{ "spore": "profile", "id": "apollo-lunar-regolith", "spore_version": "0.2", "family": "regolith", "name": "Apollo lunar regolith (returned and in-situ properties)", "role": "Reference lunar soil from the Apollo missions (returned samples plus Apollo and Lunokhod in-situ measurements), not a simulant", "category": "regolith", "type": "lunar-simulants", "summary": "Apollo lunar regolith is the loose layer of broken rock and soil that covers the Moon. Its bulk density is about 1.30 g/cm3 at the surface and rises to 1.92 g/cm3 below 100 cm (Connolly and Carrier, LPSC 2023). Twelve Apollo astronauts collected 362 kg of rock and soil from six landing sites, per the NASA users guide.", "best_for": "Reference values for lunar surface soil in landing, excavation and rover design, and as the target that lunar simulants are built to match", "weakest_at": "Not one material: density, strength and composition change with depth and region, and no crystalline silica value for returned Apollo soil was found in the sources read", "identity": { "formula": "Not one compound: crushed rock, mineral and impact-glass fragments, mainly plagioclase, pyroxene, olivine, ilmenite and glass", "designations": [], "source": "nasa-guide-2024", "where": "Section 1.0 (Introduction) and Table 3 (averaged regional lunar modal mineralogy, Apollo returned samples)" }, "tags": { "environments": [ "lunar-day", "lunar-night" ], "stresses": [], "applications": [ "structures", "in-space-manufacturing", "rovers-and-surface-systems" ] }, "properties": [ { "benchmark": "density", "label": "Lunar regolith density, Apollo 12 (rho min and rho max)", "value": 1.55, "value_high": 1.9, "bound": "range", "unit": "g/cm3", "scope": "material", "conditions": { "basis": "averaged reference row for Apollo 12 cited to Houston and Mitchell, 1971", "note": "rho(min) and rho(max) as printed; the table does not restate their definitions" }, "method": "Averaged value printed in the users guide density table, Apollo 12 row", "status": "ground", "source": "nasa-guide-2024", "where": "Table 15 (Lunar regolith density values, g/cm3), Apollo 12 row, Houston and Mitchell 1971", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "density", "label": "Lunar regolith density, Apollo 15 (rho min and rho max)", "value": 1.36, "value_high": 1.85, "bound": "range", "unit": "g/cm3", "scope": "material", "conditions": { "basis": "averaged reference row for Apollo 15 cited to Carrier et al. 1972a and Mitchell et al. 1972a", "note": "rho(min) and rho(max) as printed" }, "method": "Averaged value printed in the users guide density table, Apollo 15 row", "status": "ground", "source": "nasa-guide-2024", "where": "Table 15 (Lunar regolith density values, g/cm3), Apollo 15 row, first reference line", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "density", "label": "Lunar regolith density, Apollo 17 (rho min and rho max)", "value": 1.57, "value_high": 2.29, "bound": "range", "unit": "g/cm3", "scope": "material", "conditions": { "basis": "averaged reference row for Apollo 17 cited to Mitchell et al. 1973a", "note": "rho(min) and rho(max) as printed" }, "method": "Averaged value printed in the users guide density table, Apollo 17 row", "status": "ground", "source": "nasa-guide-2024", "where": "Table 15 (Lunar regolith density values, g/cm3), Apollo 17 row, first reference line", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "density", "label": "Bulk density at the lunar surface", "value": 1.3, "bound": "exact", "unit": "g/cm3", "scope": "material", "conditions": { "depth": "surface", "basis": "approximate average from the Connolly and Carrier model fitted to Apollo bootprint and Lunokhod penetrometer data" }, "method": "Approximate value stated in a conference abstract", "status": "ground", "source": "connolly2023", "where": "Abstract, 'Modeling Lunar Regolith as a Function of Depth', first paragraph", "source_detail": { "title": "Updating lunar subsurface geotechnical properties based upon nonlinear Winkler modeling of Apollo and Lunokhod measurements (LPSC 2023 abstract)", "id": "J.F. Connolly and W.D. Carrier, NTRS 20220018853", "url": "https://ntrs.nasa.gov/api/citations/20220018853/downloads/LPSC%202023%20Abstract_Connolly_Carrier_v2.pdf", "year": 2023, "kind": "paper", "license": "NASA public document; licence not stated in the copy read" } }, { "benchmark": "density", "label": "Bulk density below 100 cm depth", "value": 1.92, "bound": "exact", "unit": "g/cm3", "scope": "material", "conditions": { "depth": "below 100 cm, approached asymptotically", "basis": "approximate value from the Connolly and Carrier model" }, "method": "Approximate value stated in a conference abstract", "status": "ground", "source": "connolly2023", "where": "Abstract, 'Modeling Lunar Regolith as a Function of Depth', first paragraph", "source_detail": { "title": "Updating lunar subsurface geotechnical properties based upon nonlinear Winkler modeling of Apollo and Lunokhod measurements (LPSC 2023 