spore: profile
id: mgs-1-mars-simulant
spore_version: 0.2
family: regolith
name: MGS-1 Mars Global Simulant
abbreviation: MGS-1
role: Earth stand-in for Mars soil in tests
category: regolith
type: mars-simulants
summary: |
  MGS-1 Mars Global Simulant is an open-standard powder that reproduces the mineral mix of the Rocknest windblown soil at Gale crater, Mars. Its December 2022 fact sheet gives an uncompressed bulk density of 1.29 g/cm3 and a median particle size of 60 μm, and lists 27.1 wt% anorthosite and 22.9 wt% glass-rich basalt as mixed. The 2019 paper that defines the standard (Cannon et al., Icarus 317) reports the same bulk density for its prototype, a mean grain size of 122 μm by volume, and a different bulk chemistry.
best_for: Ground tests of hardware and of in-situ resource utilization on a basaltic Mars analogue, where mineral mix and volatile content matter most (Cannon et al. 2019, Section 5.1)
weakest_at: 'Bulk chemistry: the fact sheet and the Cannon et al. prototype give different oxide values (SiO2 42.9 wt% against 50.8 wt%), so no single bulk chemistry is settled'
identity:
  formula: 'Mixed mineral powder: anorthosite (plagioclase), glass-rich basalt, pyroxene, olivine, Mg-sulfate, ferrihydrite, hydrated silica, magnetite, anhydrite, Fe-carbonate and hematite'
  source: mgs1-spec-sheet
  where: Mineralogy table, As mixed (wt%), 11 components
tags:
  environments:
    - mars-surface
  stresses: []
  applications:
    - rovers-and-surface-systems
    - in-space-manufacturing
properties:
  - benchmark: bulk_density
    label: Uncompressed bulk density
    value: 1.29
    unit: g/cm3
    scope: material
    conditions:
      state: uncompressed bulk powder, as mixed
      basis: value printed on the fact sheet
    method: Printed value on the fact sheet; Cannon et al. 2019 report the same 1.29 g/cm3 for their prototype (Section 4.1)
    status: ground
    note: Cannon et al. 2019 say they could not find a published density or porosity for Rocknest soil itself.
    source: mgs1-spec-sheet
    where: Header block, Uncompressed Bulk Density
  - benchmark: angle_of_repose
    label: Average angle of repose
    value: 38.9
    unit: °
    scope: material
    conditions:
      basis: average angle of repose as printed; test method not stated
    method: Printed on the fact sheet, Geotechnical Properties block
    status: ground
    source: mgs1-spec-sheet
    where: Geotechnical Properties, Avg Angle of Repose
  - benchmark: angle_of_repose
    label: Maximum angle of repose
    value: 43.6
    unit: °
    scope: material
    conditions:
      basis: maximum angle of repose as printed; test method not stated
    method: Printed on the fact sheet, Geotechnical Properties block
    status: ground
    source: mgs1-spec-sheet
    where: Geotechnical Properties, Max Angle of Repose
  - benchmark: particle_size_mean
    label: Mean particle size (fact sheet)
    value: 90
    unit: μm
    scope: material
    conditions:
      distribution: volumetric, laser diffraction
      instrument: CILAS 1190 laser diffraction particle size analyzer
    method: Printed on the fact sheet; the volumetric distribution slide names the CILAS 1190 analyzer
    status: ground
    source: mgs1-spec-sheet
    where: Header block, Mean Particle Size; Volumetric Particle Size Distribution slide
  - benchmark: particle_size_median
    label: Median particle size (fact sheet)
    value: 60
    unit: μm
    scope: material
    conditions:
      distribution: volumetric, laser diffraction
      instrument: CILAS 1190 laser diffraction particle size analyzer
    method: Printed on the fact sheet header block
    status: ground
    source: mgs1-spec-sheet
    where: Header block, Median Particle Size
  - benchmark: particle_size_range
    label: Particle size range (fact sheet)
    value: 0.04
    value_high: 600
    bound: range
    unit: μm
    scope: material
    conditions:
      bound_note: the fact sheet prints the lower limit as greater than 0.04 μm
    method: Printed range on the fact sheet
    status: ground
    note: The lower limit is printed as greater than 0.04 μm, so 0.04 μm is a bound, not a measured minimum.
