Beta cloth

spore: profile
id: beta-cloth
spore_version: 0.2
family: glass-textiles
name: Beta cloth
role: PTFE-coated woven glass fabric for spacesuit outer layers and spacecraft covers
category: textiles
type: beta-cloth
summary: |
  Beta cloth is a woven textile made from Beta fibre, an extra-fine glass filament that Owens-Corning made under NASA contract. The filaments are nominally 3.8 microns in diameter (Dillon and Cobb, 1975). The woven fabric was coated with Teflon (PTFE). The Teflon-coated style X4190B weighed 6.6 oz/sq yd at coating level 1 and 7.8 oz/sq yd at coating level 2 (Dillon and Cobb, 1975). The fabric was noncombustible in a 100 percent oxygen atmosphere up to 16.5 psia (Dillon and Cobb, 1975), which is why it was used in the Apollo capsule and on the Apollo spacesuit outer layer. After Apollo, inspection found the fabric badly abraded by lunar dust.
best_for: Noncombustible, flexible glass textile for oxygen-rich spacecraft and spacesuit layers where abrasion from the surface is not the main load
weakest_at: Abrasion. Post-Apollo inspection found Beta cloth frayed and broken by lunar dust, and the fabric failed NASA's rotary tumbler abrasion test (ICES 2025).
identity:
  formula: Woven fine-filament glass fabric coated with PTFE (Teflon); the coating repeat unit is (CF2-CF2)n
  source: dillon-cobb-1975
  where: Abstract and Introduction (Beta fibre, Teflon coating); Appendix A table title for X4190B Teflon-coated Beta fabric. Repeat unit from Wikipedia, Polytetrafluoroethylene, Production section
  designations:
    - system: Trade name
      code: Beta Fiberglass
      source: fire-fibers-2017
      where: Development of Beta Fiber, first paragraph (trade mark of Owens-Corning Fiberglas Corporation, per the 1975 paper)
    - system: Trade name
      code: X4190B
      note: Owens-Corning style number for the Teflon-coated Beta fabric; the style number is not a trade name
      source: dillon-cobb-1975
      where: Appendix A, title of Teflon-coated Beta fabric table
    - system: Trade name
      code: X4484
      note: Owens-Corning style number for a second Teflon-coated Beta fabric, woven from Teflon-coated yarn
      source: dillon-cobb-1975
      where: Appendix A, title of X4484 Fabric/Teflon-Coated Yarn table
tags:
  environments:
    - lunar-day
    - low-earth-orbit
  stresses:
    - atomic-oxygen
  applications:
    - habitats-and-suits
    - thermal-control
    - structures
properties:
  - benchmark: max_service_temp
    label: Maximum service temperature, Beta fibre fabric
    value: 482
    unit: °C
    scope: material
    conditions:
      form: Beta fibre textile (Owens-Corning Beta Fiberglass)
      basis: range printed as -300 °F to 900 °F (-184 °C and 482 °C)
    method: Value stated in a NASA technical paper, read from the printed text
    status: ground
    source: fire-fibers-2017
    where: Development of Beta Fiber, first paragraph (quotation of Orndoff, 2016)
  - benchmark: min_service_temp
    label: Minimum service temperature, Beta fibre fabric
    value: -184
    unit: °C
    scope: material
    conditions:
      form: Beta fibre textile (Owens-Corning Beta Fiberglass)
      basis: range printed as -300 °F to 900 °F (-184 °C and 482 °C)
    method: Value stated in a NASA technical paper, read from the printed text
    status: ground
    source: fire-fibers-2017
    where: Development of Beta Fiber, first paragraph (quotation of Orndoff, 2016)
  - benchmark: degradation_temperature
    label: Degradation temperature, Beta fibre
    value: 843
    unit: °C
    scope: material
    conditions:
      form: Beta fibre
      basis: printed as degraded at 1550 °F (843 °C)
    method: Value stated in a NASA technical paper, read from the printed text
    status: ground
    source: fire-fibers-2017
    where: Development of Beta Fiber, first paragraph (quotation of Orndoff, 2016)
  - benchmark: filament_diameter
    label: Filament diameter, Beta fibre (range)
    value: 3.5
    value_high: 3.8
    bound: range
    unit: µm
    scope: material
    conditions:
      form: extra-fine Beta glass filament
      basis: printed as 3.5 to 3.8 microns
    method: Value stated in a NASA technical paper, read from the printed text
    status: ground
    source: fire-fibers-2017
    where: Development of Beta Fiber, first paragraph (quotation of Orndoff, 2016)
  - benchmark: filament_diameter
    label: Filament diameter, Beta fibre (nominal)
    value: 3.8
    unit: µm
    scope: material
    conditions:
      form: Beta filament, nominal
      basis: printed as nominally 3.8 microns, or 1/4 denier
    method: Value stated in the 1975 Owens-Corning report, read from the scanned text layer
    status: ground
    note: The same report gives the denier as 1/4; the value is read from the scanned text layer and not from the image.
