GEOTECHNICAL ENGINEERING APOLLO SOIL MECHANICS EXPERIMENT S-200 FINAL REPORT COVERING WORK PERFORMZD UNDER NASA CONTRACT NAS9-11266 3, K, Mitchell, Principal Investigator W, N, Houston, Co-Investigator W, D. Carrier, 111, Co-Investigator N, C. Costes, Co-Investigator January, 1974 Submitted to the National Aeronautics and Space Administration. SPACE SCIENCES LABORATORY SERIES 15, ISSUE 7 i UNIVERSITY OF CALIFORNIA BERKEILEY APOLLO SOIL MECHANICS EXPERIMENT S-200 FIWL REPORT J. K, Mitchell, Principal Iwestigator W, N. Houston, Co-Investigator We D, Carrier, 111, CQ-Investigator N, C, Castes, Co-Investigator Submitted to the National Aeronautics and Space Administration SPACE SCIENCES MBOMTBRY SERIES 15, ISSUE 7 "The surface i s fine and powdery. I can kick it up loosely with my toe. It does adhere i n fine layers like powdered charcoal to the sole and insides of my boots. I only go i n a small fraction of an inch--maybe an eighth of an inch, but I can see the footprints of my boots and the treads i n the fine sandy particles." Neil A. Armstrong July 20, 1969 iii, ACKNOWLEDGEMENTS The authors wish to gratefully acknowledge the assistance of the many individuals who have contributed to the success of the Soil Mechanics Experimnt. The lists of references at the end of this report indicate the active participation of those associated with the principal md co-investigators, The basic design concept of the SKI? was developed at the Geotechnical Research Laboratory of the NASA Marshall Space Flight Center Space Sciences Laboratory with the support of Teledyne-Brown Engineering Company, Huntsville, Alabama, Dr, Rolland 6, Stum, Wolanri K, Norton, George E, Campbell, and 6, T. Cohron were instru- mental in the development of this concept. The final design, construction, and qualification of the flight article were carried through by W, N, Dunaway, and W. Lyon of the NASA Manned Spacecraft Center (now Johnson Space Center) and W. Young of the General Electric Company, Charles S. Alton and W. D, Sherborne of the NASA Manned Spacecraft Gentes (now Johnson Space Center) contributed greatly to the design and development of the core tubes used on Apollo 15 and subsequent missions, Dr, We John Hovland, Dr, Arshud Mahmsod, Dr, L, I, Namiq, Dr, H. Turan Durgunoglu, C, S. @hang, Donald D. Treadwell, and Y Moriwaki, all of the soil mechanics research staff at the University of California, were responsible for many of the simulation studies, data analyses, and computations discussed in this report. Dr. Stewart W. Johnson, National Research Council Senior Postdoctoral Fellow from the Air Force Institute of Technolog~z, and Richard A. Wemer, Lisimaco Carrasco, and RaLE Schmidt of Lockheed Electronics Company participated in simulation studies at the &nned Spacecraft Center (now Johnson Space Center). CONTENTS . . . . . . . . . . DATA SOURCES AND mAL'IISIS METHODS. 6 . . PK'SISICPIL AND MEC ICAL MODEL FOR THE LUNM SOIL , 14 . . . . . . . . . . . . . . . . . . CONCLUSIONS , , , 106 REFERENCES APBEmIX 1 PUBLICATIONS RESmTING FROM LU.N A.R .R E.S .E m.C H. B.Y . . . . . SOIL MECNMICS TEAM mMBERS. 120 LIST OF FIGUIRES . . . . . . . . . . . . . . . . Apollo Simple Penetrometer 10 . . . . . . . . . . . . . . . Self-Recording Penetrometer. II . . . . . Typical Particle Types found in the Lunar Soils. 19 (a) Mineral Grains (b) Glass Droplets (c) Glass Prapents (d) Agglutinates (e) Recrystallized Breccia Matrices (f) Basalt Fragments . . . . . . . . . . Grain Size Distributions of Lunar Soil 30 . . . Varieion of Drive (Core) Tube Densities with Depth 48 Proposed Variation of Density with Depth for Apollo 15 . . . . . . . . . . . . . . . . . . . . . . Station 9 A . . 50 Variation of Density with Depth for Lunar Drill STEM . . . . . . . . . . . . . . . . . . . . . . . . Samples. 