    source: mgs1-spec-sheet
    where: Header block, Particle Size Range
  - benchmark: particle_fraction_finer_than_53um
    label: Fraction finer than 53 μm by mass (sieve)
    value: 3.6
    unit: '% by mass'
    scope: material
    conditions:
      method: sieve analysis following ASTM E11 with RO-TAP RX-30 shaker
      basis: mass
    method: Printed under Sieve Analysis; the fact sheet notes that sieving skews sizes larger because fines cling to coarse grains
    status: ground
    source: mgs1-spec-sheet
    where: Sieve Analysis table, row 270 (53 µm), Finer by Mass column
  - benchmark: particle_size_mean
    label: Mean grain size by volume (Cannon prototype)
    value: 122
    unit: μm
    scope: material
    conditions:
      basis: prototype sieved below 1 mm; volume mean
      medium: isopropyl alcohol
      instrument: Microtrac S3500 particle size analyzer
      replicates: measured in triplicate
    method: Measured at Johnson Space Center ARES facilities (Section 3.3); the paper reports the mean by volume
    status: ground
    note: Different instrument and sample preparation from the fact sheet's 90 μm mean, so the two means are not directly comparable.
    source: cannon2019
    where: Section 4.1 (Physical properties), paragraph after Fig. 3
  - benchmark: sio2
    label: SiO2, XRF (fact sheet)
    value: 42.9
    unit: wt%
    scope: material
    conditions:
      method: XRF on fused bead, relative abundances, Hamilton Analytical Lab
      basis: oxide wt%
    method: Printed in the Bulk Chemistry table as Oxide Wt.%
    status: ground
    source: mgs1-spec-sheet
    where: Bulk Chemistry table, SiO2 row
  - benchmark: sio2
    label: SiO2, XRF (Cannon prototype)
    value: 50.8
    unit: wt%
    scope: material
    conditions:
      basis: prototype MGS-1 simulant, measured by XRF in oxides mode at the UCF Materials Characterization Facility
    method: Measured by Cannon et al. (Section 3.3) and printed in Table 2, MGS-1 prototype column
    status: ground
    note: Disagrees with the fact sheet's 42.9 wt%. Cannon et al. attribute deviations from Rocknest mainly to the silicate chemistry used, with MgO and FeO most affected.
    source: cannon2019
    where: Table 2, MGS-1 prototype column, SiO2 row
  - benchmark: mgo
    label: MgO, XRF (fact sheet)
    value: 14.6
    unit: wt%
    scope: material
    conditions:
      method: XRF on fused bead, relative abundances, Hamilton Analytical Lab
      basis: oxide wt%
    method: Printed in the Bulk Chemistry table as Oxide Wt.%
    status: ground
    source: mgs1-spec-sheet
    where: Bulk Chemistry table, MgO row
  - benchmark: mgo
    label: MgO, XRF (Cannon prototype)
    value: 16.7
    unit: wt%
    scope: material
    conditions:
      basis: prototype MGS-1 simulant, measured by XRF in oxides mode at the UCF Materials Characterization Facility
    method: Measured by Cannon et al. (Section 3.3) and printed in Table 2, MGS-1 prototype column
    status: ground
    note: Disagrees with the fact sheet's 14.6 wt%.
    source: cannon2019
    where: Table 2, MGS-1 prototype column, MgO row
  - benchmark: feo
    label: FeO, XRF (fact sheet)
    value: 11.2
    unit: wt%
    scope: material
    conditions:
      method: XRF on fused bead, relative abundances, Hamilton Analytical Lab
      basis: oxide wt%
    method: Printed in the Bulk Chemistry table as Oxide Wt.%
    status: ground
    source: mgs1-spec-sheet
    where: Bulk Chemistry table, FeO row
  - benchmark: feo
    label: FeOT (total iron as FeO, Cannon prototype)
    value: 13.3
    unit: wt%
    scope: material
    conditions:
      basis: total iron expressed as FeO, prototype MGS-1 simulant
    method: Measured by Cannon et al. (Section 3.3) and printed in Table 2, MGS-1 prototype column
    status: ground
    note: Total iron as FeO in the paper; the fact sheet prints FeO. Disagrees with the fact sheet's 11.2 wt%.
    source: cannon2019
    where: Table 2, MGS-1 prototype column, FeOT row
  - benchmark: al2o3
    label: Al2O3, XRF (fact sheet)
    value: 12.8
    unit: wt%
    scope: material
    conditions:
      method: XRF on fused bead, relative abundances, Hamilton Analytical Lab
      basis: oxide wt%
    method: Printed in the Bulk Chemistry table as Oxide Wt.%
    status: ground
    source: mgs1-spec-sheet
    where: Bulk Chemistry table, Al2O3 row
  - benchmark: al2o3
    label: Al2O3, XRF (Cannon prototype)
    value: 8.9
    unit: wt%
    scope: material
    conditions:
      basis: prototype MGS-1 simulant, measured by XRF in oxides mode at the UCF Materials Characterization Facility
    method: Measured by Cannon et al. (Section 3.3) and printed in Table 2, MGS-1 prototype column
    status: ground
    note: Disagrees with the fact sheet's 12.8 wt%.
