{
  "spore": "profile",
  "id": "pg",
  "spore_version": "0.2",
  "family": "carbon-materials",
  "name": "Pyrolytic graphite",
  "abbreviation": "PG",
  "role": "thermally anisotropic carbon, deposited from hydrocarbon gas and used for heat spreading and atomic-oxygen tests in orbit",
  "category": "carbon",
  "type": "Graphite",
  "summary": "Pyrolytic graphite is a dense, layered carbon made by heating a hydrocarbon gas until it decomposes and the carbon deposits as graphite. Its heat conduction is strongly directional: a datasheet quotes thermal conductivity of 80 to 240 W/m K at 0 to 100 °C, while a secondary source quotes up to 1700 W/mK in the basal plane and 10 W/mK across it. In low Earth orbit on NASA's MISSE 2 tray, its atomic oxygen erosion yield was 4.15e-25 cm3/atom, a value that the predictive tool estimated at 3.73e-25 cm3/atom.\n",
  "best_for": "Heat spreading in one direction, where a thin, light carbon layer must carry heat away along its plane",
  "weakest_at": "Strong anisotropy: heat conducts poorly across the layers, and the material is costly to make at high temperature",
  "identity": {
    "formula": "C",
    "cas": "7440-44-0",
    "crystal_system": "hexagonal",
    "space_group": "P63mc (buckled) or P63/mmc (flat)",
    "designations": [],
    "source": "wiki-graphite",
    "where": "Infobox (formula C, hexagonal or rhombohedral, space group P63mc or P63/mmc); CAS 7440-44-0 from the OSHA chemical data page for graphite (synthetic)"
  },
  "tags": {
    "environments": [
      "low-earth-orbit"
    ],
    "stresses": [
      "atomic-oxygen"
    ],
    "applications": [
      "thermal-control"
    ]
  },
  "properties": [
    {
      "benchmark": "atomic_oxygen_erosion_yield",
      "value": 4.15e-25,
      "bound": "exact",
      "unit": "cm3/atom",
      "scope": "material",
      "conditions": {
        "exposure": "MISSE 2 PEACE tray outside the ISS Quest airlock, 2001 to 2005",
        "atomic_oxygen_fluence": "8.43e21 atoms/cm2",
        "environment": "low Earth orbit"
      },
      "method": "Measured mass loss from the flown sample, reported as erosion yield by NASA",
      "status": "flight",
      "source": "nasa-ao-2008",
      "where": "Table I, MISSE 2 PEACE polymers erosion yield data (pyrolytic graphite row); repeated in the measured table, MISSE 2 column",
      "source_detail": {
        "title": "Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit",
        "id": "NASA/TM-2008-215490 (Banks, Backus and de Groh, December 2008)",
        "url": "https://ntrs.nasa.gov/citations/20090011780",
        "year": 2008,
        "kind": "report",
        "license": "NASA public domain (cited)"
      }
    },
    {
      "benchmark": "atomic_oxygen_erosion_yield",
      "value": 3.73e-25,
      "bound": "exact",
      "unit": "cm3/atom",
      "scope": "material",
      "conditions": {
        "exposure": "predicted for the same MISSE 2 exposure",
        "atomic_oxygen_fluence": "8.43e21 atoms/cm2"
      },
      "method": "Value from the NASA predictive tool, shown next to the flown result for comparison",
      "status": "calculated",
      "source": "nasa-ao-2008",
      "where": "Measured atomic oxygen erosion yields table, Predicted column (pyrolytic graphite row)",
      "source_detail": {
        "title": "Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit",
        "id": "NASA/TM-2008-215490 (Banks, Backus and de Groh, December 2008)",
        "url": "https://ntrs.nasa.gov/citations/20090011780",
        "year": 2008,
        "kind": "report",
        "license": "NASA public domain (cited)"
      }
    },
    {
      "benchmark": "density",
      "value": 2.25,
      "bound": "exact",
      "unit": "g cm-3",
      "scope": "material",
      "conditions": {
        "temperature": "20 °C",
        "grade": "pyrolytic graphite disc, 99.99% purity, as rolled"
      },
      "method": "Datasheet value for a commercial pyrolytic graphite disc",
      "status": "ground",
      "source": "goodfellow-pg",
      "where": "Physical properties, Density (product page for pyrolitic graphite disc)",
      "source_detail": {
        "title": "Goodfellow: Pyrolytic Graphite Carbon Disk, 99.99% purity, product datasheet",
        "id": "Goodfellow Metals, grade Pyrolitic Graphite, SKU 1000037214-group",
