spore: profile
id: frsi-nomex-felt-blanket
spore_version: 0.2
family: glass-and-composites
name: FRSI (felt reusable surface insulation, coated Nomex felt)
abbreviation: FRSI
role: thermal-protection-blanket
category: thermal-protection
type: flexible-blankets
summary: |
  FRSI is a white, flexible blanket of heat-treated Nomex felt with a white silicone elastomer coating. NASA used it on Space Shuttle orbiter upper surfaces where temperatures stayed below about 700 °F. NASA sources give its emittance as 0.8 and its solar absorptance as 0.32. Its density and thermal conductivity are printed in the NASA database only in exponent form, so this profile leaves them out.
best_for: White blanket insulation for areas below about 700 °F on a re-entry vehicle, where an emittance of 0.8 is wanted
weakest_at: 'Few plain numbers for the blanket itself: the NASA database prints density, conductivity and temperature limits only in exponent form, so they are left out'
identity:
  formula: Heat-treated meta-aramid (Nomex) felt with a white silicone elastomer coating; the polymer is made from m-phenylenediamine and isophthaloyl chloride
  source: wiki-nomex
  where: Chemistry paragraph (monomers); the Shuttle use is in the Wikipedia Space Shuttle TPS article
  designations:
    - system: Trade name
      code: Nomex
      source: dupont-nomex
      where: Page text naming DuPont Nomex and its felt form
tags:
  environments:
    - re-entry
    - low-earth-orbit
  applications:
    - heat-shields
properties:
  - benchmark: thermal_emittance
    label: Emissivity (NASA TPSX table)
    value: 0.8
    unit: '-'
    scope: material
    conditions:
      table: Properties at Standard Conditions (SI units)
      stated_condition: true/assumed
      ref_column: '2'
    method: Tabulated value in the NASA Ames TPSX database entry; the same row prints an uncertainty of 0.04
    status: ground
    uncertainty: 0.04 (printed in the same row)
    source: tpsx
    where: Properties at Standard Conditions table, row Emissivity
  - benchmark: thermal_emittance
    label: Emittance of FRSI (NASA shuttle systems text)
    value: 0.8
    unit: '-'
    scope: material
    conditions:
      context: Stated for FRSI in the same sentence as the solar absorptance of 0.32
    method: Value stated in NASA KSC shuttle systems text
    status: ground
    source: ksc-sts-sys
    where: Section on Felt Reusable Surface Insulation
  - benchmark: solar_absorptance
    label: Solar absorptance of FRSI
    value: 0.32
    unit: '-'
    scope: material
    conditions:
      context: Stated in the same sentence as the emittance of 0.8
    method: Value stated in NASA KSC shuttle systems text
    status: ground
    source: ksc-sts-sys
    where: Section on Felt Reusable Surface Insulation
  - benchmark: thickness
    label: FRSI thickness on the orbiter (range set by heat load)
    value: 0.16
    value_high: 0.4
    bound: range
    unit: inch
    scope: material
    conditions:
      depends_on: Heat load encountered during entry
      form: Installed FRSI blanket
    method: Range printed in NASA KSC shuttle systems text
    status: ground
    source: ksc-sts-sys
    where: Section on Felt Reusable Surface Insulation
  - benchmark: thickness
    label: FRSI thickness on the orbiter (TPSX description)
    value: 0.16
    value_high: 0.4
    bound: range
    unit: inch
    scope: material
    conditions:
      depends_on: Heat load encountered during re-entry
      form: Installed FRSI blanket
    method: Range printed in the NASA Ames TPSX description
    status: ground
    source: tpsx
    where: Description paragraph
  - benchmark: coating_thickness
    label: Silicone elastomer coating, as spread before cure
    value: 0.006
    value_high: 0.008
    bound: range
    unit: inch
    scope: material
    conditions:
      process: Elastomer spread on a screen mesh, then partially cured
      form: Heat-treated Nomex felt
    method: Process range printed in the NASA Gordon appendix A.4; a process value, not a finished-coating measurement
    status: ground
    source: gordon
    where: A.4 Felt Reusable Surface Insulation, coating paragraph
  - benchmark: vent_hole_diameter
    label: Vent hole diameter in the FRSI coating
    value: 0.035
    unit: inch
    scope: material
    conditions:
      feature: Vent holes through the white coating
    method: Printed in the NASA Gordon appendix A.4
    status: ground
    source: gordon
