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'
  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
  - 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
  - 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
  - benchmark: density
    label: Bulk density at the lunar surface
    value: 1.3
    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
  - benchmark: density
    label: Bulk density below 100 cm depth
    value: 1.92
    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
  - benchmark: cohesion
    label: Cohesion, 0-15 cm depth (average)
    value: 0.52
    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
  - benchmark: cohesion
    label: Cohesion, 30-60 cm depth (average)
    value: 3
    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
  - benchmark: friction_angle
    label: Angle of internal friction, 0-15 cm depth (average)
    value: 42
    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
  - benchmark: friction_angle
    label: Angle of internal friction, 30-60 cm depth (average)
    value: 54
    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
  - 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
  - benchmark: modulus_of_subgrade_reaction
    label: Modulus of subgrade reaction k, Apollo bootprint average
    value: 920
    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
  - benchmark: bootprint_depth
    label: Average bootprint depth from the Apollo bootprint analysis
    value: 7.6
    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)
  - 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
  - benchmark: amorphous_content
    label: Amorphous (glass) content, Apollo 15 average
    value: 38.6
    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 (%)
  - benchmark: amorphous_content
    label: Amorphous (glass) content, Apollo 17 average
    value: 31.1
    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 (%)
  - benchmark: modal_glass
    label: Glass, modal content (low-Ti mare regional average)
    value: 32.98
    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
  - benchmark: modal_plagioclase
    label: Plagioclase feldspar, modal content (highlands regional average)
    value: 59.05
    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
  - benchmark: sio2
    label: Silicon dioxide, highlands surface regional average
    value: 45.62
    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
  - benchmark: al2o3
    label: Aluminium oxide, highlands surface regional average
    value: 24.47
    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
  - benchmark: tio2
    label: Titanium dioxide, high-Ti mare surface regional average
    value: 7.48
    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
  - benchmark: median_particle_size_d50
    label: Median particle size (Q50), low-Ti mare Apollo samples
    value: 65.1
    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
  - benchmark: median_particle_size_d50
    label: Median particle size (Q50), highlands Apollo samples
    value: 118.8
    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
  - benchmark: aspect_ratio
    label: Particle aspect ratio, Apollo samples (bulk value)
    value: 0.7
    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
  - benchmark: sqrt_form_factor
    label: Root form factor, Apollo samples (bulk value)
    value: 0.94
    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
  - 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)
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: []
    origin: 'Six Apollo landings from July 1969 to December 1972: five in the mare and one in the highlands, all in the equatorial region of the near side (users guide). The users guide also gives 3,666 grams from Chang''e-5 and Chang''e-6 and 300 grams from three Luna missions. The Wikipedia lunar soil article says Chang''e 5 returned about 2 kilograms.'
    status: Held and curated by NASA at the Johnson Space Center. NASA's Lunar Sample Compendium lists the samples by mission, for example 'These samples were collected during the Apollo 11 mission.'
    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: []
    origin: The lunar surface is a 10-15 cm upper layer of loosely consolidated regolith over a dense, consolidated lower layer (Connolly and Carrier).
    status: Not a commercial product. No producers apply.
    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.'
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
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.'
story:
  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: '-'
        share: 59.05 wt% in the highlands (users guide Table 3)
        role: The main mineral in highland soil; the rock-forming feldspar of the Moon's crust.
      - name: Pyroxene
        symbol: '-'
        share: the largest mafic share in mare soil (users guide Table 3)
        role: The main mafic mineral in mare soil.
      - name: Olivine
        symbol: '-'
        share: a minor share in every region (users guide Table 3)
        role: A minor mineral that varies with region.
      - name: Ilmenite
        symbol: '-'
        share: a major share in high-Ti mare, a minor share in the highlands (users guide Table 3)
        role: An iron-titanium oxide; its share is what separates high-Ti mare soil from highland soil.
      - name: Glass
        symbol: '-'
        share: 32.98 wt% in low-Ti mare (users guide Table 3)
        role: Formed by micrometeorite impacts and welded to other fragments (Wikipedia lunar soil).
  risk_groups:
    - title: For people
      verdict: Dust is the main concern; no hazard test found
      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).
    - 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.
  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).
    - 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).
    - 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).
    - 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).
  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
    - label: Cohesion
      benchmark: cohesion
    - label: Friction angle
      benchmark: friction_angle
  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.