    source: cannon2019
    where: Table 2, MGS-1 prototype column, Al2O3 row
  - benchmark: loss_on_ignition
    label: Loss on ignition (LOI), fact sheet
    value: 5.3
    unit: wt%
    scope: material
    conditions:
      basis: loss on ignition as footnoted in the Bulk Chemistry table
    method: Printed on the fact sheet, footnote LOI
    status: ground
    source: mgs1-spec-sheet
    where: Bulk Chemistry table, LOI row
  - benchmark: mass_loss_30_500c
    label: Mass loss on heating, 30 to 500 °C (prototype)
    value: 3.9
    unit: '%'
    scope: material
    conditions:
      range: 30 to 500 °C
      sample: MGS-1 prototype, not the fact-sheet product
      basis: relative mass
    method: Thermogravimetric analysis, reported by Cannon et al. (Section 4.4)
    status: ground
    source: cannon2019
    where: Section 4.4 (Thermogravimetry), first paragraph
  - benchmark: water_content_30_500c
    label: Water (H2O) equivalent from mass loss, 30 to 500 °C
    value: 3.2
    unit: wt%
    scope: material
    conditions:
      basis: H2O-related mass loss expressed as wt% of MGS-1
      assumption: siderite assumed to decompose completely
      sample: MGS-1 prototype
    method: Value stated by Cannon et al. from the thermogravimetry data (Section 4.4)
    status: ground
    source: cannon2019
    where: Section 4.4 (Thermogravimetry), paragraph after the 3.9% figure
  - benchmark: so3_content
    label: Sulfur trioxide (volatile), XRF
    value: 1.27
    bound: lower
    unit: wt%
    scope: material
    conditions:
      bound_note: printed as at least (≥)
      method: XRF, volatiles
    method: Printed in the Volatiles table on the fact sheet
    status: ground
    source: mgs1-spec-sheet
    where: Volatiles table, SO3 row
  - benchmark: fluorine_content
    label: Fluorine (volatile), XRF
    value: 0.1
    bound: lower
    unit: wt%
    scope: material
    conditions:
      bound_note: printed as at least (≥)
      method: XRF, volatiles
    method: Printed in the Volatiles table on the fact sheet
    status: ground
    source: mgs1-spec-sheet
    where: Volatiles table, F row
  - benchmark: chlorine_content
    label: Chlorine (volatile), XRF
    value: 0.005
    bound: lower
    unit: wt%
    scope: material
    conditions:
      bound_note: printed as at least (≥)
      method: XRF, volatiles
    method: Printed in the Volatiles table on the fact sheet
    status: ground
    source: mgs1-spec-sheet
    where: Volatiles table, Cl row
  - benchmark: mineral_fraction
    label: Anorthosite (plagioclase), as mixed
    value: 27.1
    unit: wt%
    scope: material
    conditions:
      basis: as mixed, share of the mineral components
    method: Printed in the Mineralogy table. The fact sheet calls this anorthosite; Cannon et al. Table 1 calls it plagioclase at the same 27.1 wt%
    status: ground
    source: mgs1-spec-sheet
    where: Mineralogy table, Anorthosite row
  - benchmark: mineral_fraction
    label: Glass-rich basalt (basaltic glass), as mixed
    value: 22.9
    unit: wt%
    scope: material
    conditions:
      basis: as mixed, share of the mineral components
    method: Printed in the Mineralogy table; Cannon et al. Table 1 gives basaltic glass at the same 22.9 wt%
    status: ground
    source: mgs1-spec-sheet
    where: Mineralogy table, Glass-rich basalt row
  - benchmark: mineral_fraction
    label: Pyroxene, as mixed
    value: 20.3
    unit: wt%
    scope: material
    conditions:
      basis: as mixed, share of the mineral components
    method: Printed in the Mineralogy table; Cannon et al. Table 1 gives the same 20.3 wt%
    status: ground
    source: mgs1-spec-sheet
    where: Mineralogy table, Pyroxene row
  - benchmark: mineral_fraction
    label: Olivine, as mixed
    value: 13.7
    unit: wt%
    scope: material
    conditions:
      basis: as mixed, share of the mineral components
    method: Printed in the Mineralogy table; Cannon et al. Table 1 gives the same 13.7 wt%
    status: ground
    source: mgs1-spec-sheet
    where: Mineralogy table, Olivine row
  - benchmark: mineral_fraction
    label: Mg-sulfate, as mixed
    value: 4
    unit: wt%
    scope: material
    conditions:
      basis: as mixed, share of the mineral components
    method: Printed in the Mineralogy table; Cannon et al. Table 1 gives the same 4.0 wt%
    status: ground
    source: mgs1-spec-sheet
    where: Mineralogy table, Mg-sulfate row
  - benchmark: mineral_fraction
    label: Ferrihydrite, as mixed (fact sheet)
    value: 3.5
    unit: wt%
    scope: material
    conditions:
      basis: as mixed, share of the mineral components
    method: Printed in the Mineralogy table; Cannon et al. Table 1 gives a different value (see next entry)
    status: ground
    note: Disagrees with Cannon et al. Table 1 (1.7 wt%).
