Transformative Lunar Science - Brown University...• To produced transformative science in the...

Transformative Lunar Science

May 30, 2018NASA Headquarters

Members of SSERVISolar System Exploration Research Virtual Institute

Earthrise-Apollo 8 (1968)

The Blue Marble-Apollo 17 (1972)

History of Robotic-Human Exploration of the Moon

Transformative Lunar Science: Seeing the Earth From the Moon

The Moon From Earth

Earth From the Lunar Farside-Galileo (1992)

Lunar Orbiter 1-5 (1966-1967) (5/5)Ranger 1-9 (1961-1965) (4/9) Lunar Surveyor 1-7 (1966-1968) (5/7)

There Were 21 Robotic Precursor Missions Prior to Apollo 11

Human-Robotic Partnerships!

Apollo Lunar Exploration Program

Science-Engineering-Operations Synergism!

Apollo Lunar Exploration ProgramSix Scientific Expeditions to the Moon

Established the Moon as a Cornerstone For Solar System Science

LRO-Lunar Reconnaissance Orbiter (2009-Present)

LCROSS-Lunar Crater Observation and Sensing Satellite (2009)

Post-Apollo Recent Robotic Lunar Exploration

GRAIL-Gravity Recovery and Interior Laboratory (2011-2012)

Post-Apollo Recent Robotic Lunar Exploration LADEE-Lunar Atmosphere Dust and Environment Explorer (2014-2017)

January 10-12, 2018NASA Ames Research Center

Moffett Field, CA

Brown University Graduation: May 28, 2018: Planetary Geoscience PhD and MSc Graduates:Sierra Kaufman, Erica Jawin, Adeene Denton

National Commitment: ‘Bootprints on the Moon, On To Mars’:

1) Infrastructure-Lunar Orbital Platform-Gateway Workshop.2) Commercial Capabilities and Opportunities.3) Feed Forward to Mars.4) Training the Next Generation!

Introduction• Dr. James W. Head

The Present• Dr. Carlé M. Pieters

The Beginning• Dr. Bill Bottke

The Record• Dr. David Kring

Discussion

Transformative Lunar Science Examples

The PresentImaged by Galileo spacecraft in 1992As it left the Earth-Moon System

LunarFarside


SPA

UnsampledSouth Pole Aitken:The largest, deepest, oldest basin on the Moon.

LunarFarside

Albedo


SPASPA

LunarFarside

UnsampledSouth Pole Aitken:The largest, deepest, oldest basin on the Moon.

Topography

The PresentImaged by LRO in 2015As it passes over the Moon’s pole

LRO DIVINER Temperature [+ UV albedo, + H]Unexplored deeply shadowed polar areas

GSFC/ASU/LROC M1199291564L_detail

The Present Earth-Moon System

The Moon documents the environment we share at 1AU.

LRO LROC> 300 small new craters detected (temporal pairs)

The PresentEarth-Moon System

Na exosphere (liberated by photon-stimulated desorption)

Reiner Gamma

H H+

Understand and utilize the special of the Moon (and other airless bodies).

• NEW science issues Polar, Interior, Surface (SW) OH/H2O

• Tied to origin & evolution of water in the SS.

water cycle


Polar• NEW science issues

Polar, Interior, Surface (SW) OH/H2O• Tied to origin & evolution of water

in the SS.

water cycle

Feldman et al., 2001

=> LCROSSColaprete et al.2010




in the SS.

water cycle

Interior

LCROSSColaprete et al.2010

Needham & Kring, 2017




in the SS.

water cycle

Interior

Hauri et al. 2017Ann Rev

Saal et al.2008





in the SS.

water cycle

Interior

Hauri et al. 2017Ann Rev

Surface Pieters et al., 2009Clark, 2009Sunshine et al, 2009


Saal et al.2008

Water CycleIdentified only

In the last Decade!

