List of Topics
About the Editor
Associate Editor
Section Editors
Contributors
A
Absorption, Absorption Spectrum in Lunar Studies
Definition
Lunar Spectroscopy and Sensors
Lunar Geology and Its Impact on Remote Absorption Profiles
Critical Absorption Features on the Moon
Pyroxenes
Olivine
Plagioclase Feldspar
Absorption Recorded from the Spectra of Apollo Samples
Visible to Near-Infrared (300-2600 nm)
Near-Infrared/Short Wavelength Mid-Infrared (2500-8000 nm)
Mid-Infrared (7000-9500 nm)
Observations from Orbital Missions
References
Accretion of the Moon
Synonyms
Description
Introduction
Specific Character of the Earth-Moon System
Mass
Angular Momentum
Density
Composition
Theory
Accretion
Methodologies
Simulation Fundamentals
Simulating a Large Impactor
The Impact
The Accretion
Future Directions
References
Albedo of Lunar Features
Definition
Albedo of Lunar Regions
Albedo of Lunar Swirls
Space Weathering Effects
Cross-References
References
Apollo 17: The Last Time Humans Walked on the Moon
Introduction
Apollo 17 Extravehicular Activities (Moon Walks)
EVA 1
EVA 2
EVA 3
Beyond Apollo 17
Acknowledgment
References
Apollo Lunar Roving Vehicles
Rover Carriers Increased Science Return from Moon Exploration Missions
Communication and Science Equipment Carried on the Rovers
Special Tools Carried on the Rovers
Sample Collection and Stowage on Rover Carriers
Cross-References
References
Apollo Program
Introduction
Apollo Program and Science Objectives
Primary Science Results
Regional Geological Investigations and Settings
Apollo 11 [0.67N, 23.47E]
Apollo 12 [3.01S, 23.42W]
Apollo 14 [3.64S, 17.47W]
Apollo 15 [26.13N, 3.63E]
Apollo 16 [8.97S, 15.50E]
Apollo 17 [20.19N, 30.77E]
Achievements and Contributions from Apollo Samples
Major Geochemical Distinction
Mineralogy
Petrology
Close Relationship of Samples and Remote Sensing Data
Chronology
Detection of Lunar Interiors from ALSEP
Lunar Seismology
Thermal and Magmatic Evolution of the Moon
Subsatellites on Orbits
Determining Composition from Remotely Sensed Data
Subsurface Structures Determination by Lunar Radar Sounder
Cross-References
References
ARTEMIS Mission
Theory and Application
Basic Methodology
Key Findings/Scientific Outcomes
Future Directions
References
B
Barycenter of the Earth-Moon System
Definition
Barycenters
Two-Body Problem
Earth-Moon System
References
Basalt
Introduction
Sample Studies
Basaltic Samples Collected through the Apollo Missions
Basaltic Samples Collected through the Luna Missions
Lunar Basaltic Meteorites
Remote Sensing
Conclusions
Cross-References
References
Basin
Breccia
Definition
Introduction
Lunar Breccia Classification
Formation of Different Types of Lunar Breccias
Geochemistry and Age
Research Significance of Lunar Breccias
Current Research
Summary
Cross-References
Acknowledgment
References
Breccias
C
Center of Mass and Center of Figure of Moon, Gravity, and Inertia
Definition
Calculations of Offset
Lunar Topography Evolution and Surface Materials
Cross-References
References
Chandrayaan-1 Mission
Introduction
Instruments Onboard Chandrayaan-1 (Web Resources: See References)
Terrain Mapping Camera (TMC)
Hyper-Spectral Imager (HySI)
Lunar Laser Ranging Instrument (LLRI)
CIXS (Chandrayaan-1 Imaging X-Ray Spectrometer)
High Energy X-Ray Spectrometer (HEX)
Moon Mineralogy Mapper (M3)
Sub Atomic Reflection Analyzer (SARA)
Radiation Dose Monitor (RADOM)
SIR-2 (Near Infrared Spectrometer)
MIP (Moon Impactor Probe)
Miniature Synthetic Aperture Radar (Mini-SAR)
Concept of Measurement
Sample Preparation
Method of Measurement
Quantification of Water Ice
Campbell Model
Study of Variability of Permittivity and Possible Landing Sites for Chandrayaan-2 Rover Using Multi-sensors Datasets
Variations in Permittivity
Microwave Emissivity
Possible Landing Sites for Chandrayaan-2 Rover
Circular Polarization Characteristics of South Polar Lunar Craters Using Chandrayaan-1 Mini-SAR and LRO Mini-RF
Polarization and Its Properties
Synthetic Aperture Radar (SAR) and Its Backscattered Signals
Future Directions Based upon Findings of Chandrayaan-1 Mission, Leading to Chandrayaan-2
Conclusion
Cross-References
References
Web Resources
Chandrayaan-2 Mission
Introduction
Launch and Instrument
Mission Objectives
Overview of Chandrayaan-2 Mission
Orbiter Payloads
Lander Payloads
Rover Payloads
Cross-References
Future Directions
Conclusions/Summary
References
Chang´e Missions
Cross-References
References
Chlorine
Chronology, Lunar Samples
Definition
Chronology of lunar sample and its application in the study of lunar evolution
Cross-References
References
Cis-lunar Trajectory
Description
Introduction
Mission Orbits and Trajectories
Conclusions
Cross-References
References
Clementine Mission
Introduction
Mission Information and Science Objectives
Instruments
Science Results
Topographic Mapping of the Moon
Gravity Field of the Moon and Internal Structures
Water Ice in Permanently Shaded Regions at Lunar South Poles
Distributions and Abundances of Iron and Titanium
Major Geological Terranes Division and Mineralogical Properties of the Lunar Crust
Cross-References
References
Color of the Moon
References
Complex Crater
Contribution of Surface Processes to the Lunar Exosphere
Introduction
Photon-Stimulated Desorption (PSD)
Sodium and Potassium Photodesorption Experiments
H2O Photodesorption Experiments
Solar Wind Ion Irradiation
Sputtering Yield Experiments
Ion-Induced Secondary Ion Mass Spectroscopy (SIMS) Experiments
Thermal Desorption
Thermal Desorption of Adsorbed Sodium Experiments