    source: dillon-cobb-1975
    where: Introduction, paragraph on Beta filament diameter
  - benchmark: noncombustible_pressure_in_oxygen
    label: Noncombustible limit in 100 percent oxygen, Beta fibre
    value: 16.5
    unit: psia
    scope: material
    conditions:
      atmosphere: 100 percent oxygen
      result: noncombustible up to this pressure (Apollo capsule environment), as printed
    method: Value stated in the abstract of the 1975 report
    status: ground
    source: dillon-cobb-1975
    where: Abstract; Introduction (basic requirements paragraph)
  - benchmark: fabric_weight
    label: Fabric weight, X4190B Teflon-coated Beta fabric (range over two coating levels)
    value: 6.6
    value_high: 7.8
    bound: range
    unit: oz/sq yd
    scope: material
    conditions:
      style: X4190B Teflon-coated Beta fabric
      coating_levels: level 1 gives 6.6 and level 2 gives 7.8, as printed
      test_method: ASTM D579 as printed
    method: Typical value printed in the Appendix A table of the 1975 report
    status: ground
    source: dillon-cobb-1975
    where: Appendix A table, Typical Physical Properties of X4190B Teflon-Coated Beta Fabric at Two Coating Levels, Fabric Weight row (printed page 13)
  - benchmark: yarn_count
    label: Yarn count, X4190B warp
    value: 92
    unit: yarns/in
    scope: material
    conditions:
      style: X4190B Teflon-coated Beta fabric
      direction: warp, at both coating levels
      test_method: ASTM D579 as printed
    method: Typical value printed in the Appendix A table of the 1975 report
    status: ground
    source: dillon-cobb-1975
    where: Appendix A table, Yarn Count row (printed page 13)
  - benchmark: ultimate_tensile_strength
    label: Breaking strength, X4190B warp (range over two coating levels)
    value: 90
    value_high: 115
    bound: range
    unit: lbs/in
    scope: material
    conditions:
      style: X4190B Teflon-coated Beta fabric
      direction: warp, original (not roller-creased)
      coating_levels: level 2 gives 90 and level 1 gives 115, as printed
      test_method: ASTM D1682, Instron at 0.6 in/min as printed
    method: Typical value printed in the Appendix A table of the 1975 report; printed in lbs/in and not converted here
    status: ground
    note: Read from a scanned table and checked visually. The fill value at level 1 is not legible in the scan and is left out.