    source: mgs1-spec-sheet
    where: Mineralogy table, Ferrihydrite row
  - benchmark: mineral_fraction
    label: Ferrihydrite, Cannon et al. Table 1 prototype recipe
    value: 1.7
    unit: wt%
    scope: material
    conditions:
      basis: prototype recipe, share of the mineral components
    method: Printed in Table 1 of Cannon et al. 2019
    status: ground
    note: Disagrees with the fact sheet's 3.5 wt%.
    source: cannon2019
    where: Table 1, Ferrihydrite row
  - benchmark: mineral_fraction
    label: Hydrated silica, as mixed (fact sheet)
    value: 3
    unit: wt%
    scope: material
    conditions:
      basis: as mixed, share of the mineral components
    method: Printed in the Mineralogy table; Cannon et al. Table 1 gives a different value (see next entry)
    status: ground
    note: Disagrees with Cannon et al. Table 1 (5.0 wt%, labelled hydrated silica (opal)).
    source: mgs1-spec-sheet
    where: Mineralogy table, Hydrated silica row
  - benchmark: mineral_fraction
    label: Hydrated silica (opal), Cannon et al. Table 1 prototype recipe
    value: 5
    unit: wt%
    scope: material
    conditions:
      basis: prototype recipe, share of the mineral components
    method: Printed in Table 1 of Cannon et al. 2019, amorphous phases
    status: ground
    note: Disagrees with the fact sheet's 3.0 wt%.
    source: cannon2019
    where: Table 1, Hydrated Silica (Opal) row
  - benchmark: mineral_fraction
    label: Magnetite, as mixed
    value: 1.9
    unit: wt%
    scope: material
    conditions:
      basis: as mixed, share of the mineral components
    method: Printed in the Mineralogy table; Cannon et al. Table 1 gives the same 1.9 wt%
    status: ground
    source: mgs1-spec-sheet
    where: Mineralogy table, Magnetite row
  - benchmark: mineral_fraction
    label: Anhydrite, as mixed (fact sheet)
    value: 1.7
    unit: wt%
    scope: material
    conditions:
      basis: as mixed, share of the mineral components
    method: Printed in the Mineralogy table; Cannon et al. Table 1 gives a different value (see next entry)
    status: ground
    note: Disagrees with Cannon et al. Table 1 (0.9 wt%).
    source: mgs1-spec-sheet
    where: Mineralogy table, Anhydrite row
  - benchmark: mineral_fraction
    label: Anhydrite, Cannon et al. Table 1 prototype recipe
    value: 0.9
    unit: wt%
    scope: material
    conditions:
      basis: prototype recipe, share of the mineral components
    method: Printed in Table 1 of Cannon et al. 2019
    status: ground
    note: Disagrees with the fact sheet's 1.7 wt%.
    source: cannon2019
    where: Table 1, Anhydrite row
  - benchmark: mineral_fraction
    label: Fe-carbonate (siderite), as mixed
    value: 1.4
    unit: wt%
    scope: material
    conditions:
      basis: as mixed, share of the mineral components
    method: Printed in the Mineralogy table; Cannon et al. Table 1 gives the same 1.4 wt%, named Fe-carbonated there
    status: ground
    source: mgs1-spec-sheet
    where: Mineralogy table, Fe-carbonate row
  - benchmark: mineral_fraction
    label: Hematite, as mixed (fact sheet)
    value: 0.5
    unit: wt%
    scope: material
    conditions:
      basis: as mixed, share of the mineral components
    method: Printed in the Mineralogy table; Cannon et al. Table 1 gives a different value (see next entry)
    status: ground
    note: Disagrees with Cannon et al. Table 1 (1.1 wt%).
    source: mgs1-spec-sheet
    where: Mineralogy table, Hematite row
  - benchmark: mineral_fraction
    label: Hematite, Cannon et al. Table 1 prototype recipe
    value: 1.1
    unit: wt%
    scope: material
    conditions:
      basis: prototype recipe, share of the mineral components
    method: Printed in Table 1 of Cannon et al. 2019
    status: ground
    note: Disagrees with the fact sheet's 0.5 wt%.
    source: cannon2019
    where: Table 1, Hematite row
corrosion:
  - environment: Heating from 30 to 500 °C (MGS-1 prototype)
    headline: The prototype loses 3.9% of its mass on heating from 30 to 500 °C.
    effect: Cannon et al. report 3.9% relative mass loss over 30 to 500 °C and state that the water-related part corresponds to 3.2 wt% of MGS-1, assuming the siderite decomposes completely. They also report a sharp CO2 release from siderite breakdown and SO2 and O2 release near 950 °C from Mg-sulfate breakdown.