Thermal Desorption of Adsorbed H2O Experiments
Meteorite and Micrometeorite Bombardment
Hypervelocity Impact and Pulse Laser Irradiation of Mineral Experiments
Summary and Acknowledgments
Cross-References
References
Cosmic Rays in the Lunar Environment
Summary
Introduction
Cosmic Rays in the Heliosphere and in the Earth-Moon System
Origin of Cosmic Rays
Energy Spectrum and Composition
Solar Radiation
Antimatter in Cosmic Rays
Uncharged Cosmic Rays
Interaction of Cosmic Rays with the Moon
Processes of Low-Energy Solar-Wind Ions
Production of Secondary Radiation by High-Energy Cosmic Rays and SEP
Selected Instruments
CRaTER on the Lunar Reconnaissance Orbiter
LND on Chang´E 4
Future Research
Cross-References
References
Crustal Rocks
Cryptomare and Its Mineralogy
Introduction
Different Types of Dark Halo Craters
Extent of Cryptomare Regions on the Moon
Pyroxene Mineralogy of the Cryptomare
Th Concentration in the Cryptomare Units
FeO in the Cryptomare Units
Cryptomare Versus Other Lunar Rock Lithology
Conclusions
References
Crystallization of the Lunar Magma Ocean
Description
Lunar Formation
Mode of Crystallization
Volatile Depletion
Depth of the LMO
Crystallization Sequence
Major Element Trends
Trace Element Depletions
Lunar Oxygen Fugacity (fO2)
KREEP
Rare Earth Elements (REEs)
Lunar Asymmetry
Lunar Mantle Overturn
Conditions That Enable Overturn
Summary
Cross-References
References
D
Dark Mantling Deposits
Density and Porosity
Detection of Water
Introduction
Regions of Illumination Condition
Hydrogen Distribution
Hydroxyl Distribution
Radar Experiments (Circular Polarization Ratio)
Polar Temperature
Confirming Abundance of Water Ice in Debris Plume from the Cabeus Crater in the LCROSS Impact Mission
Conclusions
References
Dielectric Constant
Differentiation of the Lunar Interior
Definition/Description
Introduction
Lunar Interior: Geochemical Constraints and Implications for Thermal Structure
Lunar Interior: Geophysical Constraints and Implications for Thermal Structure
Future Directions
Cross-References
References
E
Early Bombardment
Definition
Possible Bombardment Chronology
Lunar Samples, Basins, and Magmatism
Cross-References
References
Early Geologic History of the Moon
Introduction
Early Lunar Differentiation and Overturn
Early Magmatism
Early Paleomagnetism
Impact Processes
Summary and Future Directions
Cross-References
Acknowledgment
References
Early Lunar Structures, Engineering
Introduction
Perilous Challenges for Surviving on the Moon
Designing Lunar Habitats for Human Survival
A Hazardous ``Mantle´´ for Building Structures
Modeling Lunar Regolith for Experimentation on Earth
Simulants to Study the Chemical Behavior of Lunar Regolith when Treated
Regolith Simulants to Study Excavation and Soil Transportation
Closed-Cycle Pneumatics for Excavating and Transporting Lunar Regolith
Conclusion
References
Early Thermal Evolution of the Lunar Interiors
Definition/Description
Introduction
Formation Hypotheses and Initial State of Accreting Moonlets
Canonical Giant Impact Hypothesis
Noncanonical Giant Impact Hypotheses
Evolution of the Moonlets-Forming Disk
Initial Thermal State of Accreting Moonlets
Heat Sources
Accretional Impact-Induced Heating
Radiogenic Heating
Gravitational-Setting-Induced Heating
Tidal Heating
Cooling, Solidification, and Differentiation of the Lunar Interiors
Early Solidification by Accretion-Induced Pressure Changes
Core-Mantle Differentiation
Cooling Mechanisms: Convection and Thermal Radiation
Cooling Rates: The Balance Between Convection and Thermal Radiation
Crystallization and Fractionation of Lunar Magma Ocean and Associated Timescales
Future Directions
Cross-References
Acknowledgment
References
Eclipse, Lunar
Definition
Theory and Application: The Necessary Geometry and Types of Eclipses
Anatomy of a Lunar Eclipse
Danjon Scale
Future Directions: Scientific Uses of Lunar Eclipses
Cross-References
References
Eclipse, Solar
Definition
Theory and Application: The Necessary Geometry and Types of Eclipses
Phenomena Associated with Total Solar Eclipses
Eclipse Families
Future Directions: The Scientific Value of Total Solar Eclipses
Cross-References
References
Electromagnetic Radiation
Definition
Production of Electromagnetic Radiation
The Electromagnetic Spectrum
Radio Waves
Microwaves
Infrared Light
Visible Light
Ultraviolet Waves
X-Rays
Gamma Rays
References
Ellipsoid
Synonyms
Definition
Introduction
Ellipses and Ellipsoids
The Early Moon Orbit and Tides
Shape of the Moon´s Current Orbit
Torques and Precession
Inclination and Eccentricity
Earth-Moon Libration
Orbit Around the Sun
Cross-Reference
References
Emissivity
Introduction
Emissivity
Emissivity, Radiant and Kinetic Temperatures
Thermal Infrared Emission Spectroscopy for Compositional Mapping of Lunar Surface
References
Estimate of Lunar TiO2 and FeO with M3 Data
Introduction
Methods
Results
Conclusions
References
Evolution, Lunar: From Magma Ocean to Crust Formation
Introduction
The Lunar Magma Ocean Paradigm
New Views of the Evolution of the Lunar Crust
Remote-Sensing Records: A Compositionally Variable Lunar Crust
Lunar Meteorite Record
Sample Ages and Isotopic Anomalies
Alternative Crust Formation Models
Implications
Acknowledgment
References
Explosive Volcanic Deposits
F
FeO Abundance
Ferrous Content
Flood Volcanism
Fluorine
Formation of the Moon
G
Grabens
GRAIL Mission
Overview
Selection and Budget
Scientific Objectives and Investigations
Spacecraft
Lunar Gravity and Ranging System (LGRS)
