From habitability to life on Mars

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
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