{
  "spore": "profile",
  "id": "silica-aerogel",
  "spore_version": "0.2",
  "family": "aerogels",
  "name": "Silica aerogel",
  "abbreviation": "SiO2 aerogel",
  "role": "thermal insulator and dust collector",
  "category": "thermal-protection",
  "type": "aerogels",
  "summary": "Silica aerogel is a porous silica solid that is about 99 % air by volume, as a JPL article describes it. Pyrogel XTE, a commercial silica aerogel blanket from Aspen Aerogels, has a nominal density of 200 kg/m3 and a conductivity of 14 mW/(m·K) at 0 °C. NASA's Stardust mission used a flight-spare silica aerogel, at about 0.01 g/cm3, to catch comet and interstellar dust.\n",
  "best_for": "Very low thermal conductivity per thickness at cold and moderate temperatures",
  "weakest_at": "Upper temperature limit of the Pyrogel XTE grade (650 °C) and its rising conductivity with temperature",
  "identity": {
    "formula": "Porous amorphous silica (SiO2) network with air in the pores; the JPL article describes it as 99 % air",
    "designations": [],
    "source": "nasa-jpl-colonize-mars",
    "where": "Opening description of the article"
  },
  "tags": {
    "environments": [
      "mars-surface"
    ],
    "stresses": [
      "thermal-cycling",
      "extreme-cold"
    ],
    "applications": [
      "thermal-control"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Nominal apparent density, Pyrogel XTE",
      "value": 200,
      "bound": "exact",
      "unit": "kg/m3",
      "scope": "material",
      "conditions": {
        "product": "Pyrogel XTE blanket",
        "tolerance": "plus or minus 10 %"
      },
      "method": "Nominal value printed on the Pyrogel XTE technical data page",
      "status": "ground",
      "source": "aerogel-uk-pyrogel-xte",
      "where": "Technical data section, Nominal Apparent Density",
      "source_detail": {
        "title": "Technical data - Pyrogel XTE (Aspen Aerogels product, reproduced by aerogel.uk.com)",
        "id": "aerogel.uk.com Pyrogel XTE page",
        "url": "http://www.aerogel.uk.com/pyrogel-xte.html",
        "kind": "web",
        "license": "distributor web page, linked not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, Pyrogel XTE at 0 °C",
      "value": 14,
      "bound": "exact",
      "unit": "mW/(m·K)",
      "scope": "material",
      "conditions": {
        "temperature": "0 °C",
        "product": "Pyrogel XTE blanket"
      },
      "method": "Value printed on the Pyrogel XTE technical data page; test standard and load not stated on that page",
      "status": "ground",
      "source": "aerogel-uk-pyrogel-xte",
      "where": "Technical data section, Thermal Conductivity",
      "source_detail": {
        "title": "Technical data - Pyrogel XTE (Aspen Aerogels product, reproduced by aerogel.uk.com)",
        "id": "aerogel.uk.com Pyrogel XTE page",
        "url": "http://www.aerogel.uk.com/pyrogel-xte.html",
        "kind": "web",
        "license": "distributor web page, linked not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, Pyrogel XTE at 300 °C",
      "value": 24,
      "bound": "exact",
      "unit": "mW/(m·K)",
      "scope": "material",
      "conditions": {
        "temperature": "300 °C",
        "product": "Pyrogel XTE blanket"
      },
      "method": "Value printed on the Pyrogel XTE technical data page; test standard and load not stated on that page",
      "status": "ground",
      "source": "aerogel-uk-pyrogel-xte",
      "where": "Technical data section, Thermal Conductivity",
      "source_detail": {
        "title": "Technical data - Pyrogel XTE (Aspen Aerogels product, reproduced by aerogel.uk.com)",
        "id": "aerogel.uk.com Pyrogel XTE page",
        "url": "http://www.aerogel.uk.com/pyrogel-xte.html",
        "kind": "web",
        "license": "distributor web page, linked not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, Pyrogel XTE at 600 °C",
      "value": 62,
      "bound": "exact",
      "unit": "mW/(m·K)",
      "scope": "material",
      "conditions": {
        "temperature": "600 °C",
        "product": "Pyrogel XTE blanket"
      },
      "method": "Value printed on the Pyrogel XTE technical data page; test standard and load not stated on that page",
      "status": "ground",
      "source": "aerogel-uk-pyrogel-xte",
      "where": "Technical data section, Thermal Conductivity",
      "source_detail": {