Moon Knowledge Acquired by Middle-School Students (MoonKAM)
Launch and Lunar Transit
Science Phase and Termination
Science Data Products
Education and Public Outreach
Cross-References
Acknowledgment
References
Gravitational Field Measurements to Deduce the Lunar Interior Structure
Introduction
Spacecraft Range and Range-Rate Radio-Metric Measurements
Limitations and Innovations for Measuring the Gravity of Earth and the Moon
Gravitational Field Formulations
Subsurface Features and Compensation
Current Lunar Gravitational Field
References
H
Highland Volcanism
History of Lunar Science I
Description
Introduction
The Moon and Calendars
Motions of the Moon
The Path of the Moon
Eclipses
Lunar Standstills
Gravitational Effects
Lunar Science After the Invention of the Telescope
Theories of Lunar Formation
References
History of Lunar Science II
Description
Introduction
Lunar Exploration Missions of the Space Race
Lunar Missions after the Space Race
Highlights of Significant Discoveries from These Missions
Lunar Science as a Result of the Space Age
References
Hiten Mission
Definition
Mission Objectives and Instrumentation
Multiple Lunar Swing-by
Follow-on Missions
References
I
Impact Crater
Impact Ejecta
Definition
Introduction
Continuous Ejecta Blankets
Secondary Ejecta and Secondary Cratering
Effect of Impact Angle
Impact Melt Flows and Ponds
Depth of Excavation
References
Impact Event, Total Lunar Eclipse
Meteoroid Source
Impactor Properties and Impact Flash Temperature
Crater Size and Location
Cross-References
References
Impact Melt
Impact Processes on the Moon
Synonyms
Definition
Topographic Feature
Basic Methodology: Sample Analyses
Basic Methodology: Remote Sensing Analyses
Future Directions
Cross-References
References
For More Information Regarding Impact Crater Processes and the Cratering History of the Moon, Please See
Indigenous Lunar Volatiles
Inertia, Inertial Frame
Definition
Moment of Inertia
Lunar Reference System
Cross-References
References
Infrared Radiation
Introduction
IR Exploration of Moon
Laboratory IR Spectroscopy of Lunar Minerals and Analogues
Major Results from Infrared Exploration of Moon
Surface Mineralogy
Role and Extent of Space Weathering
Abundance and Distribution of Lunar Volatiles
Thermophysical Properties
Telescope Observations of Moon in the IR Spectral Region
Future IR Spectrometers
References
Infrared Spectroscopy
Synonyms
Definition/Description
Introduction
Principle and Applications
Applications
Basic Methodology
Conclusion/Summary
Cross-References
References
Insolation and Temperature on the Moon
Insolation
Temperature
Understanding Solar Insolation and Temperature on the Moon
Solar Insolation at the Moon
Temperatures on the Moon
Historical Observations: Ground-Based
Missions Support
Recent and Present Observations
Summary
References
Internal Structure/Mantle Motions of the Moon
References
Iron Abundance
Iron Concentration, Lunar Surface
Synonyms
Definition
Theory and Application
Basic Methodology
Using CSR Data
Lucey Model
A Linear Regression Approach
A Polynomial Regression Approach
Using LP-GRS data
Measured Gamma-Ray Counting Rate
Retrieving Iron Concentration
Influential Factors
Future Work
Cross-References
References
Iron Content
Isotopic Composition of the Moon and the Lunar Isotopic Crisis
Introduction
Origin of Isotopic Variations
Mass-Independent Isotope Composition of the Moon
Relevance of Mass-Independent Isotope Variations for the Origin of the Moon
Mass-Dependent Isotope Composition of the Moon
Relevance of Mass-Dependent Isotope Variations for the Origin of the Moon
Future Directions
Cross-References
References
Further Reading
K
Kaguya (SELENE) Mission
Definition
Mission Overview
Technical Overview
Discoveries and Research
Cross-References
References
L
Laboratory Analysis (Reflectance Spectroscopy) of Terrestrial Analogues
Theory and Application
Methodology
Research Findings
Band Center
Mineral Chemistry: Single Phase
Composite Band
Band Depth
Mineral Chemistry
Mineral Abundance: Composite Band
Particle Size Effect
Critical Mode
Future Directions
References
Large-Scale Faulting on the Moon
Definition
Styles of Lunar Faulting
Large-Scale Lunar Thrust Faults
Large-Scale Lunar Normal Faults
Future Directions
Cross-References
References
Laser Ranging
Definition
Introduction
Description of the Lunar Retroreflectors
Laser Ranging Stations
First LLR Results
Current Network
International Laser Ranging Service
Science
Lunar Analysis Centers
Last Improvements and Future
New Retroreflectors
Cross-References
References
LCROSS, Lunar Diviner Instrument
Definition
Mission Objectives
Impact Dynamics
Ejecta Plume Chemistry from Diviner
References
Legacy of the Apollo Seismic Experiments
Definition
Introduction
The Apollo Seismic Experiments
Passive Seismic Experiment (PSE)
Active Seismic Experiment (ASE)
Lunar Seismic Profiling Experiment (LSPE)
Apollo 17´s Lunar Surface Gravimeter (LSG)
Data Preservation
The Rich Legacy of the Apollo Seismic Experiments
``Expect the Unexpected´´
Shallow Structure Beneath the Stations
Crustal Thickness, Density, and Porosity
Mantle
Core
Scattering and Attenuation
Remaining Questions
Cross-References
Acknowledgment
References
LMO
LRO Mini-RF
Introduction
Miniature Radio Frequency Radar System (Mini-RF)
Mini-RF Instrument Investigation and Description
Mini-RF Instrument
Mini-RF Radar Observations for Identifying the Surface Characteristics (Rough, Smooth, or ICY) of Lunar Polar Craters
Polar Mosaics
Bistatic Observations