    source: dillon-cobb-1975
    where: Appendix A table, Break Strength (Instron 0.6 IPM), Original row (printed page 13)
  - benchmark: tongue_tear
    label: Tongue tear, X4190B warp at coating level 1
    value: 4.5
    unit: lbs
    scope: material
    conditions:
      style: X4190B Teflon-coated Beta fabric
      direction: warp, coating level 1
      test_method: ASTM D2262 as printed
    method: Typical value printed in the Appendix A table of the 1975 report
    status: ground
    source: dillon-cobb-1975
    where: Appendix A table, Tongue Tear row (printed page 13)
  - benchmark: stoll_flat_abrasion
    label: Stoll flat abrasion, X4190B warp (range over two coating levels)
    value: 282
    value_high: 738
    bound: range
    unit: cycles
    scope: material
    conditions:
      style: X4190B Teflon-coated Beta fabric
      direction: warp, 1 lb load and 3 lb pressure, as printed
      coating_levels: level 1 gives 282 and level 2 gives 738
    method: Typical value printed in the Appendix A table of the 1975 report; test method ASTM D1175-64T-A as printed
    status: ground
    source: dillon-cobb-1975
    where: Appendix A table, Stoll Abrasion Flat row (printed page 13)
  - benchmark: taber_abrasion_to_fabric_failure
    label: Taber abrasion to fabric failure, X4190B warp at coating level 1
    value: 351
    unit: cycles
    scope: material
    conditions:
      style: X4190B Teflon-coated Beta fabric
      direction: warp, coating level 1
      load: 500 g on CS 17 wheel, as printed
    method: Typical value printed in the Appendix A table of the 1975 report
    status: ground
    source: dillon-cobb-1975
    where: Appendix A table, Taber Abrasion, Fabric Failure row (printed page 13)
  - benchmark: air_permeability
    label: Air permeability, X4190B warp (range over two coating levels)
    value: 3.94
    value_high: 30.7
    bound: range
    unit: cu ft/min/sq ft
    scope: material
    conditions:
      style: X4190B Teflon-coated Beta fabric
      direction: warp, 20 in water pressure drop, as printed
      coating_levels: level 2 gives 3.94 and level 1 gives 30.7
    method: Typical value printed in the Appendix A table of the 1975 report; test method ASTM D737 as printed
    status: ground
    source: dillon-cobb-1975
    where: Appendix A table, Air Permeability row (printed page 13)
  - benchmark: seam_strength
    label: Seam strength, X4190B warp at coating level 1
    value: 14.4
    unit: lbs
    scope: material
    conditions:
      style: X4190B Teflon-coated Beta fabric
      direction: warp, coating level 1
      test_method: ASTM D434 as printed
    method: Typical value printed in the Appendix A table of the 1975 report
    status: ground
    source: dillon-cobb-1975
    where: Appendix A table, Seam Strength row (printed page 13)
  - benchmark: ignition_loss
    label: Ignition loss, X4190B warp (range over two coating levels)
    value: 12.2
    value_high: 20.4
    bound: range
    unit: '%'
    scope: material
    conditions:
      style: X4190B Teflon-coated Beta fabric
      direction: warp, coating levels 1 and 2 as printed
      test_method: OCF-DF510 as printed
    method: Typical value printed in the Appendix A table of the 1975 report; the report does not define the term beyond the test method name
    status: ground
    source: dillon-cobb-1975
    where: Appendix A table, Ignition Loss row (printed page 13)
  - benchmark: fabric_weight
    label: Fabric weight, X4484 Teflon-coated yarn fabric (warp)
    value: 6.18
    unit: oz/sq yd
    scope: material
    conditions:
      style: X4484 fabric woven from B 150 1/0 Teflon-coated sintered yarn
      direction: warp
      test_method: ASTM D579 as printed
    method: Typical value printed in the Appendix A table of the 1975 report (two tests)
    status: ground
    source: dillon-cobb-1975
    where: Appendix A table, Typical Physical Properties of X4484 Fabric/Teflon-Coated Yarn, Fabric Weight row (printed page 15)
  - benchmark: thickness
    label: Thickness, X4484 fabric (warp)
    value: 7.6
    unit: mils
    scope: material
    conditions:
      style: X4484 fabric woven from B 150 1/0 Teflon-coated sintered yarn
      direction: warp
      test_method: CCC-T-191B-5030 as printed
    method: Typical value printed in the Appendix A table of the 1975 report (five tests)
    status: ground
    source: dillon-cobb-1975
    where: Appendix A table, Thickness row (printed page 15)
  - benchmark: ultimate_tensile_strength
    label: Breaking strength, X4484 fabric (warp, original)