        "url": "https://www.goodfellow.com/usa/pyrolytic-graphite-disc-group",
        "year": 2026,
        "kind": "datasheet",
        "license": "Goodfellow terms (cited)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "value": 80,
      "value_high": 240,
      "bound": "exact",
      "unit": "W m-1 K-1",
      "scope": "material",
      "conditions": {
        "temperature": "0 to 100 °C",
        "grade": "commercial pyrolytic graphite disc (direction not stated on the page)"
      },
      "method": "Datasheet range printed as 80-240 W m-1 K-1 at 0-100 °C",
      "status": "ground",
      "source": "goodfellow-pg",
      "where": "Thermal properties, Thermal conductivity (pyrolitic graphite disc)",
      "source_detail": {
        "title": "Goodfellow: Pyrolytic Graphite Carbon Disk, 99.99% purity, product datasheet",
        "id": "Goodfellow Metals, grade Pyrolitic Graphite, SKU 1000037214-group",
        "url": "https://www.goodfellow.com/usa/pyrolytic-graphite-disc-group",
        "year": 2026,
        "kind": "datasheet",
        "license": "Goodfellow terms (cited)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "value": 1700,
      "bound": "exact",
      "unit": "W/mK",
      "scope": "material",
      "conditions": {
        "direction": "basal plane (in-plane)",
        "form": "pyrolytic graphite, formed from the gas phase"
      },
      "method": "Upper value quoted for in-plane conductivity in a secondary article; not a measured result in this profile",
      "status": "ground",
      "source": "electronics-cooling",
      "where": "Article text on pyrolytic graphite, basal-plane thermal conductivity",
      "source_detail": {
        "title": "Electronics Cooling: thermal management article on pyrolytic graphite sheet",
        "id": "electronics-cooling.com, article p=218",
        "url": "https://www.electronics-cooling.com/?p=218",
        "year": 2026,
        "kind": "web",
        "license": "cited"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "value": 10,
      "bound": "exact",
      "unit": "W/mK",
      "scope": "material",
      "conditions": {
        "direction": "perpendicular to the basal plane (through-plane)",
        "form": "pyrolytic graphite"
      },
      "method": "Value quoted in the same secondary article as the basal-plane figure",
      "status": "ground",
      "source": "electronics-cooling",
      "where": "Article text on pyrolytic graphite, perpendicular conductivity",
      "source_detail": {
        "title": "Electronics Cooling: thermal management article on pyrolytic graphite sheet",
        "id": "electronics-cooling.com, article p=218",
        "url": "https://www.electronics-cooling.com/?p=218",
        "year": 2026,
        "kind": "web",
        "license": "cited"
      }
    },
    {
      "benchmark": "specific_heat",
      "value": 712,
      "bound": "exact",
      "unit": "J K-1 kg-1",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C",
        "grade": "pyrolytic graphite disc"
      },
      "method": "Datasheet value",
      "status": "ground",
      "source": "goodfellow-pg",
      "where": "Thermal properties, Specific heat (pyrolitic graphite disc)",
      "source_detail": {
        "title": "Goodfellow: Pyrolytic Graphite Carbon Disk, 99.99% purity, product datasheet",
        "id": "Goodfellow Metals, grade Pyrolitic Graphite, SKU 1000037214-group",
        "url": "https://www.goodfellow.com/usa/pyrolytic-graphite-disc-group",
        "year": 2026,
        "kind": "datasheet",
        "license": "Goodfellow terms (cited)"
      }
    },
    {
      "benchmark": "cte",
      "value": 0.6,
      "value_high": 4.3,
      "bound": "exact",
      "unit": "x10-6 K-1",
      "scope": "material",
      "conditions": {
        "temperature": "0 to 100 °C",
        "grade": "pyrolytic graphite disc"
      },
      "method": "Datasheet range, printed as 0.6-4.3 x10-6 K-1 at 0-100 °C",
      "status": "ground",
      "source": "goodfellow-pg",
      "where": "Thermal properties, Coefficient of thermal expansion",
      "source_detail": {
        "title": "Goodfellow: Pyrolytic Graphite Carbon Disk, 99.99% purity, product datasheet",
        "id": "Goodfellow Metals, grade Pyrolitic Graphite, SKU 1000037214-group",