Mini-RF Observations for Identifying the Nature of Lunar Volatiles of the LCROSS Impact Site
Circular Polarization Ratio
Impact Site
Combined Observation of Mini-RF and Lunar Reconnaissance Orbiter Camera (LROC) of the Lunar Surface
Mini-RF Observations of the Pyroclastic Deposit of the Lunar Surface
Orientale Pyroclastic
Mini-RF Radar Observations of Lunar Impact Melts and Ejecta Flows
Mini-RF Polarimetric Data
Surface Properties of Melt Flows
Large (50+ km Diameter) Impact Craters
Medium Size Craters (20-50 km Diameter)
Small Size Craters (Diameter Less Than 20 km)
Conclusion
Cross-References
References
Web Resources
Luna Missions
Cross-References
References
Lunar Atmosphere
Introduction
Water-Group Volatiles
Helium
Argon
Metals
Conclusions
References
Lunar Atmosphere, Alkali Lunar Exosphere
Characteristics of the Lunar Alkali Exosphere
Plasma Effects
Meteoritic Influences
Atmospheric Escape
Cross-References
References
Lunar Atmosphere, Composition
Introduction
Lunar Exospheric Dust
Lunar Exospheric Structure and Composition
Remote Sensing of Na and K
Summary
Acknowledgment
References
Lunar Atmosphere, Effects of Cometary Impacts
Introduction
Stage 1: The Initial Impact
Stage 2: Fallback
Stage 3: Atmospheric Evolution
Stage 4: The Return to the Collisionless Limit
Conclusion
References
Lunar Atmosphere, Energetic Neutral Atoms
ENA Generation
ENA Measurements
The Moon Located in the Undisturbed Solar Wind
Reflection Ratio
Energy Spectrum
Magnetic Anomalies
Nightside
Backscattered Helium
Sputtered Oxygen
ENA Imaging of the Lunar Surface
The Moon Located in Earth´s Magnetosheath
The Moon Located in Earth´s Plasma Sheet
Cross-References
References
Lunar Atmosphere, Source and Loss Processes
Sources
Loss Processes
Cross-References
References
Lunar Atmosphere, Transport and Storage of Volatiles
Cross-References
References
Lunar Cartography
Synonyms
Definition
Introduction
Chronology of Lunar Mapping
1600-1958: Pre-telescope to the Space Age
1958-1972: The Beginning of Lunar Exploration by Spacecraft
Soviet Union Missions: Luna and Zond
United States Missions: Ranger, Surveyor, Lunar Orbiter, Apollo, and Mariner 10
Radar Mapping of the Moon
1989-1999: The Second Wave of Lunar Exploration
United States Missions: Galileo, Clementine, and Lunar Prospector
2003-2020: Recent Lunar Cartographic Missions
Europe: SMART-1
Japan: SELENE (Kaguya)
China Missions: Chang´e 1-4
India Missions: Chandrayaan-1, 2
United States Missions: Lunar Reconnaissance Orbiter, GRAIL
Basic Methodology
Recommended Cartographic Processing Steps
Lunar Coordinate System and Reference Frame
The Photogrammetric Control Process
Additional Online Lunar Cartographic Resources
Future Directions
Cross-References
References
Lunar Chemistry
Lunar Core Composition
Introduction
Siderophile Element Constraints on Composition of the Lunar Core
Outlook
Cross-References
References
Lunar Core Dynamo
Introduction
Timing and Lifetime of a Lunar Core Dynamo
Mechanisms for Initiating and Sustaining a Lunar Core Dynamo
Outlook
Cross-References
References
Lunar Core Formation
Introduction
Modeling Conditions of Lunar Core Formation
Outcome of Lunar Core Formation Studies Using Siderophile Element Depletions
Outlook
Cross-References
References
Lunar Crater Ejecta
Formation of Ejecta Blankets
Ejection Process
Ejecta Emplacement
Ejecta Thickness
Ejecta Blanket Classification
Morphology of Ejecta Facies
Factors Affecting Ejecta Blanket Morphology
Continuous Ejecta Blanket Features
Lunar Impact Melts
Discontinuous and Distal Ejecta Features
Distal Rays
Cross-References
References
Lunar Crater Observation and Sensing Satellite (LCROSS)
Introduction
LCROSS Mission Overview
Site Selection
Onboard Science Payload
Observational Campaign
A Deliberate Cratering Experiment
Testing the Flash, Curtain, Crater Model
Science Observations and Interpretations
Location and Time of Impact
Impact Flash
Complex Plume
Postimpact Plume Modeling
Crater
Evidence for Water
How Much Water?
Conclusions
Cross-References
References
Web Resources
Lunar Crust, Chemical Composition
Definition
Chemical Composition
Feldspathic Highlands Terrane
Procellarum KREEP Terrane (PKT)
South Pole-Aitken Terrane (SPAT)
Classification of Lunar Crustal Rocks
Pristine Basaltic Volcanic Rocks
Pristine Highland Rocks
Other Pristine Highland Rock Types
Highland Polymict Breccias
Lunar Regolith and Soil
Lunar Volatiles
Conclusions
Cross-References
References
Lunar Crust, Morphology
Definition
Morphology of the Lunar Surface
Impact Craters and Basins
Volcanic Landforms
Irregular Mare Patches (IMP)
Tectonic Features
Lunar Swirls
Conclusions
Cross-References
References
Lunar Dirt
Lunar Domes
Morphometry
Composition
Classification of Lunar Domes
Effusive Lunar Mare Domes
Putative Intrusive Domes
References
Lunar Dust Exosphere
Introduction
Impact-Generated Dust Ejecta
Electrostatically Lofted Dust
Conclusions and Future Directions
References
Lunar Dust Toxicity
Cross-References
References
Lunar Elemental
Lunar Elemental Distribution
Synonyms
Definition
Theory and Application
Basic Methodology
Lunar Soil
Lunar Mare Basalt
KREEP
Highland Rocks
Key Research Findings
Future Directions
References
Lunar Fragments
Lunar Geodesy
Lunar Geological Timescale
Cross-References
References
Lunar Glasses
Lunar Impact Event: The 11 September 2013
Meteoroid Source
Impactor Energy and Mass
Crater Size and Location
Cross-References
References
Lunar Impact Events, Luminous Efficiency and Energy of
Introduction, the Luminous Efficiency
Calculation of the Luminous Efficiency.