    where: A.4, last paragraph
  - benchmark: vent_hole_spacing
    label: Vent hole spacing in the FRSI coating
    value: 6
    unit: inch
    scope: material
    conditions:
      feature: Vent holes through the white coating
      spacing: On 6 inch centers, as printed
    method: Printed in the NASA Gordon appendix A.4
    status: ground
    source: gordon
    where: A.4, last paragraph
  - benchmark: max_service_temp
    label: Upper temperature for FRSI areas (design envelope, Gordon appendix)
    value: 750
    bound: upper
    unit: °F
    scope: material
    conditions:
      context: Upper surface areas where FRSI is used; design envelope, not a material test limit
    method: Application limit printed in the NASA Gordon appendix A.4 as less than 750°F
    status: ground
    source: gordon
    where: A.4, first paragraph
  - benchmark: max_service_temp
    label: Upper temperature for FRSI areas (design envelope, KSC shuttle systems text)
    value: 700
    bound: upper
    unit: °F
    scope: material
    conditions:
      context: Areas the FRSI blankets protect; design envelope, not a material test limit
    method: Application limit printed in NASA KSC shuttle systems text
    status: ground
    source: ksc-sts-sys
    where: Numbered item 6, White blankets of coated Nomex felt
  - benchmark: max_service_temp
    label: Upper temperature for FRSI areas (AZoM article)
    value: 371
    bound: upper
    unit: °C
    scope: material
    conditions:
      context: Areas where coated Nomex felt FRSI is used; design envelope, not a material test limit
    method: Application limit printed in the AZoM article
    status: ground
    source: azom
    where: Section on Coated Nomex Felt Reusable Surface Insulation, temperatures below 371°C
  - benchmark: design_temperature_range
    label: Temperature band protected by FRSI blankets (KSC fact sheet)
    value: 350
    value_high: 700
    bound: range
    unit: °F
    scope: material
    conditions:
      context: Orbiter surfaces protected by FRSI blankets; design band
    method: Range printed in the NASA KSC Orbiter Thermal Protection System fact sheet
    status: ground
    source: ksc-tps
    where: Felt Reusable Surface Insulation paragraph
  - benchmark: max_service_temp
    label: RTV silicone adhesive that bonds FRSI, upper temperature with bond strength kept (adhesive, not the felt)
    value: 550
    bound: upper
    unit: °F
    scope: material
    conditions:
      material: RTV silicone cement that bonds the tiles and blankets
      condition: Bond strength retained
    method: Printed in the NASA KSC fact sheet
    status: ground
    source: ksc-tps
    where: Paragraph on the RTV adhesive
  - benchmark: waterproofing_burnout_temp
    label: Waterproofing burn-out temperature for the orbiter thermal protection
    value: 1100
    unit: °F
    scope: material
    conditions:
      material: Dimethylethoxysilane waterproofing applied after flights
      applies_to: Orbiter thermal protection system, as stated by KSC
    method: Printed in the NASA KSC fact sheet
    status: ground
    source: ksc-tps
    where: Paragraph on rewaterproofing after each flight
  - benchmark: fibre_length
    label: Nomex fibre length in the felt
    value: 3
    unit: inch
    scope: material
    conditions:
      material: Nomex aramid fibres used for the felt
      form: Fibre before carding
    method: Printed in the NASA Gordon appendix A.4
    status: ground
    source: gordon
    where: A.4, second paragraph
  - benchmark: fibre_fineness
    label: Nomex fibre fineness in the felt
    value: 2
    unit: denier
    scope: material
    conditions:
      material: Nomex aramid fibres used for the felt
      form: Fibre before carding
    method: Printed in the NASA Gordon appendix A.4
    status: ground
    source: gordon
    where: A.4, second paragraph
  - benchmark: bondline_thickness
    label: RTV silicone adhesive bondline under FRSI
    value: 0.2
    unit: inch
    scope: material
    conditions:
      adhesive: RTV silicon adhesive
      installation: Bonds FRSI directly to the orbiter
    method: Printed in NASA KSC shuttle systems text
    status: ground
    source: ksc-sts-sys
    where: Section on Felt Reusable Surface Insulation
corrosion:
  - environment: Water and humidity between flights (NASA Gordon appendix)
    headline: The Gordon appendix says FRSI does not need rewaterproofing after each flight.