    value: 208
    unit: lbs/inch
    scope: material
    conditions:
      style: X4484 fabric woven from B 150 1/0 Teflon-coated sintered yarn
      direction: warp, original (not roller-creased)
      test_method: ASTM D1682-1C-E as printed
    method: Typical value printed in the Appendix A table of the 1975 report; printed in lbs/inch and not converted here
    status: ground
    source: dillon-cobb-1975
    where: Appendix A table, Breaking Strength Original row, warp column (printed page 15)
  - benchmark: mit_flex_cycles
    label: MIT flex cycles, X4484 fabric (warp)
    value: 12708
    unit: cycles
    scope: material
    conditions:
      style: X4484 fabric woven from B 150 1/0 Teflon-coated sintered yarn
      direction: warp, 1.5 kg load, 0.59 in spec, 0.01 head, as printed
      note_as_printed: fill direction printed as 18048 cycles
    method: Typical value printed in the Appendix A table of the 1975 report (five tests)
    status: ground
    source: dillon-cobb-1975
    where: Appendix A table, MIT Flex row (printed page 15)
  - benchmark: taber_abrasion_to_fabric_failure
    label: Taber abrasion, X4484 fabric (warp)
    value: 972
    unit: cycles
    scope: material
    conditions:
      style: X4484 fabric woven from B 150 1/0 Teflon-coated sintered yarn
      direction: warp, 500 g on CS 17 wheel, as printed
    method: Typical value printed in the Appendix A table of the 1975 report (five tests)
    status: ground
    source: dillon-cobb-1975
    where: Appendix A table, Taber Abrasion row (printed page 15)
  - benchmark: mullen_burst
    label: Mullen burst, X4484 fabric (warp)
    value: 482
    unit: Mullen points
    scope: material
    conditions:
      style: X4484 fabric woven from B 150 1/0 Teflon-coated sintered yarn
      direction: warp, test method OCF-DF511 as printed
    method: Typical value printed in the Appendix A table of the 1975 report (five tests)
    status: ground
    source: dillon-cobb-1975
    where: Appendix A table, Mullen Burst row (printed page 15)
corrosion:
  - environment: Atomic oxygen in low Earth orbit
    headline: Tightly woven glass is stated to resist atomic oxygen, but the coated fabric was not tested for it.
    effect: The 2025 ICES paper says that glass is inorganic and that, when woven tightly, glass fibres resist degradation from atomic oxygen in low Earth orbit. The 2017 NASA paper says glass and ceramic structures have excellent resistance to atomic oxygen, while atomic oxygen degrades organic materials over time. No atomic-oxygen test of the PTFE-coated fabric was found in the sources read.
    rating: low
    conditions:
      basis: general statements about woven glass fibres; no test data printed
      coating: PTFE (Teflon), an organic polymer
    source: ices-2025-jones
    where: Section B, Current State of the Art (Beta Cloth and Ortho Fabric)
  - environment: Lunar regolith and dust abrasion during Apollo EVA
    headline: Apollo-era Beta cloth was severely degraded by lunar dust and abrasion after short use.
    effect: Scanning electron microscopy of the outer soft layers of Apollo 12 and Apollo 17 thermal micrometeoroid garments, and of the outermost fabrics on Apollo 17 EVA gloves, found fibres frayed and broken, with lunar dust embedded in the weave. The authors say the suits did not fail during EVA, but the fabric was degraded severely for the length of use.
    rating: severe
    conditions:
      basis: post-flight inspection of Apollo hardware, as described in the paper
      exposure: relatively short Apollo EVA durations
    source: ices-2025-jones
    where: Section C, Need for Innovation
  - environment: NASA rotary tumbler abrasion test (laboratory)
    headline: Beta cloth failed the NASA rotary tumbler abrasion test and was dropped from the trade study.
    effect: The 2025 ICES trade study included Beta cloth as a benchmark, but it failed the NASA rotary tumbler abrasion test, which the authors say shows insufficient durability for sustained lunar use. The paper does not print test numbers for Beta cloth in this test.
    rating: severe
    conditions:
      test: NASA custom rotary tumbler abrasion test
      basis: statement in the trade study section; no numbers printed for Beta cloth
    source: ices-2025-jones
    where: Section on trade study results (Beta Cloth included as a benchmark, then excluded)
  - environment: Sewing, flexing and weaving of the fabric
    headline: The fragile glass fibres crack when sewn and flexed, and weaving needed silicone oil.