References
Lunar Impact Flashes, Causes and Detection
Cross-References
References
Lunar Impact Flashes, Temperature
Cross-References
References
Lunar Impact Melt Deposits
Definition
Introduction
Earlier Work
New Findings
Impact Melt at Small Craters
Impact Melt Mobility
Impact Melt Morphology and Structure
Large-Scale Mineralogical Character of Impact Melt
Impact Melt Differentiation
Future Directions
References
Lunar Interior, Geophysical Models
Introduction
Crustal Structure and Seismicity
Mantle Structure and Seismicity
The Core and the Core-Mantle Boundary
Heat Flow and Thermal Structure
Future Directions
Cross-References
References
Lunar Interior, Halogens
Synonyms
Definition
Theory and Application
Basic Methodology
Bulk Rock
Glass Beads and Melt Inclusions
Apatite
Chlorine Isotopes
Estimates of the F and Cl Contents of the Lunar Mantle
Future Directions
References
Lunar Ionosphere
Introduction
Comparison with Planetary Ionospheres
Space Plasma Environments Encountered by the Moon
Sources, Sinks, and Dynamics
In Situ Measurements During the Apollo Era
Distant Detections of Lunar Ions in the Solar Wind
Twenty-First-Century Observations from Lunar Orbit
Early Radio Occultation Measurements
Recent Radio Occultation Experiments
Possible Mechanisms for Producing a ``Dense´´ Ionosphere
Conclusions
References
Lunar Landscape, Highlands
Definition
Characteristics of Lunar Highland
The Formation of Highland
Future Directions
Cross-References
References
Lunar Landscape, Impact Craters
The Near Side
The Far Side
The Highlands
The Maria
Impact Craters
Cross-References
References
Lunar Landscape, Maria
Definition
Characteristics of Lunar Mare
The Formation of Mare
Future Directions
References
Lunar Landscape: Domes
Definition
Classification of Lunar Domes
Effusive Lunar Mare Domes
Candidate Lunar Intrusive Domes
Distribution and Morphometry
Summary
References
Lunar Landscape: Grabens
Synonyms
Definition
Theory and Application
Pattern of Grabens on the Lunar Surface
Age of Lunar Graben
Formation of Lunar Graben
Key Research Findings
References
Lunar Landscape: Rilles
Definition
Classification and Distribution
Previous Studies
Approximate Earth Observation
Remote Observation of the Moon
Based on Geology Morphology
Based on Geology Process
Summary
Cross-References
References
Lunar Landscape: Wrinkle Ridges
Wrinkle Ridge
The Definition of Wrinkle Ridge
The Characteristic of Wrinkle Ridge
The Classification of Wrinkle Ridge
Concentric Ridges
Parallel Ridges
Isolated Ridges
The Methodology of Wrinkle Ridge
Wrinkle Ridges on Other Planets
The Future Directions of Wrinkle Ridge Research
References
Lunar Lava Tubes
Heading Description
Theory and Application (as Appropriate)
Basic Methodology
Key Research Findings
Future Directions
Cross-References
References
Lunar Length of Day
Definition
Orbit and Rotation
Sidereal vs Synodic
Cross-References
References
Lunar Libration
Definition
Theory and Application: General Lunar Motion and Librations
General Lunar Motion
Libration in Longitude
Libration in Latitude
Diurnal Libration
Physical Libration
The Libration Zones
Importance of Understanding Lunar Libration
References
Lunar Magma Ocean
Synonyms
Definition
Theory and Application
Crystallization Experiments
Future Work
Cross-References
References
Lunar Magma Ocean Theory, Origins, and Rationale
Introduction
The Origin of the LMO Model
Geochemical Evidence for Large-Scale Melting of the Moon
A Global, Ancient, Plagioclase-Rich Crust
The Complimentary Geochemistry of the Crust and Mantle
The KREEP Reservoir and Its Geochemical and Isotopic Homogeneity
Concluding Remarks
References
Lunar Magma Ocean, A Benchmark of Lunar and Planetary Geologic Theory
References
Lunar Magma Ocean, Comparison to Other Planetary Magma Oceans
Introduction
Mechanisms of Heat Production during Early Planetary Evolution
Planetesimals: Asteroid Vesta and the Angrite Parent Body
Mars
Earth
Mercury
Outlook
Cross-References
References
Lunar Magma Ocean, Composition of the Bulk LMO
Introduction
Bulk LMO Estimates
Major and Trace Elements
The Taylor Perspective (TWM)
The Longhi Perspective (LPUM)
Consequences of Differing Bulk LMO Estimates
Garnet in the Lunar Mantle
Future Directions and Concluding Remarks
References
Lunar Magma Ocean, Pre-Apollo, Apollo, and Post-Apollo Views
Theory
Pre-Apollo
Apollo
Post-Apollo
Geochemical Views
Geophysical Views
Geochronological Views
Cross-References
References
Lunar Magma Ocean, Size
Introduction
Geochemical Constraints on the Depth of the LMO
Geophysical Constraints on the Depth of the LMO
Conclusions
References
Lunar Magnetic Anomalies
Former Lunar Internal Magnetizing Field
Geologic Origin of Magnetic Anomaly Sources
The Lunar Swirls and Space Weathering
Cross-References
References
Lunar Mapping
Lunar Mare Basalts, Stratigraphy of
References
Lunar Melts, Densities of
Introduction
Lunar Picritic Glasses
Quantitative Constraints on Density of Lunar Melts
Current Status
Outlook
Cross-References
References
Lunar Melts, Viscosity of
Definition
Introduction
Quantitative Constraints on Viscosities of Lunar Melts
Implications for Lunar Evolution/Current Status
Outlook
References
Lunar Meteorites
Cross-References
References
Lunar Mineral Distribution
Silicate Minerals
Pyroxene
Plagioclase
Olivine
Silica Minerals
Other Silica Minerals
Oxide Mineral
Ilmenite
Spinels
Armalcolite
Other Oxides
Sulfide Mineral
Troilite
Other Sulfides
Native Fe
Phosphate Minerals
Cross-References
References
Lunar Occultations, Grazing
Introduction
History of Grazing Occultations
Early Grazes Found by Thomas van Flandern at the USNO
References
Lunar Orbit
Lunar Particles
Lunar Permanently Shaded Areas
Definition
Introduction
Applications and Theory
Conclusion/Summary
Cross-References
References
Lunar Photometry
Lunar Orbit, Distance, and Solar Phase Angle
Photometry Introduction
Key Research Findings: Photometric Models
Geometric Albedo of the Moon
Future Directions
References
Lunar Primitive Crust, Evolution of
General Overview
Magmatic Evolution of the Lunar Crust
Lunar Crustal Composition
Lunar Crustal Rocks
Lunar Crustal Minerals
Lunar Crustal Chemistry
Crustal Variations with Depth
Limitations in Previous Studies
References
Lunar Prospector Mission
Introduction
Mission Information and Science Objectives
Instruments
Science Results
K, Th, (U), and KREEP from GRS
Elements of Lunar Composition (Fe, Ti, Mg, Al, Ca, Si, O, Gd, Sm) by GRS and NS
Improved Gravity Models and Magnetic Field of the Moon and the Core Size Derived