        "url": "https://www.goodfellow.com/usa/pyrolytic-graphite-disc-group",
        "year": 2026,
        "kind": "datasheet",
        "license": "Goodfellow terms (cited)"
      }
    },
    {
      "benchmark": "melting_point",
      "value": 3650,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "grade": "pyrolytic graphite disc"
      },
      "method": "Datasheet value",
      "status": "ground",
      "source": "goodfellow-pg",
      "where": "Thermal properties, Melting point",
      "source_detail": {
        "title": "Goodfellow: Pyrolytic Graphite Carbon Disk, 99.99% purity, product datasheet",
        "id": "Goodfellow Metals, grade Pyrolitic Graphite, SKU 1000037214-group",
        "url": "https://www.goodfellow.com/usa/pyrolytic-graphite-disc-group",
        "year": 2026,
        "kind": "datasheet",
        "license": "Goodfellow terms (cited)"
      }
    },
    {
      "benchmark": "electrical_resistivity",
      "value": 1375,
      "bound": "exact",
      "unit": "µOhm cm",
      "scope": "material",
      "conditions": {
        "temperature": "0 °C",
        "grade": "pyrolytic graphite disc"
      },
      "method": "Datasheet value",
      "status": "ground",
      "source": "goodfellow-pg",
      "where": "Electrical properties, Electrical resistivity",
      "source_detail": {
        "title": "Goodfellow: Pyrolytic Graphite Carbon Disk, 99.99% purity, product datasheet",
        "id": "Goodfellow Metals, grade Pyrolitic Graphite, SKU 1000037214-group",
        "url": "https://www.goodfellow.com/usa/pyrolytic-graphite-disc-group",
        "year": 2026,
        "kind": "datasheet",
        "license": "Goodfellow terms (cited)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "value": 4.8,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "basis": "tensile modulus; the datasheet states no test condition",
        "grade": "pyrolytic graphite disc"
      },
      "method": "Datasheet value, as printed",
      "status": "ground",
      "source": "goodfellow-pg",
      "where": "Mechanical properties, Tensile modulus",
      "source_detail": {
        "title": "Goodfellow: Pyrolytic Graphite Carbon Disk, 99.99% purity, product datasheet",
        "id": "Goodfellow Metals, grade Pyrolitic Graphite, SKU 1000037214-group",
        "url": "https://www.goodfellow.com/usa/pyrolytic-graphite-disc-group",
        "year": 2026,
        "kind": "datasheet",
        "license": "Goodfellow terms (cited)"
      }
    },
    {
      "benchmark": "osha_pel_respirable",
      "value": 5,
      "bound": "exact",
      "unit": "mg/m3",
      "scope": "material",
      "conditions": {
        "basis": "OSHA permissible exposure limit, time-weighted average, respirable fraction, for graphite (synthetic) CAS 7440-44-0"
      },
      "method": "Regulatory limit as printed on the OSHA chemical data page",
      "status": "ground",
      "source": "osha-synthetic",
      "where": "Exposure limits, OSHA PEL-TWA (15 mg/m3 total dust, 5 mg/m3 respirable fraction)",
      "source_detail": {
        "title": "OSHA chemical data: Graphite (synthetic)",
        "id": "CAS 7440-44-0, OSHA chemical sampling data",
        "url": "https://www.osha.gov/chemicaldata/533",
        "year": 2021,
        "kind": "standard",
        "license": "US government work (cited)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Atomic oxygen in low Earth orbit (MISSE 2 PEACE tray, ISS)",
      "headline": "In low Earth orbit the erosion yield was 4.15e-25 cm3/atom after an atomic oxygen fluence of 8.43e21 atoms/cm2.",
      "effect": "NASA flew pyrolytic graphite on the MISSE 2 PEACE tray and measured its erosion yield. The predictive tool, which fits the MISSE 2 data, estimated 3.73e-25 cm3/atom, so the flown and predicted values agree to within about 11%. The report also lists atomic oxygen fluence as the controlling exposure.",
      "rating": "low",
      "conditions": {
        "exposure": "outside the Quest airlock of the ISS, 2001 to 2005",
        "fluence": "8.43e21 atoms/cm2",
        "duration": "about 3.95 years (MISSE 2 PEACE exposure)"
      },
      "source": "nasa-ao-2008",
      "where": "Table I; Measured atomic oxygen erosion yields table; section 2.1 exposure details"
    },
    {
      "environment": "Thermal cycling in the MISSE 2 tray",