abstract)", "id": "J.F. Connolly and W.D. Carrier, NTRS 20220018853", "url": "https://ntrs.nasa.gov/api/citations/20220018853/downloads/LPSC%202023%20Abstract_Connolly_Carrier_v2.pdf", "year": 2023, "kind": "paper", "license": "NASA public document; licence not stated in the copy read" } }, { "benchmark": "cohesion", "label": "Cohesion, 0-15 cm depth (average)", "value": 0.52, "bound": "exact", "unit": "kPa", "scope": "material", "conditions": { "depth_range_cm": "0-15", "range_printed": "0.44-0.62 kPa", "basis": "averaged reference data modified from Carrier et al. 1999, as printed in the users guide" }, "method": "Average printed in the users guide cohesion and friction table", "status": "ground", "source": "nasa-guide-2024", "where": "Table 18 (Lunar regolith cohesion and angle of internal friction), 0-15 cm row, C (kPa) average", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "cohesion", "label": "Cohesion, 30-60 cm depth (average)", "value": 3, "bound": "exact", "unit": "kPa", "scope": "material", "conditions": { "depth_range_cm": "30-60", "range_printed": "2.40-3.80 kPa", "basis": "averaged reference data modified from Carrier et al. 1999, as printed in the users guide" }, "method": "Average printed in the users guide cohesion and friction table", "status": "ground", "source": "nasa-guide-2024", "where": "Table 18 (Lunar regolith cohesion and angle of internal friction), 30-60 cm row, C (kPa) average", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "friction_angle", "label": "Angle of internal friction, 0-15 cm depth (average)", "value": 42, "bound": "exact", "unit": "°", "scope": "material", "conditions": { "depth_range_cm": "0-15", "range_printed": "41-43 degrees", "basis": "averaged reference data modified from Carrier et al. 1999, as printed in the users guide" }, "method": "Average printed in the users guide cohesion and friction table", "status": "ground", "source": "nasa-guide-2024", "where": "Table 18 (Lunar regolith cohesion and angle of internal friction), 0-15 cm row, phi (degrees) average", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "friction_angle", "label": "Angle of internal friction, 30-60 cm depth (average)", "value": 54, "bound": "exact", "unit": "°", "scope": "material", "conditions": { "depth_range_cm": "30-60", "range_printed": "52-55 degrees", "basis": "averaged reference data modified from Carrier et al. 1999, as printed in the users guide" }, "method": "Average printed in the users guide cohesion and friction table", "status": "ground", "source": "nasa-guide-2024", "where": "Table 18 (Lunar regolith cohesion and angle of internal friction), 30-60 cm row, phi (degrees) average", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "friction_angle", "label": "Angle of internal friction estimated from Apollo experiments", "value": 30, "value_high": 50, "bound": "range", "unit": "°", "scope": "material", "conditions": { "basis": "range given as the Apollo experiments estimate; the authors say it did not allow for the increase of friction angle with depth" }, "method": "Range stated in a conference abstract, citing the Apollo estimate", "status": "ground", "source": "connolly2023", "where": "Abstract, 'Friction Angle and Normal Stress' paragraph", "source_detail": { "title": "Updating lunar subsurface geotechnical properties based upon nonlinear Winkler modeling of Apollo and Lunokhod measurements (LPSC 2023 abstract)", "id": "J.F. Connolly and W.D. Carrier, NTRS 20220018853", "url": "https://ntrs.nasa.gov/api/citations/20220018853/downloads/LPSC%202023%20Abstract_Connolly_Carrier_v2.pdf", "year": 2023, "kind": "paper", "license": "NASA public document; licence not stated in the copy read" } }, { "benchmark": "modulus_of_subgrade_reaction", "label": "Modulus of subgrade reaction k, Apollo bootprint average", "value": 920, "bound": "exact", "unit": "Pa/mm", "scope": "material", "conditions": { "basis": "average over 776 Apollo bootprints, each treated as a plate-load test", "stress": "approximately 7,000 Pa from one astronaut standing on one foot" }, "method": "Average k from the bootprint analysis, as stated by the authors", "status": "ground", "source": "connolly2023", "where": "Introduction (Modeling Lunar Regolith as a Function of Depth), paragraph on bootprint statistics", "source_detail": { "title": "Updating lunar subsurface geotechnical properties based upon nonlinear Winkler modeling of Apollo and Lunokhod measurements (LPSC 2023 abstract)", "id": "J.F. Connolly and W.D. Carrier, NTRS 20220018853", "url": "https://ntrs.nasa.gov/api/citations/20220018853/downloads/LPSC%202023%20Abstract_Connolly_Carrier_v2.pdf", "year": 2023, "kind": "paper", "license": "NASA public document; licence not stated in the copy read" } }, { "benchmark": "bootprint_depth", "label": "Average bootprint depth from the Apollo bootprint analysis", "value": 7.6, "bound": "exact", "unit": "mm", "scope": "material", "conditions": { "basis": "calculated by the authors as stress over modulus, 7000 Pa divided by 920 