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
The PresentImaged by Galileo spacecraft in 1992As it left the Earth-Moon System
SPA
UnsampledSouth Pole Aitken:The largest, deepest, oldest basin on the Moon.
LunarFarside
Albedo
The PresentImaged by Galileo spacecraft in 1992As it left the Earth-Moon System
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
Understand and utilize the special of the Moon (and other airless bodies).
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
Understand and utilize the special of the Moon (and other airless bodies).
Polar• NEW science issues
Polar, Interior, Surface (SW) OH/H2O• Tied to origin & evolution of water
in the SS.
water cycle
Interior
LCROSSColaprete et al.2010
Needham & Kring, 2017
Understand and utilize the special of the Moon (and other airless bodies).
Polar• NEW science issues
Polar, Interior, Surface (SW) OH/H2O• Tied to origin & evolution of water
in the SS.
water cycle
Interior
Hauri et al. 2017Ann Rev
Saal et al.2008
LCROSSColaprete et al.2010
Understand and utilize the special of the Moon (and other airless bodies).
Polar• NEW science issues
Polar, Interior, Surface (SW) OH/H2O• Tied to origin & evolution of water
in the SS.
water cycle
Interior
Hauri et al. 2017Ann Rev
Surface Pieters et al., 2009Clark, 2009Sunshine et al, 2009
LCROSSColaprete et al.2010
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?
Lunar exploration can reveal how the Earth-Moon system formed
Late Instability
Green: outer planetesimal disk
Clement et al. (2018)
Lunar exploration can reveal how the Earth-Moon system formed
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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Lunar Samples Provide a Record of Early Solar System Bombardment
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GSFC SVS
Lunar Samples Provide a Record of Early Solar System Bombardment
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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
Transformative Lunar Science....
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