Understand and utilize the special of the Moon

Polar 1. Identify the origin of water at 1 AU• Return samples for representative lunar pristine rocks• Measure in-situ, then obtain samples from polar deposits

2. Document mobility of volatiles on the Moon with time• Orbital measurements across latitudes at different time-of-day• Long-lived in-situ monitoring

3. Measure the magnitude of these resources [Are any renewable?]• Global assessment with modern orbital remote sensing• In-situ analyses at poles, pyroclastic deposits, young areas,

etc.

water cycle

Interior

SurfaceH2O

The PresentEarth-Moon System

Beginnings

The Beginning

Oldest lunar rocks formed 60 to 100

million years after origin of our Solar System

E.g., Boyet et al. (2015)

The Beginning

ASU,from“TheUniverse”

Over 10 to 100 Myr, hundreds of mini-planets collided and merged to yield the four inner planets

One such collision likely produced our Moon

Hartmann

Moon origin by giant impact

J. Tucciarone Color indicates temperature

Simulation data from Canup (2004); Rendering by American Museum of Natural History

How can an impact produce an Earth and Moon with identical compositions?

In most giant collisions, Moon originates primarily from impacting planet

If impactor was Mars-like, the Moon should be different than Earth. But the Earth and Moon appear identical.

Earth

Impactor

Pre-lunar disk

D17O » 0.3‰

D17O < 0.005‰D17O £ 10 ppm

D17O » 300 ppm

17O

/16O

vs.

refe

renc

e18O/16O vs. reference

Oxygen isotopes: 16O, 17O, 18O

Proposed solutions imply different Moon formation conditions

Ćuk & Stewart (2012)

Pahlevan & Stevenson (2007)

Canup (2012)

1) What is the Moon’s interior composition?

à Samples of lunar mantle

à Volcanic glasses and beads produced by explosive eruptions

2) Was the initial Moon fully molten?

à Seismic + heat flow sensor network

Lunar exploration can reveal how the Earth-Moon system formed

NASA JPL/Caltech

G. Taylor

Y. Nakamura

SPA

Gomes et al. (2005)

3) Is a Mars-like composition a good proxy for the Moon-forming impactor? Or was Mars different?

à Dating of largest lunar basins

Did giant planets migrate early as inner planets were forming? Or much later?


Late Instability

Green: outer planetesimal disk

Clement et al. (2018)


Early Instability

Earth: 1 AU; Mars: 1.5 AU

3) Is a Mars-like composition a good proxy for the Moon-forming impactor? Or was Mars different?

à Dating of largest lunar basins

Did giant planets migrate early as inner planets were forming? Or much later?

Beginnings of the Earth-Moon System

4.5 By Record for our Solar System

• It is generally recognized that many of the most influential papers in the United States are published in the journal Science.

• 124 papers with Apollo sample analyses have been published in Science, thus demonstrating that

• Lunar samples returned to Earth have generated an enormous wealth of transformative scientific knowledge.

Origin of Earth& Moon

A product ofgiant impact

Lunar magma oceanhypothesis

A differentiated worldrather than chondrite

Lunar impactcataclysm hypothesis

Wandering worldsresurface worlds

Impact-origin oflife hypothesis

Terrestrial calamities& opportunities

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• It is generally recognized that many of the most influential papers in the United States are published in the journal Science.

• 124 papers with Apollo sample analyses have been published in Science, thus demonstrating that

• Lunar samples returned to Earth have generated an enormous wealth of transformative scientific knowledge.

Origin of Earth& Moon

A product ofgiant impact

Lunar magma oceanhypothesis

A differentiated worldrather than chondrite

Lunar impactcataclysm hypothesis

Wandering worldsresurface worlds

Impact-origin oflife hypothesis

Terrestrial calamities& opportunities

Lunar magmaticepoch hypothesis

Nearside magmatismtriggered bySPA impact

Origin of Lunar(& Earth’s) Water

Delivery dominatedby asteroids,not comets

Emerging hypotheses

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Lunar Samples Provide a Record of Early Solar System Bombardment

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The Moon is the best and most accessible place in the entire Solar System to evaluate this bombardment and its consequences.