Pa/mm" }, "method": "Calculated by the authors from the stress and k values they report", "status": "calculated", "source": "connolly2023", "where": "Introduction, bootprint paragraph (7000 Pa / 920 Pa/mm = 7.6 mm)", "source_detail": { "title": "Updating lunar subsurface geotechnical properties based upon nonlinear Winkler modeling of Apollo and Lunokhod measurements (LPSC 2023 abstract)", "id": "J.F. Connolly and W.D. Carrier, NTRS 20220018853", "url": "https://ntrs.nasa.gov/api/citations/20220018853/downloads/LPSC%202023%20Abstract_Connolly_Carrier_v2.pdf", "year": 2023, "kind": "paper", "license": "NASA public document; licence not stated in the copy read" } }, { "benchmark": "upper_layer_depth", "label": "Thickness of the loosely consolidated upper regolith layer", "value": 10, "value_high": 15, "bound": "range", "unit": "cm", "scope": "material", "conditions": { "basis": "conceptual layer model stated by the authors; gardened by micrometeorite flux" }, "method": "Range stated in a conference abstract", "status": "ground", "source": "connolly2023", "where": "Abstract, 'Modeling Lunar Regolith as a Function of Depth', first paragraph", "source_detail": { "title": "Updating lunar subsurface geotechnical properties based upon nonlinear Winkler modeling of Apollo and Lunokhod measurements (LPSC 2023 abstract)", "id": "J.F. Connolly and W.D. Carrier, NTRS 20220018853", "url": "https://ntrs.nasa.gov/api/citations/20220018853/downloads/LPSC%202023%20Abstract_Connolly_Carrier_v2.pdf", "year": 2023, "kind": "paper", "license": "NASA public document; licence not stated in the copy read" } }, { "benchmark": "amorphous_content", "label": "Amorphous (glass) content, Apollo 15 average", "value": 38.6, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "basis": "average of Apollo 15 soil samples compiled from Taylor et al. 2019, as printed on the slide", "sample": "returned lunar soil" }, "method": "Average printed in the Apollo amorphous content table", "status": "ground", "source": "collins2022", "where": "Slide 18, table 'Apollo Amorphous Content Data', Apollo 15 row, Average (%)", "source_detail": { "title": "Geopolymer Concrete, a greener alternative on Earth and a feasible material for the Moon (Earth Day 2022 presentation)", "id": "P.J. Collins, A. Radlinska, J. Edmunson, M. Fiske, L. Strutzenberg, NTRS 20220005876", "url": "https://ntrs.nasa.gov/api/citations/20220005876/downloads/Earth%20Day%202022%20Geopolymer%20Concrete.pdf", "year": 2022, "kind": "report", "license": "NASA public document; licence not stated in the copy read" } }, { "benchmark": "amorphous_content", "label": "Amorphous (glass) content, Apollo 17 average", "value": 31.1, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "basis": "average of Apollo 17 soil samples compiled from Taylor et al. 2019, as printed on the slide", "sample": "returned lunar soil" }, "method": "Average printed in the Apollo amorphous content table", "status": "ground", "source": "collins2022", "where": "Slide 18, table 'Apollo Amorphous Content Data', Apollo 17 row, Average (%)", "source_detail": { "title": "Geopolymer Concrete, a greener alternative on Earth and a feasible material for the Moon (Earth Day 2022 presentation)", "id": "P.J. Collins, A. Radlinska, J. Edmunson, M. Fiske, L. Strutzenberg, NTRS 20220005876", "url": "https://ntrs.nasa.gov/api/citations/20220005876/downloads/Earth%20Day%202022%20Geopolymer%20Concrete.pdf", "year": 2022, "kind": "report", "license": "NASA public document; licence not stated in the copy read" } }, { "benchmark": "modal_glass", "label": "Glass, modal content (low-Ti mare regional average)", "value": 32.98, "bound": "exact", "unit": "wt%", "scope": "material", "conditions": { "region": "Low-Ti mare", "basis": "averaged regional value from Apollo returned sample XRD by Taylor et al. 2019, as printed in the users guide" }, "method": "Averaged value printed in the users guide modal mineralogy table", "status": "ground", "source": "nasa-guide-2024", "where": "Table 3 (Averaged regional lunar modal mineralogy), Glass row, Low-Ti Mare column", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "modal_plagioclase", "label": "Plagioclase feldspar, modal content (highlands regional average)", "value": 59.05, "bound": "exact", "unit": "wt%", "scope": "material", "conditions": { "region": "Highlands", "basis": "averaged regional value from Apollo returned sample XRD by Taylor et al. 2019, as printed in the users guide" }, "method": "Averaged value printed in the users guide modal mineralogy table", "status": "ground", "source": "nasa-guide-2024", "where": "Table 3 (Averaged regional lunar modal mineralogy), Plagioclase Feldspar row, Highlands column", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "sio2", "label": "Silicon dioxide, highlands surface regional average", "value": 45.62, "bound": "exact", "unit": "wt%", "scope": "material", "conditions": { "region": "Highlands surface", "basis": "averaged regional oxide chemistry from Apollo