Lunar Site Preparation and Outpost Setup Workshop October 20 & - - PowerPoint PPT Presentation

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Lunar Site Preparation and Outpost Setup Workshop

LUNAR SITE PLANNING WORKSHOP ASCE/NASA

October 20 & 21, 2009 Huntsville, AL

Implications of Geology for Construction

Doug Rickman

IMAGE IMAGE

American Society of Civil Engineers Aerospace Division, Space Engineering & Construction Committee p p g g NASA, Constellation Program Lunar Surface Systems, Habitation Team, MSFC Advanced Concepts Office

https://ntrs.nasa.gov/search.jsp?R=20090043187 2018-03-12T07:14:27+00:00Z

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LUNAR SITE PLANNING WORKSHOP ASCE/NASA

Basic Geology and Conclusions (Dessert First) Apollo Vistas and Interpretation (Cheese and Fruit) Minerals of the Moon with C i ith E i i M t i l (M i ) Comparisons with Engineering Materials (Main) P ti l C iti i l di C t (S ) Particle Composition, including Caveats (Soup)

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Thin Sections of the Regolith (Appetizers)

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Simplified Summary of Lunar Geology

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Initial lunar rock (highlands) ~ norite.

Data

Subsequent basaltic volcanic (& other )flows. Hypervelocity impacts in a vacuum largely destroyed original rock d d d l t f l and produced a lot of glass. Resulting broken material covering surface = Regolith.

Conclusions

Regolith is NOT soil! Composition is relatively restricted compared to Earth materials Composition is relatively restricted compared to Earth materials. It is roughly equivalent to broken igneous rock plus glass.

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Particle Size

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Net result of continuing meteor bombardment.

Data

g Impacts both reduce particle size, shock weld existing particles and melt material. Surface of Moon is a mixture of fragments - Size range: nanoscopic to large blocks of rock. Mixture believed to be meters (kilometers?) deep everywhere Mixture believed to be meters (kilometers?) deep everywhere. For Apollo mission samples - typical average particle sizes from ~ 30 to 100 μm. typical average particle sizes from 30 to 100 μm.

Conclusions

The regolith commonly has very fine particle sizes.

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Depth to bedrock is an almost meaningless concept.

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Sorting

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All natural Terrestrial materials made of particles show more or less

Data

All natural Terrestrial materials made of particles show more or less sorting based on size, shape and composition. This is due to interactions of fluid flow and gravity. There are no natural fluids on the Moon except for temporary There are no natural fluids on the Moon except for temporary

• ccurrences of molten glass.

Energy added to the lunar surface sufficient to cause particle motion will mix but not sort motion will mix but not sort.

Conclusions

For any reasonable sized sample of the regolith from the top few meters it is possible, and even probable to have particles of all size ranges and with any lunar component in the sample. g y p p Layering which affect mechanical properties does not exist.

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Particle Shape and Texture

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Particle shapes can be anything from perfect spheres to wildly

Data

p y g p p y formed pieces of splatter-welded material. The average aspect ratio of particles is estimated to be less than 0 5 0.5. Internally, the particles are commonly shattered. The affect on mechanical properties is totally unquantified.

Conclusions

Mechanical modeling of the regolith at the particle level is extremely problematic. Angular edges of the particles have not been mechanically

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Angular edges of the particles have not been mechanically abraded or smoothed.

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General Conclusions

LUNAR SITE PLANNING WORKSHOP ASCE/NASA

The surface of the Moon is covered in regolith, which is NOT soil! The regolith is shattered igneous rock plus glass. The particles are unsorted, unweathered and not abraided. Modeling of the regolith at the level of individual particles will be very problematic. Modeling of the regolith, if successful for one area, will be g g , , successful for most other areas if variation in particle size is addressed.

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Apollo Vista 1

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A hill means? Lots of Lots of fine stuff

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Apollo Vista 2

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Note the lack of sorting

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Major Minerals

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Mineral Mohs

Spec G it

Chemical Composition Abundance Mineral Mohs

Gravity

Chemical Composition Abundance

Plagioclase 6.0-6.5 2.73 (Ca,Na)(Si,Al)4O8 A Olivine 6.5-7.0 4.39 (Mg,Fe)2SiO4 M Orthopyroxene 5.0-6.0 3.4 (Mg,Fe,Ca)2[Si2O6] M Clinopyroxene 5.0-6.0 3.4 (Mg, Fe)2[Si2O6] M Spinel 7.5-8.0 3.56 MgAl2O4 m - t Hercynite 7.5-8 3.93 Fe+2Al2O4 m - t Ulvospinel 5.5-6.0 4.7 TiFe+2

2O4

m - t p

2 4

Chromite 5.5 4.7 Fe+2Cr2O4 m - t Troilite 4 4.75 FeS t? Whitlockite 5 3.12 Ca9(Mg,Fe+2)(PO4)6(PO3OH) t? Apatite 5 3 19 Ca (PO ) (F Cl) t? Apatite 5 3.19 Ca5(PO4)3(F,Cl) t? Ilmenite 5.5 4.72 Fe+2TiO3 m Native Iron 4.5 7.87 Fe t

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LUNAR SITE PLANNING WORKSHOP ASCE/NASA

Spinel

From Rickman and Street, 2008

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Particle Composition

LUNAR SITE PLANNING WORKSHOP ASCE/NASA

Caveats: L d t f ti ( t i l 20 ) tl t ll Lunar dust fraction (material < 20μm) currently not well characterized. Some aspects may or may not be important, for example the presence of nanoscopic Fe or vapor deposited rims. R lith ( i ll ) i i l d ili t l Regolith (macroscopically) is minerals and silicate glass. A mineral is: a naturally occurring substance with a a naturally occurring substance, with a characteristic, limited chemical composition and a highly ordered atomic structure. Th f th f h i l’ ti i li it d AND Therefore the range of each mineral’s properties is limited AND a mineral’s properties are independent of source (lunar or terrestrial).

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Optical Scans of Thin Sections

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64002,6019 64001,6031

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Data from Joint NASA/USGS/Intellection Study, 2008

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Particle Shapes and Textures 1

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6019 4002,6 64

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Data from Joint NASA/USGS/Intellection Study, 2008

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Particle Shapes and Textures 2

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31 01,603 6400

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Data from Joint NASA/USGS/Intellection Study, 2008

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Ditto

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31 01,603 6400

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Data from Joint NASA/USGS/Intellection Study, 2008

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Agglutinates

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31 4001,603 64 20

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Data from Joint NASA/USGS/Intellection Study, 2008

20µm

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Scale Invariance

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031 64001,6 6 10

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10µm

Data from Joint NASA/USGS/Intellection Study, 2008