        "title": "Technical data - Pyrogel XTE (Aspen Aerogels product, reproduced by aerogel.uk.com)",
        "id": "aerogel.uk.com Pyrogel XTE page",
        "url": "http://www.aerogel.uk.com/pyrogel-xte.html",
        "kind": "web",
        "license": "distributor web page, linked not reproduced"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Maximum use temperature, Pyrogel XTE",
      "value": 650,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "product": "Pyrogel XTE blanket"
      },
      "method": "Value printed on the Pyrogel XTE technical data page",
      "status": "ground",
      "source": "aerogel-uk-pyrogel-xte",
      "where": "Technical data section, Max. Use Temp.",
      "source_detail": {
        "title": "Technical data - Pyrogel XTE (Aspen Aerogels product, reproduced by aerogel.uk.com)",
        "id": "aerogel.uk.com Pyrogel XTE page",
        "url": "http://www.aerogel.uk.com/pyrogel-xte.html",
        "kind": "web",
        "license": "distributor web page, linked not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Bulk density, Stardust flight-spare silica aerogel",
      "value": 0.01,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "Stardust flight-spare low-density silica aerogel",
        "note": "stated as approximately"
      },
      "method": "Value in the abstract of an NTRS record for a Stardust interstellar dust capture study",
      "status": "ground",
      "source": "stardust-ntrs-2014",
      "where": "Abstract, aerogel density",
      "source_detail": {
        "title": "Stardust Interstellar Preliminary Examination IX: High-Speed Interstellar Dust Analog Capture in Stardust Flight-Spare Aerogel",
        "id": "NASA report ARC-E-DAA-TN19026; doi:10.1111/maps.12173",
        "url": "https://ntrs.nasa.gov/citations/20160004949",
        "year": 2014,
        "kind": "report",
        "license": "NASA public document"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, Pyrogel XTE blanket at 0 °C",
      "value": 20,
      "bound": "exact",
      "unit": "mW/(m·K)",
      "scope": "material",
      "conditions": {
        "temperature": "0 °C",
        "product": "Pyrogel XTE blanket",
        "load": "2 psi pre-load (datasheet footnote)"
      },
      "method": "ASTM C177, as printed in the manufacturer datasheet table (mean temperature)",
      "status": "ground",
      "source": "aspen-pyrogel-xte-datasheet",
      "where": "Thermal Conductivity table, mean temperature 32 °F / 0 °C (printed 0.14 BTU-in/hr-ft²-°F = 20 mW/m-K)",
      "source_detail": {
        "title": "Pyrogel XTE Product Data Sheet, Rev 4.2 (Aspen Aerogels)",
        "id": "Aspen Aerogels Rev 4.2, copyright 2023",
        "url": "https://www.aerogel.com/wp-content/uploads/2021/06/Pyrogel-XTE-Datasheet-English-v4.2.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, linked not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, Pyrogel XTE blanket at 200 °C",
      "value": 28,
      "bound": "exact",
      "unit": "mW/(m·K)",
      "scope": "material",
      "conditions": {
        "temperature": "200 °C",
        "product": "Pyrogel XTE blanket",
        "load": "2 psi pre-load (datasheet footnote)"
      },
      "method": "ASTM C177, as printed in the manufacturer datasheet table (mean temperature)",
      "status": "ground",
      "source": "aspen-pyrogel-xte-datasheet",
      "where": "Thermal Conductivity table, mean temperature 392 °F / 200 °C",
      "source_detail": {
        "title": "Pyrogel XTE Product Data Sheet, Rev 4.2 (Aspen Aerogels)",
        "id": "Aspen Aerogels Rev 4.2, copyright 2023",
        "url": "https://www.aerogel.com/wp-content/uploads/2021/06/Pyrogel-XTE-Datasheet-English-v4.2.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, linked not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, Pyrogel XTE blanket at 400 °C",
      "value": 46,
      "bound": "exact",
      "unit": "mW/(m·K)",
      "scope": "material",
      "conditions": {
        "temperature": "400 °C",
        "product": "Pyrogel XTE blanket",
        "load": "2 psi pre-load (datasheet footnote)"
      },
      "method": "ASTM C177, as printed in the manufacturer datasheet table (mean temperature)",
      "status": "ground",
      "source": "aspen-pyrogel-xte-datasheet",
      "where": "Thermal Conductivity table, mean temperature 752 °F / 400 °C",
      "source_detail": {
        "title": "Pyrogel XTE Product Data Sheet, Rev 4.2 (Aspen Aerogels)",