returned sample studies, as printed in the users guide" }, "method": "Averaged value printed in the users guide bulk chemistry table", "status": "ground", "source": "nasa-guide-2024", "where": "Table 6 (Averaged regional lunar surface oxide chemistry), SiO2 column, Highlands row", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "al2o3", "label": "Aluminium oxide, highlands surface regional average", "value": 24.47, "bound": "exact", "unit": "wt%", "scope": "material", "conditions": { "region": "Highlands surface", "basis": "averaged regional oxide chemistry from Apollo returned sample studies, as printed in the users guide" }, "method": "Averaged value printed in the users guide bulk chemistry table", "status": "ground", "source": "nasa-guide-2024", "where": "Table 6 (Averaged regional lunar surface oxide chemistry), Al2O3 column, Highlands row", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "tio2", "label": "Titanium dioxide, high-Ti mare surface regional average", "value": 7.48, "bound": "exact", "unit": "wt%", "scope": "material", "conditions": { "region": "High-Ti mare surface", "basis": "averaged regional oxide chemistry from Apollo returned sample studies, as printed in the users guide" }, "method": "Averaged value printed in the users guide bulk chemistry table", "status": "ground", "source": "nasa-guide-2024", "where": "Table 6 (Averaged regional lunar surface oxide chemistry), TiO2 column, High-Ti Mare row", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "median_particle_size_d50", "label": "Median particle size (Q50), low-Ti mare Apollo samples", "value": 65.1, "bound": "exact", "unit": "µm", "scope": "material", "conditions": { "region": "Low-Ti mare", "basis": "average Q50 of % passing grains from Apollo returned samples (Graf 1993), per the users guide; most published Apollo curves cover only the fraction under 1 cm" }, "method": "Average printed in the users guide particle size distribution table", "status": "ground", "source": "nasa-guide-2024", "where": "Table 9 (Averaged regional percent particle passing), Q50 row, Low-Ti Mare column", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "median_particle_size_d50", "label": "Median particle size (Q50), highlands Apollo samples", "value": 118.8, "bound": "exact", "unit": "µm", "scope": "material", "conditions": { "region": "Highlands", "basis": "average Q50 of % passing grains from Apollo returned samples (Graf 1993), per the users guide; most published Apollo curves cover only the fraction under 1 cm" }, "method": "Average printed in the users guide particle size distribution table", "status": "ground", "source": "nasa-guide-2024", "where": "Table 9 (Averaged regional percent particle passing), Q50 row, Highlands column", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "aspect_ratio", "label": "Particle aspect ratio, Apollo samples (bulk value)", "value": 0.7, "bound": "exact", "unit": "-", "scope": "material", "conditions": { "basis": "bulk value averaged over measured Apollo samples by Cannon and Walker 2021, as printed in the users guide" }, "method": "Bulk reference value printed in the users guide particle geometry table", "status": "ground", "source": "nasa-guide-2024", "where": "Table 12 (Averaged AR and Root Form Factor values for Apollo samples), Aspect Ratio row", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "sqrt_form_factor", "label": "Root form factor, Apollo samples (bulk value)", "value": 0.94, "bound": "exact", "unit": "-", "scope": "material", "conditions": { "basis": "bulk value averaged over measured Apollo samples by Cannon and Walker 2021, as printed in the users guide" }, "method": "Bulk reference value printed in the users guide particle geometry table", "status": "ground", "source": "nasa-guide-2024", "where": "Table 12 (Averaged AR and Root Form Factor values for Apollo samples), Root Form Factor row", "source_detail": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" } }, { "benchmark": "agglutinate_content", "label": "Agglutinate content of lunar regolith, as summarised from previous studies", "value": 15, "value_high": 60, "bound": "range", "unit": "wt%", "scope": "material", "conditions": { "basis": "range given by the authors for previous studies of lunar regolith; printed as percent by weight", "note": "a summary of earlier work, not one Apollo sample set" }, "method": "Range stated in an arXiv paper, citing earlier lunar regolith studies", "status": "ground", "source": "dotson-2024", "where": "Paragraph on the LHS-1-25A simulant in the simulant description (Section 2)", "source_detail": { "title": "Cohesion and Shear Strength of Compacted Lunar and Martian Regolith Simulants", "id": "arXiv 2403.11029; B. Dotson et al. (University of Central Florida)", "url": "https://arxiv.org/pdf/2403.11029", "year": 2024, "kind": "paper", "license": "arXiv preprint; licence not stated in the copy read" } } ], "corrosion": [ { "environment": "Lunar surface micrometeorite bombardment (space weathering of the