      "headline": "The flight tray was not reported to have failed under thermal cycling, but the report gives no separate result for pyrolytic graphite.",
      "effect": "No separate thermal-cycling result for pyrolytic graphite was found in the source. The nominal base-plate range was -30 to 40 °C; this is a condition of the exposure, not a measured effect on PG.",
      "rating": "low",
      "conditions": {
        "range": "nominal base-plate range, -30 to 40 °C",
        "material": "pyrolytic graphite on the MISSE 2 PEACE tray"
      },
      "source": "nasa-ao-2008",
      "where": "Section 2.1 exposure details"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "Dust is the hazard listed for graphite. OSHA sets a PEL-TWA of 15 mg/m3 total dust and 5 mg/m3 respirable fraction for graphite (synthetic); the NIOSH REL is not given there.",
        "ghs": [],
        "source": "osha-synthetic",
        "where": "Exposure limits"
      },
      {
        "text": "For natural graphite, OSHA lists a PEL of 15 mppcf, NIOSH a REL of 2.5 mg/m3 (respirable) and an IDLH of 1250 mg/m3. Pyrolytic graphite is not the natural mineral, so these limits are a guide for handling dust.",
        "ghs": [],
        "source": "osha-natural",
        "where": "Exposure limits (CAS 7782-42-5)"
      }
    ],
    "failure_risks": [
      {
        "mode": "Atomic oxygen erosion in low Earth orbit",
        "trigger": "Exposure to atomic oxygen, at a fluence of 8.43e21 atoms/cm2 over about 4 years on MISSE 2",
        "consequence": "Surface recession of 4.15e-25 cm3/atom erosion yield (the flown value), which the predictive tool estimated at 3.73e-25 cm3/atom.",
        "severity": "low",
        "source": "nasa-ao-2008",
        "where": "Table I and measured table, MISSE 2 PEACE"
      }
    ],
    "side_effects": [
      {
        "text": "The thermal conductivity is anisotropic, about 1700 W/mK in the basal plane against 10 W/mK across it, so a pyrolytic graphite part works as a heat spreader in its plane, not as a through-thickness conductor.",
        "affects": "Designers who assume isotropic conduction",
        "source": "electronics-cooling",
        "where": "Article text on basal-plane and perpendicular conductivity"
      }
    ],
    "handling": [
      {
        "text": "Dust control: the OSHA limits for graphite are 15 mg/m3 total dust and 5 mg/m3 respirable fraction (synthetic), so use local exhaust where machining or grinding makes dust.",
        "source": "osha-synthetic",
        "where": "Exposure limits"
      }
    ],
    "mitigations": [
      {
        "text": "Use the in-plane direction for heat spreading and do not rely on through-plane conduction; the NASA erosion test shows that the flown sample survived atomic oxygen with a yield of 4.15e-25 cm3/atom.",
        "source": "nasa-ao-2008",
        "where": "Table I"
      }
    ]
  },
  "uses": [],
  "supply": [
    {
      "subject": "Natural graphite (mine feedstock; pyrolytic graphite itself is made from a hydrocarbon gas)",
      "abundance": "Not quantified for pyrolytic graphite. The USGS world resources of graphite are described as exceeding 800 million tons of recoverable graphite outside the United States.",
      "producers": [
        {
          "country": "China",
          "share_percent": 77.8,
          "year": 2025
        },
        {
          "country": "Madagascar",
          "share_percent": 4.4,
          "year": 2025
        },
        {
          "country": "Brazil",
          "share_percent": 3.6,
          "year": 2025
        },
        {
          "country": "Mozambique",
          "share_percent": 3.3,
          "year": 2025
        }
      ],
      "critical_lists": [
        {
          "list": "USGS 2025 List of Critical Minerals (final, published 6 November 2025)",
          "listed": true
        },
        {
          "list": "EU critical raw materials list",
          "listed": false
        }
      ],
      "recycling": "USGS: information on the quantity and value of recycled graphite was not available, and the abundance of graphite in the world market inhibits recycling efforts.",
      "substitutes": [
        "USGS: synthetic graphite powder and secondary synthetic graphite from machined shapes compete for battery applications."