That inner Solar System record is also the best measure of the accretion and dynamical evolution of outer Solar System planets.

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GSFC SVS


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The bombardment of Earth was even more severe than that on the Moon

We estimate 200 impact basins 1000 km in size and 4 to 5 impact basins >5000 km in size were produced on Earth.

That collisional evolution eroded Earth’s primitive atmosphere, episodically vaporized its nascent seas, and likely affected the origin and early evolution of life.

Could life have emerged from an impact crater?

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That collisional evolution occurred when the Moon was much closer to the Earth than it is today.

Setting the Solar System’s Clock

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Ages of lunar surface samples calibrate the crater density “clock” used to estimate ages elsewhere on the Moon,

And also used to estimate the ages of all other planetary surfaces in the Solar System; for example ages on Mercury, Mars, and Dione.

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Old Lunar Terrain Young Lunar Terrain

Mercury Mars Dione

4.5 Ga

Evolution of Magmatic Worlds

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How long was the magma ocean molten?

How fast does a planetary crust form?

Do mantles overturn?

How long does the core dynamo operate?

How long does surface volcanism persist?

How does volcanism affect planetary environments?

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Each of thesequestions can beaddressed with

suitable samples.12005

• It is generally recognized that many of the most influential papersin the United States are published in the journal Science.

• 124 papers with Apollo sample analyses have been published inScience, thus demonstrating that

• Lunar samples returned to Earth have generated an enormouswealth of transformative scientific knowledge.

• To produced transformative science in the future, we need additional samples from other lunar surfacesites whose locations are guided by those past Apollomissions and the spectacular orbiting data that hasaccumulated over the past 45 years; e.g.

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Samples are the Key to Transformative Science in an Unexplored Land

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Rich ISRU potential too

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This pyroclastic vent is the largest indigenous source of volatiles in the south polar region

In addition, FeO and TiO2 in the basalt can produce oxygen and H2O via hydrogen reduction

It is not surprising this site was an ESMD target of interest for LROC.

Landing Sites & Traverses Designed for 14 d and 3 yr Missions

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14 days (one lunation) 3 years (HERACLES)

These are not hypothetical briefing concepts.

Detailed landing site and traverse studies already exist that used, for example, <1meter-resolution images produced by LO and LROC. They have been soundly vetted in the peer-reviewed literature.

The fidelity of these studies is so high that we have identified specific rock samples to be collected.

We are ready to go, so let’s go!

Exploring the Cosmic Dark Ages

NASAAstrophysicsDivisionRoadmap(2013): “DetailedmapofstructureformationintheDarkAgesviaredshifted21-cmobservations…Capabilitiesrequired:CosmicDawnMapper(21-cmlunarsurfaceradiotelescopearray).”

Other Farside Objectives

Z = (anow/athen) – 1where a is time-dependent cosmic scale factor

Integrated robotic and human exploration program

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Human and Robotic Assets

• The best results will be obtained by a well-trained crew on the lunar surface

• While that capability is being developed, significant progress can be made robotically or with an integrated robotic and human architecture (e.g., deploying crew to Earth-Moon L2 above the lunar far side in Orion or on an orbiting platform such as the Gateway)

• Robotic assets, such as the Lunar Electric Rover, can perform additional science and exploration tasks between human missions to the surface.

Five Simple Messages

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• Explore the unexplored: Go to the lunar farside and poles

• Leadership begins with meaningful missions: Land on the lunar surface

• To make truly transformative scientific discoveries, we need sample return missions to high-priority landing sites.

• An integrated robotic and human exploration program, with international and commercial partners, will produce the greatest science.

• Engage the public and Congress: Provide a communication relay to the farside with a high data rate and the capability of HD video.

Discussion ......

The accessible differentiated cousin of Earth

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