top layer)", "headline": "The sources describe the top layer as gardened by micrometeorite impacts, but none gives a corrosion or degradation rate for lunar regolith.", "effect": "Connolly and Carrier describe the lunar surface as a 10-15 cm upper layer of loosely consolidated regolith gardened by micrometeorite flux. The Wikipedia lunar soil article says glass and agglutinate particles form at the surface through impact melting and micrometeorite welding. No source read gives a rate of change or a measured degradation for this layer.", "rating": "unknown", "conditions": { "basis": "descriptive statements of formation; no measured degradation test in the sources read" }, "source": "connolly2023", "where": "Abstract, 'Modeling Lunar Regolith as a Function of Depth', first paragraph" } ], "risks": { "hazards": [ { "text": "No GHS classification and no safety data sheet for returned Apollo lunar regolith was found in the sources read. The users guide applies its silica and dust hazard statements to lunar simulants, not to returned Apollo soil.", "ghs": [], "source": "nasa-guide-2024", "where": "Section 5.5 (Potential Hazards from Simulants)" }, { "text": "The users guide says that chronic inhalation of respirable (<10 microns) particulates can lead to pneumoconiosis, including silicosis, which is usually linked to years of exposure.", "ghs": [], "source": "nasa-guide-2024", "where": "Section 5.5.2 (Illness)" }, { "text": "NASA sets an exposure limit of 0.025 mg/m3 (25 µg/m3) TWA for respirable crystalline silica, which is also the OSHA action level, according to the users guide.", "ghs": [], "source": "nasa-guide-2024", "where": "Section 5.6 (Exposure Hazards, Crystalline Silica, PNOR, Control)" }, { "text": "Table 25 of the users guide lists silica analyses for simulants and feedstocks but no returned Apollo sample row, so no crystalline silica value for Apollo lunar soil was found.", "ghs": [], "source": "nasa-guide-2024", "where": "Table 25 (Summary of total percent crystalline and respirable silica)" } ], "failure_risks": [ { "mode": "Single surface strength used for deeper design", "trigger": "Using a surface value for cohesion or friction angle in a design that reaches below 15 cm", "consequence": "Cohesion averages 0.52 kPa at 0-15 cm and 3.0 kPa at 30-60 cm, and friction angle averages 42 degrees at 0-15 cm and 54 degrees at 30-60 cm (Carrier et al. 1999 values in the users guide).", "severity": "moderate", "source": "nasa-guide-2024", "where": "Table 18 (Lunar regolith cohesion and angle of internal friction values)" }, { "mode": "Lighter surface soil underestimated for landing loads", "trigger": "Landing footpad or foundation design that uses surface density for the full depth", "consequence": "Bulk density is about 1.30 g/cm3 at the surface and rises to 1.92 g/cm3 below 100 cm, so a surface density underestimates deeper bearing soil (Connolly and Carrier).", "severity": "low", "source": "connolly2023", "where": "Abstract, 'Modeling Lunar Regolith as a Function of Depth', first paragraph" } ], "side_effects": [ { "text": "The users guide notes that handling large crystalline silica particles (over 100 microns) can generate respirable particles (under 10 microns).", "affects": "Workers and test areas", "source": "nasa-guide-2024", "where": "Section 5.4 (Crystalline Silica Content in Simulants)" } ], "handling": [ { "text": "For loose simulants, the users guide advises frequent cleaning of work areas by wet wiping or HEPA vacuuming. No Apollo-specific handling rule was found.", "source": "nasa-guide-2024", "where": "Section 5.5.1 (Injury, slips, trips and falls)" } ], "mitigations": [ { "text": "The users guide says exposure monitoring is the only method to determine occupational exposure to crystalline silica.", "source": "nasa-guide-2024", "where": "Section 5.8 (Workplace Monitoring)" } ] }, "uses": [ { "application": "structures", "device": "Footpad and foundation design (Winkler soil model)", "example": "Connolly and Carrier say the Winkler model is used on the Moon to analyze footpad-soil interaction during landing and the deployment of scientific instruments, with Apollo bootprint and Lunokhod data as inputs.", "source": "connolly2023", "where": "Abstract, Introduction paragraph on the Winkler model" }, { "application": "rovers-and-surface-systems", "device": "Rover wheel-soil interaction", "example": "The same abstract says the Winkler model is also used on the Moon to analyze wheel-soil interaction of a roving vehicle.", "source": "connolly2023", "where": "Abstract, Introduction paragraph on the Winkler model" }, { "application": "in-space-manufacturing", "device": "Geopolymer concrete from regolith (research)", "example": "The Collins et al. slides give the goal as using as much in-situ lunar resource as possible, with regolith in the as-is condition making up most of the mass. The same slides say lunar regolith simulants are the only way to progress geopolymer lunar concrete work.", "source": "collins2022", "where": "Slide 