      ],
      "source": "usgs-mcs2026-graphite",
      "where": "World Mine Production and Reserves table, 2025e (1,800,000 t world total, rounded; shares calculated by Space Mushroom from the printed production figures: China 1,400,000 t, Madagascar 80,000 t, Brazil 65,000 t, Mozambique 60,000 t); Recycling; Substitutes; critical list from usgs-critical-2025"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "NASA/TM-2008-215490: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit",
      "type": "report",
      "url": "https://ntrs.nasa.gov/citations/20090011780",
      "year": 2008
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Graphite (natural)",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-graphite.pdf",
      "year": 2026
    },
    {
      "title": "Goodfellow: Pyrolytic Graphite Carbon Disk (product and datasheet page)",
      "type": "datasheet",
      "url": "https://www.goodfellow.com/usa/pyrolytic-graphite-disc-group",
      "year": 2026
    },
    {
      "title": "Low temperature transport properties of pyrolytic graphite sheet (arXiv:1704.03204)",
      "type": "paper",
      "url": "https://arxiv.org/pdf/1704.03204",
      "year": 2017
    },
    {
      "title": "OSHA chemical data: Graphite (synthetic), CAS 7440-44-0",
      "type": "standard",
      "url": "https://www.osha.gov/chemicaldata/533",
      "year": 2021
    },
    {
      "title": "OSHA chemical data: Graphite (natural), respirable fraction, CAS 7782-42-5",
      "type": "standard",
      "url": "https://www.osha.gov/chemicaldata/665",
      "year": 2021
    }
  ],
  "gaps": [
    "No flight result for pyrolytic graphite beyond MISSE 2 erosion yield; no thermal-vacuum, radiation or UV exposure result found for pyrolytic graphite.",
    "The atomic oxygen erosion yield is not a canonical property name, so it is written as atomic_oxygen_erosion_yield.",
    "PubChem GHS classification could not be read in this run (the page returned a browser check), so no GHS entry is given.",
    "NIOSH Pocket Guide entry for graphite (natural) was not reached; the limits come from the OSHA chemical data pages.",
    "The 1700 W/mK and 10 W/mK values come from a secondary article, not from a manufacturer datasheet; the MINTEQ Pyroid datasheet returned HTTP 403.",
    "The pyrolytic graphite sheet arXiv paper gives thickness and temperature ranges but no thermal conductivity or density values for pyrolytic graphite, so it is cited for the thermal-link use only.",
    "Pyrolytic-graphite-specific supply is not quantified; the supply shares are for natural graphite, the mine feedstock, not for pyrolytic deposition.",
    "The Wikipedia Pyrolytic carbon article gives no density or thermal conductivity number and no deposition temperature for manufacture."
  ],
  "story": {
    "why": "Pyrolytic graphite is a layered carbon whose heat conduction is far higher along its planes than across them. It combines a density of 2.25 g/cm3 with a specific heat of 712 J K-1 kg-1 at room temperature, so it stores and spreads heat efficiently in one direction. Its atomic oxygen erosion in low Earth orbit was measured on NASA's MISSE 2 tray.",
    "uses": [
      {
        "where": "Heat spreading in electronics",
        "line": "A secondary article describes pyrolytic graphite as having a basal-plane conductivity up to 1700 W/mK. The same article says it has found use in high-performance, niche aerospace applications."