    effect: The appendix says the Nomex polymer is hygrophobic by nature and the silicone elastomer coating inhibits water intrusion into the felt, so FRSI does not require post-flight rewaterproofing.
    rating: low
    conditions:
      basis: Statement about the installed FRSI blanket
    source: gordon
    where: A.4 Felt Reusable Surface Insulation, first paragraph
  - environment: Water and humidity between flights (KSC fact sheet)
    headline: The KSC fact sheet says the orbiter thermal protection is rewaterproofed after each flight.
    effect: KSC says the waterproofing material burns out at 1,100 °F, which would expose the outer surface to water absorption, so the thermal protection is rewaterproofed after each flight. The sources disagree on whether FRSI needs this step.
    rating: low
    conditions:
      basis: General statement for the orbiter thermal protection, which KSC lists with FRSI
    source: ksc-tps
    where: Paragraph on rewaterproofing after each flight
  - environment: Heat during processing and service
    headline: The felt is heat treated to reduce shrinkage at high temperature.
    effect: For FRSI, the Nomex felt is heat treated at 700°F for 30 minutes and then at 750°F for 30 minutes to reduce linear shrinkage at elevated temperatures; the felt darkens to a caramel colour. The appendix gives no degradation rate for the coated blanket.
    rating: unknown
    conditions:
      process: Heat treatment before coating
    source: gordon
    where: A.4, third paragraph
risks:
  hazards:
    - text: The DuPont page describes Nomex as an inherently flame-resistant, high-temperature fibre that does not melt, drip or support combustion in air. No safety data sheet or GHS record for the coated FRSI product was read in this run.
      ghs: []
      source: dupont-nomex
      where: Page text describing Nomex
    - text: Wikipedia calls Nomex an inherently flame-resistant fabric and a trademarked term. This describes the fibre family, not a hazard test of the coated FRSI blanket.
      ghs: []
      source: wiki-nomex
      where: Lead paragraph
  failure_risks:
    - mode: Water absorption if the waterproofing has burned out
      trigger: Heating to the orbiter waterproofing burn-out temperature
      consequence: KSC says the waterproofing burns out at 1,100 °F, exposing the outer surface to water absorption until it is rewaterproofed after the flight.
      severity: moderate
      source: ksc-tps
      where: Paragraph on rewaterproofing after each flight
    - mode: Temperatures above the FRSI design envelope
      trigger: Surface heating above 700 °F (NASA shuttle systems text) or 750 °F (Gordon appendix)
      consequence: The NASA sources place FRSI only where temperatures stay below these limits. In hotter areas the orbiter used rigid tiles or other insulation. None of the sources gives a failure test result for FRSI above these limits.
      severity: high
      source: ksc-sts-sys
      where: Numbered item 6, White blankets of coated Nomex felt
  handling:
    - text: Bond FRSI with RTV silicone adhesive applied at 0.2 inch thickness, as the NASA shuttle systems text describes.
      source: ksc-sts-sys
      where: Section on Felt Reusable Surface Insulation
    - text: Trim FRSI to a cavity template and paint-seal the exposed edges with white silicone elastomer, as the NASA appendix describes.
      source: gordon
      where: A.4, third paragraph (installation)
    - text: 'Keep FRSI areas within their design envelope: 700 °F in the NASA shuttle systems text, 750 °F in the Gordon appendix.'
      source: ksc-sts-sys
      where: Numbered item 6, White blankets of coated Nomex felt
uses:
  - application: heat-shields
    device: Upper payload bay doors and upper wing surface of the Space Shuttle orbiter
    example: KSC says FRSI blankets are now used only on the upper section of the payload bay doors and the inboard sections of the wing upper surface.
