Silica aerogel SiO2 aerogel
Porous amorphous silica (SiO2) network with air in the pores
Silica aerogel is a porous silica solid that is about 99 % air by volume, as a JPL article describes it.
Evidence level
2 of 5
Lab-measured
- 0Predicted only. No one has made it, or no measurement exists.
- 1Calculated. Only calculated or predicted values from sources.
- 2Lab-measured. Measured properties with their conditions stated.
- 3Space-relevant tests. Measured in conditions relevant to space, such as vacuum or atomic oxygen.
- 4Ground-qualified. Qualified for an application on the ground.
- 5Flown or field-proven. Flight or field results exist.
Insulation
14 mW/(m·K) at 0 °C
Service limit
650 °C
Low density
0.01 g/cm3
Recipe, share of the weight
- Si not statedSilicon
- O not statedOxygen
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
Risk at a glance
- People None found. Not classified hazardous in most reports
- If it fails Moderate. Moisture uptake raises conductivity
- Corrosion Moderate. Wetting raises conductivity by about 20 to 40 %, so keep the blanket dry.
Quick facts: SiO2 aerogel
| Property | Value | Basis |
|---|---|---|
| Density | 0.01 to 0.2 g/cm³ | 2 sourced values across conditions |
| Thermal conductivity | 0.014 to 0.02 W/(m·K) | 2 sourced values across conditions |
| Maximum service temperature | 650 °C | 1 sourced value |
What is the density of Silica aerogel?
Silica aerogel has a density of 0.01 to 0.2 g/cm³. The range covers 2 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is the thermal conductivity of Silica aerogel?
Silica aerogel has a thermal conductivity of 0.014 to 0.02 W/(m·K). The range covers 2 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is the maximum service temperature of Silica aerogel?
Silica aerogel has a maximum service temperature of 650 °C. The source and test conditions are listed in the properties table on this page.
What is Silica aerogel used for?
Uses recorded in the sources include Lamp experiment simulating warming of the Mars surface under a silica aerogel layer; SiO2 aerogel composite insulation layer in the Mars rover.
Why it exists
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.
Where it's used
Mars rovers
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.
Industrial pipes and vessels
The manufacturer sells Pyrogel XTE for insulating pipes, vessels and valves, and says it resists corrosion under insulation.
Lab test of Mars surface warming
A lamp test with 2 to 3 cm of silica aerogel warmed the surface beneath it by up to 65 °C, according to JPL.
Recipe
Porous amorphous silica (SiO2) network with air in the pores; the JPL article describes it as 99 % air
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.
| Ingredient | Share of the weight | What it does |
|---|---|---|
| Silicon Si | not stated | Forms the silica network, a rigid solid framework of Si-O bonds. |
| Oxygen O | not stated | Bridges the silicon atoms, so each unit is SiO2. The pores between the network strands are filled with air. |
Weight shares are as printed in the sources.
What it can do
Insulation
14 mW/(m·K) at 0 °C
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.
Service limit
650 °C
Stay in service up to 650 °C for the Pyrogel XTE grade.
Low density
0.01 g/cm3
Collect fast particles: the Stardust flight-spare aerogel was about 0.01 g/cm3.
How it compares
Only one commercial grade is sourced here, so no comparison with other insulators is made.
The same measurements for each material, so you can compare them. Each row names the key condition under the value; the full conditions and methods are in the numbered notes under Technical details.
| Measurement | SiO2 aerogel |
|---|---|
| Thermal behavior and safety | |
| Thermal conductivity, Pyrogel XTE at 0 °C | 14 mW/(m·K)2 |
| Thermal conductivity, Pyrogel XTE at 300 °C | 24 mW/(m·K)3 |
| Thermal conductivity, Pyrogel XTE at 600 °C | 62 mW/(m·K)4 |
| Thermal conductivity, Pyrogel XTE blanket at 0 °C | 20 mW/(m·K)7 |
| Thermal conductivity, Pyrogel XTE blanket at 200 °C | 28 mW/(m·K)8 |
| Thermal conductivity, Pyrogel XTE blanket at 400 °C | 46 mW/(m·K)9 |
| Thermal conductivity, Pyrogel XTE blanket at 600 °C | 89 mW/(m·K)10 |
| Physical and electrical | |
| Nominal apparent density, Pyrogel XTE | 200 kg/m31 |
| Bulk density, Stardust flight-spare silica aerogel | 0.01 g/cm³6 |
| Other measurements | |
| Maximum use temperature, Pyrogel XTE | 650 °C5 |
| Compressive resistance, Pyrogel XTE blanket (minimum) | 3 psi11 |
| Linear shrinkage under soaking heat, Pyrogel XTE blanket | 2 %12 |
Why choose it, and why not
Good for
- Thermal blankets for Mars surface systems, where the JPL article describes insulation under a lamp experiment.