        "id": "Aspen Aerogels Rev 4.2, copyright 2023",
        "url": "https://www.aerogel.com/wp-content/uploads/2021/06/Pyrogel-XTE-Datasheet-English-v4.2.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, linked not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, Pyrogel XTE blanket at 600 °C",
      "value": 89,
      "bound": "exact",
      "unit": "mW/(m·K)",
      "scope": "material",
      "conditions": {
        "temperature": "600 °C",
        "product": "Pyrogel XTE blanket",
        "load": "2 psi pre-load (datasheet footnote)"
      },
      "method": "ASTM C177, as printed in the manufacturer datasheet table (mean temperature)",
      "status": "ground",
      "source": "aspen-pyrogel-xte-datasheet",
      "where": "Thermal Conductivity table, mean temperature 1112 °F / 600 °C",
      "source_detail": {
        "title": "Pyrogel XTE Product Data Sheet, Rev 4.2 (Aspen Aerogels)",
        "id": "Aspen Aerogels Rev 4.2, copyright 2023",
        "url": "https://www.aerogel.com/wp-content/uploads/2021/06/Pyrogel-XTE-Datasheet-English-v4.2.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, linked not reproduced"
      }
    },
    {
      "benchmark": "compressive_resistance",
      "label": "Compressive resistance, Pyrogel XTE blanket (minimum)",
      "value": 3,
      "bound": "exact",
      "unit": "psi",
      "scope": "material",
      "conditions": {
        "strain": "10 % deformation",
        "product": "Pyrogel XTE blanket",
        "note": "printed as at least 3 psi (20.7 kPa)"
      },
      "method": "ASTM C165, minimum printed in the performance table",
      "status": "ground",
      "source": "aspen-pyrogel-xte-datasheet",
      "where": "Performance properties table, Compressive Resistance",
      "source_detail": {
        "title": "Pyrogel XTE Product Data Sheet, Rev 4.2 (Aspen Aerogels)",
        "id": "Aspen Aerogels Rev 4.2, copyright 2023",
        "url": "https://www.aerogel.com/wp-content/uploads/2021/06/Pyrogel-XTE-Datasheet-English-v4.2.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, linked not reproduced"
      }
    },
    {
      "benchmark": "linear_shrinkage",
      "label": "Linear shrinkage under soaking heat, Pyrogel XTE blanket",
      "value": 2,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "temperature": "650 °C (1200 °F) soaking heat",
        "product": "Pyrogel XTE blanket",
        "note": "printed as less than 2 %"
      },
      "method": "ASTM C356, upper bound printed in the performance table",
      "status": "ground",
      "source": "aspen-pyrogel-xte-datasheet",
      "where": "Performance properties table, Linear Shrinkage Under Soaking Heat",
      "source_detail": {
        "title": "Pyrogel XTE Product Data Sheet, Rev 4.2 (Aspen Aerogels)",
        "id": "Aspen Aerogels Rev 4.2, copyright 2023",
        "url": "https://www.aerogel.com/wp-content/uploads/2021/06/Pyrogel-XTE-Datasheet-English-v4.2.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, linked not reproduced"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Wetting by liquid water or humid air (moisture uptake)",
      "headline": "Wetting raises conductivity by about 20 to 40 %, so keep the blanket dry.",
      "effect": "The paper reports that thermal conductivity of aerogel blankets can increase significantly, about 20 to 40 %, after wetting. Conductivity rose as the samples wetted over 0 to 20 hours at 90 % relative humidity.",
      "rating": "moderate",
      "conditions": {
        "exposure": "0, 4, 8, 12, 16 and 20 h wetting at 293 K and 90 % relative humidity, in a climatic chamber",
        "material": "silica aerogel blankets for building insulation (glass-fibre reinforced)",
        "test": "heat flow meter on individual slabs"
      },
      "source": "lakatos2017",
      "where": "Abstract; measurements section on wetting time"
    },
    {
      "environment": "Heating at the top service temperature (650 °C soaking heat)",
      "headline": "Linear shrinkage stays below 2 % at 650 °C.",
      "effect": "The datasheet prints linear shrinkage under soaking heat of less than 2 % at 1200 °F (650 °C), tested by ASTM C356. It does not give the shrinkage at other temperatures or times.",
      "rating": "low",
      "conditions": {
        "temperature": "650 °C (1200 °F)",
        "standard": "ASTM C356"
      },
      "source": "aspen-pyrogel-xte-datasheet",