    source: ksc-tps
    where: Felt Reusable Surface Insulation paragraph
  - application: heat-shields
    device: Thermal blankets on the orbiter payload bay doors, fuselage and upper wing surfaces
    example: The Wikipedia Nomex article says Nomex was used as thermal blankets on the payload bay doors, fuselage and upper wing surfaces of the Space Shuttle Orbiter.
    source: wiki-nomex
    where: Section on the US space program
supply:
  - subject: Nomex (meta-aramid polymer) used for the felt
    abundance: A synthetic polymer, not a mined material. Wikipedia says Nomex is produced by condensation of m-phenylenediamine and isophthaloyl chloride.
    producers: []
    substitutes: []
    source: wiki-nomex
    where: Chemistry paragraph
  - subject: Nomex felt supplier for the Shuttle FRSI (historic)
    abundance: No current producer share found. NASA KSC lists Albany International Research Co., Dedham, Mass., as the Nomex felt contractor for the Shuttle thermal protection system.
    producers: []
    substitutes: []
    source: ksc-sts-sys
    where: Contractors list at the end of the shuttle systems page
documents:
  - title: 'NASA Ames TPSX database entry: FRSI Blanket (Nomex Felt)'
    type: database
    url: https://tpsx.arc.nasa.gov/Material?id=18
  - title: Shuttle thermal protection system, Appendix A (NASA KSC public appendix, archived copy)
    type: report
    url: https://web.archive.org/web/20160307090308/http://science.ksc.nasa.gov/shuttle/nexgen/Nexgen_Downloads/Shuttle_Gordon_TPS-PUBLIC_Appendix.pdf
  - title: Space Shuttle systems, KSC shuttle technology page (archived copy)
    type: report
    url: https://web.archive.org/web/20090715235829/http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts_sys.html
  - title: Orbiter Thermal Protection System, KSC fact sheet (archived copy)
    type: report
    url: https://web.archive.org/web/20060909094330/http://www-pao.ksc.nasa.gov/kscpao/nasafact/tps.htm
  - title: DuPont Nomex 40th Anniversary page (archived copy)
    type: datasheet
    url: https://web.archive.org/web/20120217011922/http://www2.dupont.com/Nomex/en_US/news_events/40th_anniv.html
gaps:
  - Density, thermal conductivity, specific heat and the multiple-use and single-use temperature limits are printed in the NASA TPSX entry only in exponent form (for example 8.65e+01 kg/m^3); they are left out under the no-exponent rule.
  - No plain-number FRSI density, areal mass, tensile strength or tear strength was found in the sources read.
  - The NASA TPSX reference list (Kourtides, NASA TM-103925; Rasky 1995; the Rockwell design data book) has no URLs, and those reports were not opened.
  - No vacuum, thermal-cycling, outgassing or flight-derived test result for coated FRSI felt was found in the sources read.
  - No safety data sheet or GHS record for the coated product was read; hazard entries rest on NASA and DuPont text.
  - 'Coverage of the upper surfaces differs between NASA sources: about 25 percent in the KSC fact sheet and nearly 50 percent in the KSC shuttle systems text. Neither figure is recorded as a property.'
  - Rewaterproofing after flights is stated for the orbiter thermal protection in the KSC fact sheet but not for FRSI; the Gordon appendix says FRSI does not need it.
  - Upper temperature for FRSI areas is 700 °F in the KSC shuttle systems text and 371 °C in the AZoM article, and 750 °F in the Gordon appendix. The sources are recorded side by side, not averaged.
  - No current producer or country share was found for Nomex felt. The only named felt contractor is Albany International Research Co., in a Shuttle-era NASA page.
  - NASA TPSX prints Emissivity and the KSC shuttle systems text prints Emittance; both are stored under thermal_emittance.
  - Thickness, coating, vent-hole and bondline values are NASA descriptions of the Shuttle installation, not manufacturer datasheet values.
  - 'Property names not in the canonical list: thickness, coating_thickness, vent_hole_diameter, vent_hole_spacing, design_temperature_range, waterproofing_burnout_temp, fibre_length, fibre_fineness and bondline_thickness.'
