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

https://ntrs.nasa.gov/search.jsp?R=20090043187 2018-03-12T07:14:27+00:00Z ASCE Lunar Site Preparation and Outpost Setup Workshop October 20 & 21, 2009 LUNAR SITE PLANNING WORKSHOP ASCE/NASA 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

ASCE Menu LUNAR SITE PLANNING WORKSHOP ASCE/NASA Basic Geology and Conclusions (Dessert First) Apollo Vistas and Interpretation (Cheese and Fruit) Minerals of the Moon with Comparisons with Engineering Materials (Main) C i ith E i i M t i l (M i ) P Particle Composition, including Caveats (Soup) ti l C iti i l di C t (S ) Thin Sections of the Regolith (Appetizers) 2

ASCE Simplified Summary of Lunar Geology LUNAR SITE PLANNING WORKSHOP ASCE/NASA Data Initial lunar rock (highlands) ~ norite. Subsequent basaltic volcanic (& other )flows. Hypervelocity impacts in a vacuum largely destroyed original rock and produced a lot of glass. d d d l t f l 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.

ASCE Particle Size LUNAR SITE PLANNING WORKSHOP ASCE/NASA Data Net result of continuing meteor bombardment. 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 μ m. typical average particle sizes from 30 to 100 μ m. Conclusions The regolith commonly has very fine particle sizes. Depth to bedrock is an almost meaningless concept. 4

ASCE Sorting LUNAR SITE PLANNING WORKSHOP ASCE/NASA Data All natural Terrestrial materials made of particles show more or less 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 occurrences 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.

ASCE Particle Shape and Texture LUNAR SITE PLANNING WORKSHOP ASCE/NASA Data Particle shapes can be anything from perfect spheres to wildly 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 Angular edges of the particles have not been mechanically abraded or smoothed. 6

ASCE 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. 7

ASCE Apollo Vista 1 LUNAR SITE PLANNING WORKSHOP ASCE/NASA A hill means? Lots of Lots of fine stuff 8

ASCE Apollo Vista 2 LUNAR SITE PLANNING WORKSHOP ASCE/NASA Note the lack of sorting 9

ASCE Major Minerals LUNAR SITE PLANNING WORKSHOP ASCE/NASA Spec Mineral Mineral Mohs Mohs Chemical Composition Chemical Composition Abundance Abundance G Gravity it Plagioclase 6.0-6.5 2.73 (Ca,Na)(Si,Al) 4 O 8 A Olivine 6.5-7.0 4.39 (Mg,Fe) 2 SiO 4 M Orthopyroxene 5.0-6.0 3.4 (Mg,Fe,Ca) 2 [Si 2 O 6 ] M Clinopyroxene 5.0-6.0 3.4 (Mg, Fe) 2 [Si 2 O 6 ] M Spinel 7.5-8.0 3.56 MgAl 2 O 4 m - t Fe +2 Al 2 O 4 m - t Hercynite 7.5-8 3.93 Ulvospinel p 5.5-6.0 4.7 TiFe +2 2 O 4 m - t 2 4 Chromite 5.5 4.7 Fe +2 Cr 2 O 4 m - t Troilite 4 4.75 FeS t? Whitlockite 5 3.12 Ca 9 (Mg,Fe +2 )(PO 4 ) 6 (PO 3 OH) t? Apatite Apatite 5 5 3 19 3.19 Ca 5 (PO 4 ) 3 (F,Cl) Ca (PO ) (F Cl) t? t? Fe +2 TiO 3 m Ilmenite 5.5 4.72 Native Iron 4.5 7.87 Fe t

ASCE LUNAR SITE PLANNING WORKSHOP ASCE/NASA Spinel From Rickman and Street, 2008

ASCE Particle Composition LUNAR SITE PLANNING WORKSHOP ASCE/NASA Caveats: L Lunar dust fraction (material < 20 μ m) currently not well d t f ti ( t i l 20 ) tl t ll characterized. Some aspects may or may not be important, for example the presence of nanoscopic Fe or vapor deposited rims. Regolith (macroscopically) is minerals and silicate glass. R lith ( i ll ) i i l d ili t l 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. Therefore the range of each mineral’s properties is limited AND a Th f th f h i l’ ti i li it d AND mineral’s properties are independent of source (lunar or terrestrial).

ASCE Optical Scans of Thin Sections LUNAR SITE PLANNING WORKSHOP ASCE/NASA 64002,6019 64001,6031 Data from Joint NASA/USGS/Intellection Study, 2008 13

ASCE Particle Shapes and Textures 1 LUNAR SITE PLANNING WORKSHOP ASCE/NASA 6019 4002,6 64 Data from Joint NASA/USGS/Intellection Study, 2008 14

ASCE Particle Shapes and Textures 2 LUNAR SITE PLANNING WORKSHOP ASCE/NASA 31 01,603 6400 Data from Joint NASA/USGS/Intellection Study, 2008 15

ASCE Ditto LUNAR SITE PLANNING WORKSHOP ASCE/NASA 31 01,603 6400 Data from Joint NASA/USGS/Intellection Study, 2008 16

ASCE Agglutinates LUNAR SITE PLANNING WORKSHOP ASCE/NASA 31 4001,603 64 20 20µm Data from Joint NASA/USGS/Intellection Study, 2008 17

ASCE Scale Invariance LUNAR SITE PLANNING WORKSHOP ASCE/NASA 031 64001,6 6 10 10µm Data from Joint NASA/USGS/Intellection Study, 2008 18