15 (Supporting reasons for geopolymer lunar concrete) and slide 16" } ], "supply": [ { "subject": "Returned Apollo lunar samples", "abundance": "362 kg (842 lb.) of lunar rock and soil collected by twelve Apollo astronauts, per the users guide. The 2019 Ogunyinka dissertation gives approximately 382 kg of Moon rock returned by Apollo. Both are recorded side by side.", "producers": [], "critical_lists": [], "substitutes": [], "source": "nasa-guide-2024", "where": "Section 1.0 (Introduction)" }, { "subject": "In-situ lunar regolith", "abundance": "No tonnage or resource estimate for lunar regolith was found in the sources read.", "producers": [], "critical_lists": [], "substitutes": [], "source": "connolly2023", "where": "Abstract, 'Modeling Lunar Regolith as a Function of Depth', first paragraph" } ], "media": [], "documents": [ { "title": "NASA/TM-20240011783, Lunar Regolith Simulant User's Guide, Revision A", "type": "report", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024 }, { "title": "Connolly and Carrier, Updating lunar subsurface geotechnical properties based upon nonlinear Winkler modeling of Apollo and Lunokhod measurements (LPSC 2023 abstract)", "type": "paper", "url": "https://ntrs.nasa.gov/api/citations/20220018853/downloads/LPSC%202023%20Abstract_Connolly_Carrier_v2.pdf", "year": 2023 }, { "title": "Collins et al., Geopolymer Concrete, a greener alternative on Earth and a feasible material for the Moon (Earth Day 2022 slides, NTRS 20220005876)", "type": "report", "url": "https://ntrs.nasa.gov/api/citations/20220005876/downloads/Earth%20Day%202022%20Geopolymer%20Concrete.pdf", "year": 2022 }, { "title": "Ogunyinka 2019, Investigation of Material Properties of Sintered Black Point-1 Lunar Regolith Simulant (UCT MPhil dissertation)", "type": "report", "url": "https://open.uct.ac.za/server/api/core/bitstreams/ead778a3-7849-4fc1-9289-f09448b8c30b/content", "year": 2019 }, { "title": "Dotson et al. 2024, Cohesion and Shear Strength of Compacted Lunar and Martian Regolith Simulants (arXiv 2403.11029)", "type": "paper", "url": "https://arxiv.org/pdf/2403.11029", "year": 2024 }, { "title": "NASA Lunar Sample Compendium (Johnson Space Center Astromaterials Curation)", "type": "database", "url": "https://curator.jsc.nasa.gov/lunar/lsc" } ], "gaps": [ "Crystalline silica for returned Apollo lunar soil was not found: the users guide silica summary (Table 25) has no Apollo row, so no Apollo silica value is recorded.", "No hazard test, GHS classification or safety data sheet for Apollo lunar regolith was found. The hazard entries use the users guide statements written for simulants and say so.", "Grain density and porosity of Apollo regolith are not in any source read.", "Oxide values for Apollo missions in the Collins et al. slides (SiO2 and Al2O3 by mission, Slide 19) are printed without a unit, so they are not recorded.", "The Collins et al. slide gives the lunar atmospheric pressure as a power of ten (exponent form), so it is not recorded. Connolly and Carrier's nonlinear exponent (n = 1.86) and their k value in units with a superscript exponent are also not recorded for the same reason.", "Connolly and Carrier's Figure 1 shear-strength curve and their cohesion statement ('quickly increases beyond 3 kPa at depths below 50 cm') are described only qualitatively in the abstract, so only the users guide Table 18 values are recorded for cohesion.", "The original Carrier et al. 1999 and Connolly and Carrier 2022 engineer's guide were not opened; Table 18 values are taken as printed in the users guide, which says they were modified from Carrier et al. 1999.", "Sample totals conflict: 362 kg (users guide) against approximately 382 kg (Ogunyinka 2019). Both are recorded, and neither is preferred.", "Apollo mission density values in Table 15 are averages of reference rows and do not give a grain density or the measurement method for each row.", "Corrosion and degradation ratings are not given by any source read, so the single corrosion entry is recorded as unknown.", "Lunar-day and lunar-night tags rest on the NSSDC Moon fact sheet diurnal range (95 K to 390 K at the equator); no source read gives a regolith test under those conditions.", "Vacuum, radiation and thermal-cycling behaviour of regolith under test was not found in any source read.", "Critical-mineral lists (USGS, EU) were not checked for regolith; no producer shares apply.", "Wikipedia is used only for composition and history (the seven-element composition and the Chang'e 5 return mass) as the profile standard requires.", "Property names not in spores/property-canon.yaml: cohesion, friction_angle, modulus_of_subgrade_reaction, bootprint_depth, upper_layer_depth, amorphous_content, modal_glass, modal_plagioclase, sio2, al2o3, tio2, agglutinate_content, aspect_ratio and sqrt_form_factor. Names follow the BP-1 profile where one exists." ], "story": { "why": "Apollo lunar regolith is the reference for how lunar soil behaves. Twelve Apollo