  - The NASA STS-6 press kit linked from Wikipedia returned an HTML page instead of a PDF, so it was not read. Critical-mineral lists were not checked for an aramid polymer.
  - The web search budget for this run ran out, so no further sources were searched for beyond the links in the sources already read.
story:
  recipe:
    line: Nomex is a meta-aramid polymer made by condensation of m-phenylenediamine and isophthaloyl chloride, and it is sold as fibre, paper and felt. FRSI is heat-treated Nomex felt with a white silicone elastomer coating, vented by 0.035 inch holes on 6 inch centers.
    parts:
      - name: m-Phenylenediamine
        role: Monomer. Wikipedia names it as one of the two monomers that react to form Nomex.
        source: wiki-nomex
        where: Chemistry paragraph
      - name: Isophthaloyl chloride
        role: Monomer. The second monomer that reacts with m-phenylenediamine to form Nomex.
        source: wiki-nomex
        where: Chemistry paragraph
      - name: Silicone elastomer coating
        role: White outer layer that waterproofs the felt and gives the blanket its thermal and optical properties.
        source: gordon
        where: A.4 Felt Reusable Surface Insulation
  risk_groups:
    - title: For people
      level: 0
      verdict: No hazard data found
      lead: No safety data sheet or GHS record for the coated product was read in this run.
      points:
        - label: Fibre family
          line: DuPont describes Nomex as an inherently flame-resistant, high-temperature fibre that does not melt, drip or support combustion in air.
        - label: Gap
          line: The product itself has no hazard record in this profile yet.
    - title: If the blanket overheats
      lead: These are design limits from NASA sources, not test results.
      points:
        - label: Envelope
          line: NASA places FRSI only where temperatures stay below 700 °F in one source and below 750 °F in another.
        - label: Waterproofing
          line: KSC says the waterproofing burns out at 1,100 °F, which exposes the outer surface to water absorption.
    - title: Handling and installation
      points:
        - label: Adhesive
          line: The NASA shuttle systems text bonds FRSI with RTV silicone adhesive at 0.2 inch thickness.
        - label: Edges
          line: Trimmed to a cavity template and paint-sealed with white silicone elastomer, according to the Gordon appendix.
  why: FRSI (felt reusable surface insulation) is a white, flexible blanket of heat-treated Nomex felt with a white silicone elastomer coating. NASA bonded it directly to the Space Shuttle orbiter skin with RTV silicone adhesive, and placed it on surfaces where temperatures stayed below about 700 °F. The NASA sources give few plain numbers for the blanket itself, so this profile records only the values printed in the fetched pages.
  uses:
    - where: Space Shuttle orbiter upper surfaces
      line: NASA KSC says FRSI blankets are now used only on the upper section of the payload bay doors and the inboard sections of the wing upper surface. Wikipedia's Nomex article says Nomex was used as thermal blankets on the payload bay doors, fuselage and upper wing surfaces of the orbiter.
  can_do:
    - label: Emissivity
      benchmark: thermal_emittance
      line: The NASA TPSX entry gives an emissivity of 0.8, with an uncertainty of 0.04 printed in the same row. A NASA shuttle systems page gives the same emittance of 0.8 for FRSI.
    - label: Solar absorptance
      benchmark: solar_absorptance
      line: The NASA shuttle systems page gives a solar absorptance of 0.32, in the same sentence as the emittance of 0.8.
    - label: Use temperature
      value: Below 700 °F in one NASA source
      line: The NASA shuttle systems page says FRSI blankets protect areas where temperatures are below 700 F. The Gordon appendix says 750 °F, and the AZoM article gives 371 °C.
    - label: Thickness
      value: 0.16 to 0.4 inch
      line: NASA gives the installed FRSI thickness as 0.16 to 0.4 inch, set by the heat load encountered during entry.
  compare: 'FRSI is a low-temperature blanket: NASA places its use below 700 °F, and it is the lower of the two NASA design limits. The NASA sources disagree on the upper limit, giving 700 °F in the KSC shuttle systems text and 750 °F in the Gordon appendix, with 371 °C in the AZoM article. The NASA TPSX entry is the only database record here that gives emissivity as a table value, and it prints density and conductivity only in exponent form, so this profile does not compare those.'
  compare_rows:
    - label: Emissivity
      benchmark: thermal_emittance
    - label: Solar absorptance
      benchmark: solar_absorptance
    - label: Upper use temperature
      benchmark: max_service_temp
  handling:
    - 'Keep FRSI areas within their design envelope: 700 °F in the NASA shuttle systems text, and 750 °F in the Gordon appendix.'