Potential Evidence of Presence of Water Ice at the Poles
Maps of Neutron Flux
Cross-References
References
Lunar Reconnaissance Orbiter (LRO) Mission
Introduction
Mission Information and Science Objectives
Instruments
Main Science Results
Submeter-Scale Images for Assessing Past and Future Landing Sites and Feature Sites
Morphology and Tectonics Studies of the Lunar Surface with High-Resolution Topographic Maps
Illumination Condition at the Poles
Water Ice Deposits at the Poles
The Newest Distribution of Permanently Illuminated and Shadowed Areas on the Moon
Distribution of Silicate Rocks and Highly Evolved Magma
Maps and Images from LRO Mission
References
Lunar Regolith Simulants
Synonyms
Definition
Application
Need for Simulants
Types of Simulants
Producing a Simulant
Limitations of Simulants
Examples of Simulants
Cross-References
References
Lunar Regolith: Materials
Synonyms
Introduction
Lunar Volcanic Glasses
Lunar Impact Glasses
Glass Spheres Versus Glass Shards (Angular Fragments)
Target Material
Crater Size
Agglutinates
Other Glassy Particles
Human Exploration
Particulate Matter
Helium-3
Water
Conclusion
References
Lunar Rocks
Synonyms
Definition
Theory and Application
Basic Methodology
Concepts and Examples
Ferroan Anorthositic Suite
Magnesian Intrusive Suite
Alkali Intrusive Suite
KREEP Basalts
Breccias
Mare Basalts
Pyroclastic Deposits
Lunar Meteorites
Recent Key Research Findings
Future Directions
More Information
References
Lunar Soil
Lunar Soil Simulants
Lunar Surface Composition from X-ray Fluorescence Measurements
X-Ray Fluorescence (XRF)
X-Ray Fluorescence for Elemental Mapping
Summary
Cross-References
References
Lunar Surface, Bulk Density and Porosity
Synonyms
Definition
Theory and Application
Basic Methodology
Early Inferred Values of Bulk Density Based on Remote Sensing
Robotic Measurements of Bulk Density on the Lunar Surface
Inferred Values of Bulk Density Based on Correlations with Simulated Lunar Soil
Measurements of Bulk Density on Returned Core Samples
Best Estimates of Bulk Density
Porosity of Lunar Soil
Density Versus Depth: Some Speculation
Future Directions
Cross-References
References
Lunar Surface, Dielectric Permittivity
Synonyms
Definition
Theory and Application
Basic Methodology
Best Estimates
Future Works
Cross-References
References
Lunar Surface, Electrical Conductivity
Synonyms
Definition
Theory and Application
Basic Methodology
Best Estimates of Electrical Conductivity
Related Work
Cross-References
References
Lunar Surface, Gravity Field
Definition
Theory and Application
Basic Methodology
Spherical Harmonic Potential Model
Discrete Mass Model
Line of Sight (LOS) Acceleration Model
Development of Gravity Model
Lun60D Model
Gravity Models from Clementine: GLGM-1, 2, and 3
Models Based on Lunar Prospector Data
Models Based on SELENE Data
Models Based on Chang´E Data
Models Based on LRO LOLA Data
Models Based on Grail Data
Future Work
Cross-References
References
Lunar Surface, Interaction of the Solar Wind with Upper Regolith
Definition
Implantation of Protons
Amount of OH
Alteration of the Regolith
Wind Spacecraft
The Apollo SWC Experiment
Cross-References
References
Lunar Surface, Magnetic Field
Definition
Theory and Application
Basic Methodology
Measurement at Moon Surface
Measurement from Lunar Orbit
Indirect Measurements
Best Estimates
Future Work
Cross-References
References
Lunar Surface, Seismic Properties
The Apollo Passive Seismic Experiment
The Sources of Seismicity
Deep Moonquakes
Thermal Moonquakes
Shallow Moonquakes
Meteoroid Impacts
The Application of the Seismic Data
Future Work
Need for a Global Lunar Seismic Network
Required Technological Advances
Cross-References
References
Lunar Tectonics
Cross-References
References
Lunar Tectonism, History of
Definition
Introduction
Extensional Structures
Shortening Structures
Synthesis
Cross-References
References
Lunar Terrane Tectonics
Highland-Mare Dichotomy
FHT-PKT-SPAT Ternary Geochemical Terrane Tectonics
Highland-Mare-SPA Ternary Terrane Tectonics
Cross-References
References
Lunar Transient Phenomena
Definition
Overview
History
Observing Programs
TLP Statistics
Theories
Summary
References
Lunar Ultraviolet Spectroscopy
Definition/Description
Past and Current Projects
Composition of the Lunar Exosphere
Albedo
Hydration
Weathering
Lunar Swirls
References
Lunar Volatiles
M
Magmasphere
Magnetic Properties at the Lunar Surface
Definition
The Apollo Mission and Natural Remanent Magnetization
Present Study of Magnetic Field
Investigation on Origin of Lunar Magnetism
Cross-References
References
Magnetometry
Definition/Description
Introduction
Orbital Lunar Magnetometers
Surface Lunar Magnetometers
Toward the Future
References
Mantle
Introduction
Geophysical Constraints
Remote Sensing Constraints
Lithological Constraints
Geochemical Constraints
Cross-References
References
Mantle Convection
Introduction
General Concept of Mantle Convection
The Initial Stage Is Set by LMO Crystallization
Symmetric LMO Crystallization and Mantle Overturn
Symmetric LMO Crystallization and Mantle Mixing
Asymmetric LMO Crystallization and Mantle Dynamics
Conclusion and Outlook
Cross-References
References
Mantle Rocks
Mare Basalt
Mascons
Definition
Morphology and Formation
Examples of Mascons
Cross-References
References
MIDAS System
Cross-References
References
Modeling of the Lunar Magma Ocean
Definition/Description
Introduction
Key Model Parameters
Crystallization Sequence
Interstitial Melt
Bulk Composition and Initial Thickness
Heat Budget
Tidal Heating
Key Constraints on Models
Thickness and Age of the Crust
Hemispheric Asymmetry
Outlook
Cross-References
References
Moon
History
Overall Lunar Geology
Lunar Magma Ocean and the Lunar Interior
Impact Processes and the Lunar Surface
Lunar Regolith
Major Lunar Terranes
Procellarum KREEP Terrane
The Lunar Basaltic Maria
Feldspathic Highlands Terrane
The Plutonic Suites
South Pole-Aitken Terrane
Summary
References
Moon: Origin, Alternative Theories
Definition
Capture
Fission
Co-accretion
References
Moon: Seismicity
Definition
Introduction
Artificial Impacts
Meteoroid Impacts
Shallow Moonquakes
Deep Moonquakes
Thermal Moonquakes
Acknowledgment
References
Multi-ring Basin
N
Noble Gases
Definition
Introduction
Helium
Neon
Argon
Radon
Summary
Cross-References
References
Non-mare Volcanism
O
Opposition Effect
Definition
Theory and Application: Physical Causes and Mechanisms
Observations and Results
Modeling the Opposition Surge
Summary
Cross-References
References
Optical Maturity (OMAT)
Definition
Introduction
