Lecture EPFL Water on Mars

Water on Mars. Past and presentLecture 7

Tuesday, November 12 2013 Dr Harold Clenet, EPSL, EPFL

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Outline


• History of Mars exploration and relationship with water• Why Mars and why water?• Insight from space probes• Water on Mars through time

• Actual water reservoirs• Today’s atmospheric conditions• Polar ice caps• Near subsurface ice• Subsurface ice

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Why Mars and why water?


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Why Mars and why water?


©NASA

What are the current outstanding questions to drive future exploration?• When and where did liquid water persist with a

sufficiently high activity to support life? Did life or pre-biotic chemistry develop?

• What drove a fundamental change, from the Noachian to Hesperian periods, in the surface environment recorded in aqueous deposits?

• How did Mars' internal evolution influence the surface environment?

5Tuesday, November 12 2013 Dr Harold Clenet, EPSL, EPFL

Insight from space probes

Percival Lowell(≈1900)




Mariner(1965-1971)

Viking(1975)




Viking(1975)



Mars Global Surveyor1996

Mars Express2003

Mars Reconnaissance Orbiter2005Mars Odyssey

2001

Global mapping with many observation techniques



MGSMOC - 1996

MExHRSC - 2003

MROCTX & HiRISE - 2005

MOGRS - 2001

MOTHEMIS - 2001

MGSTES - 1996

MExOMEGA - 2003

MROCRISM - 2005

MROSHARAD - 2005

MExMARSIS - 2003

Radar

Thermal infrared

Visible – Near Infrared spectroscopyVisible optical imagery

Gamma spectroscopy



Radar

Thermal infrared

Visible – Near Infrared spectroscopyVisible optical imagery

Gamma spectroscopy



MGSMOLA - 1996

MGSMOC - 1996

MExHRSC - 2003

MROCTX & HiRISE - 2005


Water on Mars through time

Evidence of water from:• Morphology• Mineralogy



Evidence of water from:• Morphology• Mineralogy



Valley networks

THEMIS IR Mosaic in the Warrego Valles area

HIRISE image Small Valley Networks in the AncientSouthern Highlands (ESP_012519_1320)



High rate of erosion for the craters in the southern

hemisphere

Lake deltas and fans











Large scale detections: Clays in Mawrth Vallis

Local detections: Clays in Nili Fossae region

Minerals that need water to be produced





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Outflow channels

MOLA in the Kasei Valles area



Resurfacing of North planes and rampart craters



Terra Meridiani (Opportunity)Interior Layered Deposits (ILD) in Valles Marineris (HRSC)



Sulfates in ILD Sulfate over clays in Colombus crater



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Layered deposits on the North polar cap



Gullies



gullies

viscous flow

Low-latitude gullies

Brine with ferric sulfate

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Outline

Tuesday, November 12 2013

• History of Mars exploration and relationship with water• Why Mars and why water?• Insight from space probes• Water on Mars through time

• Actual water reservoirs• Today’s atmospheric conditions• Polar ice caps• Near subsurface ice• Subsurface ice

Dr Harold Clenet, EPSL, EPFL


Today’s atmospheric conditions

Atmospheric pressure560 Pa

Temperatures-133°C / 27°C

Atmosphere95.3% CO2

No liquid water at surface conditions


Polar ice caps


Polar ice caps


Polar ice caps

South Polar Ice Cap: 1.6 x 106 km3, which is equivalent to a global water layer of approximately 11 meters thick


Near subsurface ice


Near subsurface ice


Near subsurface ice


Subsurface ice

Found in few place under the surface (depths 1 to 3 km)Represent 1% of the total water volume contained in the polar

caps, equivalent to a global water layer 20 cm thick.

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Summary

Tuesday, November 12 2013

• Evidence for liquid water during Mars history• Noachian warm and wet

• Valley networks• Craters erosion• Deltas and fans• Hydrated minerals

• Hesperian colder and dryer but water still present• Outflow channels• Rampart craters• Sulfates and layered deposits

• Amazonian to present• Almost no water activity except at high latitudes and in polar caps

• Actual water reservoirs• Polar ice caps• Near subsurface ice• Subsurface ice

Dr Harold Clenet, EPSL, EPFL

Education

Lecture EPFL Water on Mars