale Through Nested Investigations Pasteur Payload Instruments Panoramic Camera System IR Spectrometer Shallow Ground-Penetrating Radar Subsurface Neutron Detector Close-Up Imager Drill IR Spectrometer Subsurface Drill Sample Preparation and Distribution System MicrOmega Raman Laser Spectrometer Mars Organic Molecule Analyzer The Reference Surface Mission A Suitable Landing Site Scientific Constraints Engineering Constraints Planetary Protection Constraints Possible Locations for Landing Oxia Planum (18.159°N, 335.666°E; -3km MOLA) Mawrth Vallis (22.160°N, 342.050°E; -2km MOLA) Conclusions Acknowledgments References 13. Concluding Remarks: Bridging Strategic Knowledge Gaps in the Search for Biosignatures on Mars—A Blueprint Overview: The Current Challenge Historic Perspective on Coevolution Revisiting the Intellectual Framework: Coevolution as a Guiding Exploration Principle Understanding Coevolution in a Polyextreme Environment Exploring Coevolution Investigating Loops and Feedback Mechanisms in Polyextreme Environments Crossing the Uncertainty Threshold Moving Biosignature Exploration Forward: An Ecosystem Approach to Landing Site Selection and Surface Operations Beyond Mars Acknowledgment References Index A B C D E F G H I J K L M N O P R S T U V W X Y Back Cover