Theory and Application: How OMAT Is Determined
Results and Applications of OMAT
Conclusions and Future Directions
Cross-References
References
Orbit of the Moon
Origin and Evolution of the Moon: Tungsten Isotopic Constraints
Introduction
Key Principles: Tungsten Isotopes and the Hf-W Chronometer
Tungsten Isotope Studies of Lunar Samples
Key Research Findings
Timescales of Lunar Differentiation
Origin of 182W Excess in the Moon
Constraints on the Origin of the Moon
Conclusions and Outlook
References
Origin of the Moon, Impactor Theory
Definition
Impactor Theory
Evidence for Planet-Scale Collision
Theia
Isotope Constraints
References
P
Peak-Ring Crater
Plasma Environment of the Moon
Global Plasma Interaction with the Moon
Near-Surface Plasma Interaction
Lunar Magnetic Anomalies
Final Remarks
Acknowledgment
References
Polar Ice on the Moon
Definition
Observational and Theoretical Evidences
Characteristics of H2O Occurrence
Modeling of Polar H2O on the Moon
Ice Formation Methods
References
Polarimetry Measurements of the Moon
Theory, History, and Application
Basic Methodology
Disk-Integrated Polarization Results
Disk-Resolved Polarization Measurements
Earthshine Studies
Polarization of the Moonlit Sky
Radio Studies
Key Research Findings
Future Directions
Cross-References
References
Pristine Rocks
Pyroclastic Deposits, Remote Sensing of
Synonyms
Definition
General Overview
Detailed Description of Lunar Pyroclastic Deposits from Remote Sensing Data
Remote Sensing of Regional Pyroclastic Deposits
Remote Sensing of Localized Pyroclastic Deposits
Marius Hills
Broader Impacts and Future Directions
Cross-References
References
R
Radiation Environment of the Moon
Introduction
Basic Concepts
Space Radiation Environment on the Lunar Surface
Cancer Risk Evaluation
References
Radio Astronomy with the Moon
Introduction
Lunar Environment
Lunar Radio Pathfinder Missions
Future Directions and Plans
References
Ranger Missions
The Beginnings
Block I and II Ranger Missions
Block III Ranger Missions
Reflectance Spectrophotometry
Reflectance Spectroscopy
Synonyms
Definition/Description
Introduction
Theory and Applications
Basic Methodology
Future Directions
Conclusions/Summary
Cross-References
References
Reflection and Emission of Radiation from the Moon
Definition
Theory and Application
Basic Methodology
Optical Astronomy
Radar Astronomy
Thermal Emission Astronomy
Future Work
Cross-References
References
Reflectivity
Definition
Theory and Application
Identification and Mapping of Lunar Major Minerals
Identification and Mapping of Lunar Major Elements
Identification and Mapping of Lunar Hydrated Minerals
Interpretation of Lunar Maturity
Key Research Findings
Conclusion
References
Regolith Physical Properties
Definition
Regolith Thickness
Particle Size
Particle Shape
Specific Gravity
Porosity
Bulk Density
Thermal Conductivity
Thermal Capacity
Electrical Conductivity
Photoconductivity
Dielectric Permittivity
Cross-References
References
Regolith Production by Thermal Stress Weathering
Definition/Description
Introduction
Thermal Breakdown of Regolith
References
Regolith Structure
Basic Theory of the Regolith Structure
The Concept of the Lunar Regolith
The Formation Process of Lunar Regolith
The Characteristics of the Lunar Regolith
The Composition of the Lunar Regolith
Agglutinates
Crystalline Lithic Fragments
Breccias
Mineral Fragments
Glass
The Key Research Findings of the Lunar Regolith
The Studies of Lunar Regolith Samples
The Measurements to the Lunar Regolith Thickness
The Spectral Properties of the Lunar Regolith
The Future Directions of the Lunar Regolith
Cross-References
References
Regolith Thickness
Introduction
Methodology
Results and Discussion
Regolith Thickness from In Situ FeO+TiO2 Values
Regolith Thickness Estimation over Infilled Crater Floor
Summary
References
Remote Sensing in the Thermal Infrared
Description
Background
Earth-based Observations
Spacecraft Observations
Future Observations
References
S
Saros Cycle
Definition
Introduction: A Brief History
Description of How Saros Works
A Harmony of Months
Saros and Solar Eclipses
Saros and Lunar Eclipses
Conclusion
Cross-References
References
Satellite, Natural
Definition
Theory and Application: The Earth-Moon System
Origins and Orbits
Summary
Cross-References
References
Selenodesy
Synonyms
Definition
Introduction
History of Selenodesy
Theory and Application
The Figure(s) of the Moon
Lunar Coordinate System and Reference Frame
Basic Methodology
Point Positioning
Telescopic Measurements
Photogrammetry
Ranging
Laser Altimetry
Measuring the Moon´s Gravity Field
Satellite Gravimetry
Surface Gravimetry
Additional Online Selenodesy Resources
Future Directions
Cross-References
References
Shock Metamorphism
Definition
Introduction
Shock Features
Shatter Cones
Undulatory Extinction
Mosaicism
Planar Microstructures
Diaplectic Glass
High-Pressure Polymorphs
Methods to Study Shock Features
X-Ray Diffraction
Cathodoluminescence (CL)
Infrared Spectroscopy
Raman Spectroscopy
Dynamic Shock Experiments
Progressive Shock Metamorphism
Future Directions
Cross-References
References
Sidereal Period
Definition
Theory and Application: Sidereal Versus Synodic Period
Orbital Period Defined
The Lunar Months and the Lunar Sidereal Period
Summary
Cross-References
References
Siderophile Elements in the Lunar Mantle
Introduction
Estimating Siderophile Elements in the Bulk Silicate Moon
Abundances of Siderophile Elements in the Lunar Mantle
Outlook
References
Silica, Silicate
Introduction
Lunar Mineralogy
Silicate Minerals
Olivine
Pyroxene
Plagioclase Feldspar
Silica
Rare Silicate Minerals
Global Lunar Silicates Obtained Through Remote Sensing
Summary
References
Silicic Volcanism
Silicic Volcanism on the Moon
Synonyms
Description/Comments
Definition
Overview
Key Research Findings
Future Directions
Cross-References
References
Simple Crater
SMART-1 Mission
Introduction
Mission Design
Technology Objectives
Scientific Objectives
Spacecraft
Solar Electric Primary Propulsion
Payload
Trajectory Design
Mission Operations
Launch and Early Operations
Cruise Phase
Lunar Phase
Impact and End of Mission
Science and Exploration Results
Lunar Polar Studies
Collaborations with Other Lunar Missions and Preparation for Future Exploration
Conclusion
Acknowledgment
References
Bibliography
Specific Conductance
Spectral Reflectance
Subsurface Geology from Remote Sensing
References
Sulfides in the Moon
Introduction
Formation Mechanisms and Chemical Composition of Primary Troilite in Lunar Samples
Sulfide Saturation of the Lunar Mantle?
