Habitability of Mars as Inferred Landed Mission Observations

Ray Arvidson

Washington University in Saint Louis

Ninth International Mars Conference

7/22/19

This slide package was presented at the Ninth International Conference on Mars and is being shared, with permission from the plenary presenter. The original file has been compressed in size and converted to .pdf – please contact the presenter if interested in the original presentation.

What Does Life Need?

• Sustained environment with liquid water (i.e., the solvent)

• Biochemically crucial elements (e.g., carbon)

• Energy sources (other life, solar radiation, inorganic compounds)

• Protection from harmful effects (e.g., solar ultraviolet rays, solar flares, cosmic radiation)

• Leads to the concept of a “habitable zone” within the solar system and beyond

• Focus on what landed missions have told us about habitability on Mars

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Successful Landed Missions to Mars

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Phoenix Sol 148 SSI Mosaic 5

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What Spirit Found

Fig 22 8

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Sulfate-rich Fumarole and Silica Sinter Hydrothermal Deposits

Innocent Bystander

Norma Luker

Pancam Sol 1234 Image

Opportunity’s Traverses

Endeavour

Victoria

Endurance

Santa Maria

Cape York

Eagle

Botany Bay

Cape Tribulation

Cape Byron

Marathon Valley

Perseverance Valley

Record-holding 45.141 km

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Eagle crater

Rocks

Exit

First exit try

Eagle Crater

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First exit try

Exit

Rocks produced in an aqueous environment

Portion of Pancam Lion King Panorama

Cross Bedding Indicates Flowing Surface Water

MI

Crossbeds

Sulfate-rich Sandstones With Hematitic Concretions13

Last Chance

Portion of Pancam Sol 40 Mosaic

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Endurance

Burns cliff

Burns cliff

Burns cliff sulfate-rich sandstones provided crucial evidence for a dry-wet sabkha environment with rising ground water that led to deposition of the Burns formation strata

Pancam Sol 95 Mosaic

15Figure courtesy Joel Hurowitz, Stony Brook University

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Opportunity’s Work onEndeavour Crater’s Rim

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Cape York and Discovery of Uplifted Protolith Beneath Shoemaker Formation Impact Ejecta

Navcam Sol 3132Mosaic

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20Figure courtesy David Mittlefehldt, NASA/Johnson Space Center

Gale Crater

Mount Sharp

Curiosity

Curiosity Rover’s Setting

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Landing Wheels-Down With the Skycrane

Blast Zones

Sol 16 Navcam Mosaic22

Fluvial Conglomerate Deposits Exposed in Blast Zone

Sol 9 Mastcam Mosaic Goulburn

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Curiosity’s Traverses Midway to Mount Sharp

A 24

Mastcam View Looking South at Pahrump Hills

Mount Sharp

Organics Found

Sol 887 Mastcam ImageSol 887 Mastcam Mosaic 25

Cross Bedded Sandstones Deposited in Fluvial Channel

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Conglomerates and Sandstones Deposited in Fluvial Channel

B

Sol 796 Mastcam Image 27

Old Soakermudcracksfrom drying lake

Calcium sulfate veinsfrom rising ground water

And More Evidence From Mastcam Data for the Role of Water

Sol 1555 Mastcam Image

Sol 929 Mastcam Image 28

Fluvial and Deltaic Deposits

Lake deposits

Mount SharpOverall Model to Explain the Rock Record

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Marias Pass – Sol 1065 – A Curiosity “Selfie”

Mount Sharp

Lakebed mudstones

Fluvial sandstones

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Crystalline hematite

Smectites

Sulfate-bearing Strata

HiRISE BasemapRGB (CRISM FRT0000B6F1)2.3 µm Smectite Fe-OH3.0 µm HydrationHigh Calcium Pyroxene

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Curiosity’s Current Work

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Sol 2247 Mastcam Mosaic of Mount SharpGediz Vallis ridge

Greenheugh pediment

Glen Torridon

Sulfate-bearing Strata

Gediz Vallis

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Mars Habitability and Life Scorecard

• Sustained presence of water – yes, early in geologic time, both surface ground water

• Biochemically crucial elements – yes, remains to be seen if they were bound in appropriate compounds

• Energy sources – yes, solar, inorganic, perhaps other life

• Protected environments – yes, early Mars had a magnetic field and denser atmosphere

• More to come with Curiosity, the 2020 rover, sample return, ….

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