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Astronomy 4800 – Space Science: Practice & Policy

ASTR 4800 - Space Science: Practice & PolicyToday: Prof. B. Hynek on Robotic Exploration of Mars

• Next Class: Student presentation on How do we get humans to Mars? Reading: link on class website.

• Interview with a Space Scientist paper – names and bios due to me by Oct. 21!

• Please read your E-mail about the class 1-2 times per week.

Astronomy 4800 – Space Science: Practice & Policy

Class ExerciseDo you think NASA should spend over $10 billion on a robotic Mars sample return mission? Will we learn for certain if there is life on Mars?

The Robotic

Exploration of MarsBrian Hynek

Laboratory for Atmospheric and Space Physics

Department of Geological Sciences

University of Colorado

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NASA’s Goals:

• To advance and communicate scientific knowledge and

understanding of Earth, the Solar System, and the universe.

• To advance human exploration, use, and development of

space.

• To research, develop, verify, and transfer advanced

aeronautics and space technologies

• Mars-specific top level goals:1) Determine whether life ever arose on Mars

2) Characterize the climate of Mars

3) Characterize the geology of Mars

4) Prepare for human exploration

Mars and NASA

• Mars Exploration Program– Different than other solar system body exploration in

that it is an official program.

• Comprises roughly 1/3 of the planetary science budget of NASA– Planetary science = ~$1.6B/yr

• Large scope results in an official “architecture” to the mission scheme.– Each mission builds on prior work and

enables/enhances future missions.

– Mix of mission types – competed and NASA-center

A vibrant program of exploration:

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OK, back to the Mars Exploration

Program Top-Level Goals:Goal 1 -- Life: Determine if life ever arose on Mars

Determine if life exists today or existed on Mars in the past

Assess the extent of prebiotic organic chemical evolution on Mars

Goal 2 -- ClimateCharacterize Mars’ present and ancient climate and climate processes

Goal 3 – GeologyDetermine the geological processes that have resulted in formation of the

Martian crust and surface

Characterize the structure, dynamics, and history of Mars interior

Goal 4 -- Prepare for human explorationAcquire Martian environmental data set (such as radiation)

Conduct in-situ engineering/science demonstration

Establish infrastructure for future missions

NASA’s Exploration Plan:

“Follow the Water”

LIFE

CLIMATE

GEOLOGY

Prepare for Human

Exploration

When • Where • Form • Amount

WATE

R

Case for a Warm and Wet Mars I: Rivers

• Dense river valley networksobserved across the ancientterrains of Mars.

• Viking data suggested groundwater formation under cold-dry conditions.

• Recent data provide evidence for active, long-lived hydrologic cycle.

Mars river valley

10 km

Case for a Warm and Wet Mars II: Deltas

10 km

• Deltas require a

standing body of water.

• Over 50 known deltas

on Mars.

• Ages seem to be

coeval with valley

network formation.

Case for a Warm and Wet Mars II: Deltas

• 22 of deltas have no

local topographic

basin and open to the

northern plains.• These are all at the

same elevation, as

are 15 more nearby

deltas.

• Suggestive of a

northern ocean on

ancient Mars.

Di Achille and Hynek, 2010

Mars 3.7 billion years ago?

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fieldwork to a modern stepped fan

Case for a Warm and Wet Mars III: Minerals

Clay minerals seen across half of Mars in the ancient highlands

Ehlmann et al., 2011

3.8-3.5 Ga>3.8 Ga >3.5 Ga

River Valleys

Paleolakes

Hydrothermal activity

Ocean?

Hydrothermal

Activity

Ice

Glaciers

Groundwater

Hydrothermal activity

Elhmann et al., 2011

Definitive Signs

of Life on Earth

Early History of Mars

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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

Successful Landed Missions to Mars

'

MJLA•Based a vabons m

Curiosity e

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sulfates and silica deposits dug up

by the rover wheels

3 cm pyroclastic bomb sagSpirit rover uncovered clear signs

of acidic hydrothermal activity

Home Plate, within Gusev Crater

30 cm

Relic hydrothermal systems detected around Mars

sulfates and silica deposits

dug up by the rover wheels

Eagle EnduranceOpportunity's Traverses

Record-holding45.141km

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Victoria

Santa Maria

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BotanyBayJ

Cape Tribulation

Cape Byron t

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Cross Bedding Indicates Flowing Surface Water

- LastChance

Crossbeds

Sulfate-rich Sandstones With Hematitic Concretions

2011 Mars Science Laboratory - Curiosity

Launch: Nov. 26, 2011 on an Atlas V rocket

Land: Aug. 6, 2012

Two Earth years of planned operations while

traveling at least 20 km.

Main goals are to characterize a site that:– was a habitable environment.

– is likely to have preserved biosignatures.

– can be related to the “Big Picture”.

The Mars Rover

Family Portrait 10 feet long, nearly 2000 lbs

Wheel-base equal to a mini cooper

Nuclear powered

2003 Mars

Exploration

Rover1996 Pathfinder

2011 Mars

Science

Laboratory

A most capable robotic geologist!MSL "Curiosity" Rover Final Testing @ JPL

... -----........

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More than 5 km of strata are preserved in the central mound

Why Gale Crater?