Sulfur Contents of the Bulk Moon and Loss of S?
Outlook
Cross-References
References
Surface and Near-Surface Thermal Environment of the Moon
Introduction
Observations
Remote Sensing of Surface Temperature
Bolometric Brightness Temperature
Field of View of the Instrument and Integration Time
The Nature of Lunar Regolith
Emissivity of the Lunar Surface
Surface Roughness
Thermal Skin Depth
Scientific Results and Questions
Permanently Shadowed Regions and Cold Trapping of Volatiles
Heat Flow
Cold Spots
Surface Rock Abundance
References
Surface of the Moon, Distribution of Materials and Structures
Introduction
Lunar Rocks
Mare Basalt
Highland Anorthosite
Lunar Minerals
Silicate Minerals
Oxide Minerals
Lunar Chemistry
PKT
FHT
SPA
Lunar Structure
Lunar Water
Future Directions
References
Surveyor Imagery
Introduction
Comments on the Quality of the Images
Sample Image Frame
Brief Science Results from the Imagery
References
Journal Articles
Conference Papers
Technical Reports
Books
Surveyor: The Science
Surveyor: The Science
Experiments Onboard the Surveyor Landings
Summary of the Major Scientific Results of the Five Successful Surveyor Landings
Results Specific to Each Experiment
Television
Topographic Mapping Methods
Soil Mechanics and Surface Sampling Experiment (SM/SS)
Alpha-Scattering Instrument Experiment (ASI) (Fig. 9)
Lunar Surface Temperatures and Thermal Characteristics (Missions All)
Lunar Surface Electromagnetic and Magnetic Properties (Missions V, VI, VII)
Magnet Experiments (Missions V-VII)
Laser Beams Pointing Tests (Mission VII)
Astronomical Observations
Effects of Lunar Particles on Spacecraft Surfaces (Missions All)
Unexpected Observations
Summary
Cross-References
References
Journal Articles
Technical Reports
Surveyor: The Spacecraft
Surveyor Pointed the Way to the Moon
Basic Design Features
The Pathfinder Surveyor-1 Test, Launch and Mission History
A Personal View of the Surveyor Project and the Climate of the Times: Walt McCandless, Surveyor-1 Test Director, Hughes Aircra...
The Technology Base
Teamwork
Top-Down Support
Result
Instruments Aboard Surveyor Missions
The Surveyor Television Camera
Camera Optical System
Camera Modes of Operation
Camera Calibration
Lunar Environment Results
The Soil Mechanics and Surface Sampler Instrument (SM/SS)
Alpha Scattering Instrument
Summary
Cross-References
References
T
The Giant Impact Hypothesis
The Lunar Atmosphere and Dust Environment Experiment (LADEE) Mission
Definition
Introduction
LADEE Mission
Spacecraft
Instrumentation
Neutral Mass Spectrometer (NMS)
Ultraviolet-Visible Spectrometer (UVIS)
Lunar Dust Experiment (LDEX)
Laser Communication Demonstration
References
Thermal Infrared Spectroscopy
Thermal Stress Weathering of Boulders on Airless Bodies
Definition
Types of Stresses
Rock Properties
Damage Effects
Cross-References
References
Thermophysical Behavior of the Lunar Surface
Introduction
Significance of Thermophysical Behavior and Heat Flow on the Moon
Previous Measurements and Inferences
Remote Observations
Ground-Based Observations
Orbiter Observations
In Situ Observations
Model Studies
Status of Current Understanding
Lunar Surface Thermophysical Properties and Their Interdependence
Open Questions
Summary and Future Course of Directions
Cross-References
References
Topographic Studies of the Moon
Introduction
Scope
Lunar Topographic Structures
Techniques
Telescopic
Spacecraft
Data Sources and Software
Atlases
Books
Amateur Images
Solar System Exploration Research Virtual Institute
Lunar and Planetary Institute
SAO/NASA Astrophysics Data System
Software
Lunar Terminator Visualization Tool
Ephemeris Data
References
Total Lunar Occultations
Basics of Occultations
Scientific Uses of Occultations
Lunar Occultations
What You Need in the Way of Knowledge and Equipment
What an Observer Should Expect to See
The Need for Accurate Timing
IOTA
Cross-References
References
U
Ultraviolet Radiation
Definition
Lunar Dusty Plasma
Apollo 17 UVS
LADEE UVS
Cross-References
References
V
Vibrational Spectroscopy
Visible and Near-Infrared Spectroscopy
Synonyms
Definition/Description
Introduction
Theory and Applications
Spectral Characteristics of Important Lunar Minerals in VNIR Region
Key Research Findings
Future Directions
Conclusion
Cross-References
References
Volatiles on the Lunar Surface and Subsurface
Definition
Introduction
Lunar Polar Volatiles
Global, Nonpolar Lunar Volatiles
Summary
Cross-References
References
Volcanic Glass
Volcanic Processes on the Moon
Synonyms
Definition
Basic Methodology
Concepts and Examples
Composition of Returned Lunar Basalts
Flood Basalts
Shield Volcanoes
Pyroclastic Deposits
Nonbasaltic Volcanism
Sinuous Rilles and Lava Tubes
Cryptomaria and Dark-Haloed Craters
Domes and Cones
Ages of Basalts
References
W
Water in the LMO
The Dry Moon Paradigm
The Fate of H2O, F, and Cl in the LMO
Abundance of Volatiles in the Mantle
Abundance of Volatiles in urKREEP
Abundance of Volatiles in the Bulk Silicate Moon
Source(s) and Timing of Delivery of Indigenous Lunar Water
Future Directions
References
Weathering
Definition/Description
Space Weathering: A Historical Perspective
Space Weathering Processes: The Different Agents of Space Weathering
Impact from Micrometeoroids (Small ``Dust´´ Particles or Debris)
Radiation Damage from Electromagnetic Radiation and Energetic Particles
The Primary Agents of Space Weathering
Solar Wind
Solar Cosmic Rays
Galactic Cosmic Rays
Maturation and Evolution of the Lunar Regolith
The Effects of Space Weathering
References
Y
Young Volcanism on the Moon
Introduction
The Topical Phase of Lunar Volcanism (<100 Ma)
The Lowell Crater Formation, Orientale Basin
The Ina and Similar Features
Discussion
Concluding Remarks
References
Z
Zond Missions
Cross-References
References
