Transcript Polar design impleme..

Lunar Precursor Robotics Program
Lunar Polar Missions: Science and Instrumentation
Dr. Barbara Cohen
VP40, Lunar Precursor Robotics Program
MSFC
[email protected]
highlands
mare/maria
feldspathic
basaltic
Impact basins
Aitken crater
South Pole Impact craters
Near side
Aitken Basin
South Pole
Far side
The Moon is a terrestrial planet
Lunar Precursor Robotics Program
• The Moon today presents a record of geologic processes of early
planetary evolution:
– Interior retains a record of the initial stages of planetary evolution
– Crust has never been altered by plate tectonics (Earth) planetwide
volcanism (Venus), or wind and water (Mars & Earth)
– Surface exposed to billions of years of volatile input
• The Moon holds a unique place in the evolution of rocky worlds many fundamental concepts of planetary evolution were developed
using the Moon
· The Moon is ancient and preserves an early history
· The Moon and Earth are related and formed from a common reservoir
· Moon rocks originated through high-temperature processes with no
involvement with water or organics
Lunar framework: Giant impact
Lunar Precursor Robotics Program
• Mars-sized body slammed into the proto-Earth at 4.56 Ga
• Moon formed out of
crust/upper mantle
component - lack of
metal
• Moon material was
hot - lack of volatile
elements
• Moon/Earth have
shared angular
momentum &
oxygen isotopes
Lunar framework: Magma ocean
Lunar Precursor Robotics Program
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Differentiation via igneous processes
Basaltic volcanism via mantle density overturn
Incompatible elements in KREEP layer
Redistribution by impact processes
Lunar framework: Crater history
Lunar Precursor Robotics Program
• The Moon is the only place where
the link is forged between
radiometric ages of rocks and
relative ages by crater counting
• Crater record of the Moon reflects
the flux of impactors in the inner
solar system
• Bombardment history of the Moon
is magnified on the Earth
Lunar framework: Volatile record
Lunar Precursor Robotics Program
• Lunar plasma environment, atmosphere, regolith and polar regions
in permanent shade constitute a single system in dynamic flux that
links the interior of the Moon with the space environment and the
volatile history of the solar system
Priorities for lunar science
Lunar Precursor Robotics Program
1) Test the cataclysm hypothesis by determining the spacing in time of the creation of the
lunar basins.
2) Anchor the early Earth-Moon impact flux curve by determining the age of the oldest
lunar basin (South Pole-Aitken Basin).
3) Establish a precise absolute chronology.
4) Determine the compositional state (elemental, isotopic, mineralogic) and compositional
distribution (lateral and depth) of the volatile component in lunar polar regions.
5) Determine the lateral extent and composition of the primary feldspathic crust, KREEP
layer, and other products of planetary differentiation.
6) Determine the thickness of the lunar crust (upper and lower) and characterize its lateral
variability on regional and global scales.
7) Characterize the chemical/physical stratification in the mantle, particularly the nature of
the putative 500-km discontinuity and the composition of the lower mantle.
8) Determine the global density, composition, and time variability of the fragile lunar
atmosphere before it is perturbed by further human activity.
9) Determine the size, composition, and state (solid/liquid) of the core of the Moon.
10) Inventory the variety, age, distribution, and origin of lunar rock types.
11) Determine the size, charge, and spatial distribution of electrostatically transported dust
grains and assess their likely effects on lunar exploration and lunar-based astronomy.
Robotic lunar exploration objectives
Lunar Precursor Robotics Program
• Global mapping of the lunar surface
• Identify optimal landing site(s) on the Moon for robotic
and human explorers
• Find and characterize resources that make
exploration affordable and sustainable
• Locate and characterize lunar volatiles
• Characterize sunlight and surface environment of
poles
• Field test new equipment, technologies and
approaches (e.g., dust and radiation mitigation)
• Support demonstration, validation, and establishment
of heritage of systems for use on human missions
• Determine how life will adapt to space environments
• Emplace infrastructure to support human exploration
• Gain operational experience in lunar environments
• Provide opportunities for industry, educational and
international partners
The “dark side” and eternal light
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Permanent sunlight and shadow
Lunar Precursor Robotics Program
• Because of solar
inclination angle,
topography is
important at the poles
• Some polar high points
are in near-permanent
sunlight
• Some polar crater
floors are in permanent
shadow - cold traps!