    rating: moderate
    conditions:
      method: thermogravimetry with evolved-gas analysis
      sample: MGS-1 prototype, not the fact-sheet product
    source: cannon2019
    where: Section 4.4 (Thermogravimetry)
risks:
  hazards:
    - text: The fact sheet names dust inhalation as the primary hazard and advises a respirator in dusty conditions.
      ghs: []
      source: mgs1-spec-sheet
      where: Safety block, page 1
    - text: The fact sheet refers readers to a separate safety data sheet for details. That sheet is not in the sources held, so no GHS classification is recorded here.
      ghs: []
      source: mgs1-spec-sheet
      where: Safety block, page 1
    - text: Sodium metasilicate, the binder named in the Cannon et al. prototype recipe, is classed in the Gelest SDS (CAS 6834-92-0) with hazard statements H302 (harmful if swallowed), H314 (causes severe skin burns and eye damage) and H335 (may cause respiratory irritation). The SDS signal word is Danger. The SDS covers the pure chemical, not MGS-1.
      ghs:
        - H302
        - H314
        - H335
      source: gelest-sds
      where: Hazard statements (GHS-US) and Signal word lines
  failure_risks: []
  side_effects:
    - text: On heating the prototype, Cannon et al. report a broad water release, a sharp CO2 release from siderite breakdown, and SO2 and O2 release near 950 °C from Mg-sulfate breakdown.
      affects: Gas analysis and furnace or oven exhaust during heating tests
      source: cannon2019
      where: Section 4.4 (Thermogravimetry)
  handling:
    - text: Wear a respirator in dusty conditions (fact sheet safety note).
      source: mgs1-spec-sheet
      where: Safety block, page 1
    - text: Cannon et al. made prototypes by drying a paste in a microwave oven, then grinding, mixing and sieving below 1 mm. The paper says the sieve size is adjustable and is not an inherent property of the simulant.
      source: cannon2019
      where: Section 3.2 (Simulant preparation)
  mitigations: []
uses:
  - application: rovers-and-surface-systems
    device: Ground hardware testing
    example: Cannon et al. say researchers and engineers rely on terrestrial simulants to test future hardware, and that MGS-1 simulants are appropriate for testing flight hardware.
    source: cannon2019
    where: Abstract; Section 5.1 (Applications)
  - application: in-space-manufacturing
    device: In-situ resource utilization (ISRU) technology development
    example: Cannon et al. list ISRU technology development among the applications where MGS-1 simulants are most recommended, because mineralogy and volatile contents are important controlling factors.
    source: cannon2019
    where: Section 5.1 (Applications)
supply:
  - subject: MGS-1 simulant (the product)
    abundance: 'Not applicable: a manufactured mix of Earth minerals, not a mined commodity'
    producers: []
    critical_lists: []
    recycling: Not found in the sources held.
    substitutes: []
    note: Cannon et al. say modest amounts will be produced by the Center for Lunar & Asteroid Surface Science (CLASS) Exolith Lab to distribute to other researchers. No producer shares by country were found.
    source: cannon2019
    where: Abstract
  - subject: MGS-1 simulant (current supplier)
    abundance: Not applicable
    producers: []
    critical_lists: []
    recycling: Not found in the sources held.
    substitutes: []
    note: The UCF simulant page states that UCF has ceased production and that Space Resource Technologies now offers the simulant. The page was read as text in a later run; the wording here is paraphrased.
    source: ucf-mgs1
    where: MGS-1 Mars Global Simulant section (read as page text)
  - subject: Mineral feedstock (plagioclase, pyroxene, olivine)
    abundance: Not found in the sources held
    producers: []
    critical_lists: []
    recycling: Not found in the sources held.
    substitutes: []
    note: 'Cannon et al. name the feedstock: plagioclase from North Carolina, a bronzite-variety pyroxene from Brazil, and highly forsteritic San Carlos olivine. Measured chemistries for the silicates are in their Supplementary Table 1.'
    source: cannon2019
    where: Section 3.1
documents:
  - title: MGS-1 Mars Global Simulant | Fact Sheet (December 2022)
    type: datasheet
    url: https://www.sshade.eu/file/2023/06/10/686b4bf4-0361-5d31-a051-f244efd51649/mgs-1-spec-sheet-Dec2022.pdf
    year: 2022
  - title: 'Mars global simulant MGS-1: A Rocknest-based open standard for basaltic martian regolith simulants (Icarus 317, 470-478)'
    type: paper
    url: https://sciences.ucf.edu/class/wp-content/uploads/sites/23/2019/11/Cannon2019.pdf
    year: 2019
  - title: Sodium metasilicate, safety data sheet (Gelest product SIS6982.0, CAS 6834-92-0)
    type: sds
    url: https://www.gelest.com/wp-content/uploads/product_msds/SIS6982.0-msds.pdf
  - title: 'Chemistry, mineralogy, and grain properties at Namib and High dunes, Bagnold dune field, Gale crater, Mars: A synthesis of Curiosity rover observations'
    type: paper
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC5815393/
    year: 2017
  - title: Mineralogy of Eolian Sands at Gale Crater
    type: paper
    url: https://ntrs.nasa.gov/citations/20160002646
    year: 2016
  - title: 'First X-Ray Diffraction Results from Mars Science Laboratory: Mineralogy of Rocknest Aeolian Bedform at Gale Crater (LPSC 2013 abstract)'
    type: paper
    url: https://ntrs.nasa.gov/citations/20130009935
    year: 2013
gaps:
  - The fact sheet and the Cannon et al. 2019 paper were read as full text. The UCF simulant page was read as page text in this run, so its production-status statement is quoted, not paraphrased.