astronauts collected 362 kg of rock and soil from six landing sites, and the returned samples are the ground truth that simulants are compared with. Connolly and Carrier also used Apollo bootprints and Lunokhod penetrometer tests to estimate how density and strength grow with depth, which matters for landers, footpads and rovers. The users guide notes that most Apollo grain-size curves cover only the fraction under 1 cm.", "uses": [ { "where": "Landing and footpad design", "line": "Connolly and Carrier use the Winkler soil model on the Moon to analyze footpad-soil interaction during landing, with Apollo bootprint and Lunokhod data as inputs." }, { "where": "Rover wheel-soil interaction", "line": "The same abstract applies the Winkler model to wheel-soil interaction of a roving vehicle." }, { "where": "Geopolymer concrete research", "line": "Collins et al. describe regolith in its as-is condition as the bulk of the mass for geopolymer lunar concrete, but say simulants are the only way to progress that work." } ], "can_do": [ { "label": "Show how density grows with depth", "line": "1.30 g/cm3 at the surface and 1.92 g/cm3 below a depth of 100 cm (Connolly and Carrier, LPSC 2023).", "scope": "material" }, { "label": "Give a depth-dependent strength range", "line": "cohesion 0.52 kPa at 0-15 cm and 3.0 kPa at 30-60 cm, with friction angle 42 degrees and 54 degrees over the same depths (users guide Table 18).", "scope": "material" }, { "label": "Compare regional mineral content", "line": "plagioclase feldspar is 59.05 wt% in the highlands, while glass is 32.98 wt% in low-Ti mare (users guide Table 3).", "scope": "material" }, { "label": "Give the bulk shape of Apollo grains", "line": "aspect ratio 0.7 and root form factor 0.94 (Cannon and Walker 2021, as printed in the users guide Table 12).", "scope": "material" } ], "compare": "Apollo lunar regolith is the reference that simulants are built to match, not a simulant itself. Users guide Table 15 gives mission density ranges from 1.36 to 2.29 g/cm3 for Apollo 15 and Apollo 17 rows, which shows the spread between sites. The table compares density, cohesion and friction angle with the same benchmarks used for the simulant profiles in this collection.", "compare_rows": [ { "label": "Density", "benchmark": "density", "scope": "material" }, { "label": "Cohesion", "benchmark": "cohesion", "scope": "material" }, { "label": "Friction angle", "benchmark": "friction_angle", "scope": "material" } ], "handling": [ "Use a dust mask or respirator where dust forms, following the users guide controls for simulants until an Apollo-specific hazard analysis is available.", "Monitor exposure to crystalline silica, because the users guide says monitoring is the only method to measure occupational exposure.", "Do not use one surface value for strength or density in a design that reaches below 15 cm." ], "good_for": [ "Reference values for lunar surface soil in landing, excavation and rover design (Connolly and Carrier).", "Setting the target properties that lunar simulants should match, using averaged Apollo data (users guide)." ], "watch_out": [ "Density, strength and composition change with depth and region, so one value does not describe all lunar soil.", "Crystalline silica of returned Apollo soil is not measured in any source read.", "The mass returned by Apollo differs by source: 362 kg in the users guide against approximately 382 kg in the 2019 dissertation." ], "verdict": "Apollo lunar regolith is the reference for lunar soil properties, but the sources read give depth- and region-specific averages rather than one value. No source read tests it under lunar vacuum or thermal cycling.", "recipe": { "line": "Apollo lunar regolith is not a compound. It is a mixture of crushed rock and mineral fragments, plus glass formed by micrometeorite impacts, and its mineral mix depends on the region. The users guide gives regional averages from Apollo returned samples. Wikipedia reports that seven elements make up 98-99% of the composition of lunar rocks and soil.", "parts": [ { "name": "Plagioclase feldspar", "symbol": "-", "role": "The main mineral in highland soil; the rock-forming feldspar of the Moon's crust." }, { "name": "Pyroxene", "symbol": "-", "role": "The main mafic mineral in mare soil." }, { "name": "Olivine", "symbol": "-", "role": "A minor mineral that varies with region." }, { "name": "Ilmenite", "symbol": "-", "role": "An iron-titanium oxide; its share is what separates high-Ti mare soil from highland soil." }, { "name": "Glass", "symbol": "-", "role": "Formed by micrometeorite impacts and welded to other fragments (Wikipedia lunar soil)." } ] }, "risk_groups": [ { "title": "For people", "lead": "No GHS classification or safety data sheet for returned Apollo regolith was found. The users guide gives silica and dust hazard statements written for simulants.", "points": [ { "label": "Crystalline silica", "line": "No Apollo sample is in the users guide silica summary, so the crystalline