      "where": "Performance properties table"
    },
    {
      "environment": "Long storage and repeated handling (mechanical ageing)",
      "headline": "Aged aerogel gets stiffer and stronger in compression, but breaks at lower strain.",
      "effect": "A NASA report on silica aerogels states that aging increased compressive strength and elastic moduli and decreased strain at fracture. Desiccation, which removed trapped moisture, did not appreciably change the mechanical properties. The abstract gives no ageing times or conditions.",
      "rating": "low",
      "conditions": {
        "material": "fibre-reinforced silica aerogel",
        "note": "magnitudes and ageing conditions not given in the abstract"
      },
      "source": "parmenter-milstein-1995",
      "where": "Abstract"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "PubChem records silica (CID 24261) as not meeting GHS hazard criteria in 7,724 of 9,127 company reports (about 85 %). Only 1,403 reports give hazard codes.",
        "ghs": [],
        "source": "pubchem-silica",
        "where": "GHS Classification, first aggregate block (9,127 reports)"
      },
      {
        "text": "In the 2,540 reports that give a classification, H315 (skin irritation), H319 (serious eye irritation) and H335 (may cause respiratory irritation) each appear in 56.3 % of the notifications. 889 of those 2,540 reports say it does not meet GHS criteria.",
        "ghs": [
          "H315",
          "H319",
          "H335"
        ],
        "source": "pubchem-silica",
        "where": "GHS Classification, second aggregate block (2,540 reports)"
      }
    ],
    "failure_risks": [
      {
        "mode": "Moisture uptake raises conductivity",
        "trigger": "Wetting for 0 to 20 hours at 293 K and 90 % relative humidity",
        "consequence": "Thermal conductivity increases by about 20 to 40 % after wetting, per the paper.",
        "severity": "moderate",
        "source": "lakatos2017",
        "where": "Abstract"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "The manufacturer says a Pyrogel XTE blanket can be removed and reused several times without degradation, after inspection.",
        "source": "aspen-pyrogel-xte-web",
        "where": "Benefits, Remove and Reuse"
      },
      {
        "text": "The blanket is hydrophobic and resists liquid water, but wetting still degrades conductivity, so seal it against water.",
        "source": "lakatos2017",
        "where": "Abstract"
      }
    ],
    "mitigations": [
      {
        "text": "Use the hydrophobic blanket to keep the insulation and the asset drier, which limits the moisture-driven conductivity rise.",
        "source": "aspen-pyrogel-xte-datasheet",
        "where": "Advantages, first bullet"
      }
    ]
  },
  "uses": [
    {
      "application": "thermal-control",
      "device": "Lamp experiment simulating warming of the Mars surface under a silica aerogel layer",
      "example": "A JPL article describes a lamp experiment with 2-3 centimeters of silica aerogel, which warmed the surface to up to 65 °C.",
      "source": "nasa-jpl-colonize-mars",
      "where": "Article text on the lamp experiment"
    },
    {
      "application": "rovers-and-surface-systems",
      "device": "SiO2 aerogel composite insulation layer in the Mars rover",
      "example": "A 2025 review says the aerogel composite was used as an insulation layer in the Mars rover, which let it withstand temperatures below -100 °C.",
      "source": "pmc12113059-aerogel-review",
      "where": "Aerospace section, Mars rover paragraph and its Figure 9 caption"
    }
  ],
  "supply": [
    {
      "subject": "Silicon metal (related commodity; the silica feedstock chain for aerogel is not covered by this table)",
      "abundance": "Not read in this run. USGS says the silicon comes from silica in natural forms such as quartzite and that resources are abundant.",
      "producers": [
        {
          "country": "China",
          "share_percent": 87,
          "year": 2025
        },
        {
          "country": "Brazil",
          "share_percent": 3.9,
          "year": 2025
        },
        {
          "country": "Norway",
          "share_percent": 2.8,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "substitutes": [],
      "source": "usgs-silicon-2026",