Watch out for
- 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.
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.
Technical details
For scientists and researchers. Everything above comes from the record below: every number with its method, its conditions and its source.
Notes
The method, full conditions and any caveat for the numbered rows above.
| # | Measurement | Method | Conditions | Caveat |
|---|---|---|---|---|
| 1 | Nominal apparent density, Pyrogel XTE | Nominal value printed on the Pyrogel XTE technical data page | product Pyrogel XTE blankettolerance plus or minus 10 % | — |
| 2 | Thermal conductivity, Pyrogel XTE at 0 °C | Value printed on the Pyrogel XTE technical data page; test standard and load not stated on that page | temperature 0 °Cproduct Pyrogel XTE blanket | — |
| 3 | Thermal conductivity, Pyrogel XTE at 300 °C | Value printed on the Pyrogel XTE technical data page; test standard and load not stated on that page | temperature 300 °Cproduct Pyrogel XTE blanket | — |
| 4 | Thermal conductivity, Pyrogel XTE at 600 °C | Value printed on the Pyrogel XTE technical data page; test standard and load not stated on that page | temperature 600 °Cproduct Pyrogel XTE blanket | — |
| 5 | Maximum use temperature, Pyrogel XTE | Value printed on the Pyrogel XTE technical data page | product Pyrogel XTE blanket | — |
| 6 | Bulk density, Stardust flight-spare silica aerogel | Value in the abstract of an NTRS record for a Stardust interstellar dust capture study | form Stardust flight-spare low-density silica aerogelnote stated as approximately | — |
| 7 | Thermal conductivity, Pyrogel XTE blanket at 0 °C | ASTM C177, as printed in the manufacturer datasheet table (mean temperature) | temperature 0 °Cproduct Pyrogel XTE blanketload 2 psi pre-load (datasheet footnote) | — |
| 8 | Thermal conductivity, Pyrogel XTE blanket at 200 °C | ASTM C177, as printed in the manufacturer datasheet table (mean temperature) | temperature 200 °Cproduct Pyrogel XTE blanketload 2 psi pre-load (datasheet footnote) | — |
| 9 | Thermal conductivity, Pyrogel XTE blanket at 400 °C | ASTM C177, as printed in the manufacturer datasheet table (mean temperature) | temperature 400 °Cproduct Pyrogel XTE blanketload 2 psi pre-load (datasheet footnote) | — |
| 10 | Thermal conductivity, Pyrogel XTE blanket at 600 °C | ASTM C177, as printed in the manufacturer datasheet table (mean temperature) | temperature 600 °Cproduct Pyrogel XTE blanketload 2 psi pre-load (datasheet footnote) | — |
| 11 | Compressive resistance, Pyrogel XTE blanket (minimum) | ASTM C165, minimum printed in the performance table | strain 10 % deformationproduct Pyrogel XTE blanketnote printed as at least 3 psi (20.7 kPa) | — |
| 12 | Linear shrinkage under soaking heat, Pyrogel XTE blanket | ASTM C356, upper bound printed in the performance table | temperature 650 °C (1200 °F) soaking heatproduct Pyrogel XTE blanketnote printed as less than 2 % | — |
Corrosion and compatibility
What happens when it meets other materials and environments.
| Environment | Concern | What happens |
|---|---|---|
| Wetting by liquid water or humid air (moisture uptake) | moderate | Wetting raises conductivity by about 20 to 40 %, so keep the blanket dry.1 |
| Heating at the top service temperature (650 °C soaking heat) | low | Linear shrinkage stays below 2 % at 650 °C.2 |
| Long storage and repeated handling (mechanical ageing) | low | Aged aerogel gets stiffer and stronger in compression, but breaks at lower strain.3 |
| # | Environment | Details | Test conditions |
|---|---|---|---|
| 1 | Wetting by liquid water or humid air (moisture uptake) | 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. | exposure 0, 4, 8, 12, 16 and 20 h wetting at 293 K and 90 % relative humidity, in a climatic chambermaterial silica aerogel blankets for building insulation (glass-fibre reinforced)test heat flow meter on individual slabs |
| 2 | Heating at the top service temperature (650 °C soaking heat) | 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. | temperature 650 °C (1200 °F)standard ASTM C356 |
| 3 | Long storage and repeated handling (mechanical ageing) | 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. | material fibre-reinforced silica aerogelnote magnitudes and ageing conditions not given in the abstract |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
PubChem lists silica as not meeting GHS hazard criteria in most company reports, but some reports give irritation codes.
- The substance
- PubChem records 7,724 of 9,127 company reports (about 85 %) as not meeting GHS hazard criteria. Only 1,403 reports give hazard codes.
- Irritation
- 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.
- Dust
- 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.
If it fails
The main failure mode in the sourced data is moisture.