    effect: The 2025 ICES paper says the fabric was difficult to assemble into a garment because the fragile glass fibres tended to crack when sewn and flexed. Silicone oil had to be applied to keep the fibres together during weaving, and it made sewn seams pull out easily, so seam edges were coated with cement.
    rating: moderate
    conditions:
      basis: manufacturing experience described in the paper; no flex-cycle data printed for Beta cloth
    source: ices-2025-jones
    where: Section C, Need for Innovation
risks:
  hazards:
    - text: NIOSH's fibrous glass entry, which covers glass filaments and glass wool in general and is not an entry for Beta fibre, lists the symptoms as "irritation eyes, skin, nose, throat; dyspnea (breathing difficulty)". Its NIOSH REL is "TWA 3 fibers/cm3 (fibers ≤ 3.5 µm in diameter & ≥ 10 µm in length) TWA 5 mg/m3 (total)". Beta filaments are printed as 3.5 to 3.8 µm in diameter (Dillon and Cobb, 1975).
      ghs: []
      source: niosh-npg-fibrous-glass
      where: Synonyms and Trade Names, Physical Description, Exposure Limits (NIOSH REL) and Symptoms fields of the NIOSH Pocket Guide fibrous glass entry
    - text: Daikin's 2011 safety data sheet for POLYFLON PTFE M-532, a PTFE product and not the coated Beta fabric, states that the substance is not classified under the CLP regulation, with no hazard pictograms, signal word or hazard statements. It says that vapours and fumes from hot processing ("above 260 ℃") may cause flu-like symptoms, and that the material has a "Danger of toxic fluorine based pyrolysis products" when it decomposes.
      ghs: []
      source: daikin-ptfe-sds
      where: Section 2 (classification and labelling), Section 4 (information for doctor), Section 10 (hazardous decomposition products)
  failure_risks:
    - mode: Abrasion failure in lunar dust
      trigger: Lunar regolith and dust rubbing the outer fabric during EVA
      consequence: Fibres frayed and broken, with dust embedded in the weave; the fabric is not durable enough for a sustained lunar presence
      severity: high
      source: ices-2025-jones
      where: Section C, Need for Innovation
    - mode: Fibre cracking in garment manufacture
      trigger: Sewing or flexing the fragile glass filaments
      consequence: Fibres crack, and seams need cement to hold
      severity: moderate
      source: ices-2025-jones
      where: Section C, Need for Innovation
  side_effects:
    - text: Coating the woven surface with Teflon reduced the tear strength of the fabric; coating the individual yarns before weaving fixed this but was costly.
      affects: Garment tear resistance
      source: ices-2025-jones
      where: Section C, Need for Innovation
  handling:
    - text: Chalk bags were used to mark patterns instead of pencils to avoid degrading the fabric during garment assembly.
      source: ices-2025-jones
      where: Section C, Need for Innovation
    - text: Silicone oil used in weaving makes sewn seams pull out easily, so seam edges were coated with cement.
      source: ices-2025-jones
      where: Section C, Need for Innovation
  mitigations:
    - text: Applying the Teflon coating to individual yarns before weaving avoided the tear-strength loss but added processing cost.
      source: ices-2025-jones
      where: Section C, Need for Innovation
uses:
  - application: habitats-and-suits
    device: Apollo spacesuit outer layer and flight suits
    example: Woven Beta fabrics were selected for the outer layer of Apollo space suits and flight suits, for the interior liner of the Apollo command module, and for several crew equipment items and fire protective covers. The paper credits Orndoff (2016) for this summary.
    source: fire-fibers-2017
    where: Development of Beta Fiber, first paragraph (quotation of Orndoff, 2016)
  - application: structures
    device: Space Shuttle cargo bay contamination control cover
    example: The largest use of Beta fabric in the Space Shuttle Program's Orbiter was the contamination control cover of the cargo bay. Between 1967 and 1990 approximately 10450 lb of Beta fabrics were used in the Apollo, Skylab, Apollo-Soyuz, Space Shuttle and Spacelab programs combined.
    source: fire-fibers-2017
    where: Development of Beta Fiber, first paragraph (quotation of Orndoff, 2016)
  - application: thermal-control
    device: Spacer in aluminised Kapton superinsulation (ITMG)
    example: Beta marquisette was used as a spacer material between aluminised Kapton layers in the ITMG superinsulation system.