      "where": "World Production table, silicon metal, 2024 and 2025; Events, Trends and Issues"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Technical data - Pyrogel XTE (Aspen Aerogels, reproduced by aerogel.uk.com)",
      "type": "datasheet",
      "url": "http://www.aerogel.uk.com/pyrogel-xte.html"
    },
    {
      "title": "Stardust Interstellar Preliminary Examination IX (NASA NTRS)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/citations/20160004949",
      "year": 2014
    },
    {
      "title": "Pyrogel XTE Product Data Sheet, Rev 4.2 (Aspen Aerogels)",
      "type": "datasheet",
      "url": "https://www.aerogel.com/wp-content/uploads/2021/06/Pyrogel-XTE-Datasheet-English-v4.2.pdf",
      "year": 2023
    },
    {
      "title": "Investigation of the moisture induced degradation of the thermal properties of Aerogel blankets (Lakatos, Energy and Buildings)",
      "type": "paper",
      "url": "https://dea.lib.unideb.hu/dea/bitstream/2437/234306/1/FILE_UP_0_1-s2.0-S0378778816316589-main.pdf",
      "year": 2017
    },
    {
      "title": "Mechanical Properties of Aerogels (NASA NTRS 19960016728)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/citations/19960016728",
      "year": 1995
    },
    {
      "title": "Silicon, Mineral Commodity Summaries 2026 (USGS)",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silicon.pdf",
      "year": 2026
    },
    {
      "title": "PubChem CID 24261, Silica",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/24261"
    },
    {
      "title": "Silica Aerogel: Synthesis and Applications (Journal of Nanomaterials)",
      "type": "paper",
      "url": "https://sonar.ch/global/documents/196790",
      "year": 2010
    },
    {
      "title": "Review of Lightweight, High-Temperature Thermal Insulation Materials for Aerospace (MDPI Materials, 2025)",
      "type": "paper",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC12113059",
      "year": 2025
    }
  ],
  "gaps": [
    "Rover use: the JPL article and a 2025 MDPI review (PMC12113059) both say aerogel insulated the Mars rover. No primary NASA rover document was read, so the review is the only source for the rover detail.",
    "Stardust: no NASA page on the Stardust aerogel's design was read. The 0.01 g/cm3 value comes from one NTRS abstract, and the NASA PDF link redirects to a page not read.",
    "Distributor and datasheet disagree: the distributor page prints 14 mW/(m·K) at 0 °C, the Aspen datasheet 20 mW/(m·K). Both are kept with their sources.",
    "Pyrogel XTE test standard is now read (ASTM C177 at 2 psi pre-load, footnote). Conductivity below 0 °C is not in the datasheet.",
    "Cryogel and other Aspen grades: Cryogel Z page exists but its datasheet was not read.",
    "Producers: the country shares of aerogel makers were not read. IDTechEx claims about China capacity are behind a paywall. Aspen Aerogels is headquartered in Northborough, MA, USA (datasheet footer). Cabot describes continuous ambient-condition production but names no location.",
    "Supply abundance for silica or silicon was not read beyond the USGS note that the source is silica.",
    "Critical-mineral listing for silicon was not checked.",
    "Outgassing in vacuum, tensile strength and hydrophobicity numbers (contact angle) were not read.",
    "Silica dust safety data sheet and exposure limit were not read, so no side effects of dust are sourced.",
    "Compressive resistance and linear shrinkage are not in spores/property-canon.yaml; short snake_case names are used.",
    "Moisture data come from building-insulation blankets wetted for up to 20 hours, not from space conditions."
  ],
  "story": {
    "why": "Silica aerogel is a very low-density insulator. Pyrogel XTE has a nominal density of 200 kg/m3 and a conductivity of 14 mW/(m·K) at 0 °C.",
    "uses": [
      {
        "where": "Mars rovers",
        "line": "NASA JPL says aerogel has been used as insulation on all of NASA's Mars rovers. It is the one space application for which this profile holds a source."
      },
      {
        "where": "Industrial pipes and vessels",
        "line": "The manufacturer sells Pyrogel XTE for insulating pipes, vessels and valves, and says it resists corrosion under insulation."
      },
      {
        "where": "Lab test of Mars surface warming",
        "line": "A lamp test with 2 to 3 cm of silica aerogel warmed the surface beneath it by up to 65 °C, according to JPL."