- Wetting
- The Lakatos paper reports that wetting raised conductivity by about 20 to 40 % over 0 to 20 hours at 90 % relative humidity.
- Ageing
- NASA reports that ageing made the aerogel stiffer and stronger in compression, and that it broke at lower strain.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Moisture uptake raises conductivitymoderate severity | Wetting for 0 to 20 hours at 293 K and 90 % relative humidityThermal conductivity increases by about 20 to 40 % after wetting, per the paper. |
Handling and storage
- The manufacturer says a Pyrogel XTE blanket can be removed and reused several times without degradation, after inspection.
- The blanket is hydrophobic and resists liquid water, but wetting still degrades conductivity, so seal it against water.
Mitigations
- Use the hydrophobic blanket to keep the insulation and the asset drier, which limits the moisture-driven conductivity rise.
Supply and geography
How common the raw materials are and where they come from.
Silicon metal (related commodity; the silica feedstock chain for aerogel is not covered by this table)
Not read in this run. USGS says the silicon comes from silica in natural forms such as quartzite and that resources are abundant.
- Top producers (2025)
- China 87%, Brazil 3.9%, Norway 2.8%
Documents
Datasheets, safety data sheets, papers and standards you can open.
Full record
The complete spore, as stored. Free to reuse under CC-BY-4.0. Images keep the licence shown with each one.
Show the full YAML
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.
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
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
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
- benchmark: thermal_conductivity
label: Thermal conductivity, Pyrogel XTE at 0 °C
value: 14
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
- benchmark: thermal_conductivity
label: Thermal conductivity, Pyrogel XTE at 300 °C
value: 24
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
- benchmark: thermal_conductivity
label: Thermal conductivity, Pyrogel XTE at 600 °C
value: 62
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
- benchmark: max_service_temp
label: Maximum use temperature, Pyrogel XTE
value: 650
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.
- benchmark: density
label: Bulk density, Stardust flight-spare silica aerogel
value: 0.01
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
- benchmark: thermal_conductivity
label: Thermal conductivity, Pyrogel XTE blanket at 0 °C
value: 20
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)
- benchmark: thermal_conductivity
label: Thermal conductivity, Pyrogel XTE blanket at 200 °C
value: 28
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
- benchmark: thermal_conductivity
label: Thermal conductivity, Pyrogel XTE blanket at 400 °C
value: 46
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
- benchmark: thermal_conductivity
label: Thermal conductivity, Pyrogel XTE blanket at 600 °C
value: 89
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
- benchmark: compressive_resistance
label: Compressive resistance, Pyrogel XTE blanket (minimum)
value: 3
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
- benchmark: linear_shrinkage
label: Linear shrinkage under soaking heat, Pyrogel XTE blanket
value: 2
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
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"
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.
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
kind: datasheet
year: 2023
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
kind: paper
year: 2017
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
kind: report
year: 1995
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
kind: report
year: 2026
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
kind: paper
year: 2010
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
updated: '2026-10-19'
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.
can_do:
- label: Insulation
value: 14 mW/(m·K) at 0 °C
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.'
- label: Service limit
value: 650 °C
line: Stay in service up to 650 °C for the Pyrogel XTE grade.
- label: Low density
value: 0.01 g/cm3
line: 'Collect fast particles: the Stardust flight-spare aerogel was about 0.01 g/cm3.'
compare: Only one commercial grade is sourced here, so no comparison with other insulators is made.
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.
risk_groups:
- title: For people
level: 0
verdict: Not classified hazardous in most reports
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.
- 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.
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
atoms: 1
role: Forms the silica network, a rigid solid framework of Si-O bonds.
- name: Oxygen
symbol: O
atoms: 2
role: Bridges the silicon atoms, so each unit is SiO2. The pores between the network strands are filled with air.
source: journal-nanomat-2010
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.
compare_rows:
- label: Thermal conductivity at 0 °C
benchmark: thermal_conductivity
- label: Density
benchmark: density
- label: Maximum use temperature
benchmark: max_service_temp
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.
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
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
basis: 'computed: 4,000 thousand t of 4,600 thousand t world silicon metal (USGS table, 2025)'
- country: Brazil
share_percent: 3.9
year: 2025
basis: 'computed: 180 thousand t of 4,600 thousand t'
- country: Norway
share_percent: 2.8
year: 2025
basis: 'computed: 130 thousand t of 4,600 thousand t'
supply_note: Shares are computed by the assistant from the printed tonnage and the printed world total (USGS rounds its world totals), not printed by USGS. Units are thousand metric tons of silicon content.
critical_lists: []
source: usgs-silicon-2026
where: World Production table, silicon metal, 2024 and 2025; Events, Trends and Issues
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.'
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
References
Every number above carries a reference number. Click one to see the source and where in it the value comes from.