150-km diameter crater

5o S, 222.5

oW

“Sedimentary layers are deposited in a time sequence, with

the oldest on the bottom and the youngest on the top.”

-Nicholas Steno, 17th century

“The processes operating today are the same as

those in the past.”

-James Hutton, 18th century

Example: The Grand Canyon

• 40 distinct rock layers are exposed,

spanning 2 billion years of geologic

history!

• Walking from the Colorado River up

to the rim, one can study what the

local environment was like for

nearly half of the history of the

Earth!

The Grand Canyon

times of lava flows

and mountain

building, then

massive erosion

sand dunes shallow to deep

sea sediments

with trilobite

and fish fossils

swamp muds with

fossils of ferns andsphinaelloswanmdarreinpetilecarbontraatceksswith

fosvsailstsedaesheertllosf

Vishnu Schist

layers with sulfates – acidic groundwater

and petrified dunes?

thin layers with clays – ancient lake?

massive units with

volcanic signature –

volcanic ash deposits?

We are applying the same principles at Gale Crater to assess the

geologic history of the sediments.

A traverse up the central mound will reveal the depositional environments,

the amount, duration, and chemistry of the water and address habitability

through time on ancient Mars. Mastcam-34 mosaic of Mount Sharp, descent

rocket scours, and rover shadow

NASA/JPL-

Caltech/MSSS

The Goulburn scour revealed the first look at

underlying bedrock

NASA/JPL-

Caltech/MSSS

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NASA/JPL-

Link

NASA/JPL-Caltech/MSSS

Curiosity’s Selfie Detour—Yellowknife Bay

Deviations from the plan.NASA/JPL-

Caltech/MSSS

Shaler rocks show inclined, fine layers that record

pulses of subaqueous deposition

NASA/JPL-Caltech/MSSS

Sheepbed rocks contain many spherules and filled

fractures suggesting that water percolated though pores

NASA/JPL-Caltech/MSSS

NASA/JPL-

An Ancient Habitable Environment

at Yellowknife Bay

• Key chemical ingredients for life are present, such as carbon,

hydrogen, oxygen, phosphorus, and sulfur.

• Mineralogy indicates neutral pH water and conditions were

not strongly oxidizing.

• The regional geology and fine-grained rock suggest that

Sheepbed was likely an intermittently wet lake bed.

Grotzinger et al., Science, 2014.

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from drying lak e

S6i 1555 Mastcam Image

Mount Sharp

Overall Model to Explain the RockRecord

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centimeter0 40- 60 8 0 100- -

DeltaRivers

River

deposits

Lake deposits Delta deposits

Lake deposits

NASA's Curiosit y rover drilled this two -inch-deep hole in aMartian rock as part of its examinat ionsof

the red planet's soil compo sition.

P H O T O G R A P H B Y N A S A

1 EX PLO RI N G M AR S

Building Blocks of Life Found on

MarsTwo landmark discoveriesreveal organic carb on on the red planet, shaping

the fut ure hunt for life on Mars.

SAM

• Some of the molecules

identified include

thiophenes, benzene,

toluene, and small

carbon chains, such as

propane or butene

• •... '..•ethymid

l suUide

2-methy lth iophene

3-met hylth iophene

ORGANIC MOLECULES CONTAINING SULFUR FOUND IN PAHRU MP HIL

methanethiol

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t t-::ecarbon disulfid e

,c ,o,;·•

c arbonyl sulfide

benzene chlorobenzene naphtha lene

A Lakdawalla

ORGANIC MOLECULES LACKIN G SULFUR FOUN D IN PAHRU MP HILLS SAMPLES BY CURIO SITY'S SAM INSTRUMENT

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(a) Example of a keroge n fragn1ent (b) Example of a kerogen molecule

Rgure 1fromJ.Colle/ et of.2014(DOI:http:lldx.doi.org/10.1016/j.micromeso.2014.06.016)

MODELS OF KEROGEN MOLECULES

Kerogens are large carb on-co ntaining com poun ds made of a mixture of hydrocarbon rings and chains with a smattering

of other atoms (black is for carbon, white for hydrogen, red for oxygen, yellow for sulfur, and blue for nitrogen).

Methane on Mars BUT:

The best is yet to come!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, ….

Mars 2020 Lander(will cache samples for future return to Earth)

Studying Mars' Habitability, Seeking Signs of Past Microbial Life, Collecting

and Caching Samples, and Preparing for Future Human Missions

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Key Issues with Detecting Life at Mars

• What would Mars life look like?

– We are severely biased by Earth life, which

all originated from a common ancestor.

• E.g., all Earth life has DNA/RNA; can we look for

these same characteristics for Mars life?

– Mars life probably didn’t evolve past

microbes. What instruments can definitively

detect biosignatures?

• Is sample return required?

A big worry: What if we find life on Mars but it is

just microbes we brought from Earth?

Also, what are the ethics of contaminating Mars

with Earth life?

And should we be concerned about bringing

Mars life back to Earth?

Version 7-6 / 61

Summary• The Mars Exploration Program has provided

amazing scientific discoveries in the past two

decades.

• Upcoming missions will search for evidence of

past/present life at Mars.

– Budget remains secure…fornow

• Human exploration is envisaged in the

2030s…but many details remain to be worked out