  - The fact sheet's safety data sheet is not in the sources held. No GHS classification, toxicology, storage rule or failure-mode data for MGS-1 is recorded.
  - No humidity, UV, long-term storage or ageing data for the simulant were found in the sources held.
  - Cannon et al. 2019 say no published density or porosity was found for the Rocknest soil itself. Porosity and specific surface of the simulant were not found.
  - The fact sheet and Cannon et al. 2019 disagree on the four oxides listed side by side (SiO2, MgO, FeO, Al2O3) and on four minor minerals (ferrihydrite, hydrated silica, anhydrite, hematite). Both values are listed; neither is resolved. Other oxides from the fact sheet's Bulk Chemistry table are not transcribed.
  - The fact sheet's trace-element table (Ni, Cr, V and others) and its reflectance and FTIR spectra are not transcribed here.
  - 'Particle-size methods differ: the fact sheet uses CILAS 1190 laser diffraction and sieving, and Cannon et al. use a Microtrac S3500. The two mean sizes are not directly comparable.'
  - Feedstock shares by country and critical-mineral status for the plagioclase, pyroxene and olivine sources were not found in the sources held. The USGS and EU critical-mineral lists were not checked for this profile.
  - 'Five further sources were read in this run: the JPL Rocknest wheel-scuff caption, the NTRS 2016 Rocknest eolian-sand abstract, the 2017 JGR Planets Namib and High dunes paper, the Gelest sodium metasilicate SDS and the NTRS 2013 Bish et al. Rocknest abstract. The Achilles et al. 2017 Rocknest mineralogy paper that Cannon et al. cite was not opened.'
  - The NTRS 2013 Bish et al. abstract does not print the Rocknest phase values, so no Rocknest CheMin phase values are transcribed.
  - The Space Resource Technologies product page returned HTTP 429 on every attempt in this run, so its price and stock status are not recorded.
  - The PubChem record for sodium metasilicate could not be opened (browser check). The binder hazard entry therefore comes from the Gelest SDS for the pure chemical, not from MGS-1 or PubChem.
  - 'Property names not in spores/property-canon.yaml, used as short snake_case names: bulk_density, angle_of_repose, particle_size_mean, particle_size_median, particle_size_range, particle_fraction_finer_than_53um, sio2, mgo, feo, al2o3, loss_on_ignition, mass_loss_30_500c, water_content_30_500c, so3_content, fluorine_content, chlorine_content and mineral_fraction.'
sources:
  mgs1-spec-sheet:
    title: MGS-1 Mars Global Simulant | Fact Sheet
    id: Fact sheet, December 2022 (PDF hosted on sshade.eu)
    url: https://www.sshade.eu/file/2023/06/10/686b4bf4-0361-5d31-a051-f244efd51649/mgs-1-spec-sheet-Dec2022.pdf
    year: 2022
    kind: datasheet
    license: publisher-supplied; cited, not reproduced
  cannon2019:
    title: 'Mars global simulant MGS-1: A Rocknest-based open standard for basaltic martian regolith simulants'
    id: doi:10.1016/j.icarus.2018.08.019 (Icarus 317, 470-478)
    url: https://sciences.ucf.edu/class/wp-content/uploads/sites/23/2019/11/Cannon2019.pdf
    year: 2019
    kind: paper
    license: publisher copyright; cited, not reproduced
  ucf-mgs1:
    title: MGS-1 Mars Global Simulant (UCF simulant page)
    id: University of Central Florida, class simulant page
    url: https://sciences.ucf.edu/class/simulant_marsglobal/
    kind: web
    license: web page; cited, not reproduced
  jpl-rocknest-scuff:
    title: Wheel scuff mark at Rocknest (JPL image PIA16205)
    id: NASA JPL image PIA16205
    url: https://www.jpl.nasa.gov/images/pia16205-wheel-scuff-mark-at-rocknest
    year: 2012
    kind: web
  ntrs-eolian-2016:
    title: Mineralogy of Eolian Sands at Gale Crater
    id: NASA NTRS 20160002646 (Achilles, Vaniman, Blake et al., 2016 abstract)
    url: https://ntrs.nasa.gov/citations/20160002646
    year: 2016
    kind: paper
  namib-2017:
    title: 'Chemistry, mineralogy, and grain properties at Namib and High dunes, Bagnold dune field, Gale crater, Mars: A synthesis of Curiosity rover observations'
    id: J Geophys Res Planets 122(12), 2510-2543; PMC5815393
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC5815393/
    year: 2017
    kind: paper
  gelest-sds:
    title: Sodium metasilicate, safety data sheet (Gelest product SIS6982.0, CAS 6834-92-0)
    id: Gelest SIS6982.0 SDS, CAS 6834-92-0
    url: https://www.gelest.com/wp-content/uploads/product_msds/SIS6982.0-msds.pdf
    kind: datasheet
  ntrs-bish-2013:
    title: 'First X-Ray Diffraction Results from Mars Science Laboratory: Mineralogy of Rocknest Aeolian Bedform at Gale Crater (LPSC 2013 abstract)'
    id: NASA NTRS 20130009935 (Bish, Blake, Vaniman et al., 2013)
    url: https://ntrs.nasa.gov/citations/20130009935
    year: 2013
    kind: paper
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 37
  unreachable: 0
  caveats: 1
  note: Written by an AI assistant on 2026-11-01 from the December 2022 fact sheet and the Cannon et al. 2019 PDF, both read as text. The UCF page was read as page text and used for supplier status. Deepened in a later run with five more sources (JPL PIA16205, NTRS 20160002646, NTRS 20130009935, a 2017 JGR Planets paper on the Namib and High dunes, and the Gelest sodium metasilicate SDS for the binder hazards); the quality bar now passes. verify-values found all 37 values in the cited source text (0 not found).
story:
  recipe:
    line: MGS-1 is a mixture of mineral powders, not one compound. The fact sheet lists 11 components as mixed, in weight percent, which together make up the whole mix. Cannon et al. made their prototypes by mixing plagioclase, pyroxene, olivine, basaltic glass and magnetite with water and a sodium metasilicate binder, drying the paste into hard cobbles, grinding the cobbles and mixing them with the secondary phases.
    parts:
      - name: Anorthosite (plagioclase)
        share_percent: 27.1
        role: Largest crystalline component. The fact sheet calls it anorthosite; Cannon et al. call it plagioclase.
      - name: Glass-rich basalt (basaltic glass)
        share_percent: 22.9
        role: Amorphous basaltic glass, an X-ray amorphous phase in the mix.
      - name: Pyroxene
        share_percent: 20.3
        role: Crystalline silicate. Cannon et al. used a bronzite-variety pyroxene from Brazil.
      - name: Olivine
        share_percent: 13.7
        role: Crystalline silicate. Cannon et al. used highly forsteritic San Carlos olivine.
      - name: Mg-sulfate
        share_percent: 4
        role: Sulfate. Its breakdown releases SO2 and O2 near 950 °C on heating.
      - name: Ferrihydrite
        share_percent: 3.5
        role: Iron oxyhydroxide. Cannon et al. say ferrihydrite and hematite act as strong pigments. Table 1 gives 1.7 wt%.
      - name: Hydrated silica
        share_percent: 3
        role: Secondary phase. Cannon et al. Table 1 lists it as hydrated silica (opal) at 5.0 wt%.
      - name: Magnetite
        share_percent: 1.9
        role: Magnetic iron oxide. Cannon et al. say magnetite matters for the magnetic properties.
      - name: Anhydrite
        share_percent: 1.7
        role: Sulfate. Cannon et al. use anhydrite for sulfur content. Table 1 gives 0.9 wt%.
      - name: Fe-carbonate (siderite)
        share_percent: 1.4
        role: Iron carbonate. Its breakdown gives a sharp CO2 release on heating.
      - name: Hematite
        share_percent: 0.5
        role: Iron oxide and pigment. Cannon et al. Table 1 gives 1.1 wt%.
  risk_groups:
    - title: For people
      level: 0
      verdict: Dust is the stated hazard; use a respirator.
      lead: The fact sheet's only stated hazard is dust inhalation. The sources held give no GHS classification or toxicology for MGS-1 itself.
      points:
        - label: The powder
          line: The fact sheet names dust inhalation as the primary hazard and advises a respirator in dusty conditions. It refers to a separate safety data sheet for details, which is not in the sources held.
        - label: Fine fraction
          line: The fact sheet gives 3.6% by mass finer than 53 μm.
    - title: If the simulant is heated
      lead: These results come from laboratory heating of the Cannon et al. prototype, not from field incidents.
      points:
        - label: Mass loss
          line: The prototype lost 3.9% of its mass between 30 and 500 °C. Cannon et al. state that 3.2 wt% of MGS-1 is water-related loss, assuming the siderite decomposes completely.