    - Bond with RTV silicone adhesive at 0.2 inch thickness, as the NASA shuttle systems text describes.
    - Trim to a cavity template and paint-seal the exposed edges, as the Gordon appendix describes.
  good_for:
    - Surfaces below about 700 °F on a re-entry vehicle, the design use NASA describes for FRSI.
    - Places where a white surface with an emissivity of 0.8 is wanted for thermal control, as the NASA sources describe the coating.
  watch_out:
    - 'The upper limits disagree between NASA sources: 700 °F in one, 750 °F in another, and 371 °C in the AZoM article.'
    - The sources disagree on whether FRSI needs rewaterproofing after each flight.
    - Density, thermal conductivity and specific heat are printed only in exponent form, so no values are shown for them.
    - The RTV adhesive that bonds FRSI is rated to 550 °F. The adhesive, not the felt, sets that bond limit.
  verdict: FRSI is a white Nomex felt blanket that NASA used on Shuttle upper surfaces. This profile can state its temperature envelope, optical values and installation dimensions from NASA pages only; its density and conductivity are left out until a plain-number source is read.
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 17
  unreachable: 0
  caveats: 2
  note: Read by an AI assistant on 2026-11-01 from NASA, KSC, AZoM, Wikipedia and DuPont pages fetched in this run. Density, conductivity, specific heat and temperature limits in the NASA TPSX entry are printed only in exponent form and are left out.
sources:
  tpsx:
    title: 'NASA Ames Thermal Protection Materials database: FRSI Blanket (Nomex Felt)'
    url: https://tpsx.arc.nasa.gov/Material?id=18
    kind: database
    license: Public domain (NASA)
  azom:
    title: Materials Used in Space Shuttle Thermal Protection Systems (AZoM, Alessandro Pirolini)
    url: https://www.azom.com/article.aspx?ArticleID=11443
    year: 2020
    kind: web
    license: AZoM terms (cited, not reproduced)
  wiki-tps:
    title: Space Shuttle thermal protection system (Wikipedia)
    url: https://en.wikipedia.org/wiki/Space_Shuttle_thermal_protection_system
    kind: web
    license: CC BY-SA 4.0 (Wikipedia)
  wiki-nomex:
    title: Nomex (Wikipedia)
    url: https://en.wikipedia.org/wiki/Nomex
    kind: web
    license: CC BY-SA 4.0 (Wikipedia)
  ksc-tps:
    title: Orbiter Thermal Protection System, KSC fact sheet (archived copy, 2006 snapshot)
    url: https://web.archive.org/web/20060909094330/http://www-pao.ksc.nasa.gov/kscpao/nasafact/tps.htm
    year: 2006
    kind: report
    license: Public domain (NASA)
  ksc-sts-sys:
    title: Space Shuttle systems, KSC shuttle technology page (archived copy, 2009 snapshot)
    url: https://web.archive.org/web/20090715235829/http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts_sys.html
    year: 2009
    kind: report
    license: Public domain (NASA)
  gordon:
    title: Shuttle thermal protection system, Appendix A (NASA KSC public appendix, archived copy)
    url: https://web.archive.org/web/20160307090308/http://science.ksc.nasa.gov/shuttle/nexgen/Nexgen_Downloads/Shuttle_Gordon_TPS-PUBLIC_Appendix.pdf
    kind: report
    license: Public domain (NASA)
  dupont-nomex:
    title: DuPont Nomex 40th Anniversary page (archived copy, 2012 snapshot)
    url: https://web.archive.org/web/20120217011922/http://www2.dupont.com/Nomex/en_US/news_events/40th_anniv.html
    year: 2007
    kind: web
    license: DuPont terms (cited, not reproduced)
license: CC-BY-4.0