      },
      {
        "where": "Thermal link in cryogenic systems",
        "line": "A 2017 study of pyrolytic graphite sheet measured its low-temperature transport properties and describes it as a light, highly conducting thermal link over a wide temperature range."
      },
      {
        "where": "Atomic-oxygen exposure in low Earth orbit",
        "line": "NASA flew pyrolytic graphite on the MISSE 2 tray outside the ISS airlock, with an erosion yield of 4.15e-25 cm3/atom."
      }
    ],
    "can_do": [
      {
        "label": "Thermal conduction",
        "line": "A datasheet quotes thermal conductivity of 80 to 240 W m-1 K-1 at 0 to 100 °C for a commercial pyrolytic graphite disc. A secondary source quotes up to 1700 W/mK in the basal plane and 10 W/mK across it.",
        "benchmark": "thermal_conductivity",
        "scope": "material",
        "value": "80"
      },
      {
        "label": "Density",
        "line": "The datasheet density is 2.25 g/cm3 at 20 °C.",
        "benchmark": "density",
        "scope": "material",
        "value": "2.25"
      },
      {
        "label": "Orbital survival",
        "line": "On MISSE 2 it recorded 4.15e-25 cm3/atom after about 4 years in low Earth orbit, and the NASA predictive tool estimated 3.73e-25 cm3/atom.",
        "benchmark": "atomic_oxygen_erosion_yield",
        "scope": "material",
        "value": "4.15e-25"
      }
    ],
    "compare": "Pyrolytic graphite is a dense, thermally anisotropic carbon. Its in-plane conductivity is far higher than most materials in this collection, but across the layers it is much lower, so it suits in-plane heat spreading. The table compares it with other materials on conductivity, density and the orbital erosion measurement.",
    "compare_rows": [
      {
        "label": "Thermal conductivity",
        "benchmark": "thermal_conductivity",
        "scope": "material"
      },
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Atomic oxygen erosion yield",
        "benchmark": "atomic_oxygen_erosion_yield",
        "scope": "material"
      }
    ],
    "handling": [
      "Dust is the hazard for graphite: keep dust below the OSHA limits with local exhaust in machining and grinding.",
      "Use the material in its plane for heat spreading; it conducts far less across the layers.",
      "In low Earth orbit the surface recedes by atomic oxygen erosion, at 4.15e-25 cm3/atom on MISSE 2."
    ],
    "good_for": [
      "In-plane heat spreading, where a light, thin carbon layer carries heat along its plane.",
      "Carbon flown on NASA's MISSE 2 tray, with a documented erosion yield for low Earth orbit."
    ],
    "watch_out": [
      "Strong anisotropy: 1700 W/mK in the basal plane against 10 W/mK across it, so it is a poor through-thickness conductor.",
      "Costly to make, because the deposition needs very high temperatures; a secondary article says so without giving a process value."
    ],
    "verdict": "Pyrolytic graphite is a directional heat spreader with a measured orbital erosion yield. It is the right choice when heat must travel in one plane, and the wrong choice when it must cross the layers.",
    "recipe": {
      "line": "Pyrolytic graphite is pure carbon. It is made by heating a hydrocarbon gas nearly to its decomposition temperature so that the carbon deposits as graphite, the layered hexagonal form of carbon.",
      "parts": [
        {
          "name": "Carbon",
          "symbol": "C",
          "role": "The only element in the material. Carbon atoms form flat hexagonal sheets, and the sheets stack into the layered structure that makes conduction strongly directional.",
          "atoms": 1,
          "atomic_weight": 12.011
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "Pyrolytic graphite is a carbon material with OSHA exposure limits for graphite dust. No hazard classification was read in this run.",
        "points": [
          {
            "label": "Dust",
            "line": "OSHA sets a limit of 15 mg/m3 for total dust and 5 mg/m3 for respirable dust for synthetic graphite, so machining and grinding need dust control."
          },
          {
            "label": "Natural graphite",
            "line": "For natural graphite, NIOSH sets a respirable REL of 2.5 mg/m3 and an IDLH of 1250 mg/m3."