54 Correlation of Apollo 16 Station 4 Double-Core-Tube . . . . . . . . . . . . . . . Stratigraphy with S W Test 4 68 Approximate Soil Profile Between Apollo 16 Station 10 Double-Core-Tube Site and Deep-Drill-Stem Site in Alsep Area..................e........ 70 Penetration Resistance of the Lunar Surface at Different . . . . . . . . . . . . . . . . . . . . . . . . Locations 71 Friction Angle as a Function of .Po.ro.si.ty. f.or. L.un.ar. S.oi.l. . simulant No. 2 (Ground Basalt) 73 Cohesion as a Function of Porosity for Lunar Soil . . . . . . . . . . . . . . . Sintulant No. 2 (Ground Basalt) 74 Relationships of Cohesion as a Function of Friction Angle Required to develop Measured Pen.et.ra.ti.on. . . . . . . Resistances at Apollo 16 Station 4. 78 vii. Relationships of Cohesion as a Function of Friction Angle Required to Develop Measured Penetration . . . . . . . Resistances at Apollo 16 Station 10, Test 1 79 One-Dimensional Compression Curves for LSS No. 2 . . . . . . . . . . . . . . . . . at l,9% Water Content 87 Predicted Variation of Void Ratio with Depth for Actual Lunar Soil under Lunar Gravity 89 m e . . . . . e . bmparison of One-Dimensional Compression Curves . . . . . . . . . for Apollo 12 Lunar Soil and LSS No. 2 91 Comparison of Compression Characteristics for Apollo 12 Lunar Soil and LSS No, 2 on Relative . . . . . . . . . . . . . . . . . . . R e . Density Basis 93 Example Assumed Conapression Patterns for Lunar . . . . . . . . . . . . . . . . . . . . . . . . Soil.. 95 Depth of Astronaut Bootprints used to Determine . . Modulus of Subgrade Reaction for the Lunar Surface 97 I, Measured Energy Consumption of the Rover in Rel.ation to the Predicted Va.lu.es. B.as.ed. o.n .th.e .So.il. P.ro.pe.rt.ie.s . . . bndicated.... 104 LIST OF TABLES Page . . . Distribution of Partiele Types in Lmar Soils 27 ... . . . . . . . . . . . Luraar Sample Location 28 . Lunar Soil Grain Size Parameters: Apo1.l~ 11-15 , 31 . . . . . . . . . . Specific Gravity of Lunar Soils 35 Maximm an.d .M .i nim.m .D .e n.s i.ti e.s .s f. C. ru.s h.e d. B. a.s a.l t . . . Simulant , 38 . . .. . Minimum and Maximum Density of Lunar Soils 40 Data Saure.e s for Inf.e .rr i.n g. L. m.a.r S. o.i l. D .e n.s it.y .o .r . . Porosity .,, , 44 . . Proposed Variation of berage Density with Depth 52 ry of Results of Statistical halysis. o.f . . . Porosities Deduced from Footprint Depths , 56 Average Haterial Properties of SurficiaB Lunar . . . %siba t ApoZPo 14-17 and Euna 17 Landing Sites 59 ary of. R. e.s u.l ts f.r o.m .D .e n.s i.ty .a n.d .P o. ro. sity . . . . Studies , , , 64 Estimates of Lunar Soil C.o h.e sion. a.n d. F. ri.c t.i o.n A.n g.le . Based on Pre-Apollo Data , , 75 Lunar Soil Cohesion and Friction h g l e Values 80 APQLLQ SOIL MECHANICS INVESTIGATION - FINAL REPORT - CHAPTER 1 INTRODUCTION Soil mechanics investigations during the Apollo Program were organized to meet the following obje ctives : (1) to obtain an understanding of the compositional, textural, and mechanical properties of lunar soils and the variations of these properties with depth and among different locations an the lunar surface, (2) to use this understanding to aid in the formulation, verifica- tion or mdification of theories for lunar history and processes, (3) to use lunar soil data to aid in the interpretation of data obtained from other lunar surface activities and experiments, (4) to develop %mar surface models that were useful for the solution of engineering problems in subsequent Apollo dssions; e.g., core tube sampling, drilling in the lunar surface, traf ficabilit y, (5) to obtain infomation which can be used Fn planning future exploration and development of the Moon. Thus the Soil Mechanics Experiment (S-208) was mique among the experiments assiped to the Apollo missions in that the results have both science and engineering applications. Types of problems for which an understmding of lmar soil properties is important include (1) formation