Polar volatiles
Lunar Precursor Robotics Program
• Lunar Prospector - orbiter in 1990’s
• Carried a Neutron Spectrometer to measure H - but LP NS pixels are
large (> 40 km)
• LP data indicate polar H content of ~150-200 ppm
– H could be from solar wind (uniform distribution over light & dark areas)
– H could be as OH- or H2O from comet and asteroid input cold-trapped in
permanent shadow (heterogeneous distribution only in dark areas)
• Mission data that can help:
• Measure H content of illuminated regolith:
– If H content ~ 150 ppm, then H is of solar wind origin and uniformly
distributed
– If H content << 150 ppm, then H is probably segregated and concentrated
in cold traps
• Explore shadowed areas to determine the form, distribution, and
useability of H and other volatiles such as CO2, organic, etc.
Neutron signature
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Radar signature
Lunar Precursor Robotics Program
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
Notational site - Shackleton
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Permanently dark crater
South Pole
(Approx.)
To Earth
Landing Zone
Shackleton Rim Candidate site
0
5 km
Possible mission elements
Lunar Precursor Robotics Program
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Surface Morphology / Lighting
– Mast-mounted stereo imaging system OR alternative in dark regions such as radar /
lidar / UV / enhanced vis-IR
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Regional subsurface structure
– Seismic using an active source (lander) and passive distributed receivers
– Several mining techniques could help in this area but as yet are not fully described
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Regolith H (and other volatiles) nature and content
– Drill/penetrometers (need to penetrate below ~10 cm desiccated layer; from LP
neutron data)
– Mass Specrometer (MS) system to measure volatile species, concentration, and
isotopic ratios
– Sample handling system to get sample to instruments OR instrument to sample
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Neutron Signature
– Neutron spectrometer (ground truth orbital data)
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Geotechnical Properties
– Drill / arm to measure properties in situ with exchangeable end-effectors
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Remote sensing of Elemental and Mineralogy
– X-ray techniques (APXS from MER, Raman spectroscopy, X-ray Fluorescence XRF,
etc.)
Some possible instruments
Lunar Precursor Robotics Program
Payload Element
Objective
Mass (kg)
Mass with 30% Power
Margin (kg)
(W)
Power 30%
Margin (W)
Stereo imaging system OR Radar
OR Lidar
Acquire images of surface for geology,
topography and navigation
0.8
1.0
6.0
7.8
Mast for stereo imaging system
Provide elevation for imaging
3.5
4.6
9.5
12.4
Drill and drill deployment
mechanism
Recover regolith samples from depths of 2 m
20.0
26.0
30.0
39.0
Belly Cam
Imaging of drill interface with surface
0.4
0.5
3.8
4.9
Arm
Deploy instruments, conduct geotechnical
experiments, collect regolith samples
13.0
16.9
43.0
55.9
Scoop
Recover surface regolith samples to a depth of
TBD cm
0.5
0.7
0.0
0.0
Mass Spectrometer
Determine the various volatile compounds
present and their isotopic composition
19.0
24.7
75.0
97.5
Sample processing system for MS
Process core or scoop material for analysis.
Neutron Spectrometer
Determine the flux and energies of neutrons to
determine H content of regolith
1.0
1.3
1.8
2.3
Geotechnical Experiments - cone
penetrometer (3)
End effector for geotech properties
1.5
2.0
0.0
0.0
Geotech - bearing plate
End effector for geotech properties
1.0
1.3
0.0
0.0
Geotech - shear vane
End effector for geotech properties
0.5
0.7
0.0
0.0
Magnets
Determine magnetism of regolith particles
0.5
0.7
0.0
0.0
XRD / XRF
Mineralogy and chemistry of regolith
2
2.6
10
13
Beacon
Navigation reference
1.0
1.3
5.0
6.5
Current missions: LRO/LCROSS
Lunar Precursor Robotics Program
Proposed penetrometer missions
Lunar Precursor Robotics Program
• JAXA mission Lunar-A (now cancelled)
• http://www.isas.jaxa.jp/e/enterp/missions/lunar-a/index.shtml
• Two penetrometers, payload mass on each ~10 kg?
– Two-component seismometer
– Heat-flow probe
– Tiltmeter and accelerometer
• UK Penetrometer studies and proposals
• http://www.mssl.ucl.ac.uk/planetary/missions/Micro_Penetrators.php
• Penetrometer payload, Total Mass ~2Kg
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Accelerometer & tiltmeter
Seismometers
Thermal
Geochemistry
Options: mineralogy camera, radiation monitor, magnetometer