          }
        ],
        "level": 0,
        "verdict": "Dust is the main concern"
      },
      {
        "title": "In orbit",
        "lead": "The orbital data concern the surface, not the health of people.",
        "points": [
          {
            "label": "Atomic oxygen",
            "line": "On the MISSE 2 tray the erosion yield was 4.15e-25 cm3/atom, with an atomic oxygen fluence of 8.43e21 atoms/cm2."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-16",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 12,
    "unreachable": 0,
    "caveats": 0,
    "note": "Values read by an AI assistant from pages fetched in this run; the MISSE 2 flight record and the Goodfellow datasheet are the primary values."
  },
  "sources": {
    "nasa-ao-2008": {
      "title": "Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit",
      "id": "NASA/TM-2008-215490 (Banks, Backus and de Groh, December 2008)",
      "url": "https://ntrs.nasa.gov/citations/20090011780",
      "year": 2008,
      "kind": "report",
      "license": "NASA public domain (cited)"
    },
    "usgs-mcs2026-graphite": {
      "title": "USGS Mineral Commodity Summaries 2026: Graphite (natural)",
      "id": "USGS MCS 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-graphite.pdf",
      "year": 2026,
      "kind": "report",
      "license": "US government work (cited)"
    },
    "usgs-critical-2025": {
      "title": "Interior Department releases final 2025 List of Critical Minerals",
      "id": "USGS science snippet, 14 November 2025",
      "url": "https://www.usgs.gov/news/science-snippet/interior-department-releases-final-2025-list-critical-minerals",
      "year": 2025,
      "kind": "web",
      "license": "US government work (cited)"
    },
    "goodfellow-pg": {
      "title": "Goodfellow: Pyrolytic Graphite Carbon Disk, 99.99% purity, product datasheet",
      "id": "Goodfellow Metals, grade Pyrolitic Graphite, SKU 1000037214-group",
      "url": "https://www.goodfellow.com/usa/pyrolytic-graphite-disc-group",
      "year": 2026,
      "kind": "datasheet",
      "license": "Goodfellow terms (cited)"
    },
    "electronics-cooling": {
      "title": "Electronics Cooling: thermal management article on pyrolytic graphite sheet",
      "id": "electronics-cooling.com, article p=218",
      "url": "https://www.electronics-cooling.com/?p=218",
      "year": 2026,
      "kind": "web",
      "license": "cited"
    },
    "arxiv-pgs-2017": {
      "title": "Low temperature transport properties of pyrolytic graphite sheet",
      "id": "arXiv:1704.03204 (Nakamura, Miyafuji, Fujii, Matsui, Fukuyama)",
      "url": "https://arxiv.org/pdf/1704.03204",
      "year": 2017,
      "kind": "paper",
      "license": "arXiv (cited)"
    },
    "wiki-pyrolytic-carbon": {
      "title": "Wikipedia: Pyrolytic carbon",
      "id": "en.wikipedia.org, Pyrolytic_carbon",
      "url": "https://en.wikipedia.org/wiki/Pyrolytic_carbon",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA 4.0 (cited)"
    },
    "wiki-graphite": {
      "title": "Wikipedia: Graphite",
      "id": "en.wikipedia.org, Graphite",
      "url": "https://en.wikipedia.org/wiki/Graphite",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA 4.0 (cited)"
    },
    "wiki-carbon": {
      "title": "Wikipedia: Carbon",
      "id": "en.wikipedia.org, Carbon (standard atomic weight from CIAAW 2021)",
      "url": "https://en.wikipedia.org/wiki/Carbon",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA 4.0 (cited)"
    },
    "osha-synthetic": {
      "title": "OSHA chemical data: Graphite (synthetic)",
      "id": "CAS 7440-44-0, OSHA chemical sampling data",
      "url": "https://www.osha.gov/chemicaldata/533",
      "year": 2021,
      "kind": "standard",
      "license": "US government work (cited)"
    },
    "osha-natural": {
      "title": "OSHA chemical data: Graphite (natural), respirable fraction",
      "id": "CAS 7782-42-5, OSHA chemical sampling data",
      "url": "https://www.osha.gov/chemicaldata/665",
      "year": 2021,
      "kind": "standard",
      "license": "US government work (cited)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/pg/"
}