        - label: Gas release
          line: Cannon et al. report a sharp CO2 release from siderite breakdown, and SO2 and O2 release near 950 °C from Mg-sulfate breakdown.
    - title: Handling and storage
      points:
        - label: Storage
          line: The sources held give no storage rule for MGS-1. The fact sheet refers to its safety data sheet, which is not in the sources held.
        - label: Dust control
          line: The fact sheet advises a respirator in dusty conditions.
  why: MGS-1 is an open-standard simulant of basaltic Martian regolith. Its mineral recipe follows the quantitative mineralogy of the Rocknest windblown soil that the Curiosity rover analysed in Gale crater. Cannon et al. say earlier Mars simulants sacrificed accuracy for convenience and had poor documentation, and that JSC Mars-1 and the Mojave Mars Simulant are no longer available outside NASA. They publish the recipe and production method so that other groups can recreate the simulant. The Rocknest sample was an eolian sand deposit, which the NASA abstract calls the Rocknest "sand shadow" (Achilles et al. 2016, NTRS 20160002646). Curiosity cut a wheel scuff mark into a wind-formed ripple there so researchers could examine the particle-size distribution of the ripple material (JPL image PIA16205). A 2017 JGR Planets study of the Namib and High dunes reports that Bagnold and Rocknest mineralogy are similar, with plagioclase, olivine and pyroxenes in similar proportions (PMC5815393).
  uses:
    - where: Hardware testing
      line: Cannon et al. say researchers and engineers rely on terrestrial simulants to test future hardware, and that MGS-1 simulants are appropriate for testing flight hardware.
    - where: In-situ resource utilization
      line: Cannon et al. list ISRU technology development among the applications where MGS-1 simulants are most recommended, because mineralogy and volatile contents are important controlling factors.
  can_do:
    - label: Bulk density
      benchmark: bulk_density
      line: The uncompressed bulk density is 1.29 g/cm3 per the fact sheet, and Cannon et al. report the same value for their prototype.
    - label: Flow behaviour
      benchmark: angle_of_repose
      line: The fact sheet gives an average angle of repose of 38.9° and a maximum of 43.6°.
    - label: Particle size
      benchmark: particle_size_median
      line: The fact sheet gives a mean particle size of 90 μm and a median of 60 μm from laser diffraction. Cannon et al.'s prototype has a mean of 122 μm by volume, measured with a different instrument.
    - label: Water on heating
      benchmark: water_content_30_500c
      line: Heated from 30 to 500 °C, the prototype released water equal to 3.2 wt% of MGS-1 (Cannon et al. 2019, Section 4.4).
    - label: Volatile sulfur
      benchmark: so3_content
      line: The fact sheet gives SO3 of at least 1.27 wt%, measured by XRF.
  compare: Cannon et al. say earlier Mars simulants did not superficially match Mars in spectral or bulk chemical properties, and that JSC Mars-1 has an unrealistically high water content from its heating test. MGS-1 is designed as a mineralogical match to Rocknest instead. The prototype's bulk density of 1.29 g/cm3 falls inside the range the paper gives for the Pathfinder landing site (Section 4.1). The fact sheet and the Cannon prototype disagree on bulk chemistry, with SiO2 at 42.9 wt% on the fact sheet and 50.8 wt% in the prototype, so use the mineral recipe for chemistry-sensitive work and check the oxide values for the product you buy.
  compare_rows:
    - label: Bulk density
      benchmark: bulk_density
    - label: Median particle size
      benchmark: particle_size_median
    - label: Angle of repose (average)
      benchmark: angle_of_repose
  handling:
    - Wear a respirator where there is dust. The fact sheet names dust inhalation as the primary hazard.
    - Store it as the supplier's safety data sheet directs. That sheet is not in the sources held, so no storage rule is recorded here.
    - Heating releases water, CO2, SO2 and O2 in the Cannon et al. tests. Plan the exhaust for that.
  good_for:
    - Hardware and ISRU tests where mineralogy and volatile content matter. Cannon et al. recommend MGS-1 for those uses.
    - Tests that need a documented, reproducible recipe. Cannon et al. publish the recipe and production method.
  watch_out:
    - 'Bulk chemistry: the fact sheet and the Cannon prototype disagree (SiO2 42.9 wt% against 50.8 wt%; MgO 14.6 wt% against 16.7 wt%).'
    - Four minor minerals (ferrihydrite, hydrated silica, anhydrite and hematite) differ between the fact sheet and Cannon et al. Table 1.
    - 'Mean particle size: 90 μm from the fact sheet''s laser method, against 122 μm by volume in the Cannon prototype.'
    - The Cannon values come from a lab-made prototype. The commercial product may differ.
  verdict: MGS-1 is a published, open recipe for basaltic Martian regolith with sourced density, particle-size and mineral-mix values. Its bulk chemistry and four minor mineral fractions differ between the fact sheet and the 2019 paper, so state which source you use for each number.