      }
    ],
    "can_do": [
      {
        "label": "Insulation",
        "line": "Insulate at cold temperatures: the Pyrogel XTE datasheet prints 20 mW/(m·K) at 0 °C, rising to 28 at 200 °C and 89 at 600 °C. A distributor reproduction of the same product prints 14 mW/(m·K) at 0 °C; the datasheet is the manufacturer source.",
        "scope": "material",
        "value": "14 mW/(m·K) at 0 °C"
      },
      {
        "label": "Service limit",
        "line": "Stay in service up to 650 °C for the Pyrogel XTE grade.",
        "scope": "material",
        "value": "650 °C"
      },
      {
        "label": "Low density",
        "line": "Collect fast particles: the Stardust flight-spare aerogel was about 0.01 g/cm3.",
        "scope": "material",
        "value": "0.01 g/cm3"
      }
    ],
    "compare": "Only one commercial grade is sourced here, so no comparison with other insulators is made.",
    "compare_rows": [
      {
        "label": "Thermal conductivity at 0 °C",
        "benchmark": "thermal_conductivity",
        "scope": "material"
      },
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Maximum use temperature",
        "benchmark": "max_service_temp",
        "scope": "material"
      }
    ],
    "handling": [
      "Keep the blanket dry. It is hydrophobic, but the Lakatos paper shows that wetting can raise conductivity by about 20 to 40 %.",
      "The manufacturer says a Pyrogel XTE blanket can be removed and reused several times without degradation, after inspection.",
      "No safety data sheet for silica aerogel was read, so dust handling is not sourced here."
    ],
    "good_for": [
      "Thermal blankets for Mars surface systems, where the JPL article describes insulation under a lamp experiment."
    ],
    "watch_out": [
      "Conductivity rises with temperature: 89 mW/(m·K) at 600 °C is more than four times the 20 mW/(m·K) at 0 °C in the datasheet.",
      "The datasheet values are for a fibre-batting blanket with aerogel inside, not for pure aerogel.",
      "Wetting raises conductivity by about 20 to 40 %, per the Lakatos paper, which tested building blankets rather than space hardware."
    ],
    "verdict": "Strong insulation at low temperature, with datasheet values for one blanket grade. Moisture is the main weakness, and the rover use is now sourced to a JPL article but not to a primary rover document.",
    "recipe": {
      "line": "Silica aerogel is amorphous silicon dioxide (SiO2) with air filling most of its volume. A silicon alkoxide such as TMOS or TEOS in alcohol forms a silica gel by sol-gel processing. The liquid in the gel is then removed by supercritical drying, which keeps the network from collapsing into a dense solid. The review says supercritical drying is the most common method; Wikipedia names supercritical CO2 or freeze-drying.",
      "parts": [
        {
          "name": "Silicon",
          "symbol": "Si",
          "role": "Forms the silica network, a rigid solid framework of Si-O bonds.",
          "atoms": 1
        },
        {
          "name": "Oxygen",
          "symbol": "O",
          "role": "Bridges the silicon atoms, so each unit is SiO2. The pores between the network strands are filled with air.",
          "atoms": 2
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "PubChem lists silica as not meeting GHS hazard criteria in most company reports, but some reports give irritation codes.",
        "points": [
          {
            "label": "The substance",
            "line": "PubChem records 7,724 of 9,127 company reports (about 85 %) as not meeting GHS hazard criteria. Only 1,403 reports give hazard codes."
          },
          {
            "label": "Irritation",
            "line": "In the 2,540 reports that give a classification, the codes H315 (skin irritation), H319 (serious eye irritation) and H335 (may cause respiratory irritation) each appear in 56.3 % of the notifications. 889 of those 2,540 reports say it does not meet criteria."
          },
          {
            "label": "Dust",
            "line": "No safety data sheet or dust-exposure limit for silica aerogel was read in this run. Treat loose dust as an irritant until the supplier sheet says otherwise."
          }
        ],
        "level": 0,
        "verdict": "Not classified hazardous in most reports"
      },
      {
        "title": "If it fails",
        "lead": "The main failure mode in the sourced data is moisture.",
        "points": [
          {
            "label": "Wetting",
            "line": "The Lakatos paper reports that wetting raised conductivity by about 20 to 40 % over 0 to 20 hours at 90 % relative humidity."
          },
          {
            "label": "Ageing",
            "line": "NASA reports that ageing made the aerogel stiffer and stronger in compression, and that it broke at lower strain."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-19",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 6,
    "unreachable": 1,
    "caveats": 3,
    "note": "Deepened on 2026-10-19: six datasheet and NASA values added, each read in this run. The Stardust PDF and the IDTechEx article could not be read."