silica content of returned Apollo soil is unknown from the sources read." }, { "label": "Respirable dust", "line": "The users guide says chronic inhalation of respirable (under 10 microns) particulates can lead to pneumoconiosis, including silicosis." }, { "label": "Exposure limit", "line": "NASA sets 0.025 mg/m3 (25 µg/m3) as an 8-hour TWA limit for respirable crystalline silica, which is also the OSHA action level (users guide, Section 5.6)." } ], "verdict": "Dust is the main concern; no hazard test found" }, { "title": "For a rover or test bed", "lead": "Strength and density change with depth, so a single surface value can mislead a design.", "points": [ { "label": "Depth", "line": "Cohesion averages 0.52 kPa at 0-15 cm and 3.0 kPa at 30-60 cm (users guide Table 18)." }, { "label": "Density", "line": "Bulk density is about 1.30 g/cm3 at the surface and 1.92 g/cm3 below 100 cm (Connolly and Carrier)." } ] }, { "title": "Handling and storage", "points": [ { "label": "Cleaning", "line": "For loose simulants, the users guide advises wet wiping or HEPA vacuuming of work areas. No Apollo-specific instruction was found." }, { "label": "Monitoring", "line": "The users guide says exposure monitoring is the only method to determine occupational exposure to crystalline silica." } ] } ] }, "updated": "2026-11-01", "review": { "status": "draft", "method": "assistant", "checked_values": 25, "unreachable": 0, "caveats": 4, "note": "Written by an AI assistant on 2026-11-01. Documents opened: the NASA users guide NASA/TM-20240011783 (PDF text, Tables 3, 6, 9, 12, 15, 18 and 25, Sections 1.0 and 5.4 to 5.8), the Connolly and Carrier LPSC 2023 abstract (PDF text), the Collins et al. Earth Day 2022 slides (PDF text), the Wikipedia lunar soil article (composition and history only), the NSSDC Moon fact sheet, the Ogunyinka 2019 dissertation (PDF text, lunar context only), the Dotson et al. 2024 arXiv paper (PDF text) and the NASA Lunar Sample Compendium page. The WebSearch budget for this run was exhausted, so no further search was made. Not opened: Carrier et al. 1991 and 1999, Connolly and Carrier 2022 engineer's guide, Slyuta 2014 review, Heiken et al. 1991 Lunar Sourcebook." }, "sources": { "nasa-guide-2024": { "title": "Lunar Regolith Simulant User's Guide, Revision A", "id": "NASA/TM-20240011783, effective 10/24/2024 (NTRS 20240011783)", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "NASA public document" }, "connolly2023": { "title": "Updating lunar subsurface geotechnical properties based upon nonlinear Winkler modeling of Apollo and Lunokhod measurements (LPSC 2023 abstract)", "id": "J.F. Connolly and W.D. Carrier, NTRS 20220018853", "url": "https://ntrs.nasa.gov/api/citations/20220018853/downloads/LPSC%202023%20Abstract_Connolly_Carrier_v2.pdf", "year": 2023, "kind": "paper", "license": "NASA public document; licence not stated in the copy read" }, "collins2022": { "title": "Geopolymer Concrete, a greener alternative on Earth and a feasible material for the Moon (Earth Day 2022 presentation)", "id": "P.J. Collins, A. Radlinska, J. Edmunson, M. Fiske, L. Strutzenberg, NTRS 20220005876", "url": "https://ntrs.nasa.gov/api/citations/20220005876/downloads/Earth%20Day%202022%20Geopolymer%20Concrete.pdf", "year": 2022, "kind": "report", "license": "NASA public document; licence not stated in the copy read" }, "wiki-lunar-soil": { "title": "Lunar soil (Wikipedia)", "id": "Wikipedia, English edition", "url": "https://en.wikipedia.org/wiki/Lunar_soil", "kind": "web", "license": "CC BY-SA 4.0 (Wikipedia); used for composition and history only" }, "nasa-moonfact": { "title": "Moon fact sheet (NASA NSSDC)", "id": "NSSDC planetary fact sheet", "url": "https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html", "kind": "web", "license": "NASA public information" }, "uct-ogunyinka-2019": { "title": "Investigation of Material Properties of Sintered Black Point-1 Lunar Regolith Simulant (MPhil dissertation, Adebayo Olutumbi Ogunyinka)", "id": "University of Cape Town, SpaceLab, SL19-010M, September 2019", "url": "https://open.uct.ac.za/server/api/core/bitstreams/ead778a3-7849-4fc1-9289-f09448b8c30b/content", "year": 2019, "kind": "report", "license": "University of Cape Town thesis; the title page limits use to private study or non-commercial research" }, "dotson-2024": { "title": "Cohesion and Shear Strength of Compacted Lunar and Martian Regolith Simulants", "id": "arXiv 2403.11029; B. Dotson et al. (University of Central Florida)", "url": "https://arxiv.org/pdf/2403.11029", "year": 2024, "kind": "paper", "license": "arXiv preprint; licence not stated in the copy read" }, "lunar-sample-compendium": { "title": "Lunar Sample Compendium (NASA Johnson Space Center, Astromaterials Curation)", "id": "NASA JSC Lunar Sample Compendium", "url": "https://curator.jsc.nasa.gov/lunar/lsc", "kind": "database", "license": "NASA public information" } }, "license": "CC-BY-4.0", "url": "https://spacemushroom.com/profiles/apollo-lunar-regolith/" }