  },
  "sources": {
    "aerogel-uk-pyrogel-xte": {
      "title": "Technical data - Pyrogel XTE (Aspen Aerogels product, reproduced by aerogel.uk.com)",
      "id": "aerogel.uk.com Pyrogel XTE page",
      "url": "http://www.aerogel.uk.com/pyrogel-xte.html",
      "kind": "web",
      "license": "distributor web page, linked not reproduced"
    },
    "stardust-ntrs-2014": {
      "title": "Stardust Interstellar Preliminary Examination IX: High-Speed Interstellar Dust Analog Capture in Stardust Flight-Spare Aerogel",
      "id": "NASA report ARC-E-DAA-TN19026; doi:10.1111/maps.12173",
      "url": "https://ntrs.nasa.gov/citations/20160004949",
      "year": 2014,
      "kind": "report",
      "license": "NASA public document"
    },
    "nasa-jpl-colonize-mars": {
      "title": "Want to Colonize Mars? Aerogel Could Help (NASA JPL news)",
      "id": "JPL news article",
      "url": "https://www.jpl.nasa.gov/news/want-to-colonize-mars-aerogel-could-help/",
      "kind": "web",
      "license": "NASA public web page"
    },
    "aspen-pyrogel-xte-datasheet": {
      "title": "Pyrogel XTE Product Data Sheet, Rev 4.2 (Aspen Aerogels)",
      "id": "Aspen Aerogels Rev 4.2, copyright 2023",
      "url": "https://www.aerogel.com/wp-content/uploads/2021/06/Pyrogel-XTE-Datasheet-English-v4.2.pdf",
      "year": 2023,
      "kind": "datasheet",
      "license": "manufacturer datasheet, linked not reproduced"
    },
    "aspen-pyrogel-xte-web": {
      "title": "Pyrogel XTE product page (Aspen Aerogels)",
      "id": "aerogel.com product page",
      "url": "https://www.aerogel.com/product/pyrogel-xte/",
      "kind": "web",
      "license": "manufacturer web page, linked not reproduced"
    },
    "lakatos2017": {
      "title": "Investigation of the moisture induced degradation of the thermal properties of Aerogel blankets: measurements, calculations, simulations",
      "id": "doi:10.1016/j.enbuild.2017.01.054",
      "url": "https://dea.lib.unideb.hu/dea/bitstream/2437/234306/1/FILE_UP_0_1-s2.0-S0378778816316589-main.pdf",
      "year": 2017,
      "kind": "paper",
      "license": "accepted manuscript in institutional repository"
    },
    "parmenter-milstein-1995": {
      "title": "Mechanical Properties of Aerogels (Parmenter and Milstein, UC Santa Barbara)",
      "id": "NASA NTRS 19960016728",
      "url": "https://ntrs.nasa.gov/citations/19960016728",
      "year": 1995,
      "kind": "report",
      "license": "NASA public document"
    },
    "usgs-silicon-2026": {
      "title": "Silicon, Mineral Commodity Summaries 2026 (USGS)",
      "id": "USGS MCS 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silicon.pdf",
      "year": 2026,
      "kind": "report",
      "license": "US government public domain"
    },
    "cabot-aerogel": {
      "title": "Cabot Corporation, aerogel products page",
      "id": "cabotcorp.com aerogel page",
      "url": "https://www.cabotcorp.com/solutions/products-plus/aerogel",
      "kind": "web",
      "license": "corporate web page, linked not reproduced"
    },
    "pubchem-silica": {
      "title": "PubChem compound CID 24261, Silica (GHS classification)",
      "id": "PubChem CID 24261",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/24261",
      "kind": "database",
      "license": "PubChem public database"
    },
    "journal-nanomat-2010": {
      "title": "Silica Aerogel: Synthesis and Applications",
      "id": "Journal of Nanomaterials, 2010",
      "url": "https://sonar.ch/global/documents/196790",
      "year": 2010,
      "kind": "paper",
      "license": "repository copy, linked not reproduced"
    },
    "pmc12113059-aerogel-review": {
      "title": "Review of Lightweight, High-Temperature Thermal Insulation Materials for Aerospace (Materials, MDPI, 2025)",
      "id": "PMC12113059",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC12113059",
      "year": 2025,
      "kind": "paper",
      "license": "Open access, as listed by PMC"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/silica-aerogel/"
}