    source: dillon-cobb-1975
    where: Section 2, Textile End-Item Development, list of end items
  - application: electronics-and-chips
    device: Teflon-coated bags around electrical connectors and encapsulation of flammable flight items
    example: Teflon-coated Beta fabrics were used for bags placed around electrical connectors and for encapsulating flammable flight items. In a tissue container, the fabric protected the facial tissues against flame impingement at 1800 °F in an oxygen atmosphere for 8 minutes without charring them.
    source: dillon-cobb-1975
    where: Section 1, paragraph on Teflon coatings (Dillon and Cobb, 1975)
supply:
  - subject: Beta fibre (Owens-Corning) and Teflon coating
    demand: Between 1967 and 1990 approximately 10450 lb of Beta fabrics were used across Apollo, Skylab, Apollo-Soyuz, Space Shuttle and Spacelab combined.
    routes: Owens-Corning drew the Beta fibre to micrometre scale in a two-storey plant that used gravity to assist drawing. The Teflon coatings on X4190B-type fabrics were applied by E. I. duPont at Fairfield, Connecticut, and the fabric was produced by J. P. Stevens and Company.
    producers: []
    critical_lists: []
    substitutes: []
    source: fire-fibers-2017
    where: Development of Beta Fiber; Summary of production (quotation of Orndoff, 2016)
    abundance: Not found in any source read.
  - subject: Fluorspar (calcium fluoride), the feedstock for the hydrogen fluoride used to make PTFE
    demand: Aqueous HF is the primary feedstock for the manufacture of virtually all fluorine-bearing chemicals, particularly refrigerants and fluoropolymers (USGS, Mineral Commodity Summaries 2026, Fluorspar).
    routes: The United States has not reported significant fluorspar mine production since 1995 and was 100% net import reliant in 2025. World mine production in 2025 was 10,000 thousand metric tons (rounded), of which China gave 6,000 thousand metric tons.
    producers: []
    critical_lists: []
    substitutes: []
    source: usgs-mcs2026-fluorspar
    where: Fluorspar chapter, Domestic Production and Use paragraph and Net import reliance row; World Mine Production and Reserves table, 2025 column
    abundance: World fluorspar reserves are 330,000 thousand metric tons (rounded) in the same USGS table; reserves for the Beta glass fibre and the Teflon coating are not found in any source read.
documents:
  - title: Research, development and application of noncombustible Beta fiber structures (Dillon and Cobb, Owens-Corning Fiberglas Corp., 1975)
    type: report
    url: https://ntrs.nasa.gov/citations/19750021113
    year: 1975
  - title: Flame Retardant Fibers for Human Space Exploration - Past, Present, and Future (NASA NTRS 20170008542)
    type: report
    url: https://ntrs.nasa.gov/citations/20170008542
    year: 2017
  - title: Artemis Suit Material Project Overview, ICES-2025-56 (Jones, McFarland, Rodgers-Ahnen, Rhodes, 54th ICES, Prague, 2025)
    type: paper
    url: https://ntrs.nasa.gov/citations/20250003726
    year: 2025
  - title: Mineral Commodity Summaries 2026, Fluorspar (U.S. Geological Survey)
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-fluorspar.pdf
    year: 2026
  - title: Safety data sheet, POLYFLON PTFE M-532 (Daikin Chemicals, printed 20.01.2011)
    type: sds
    url: https://www.daikinchemicals.com/library/pb_common/pdf/sds/Fluoropolymer/PTFE-M/sds-m-532-E_20110120.pdf
    year: 2011
gaps:
  - No hazard data for the woven Beta cloth or its PTFE coating was found. The hazards entries use NIOSH's generic fibrous glass entry and Daikin's 2011 safety data sheet for a PTFE product (POLYFLON PTFE M-532), not Beta fabric. No PubChem GHS entry for PTFE was read in this run, and no GHS classification of Beta fibre was found.
  - No composition by weight or share for the Beta glass was printed in any source read; the glass is described only as high-purity glass.
  - Producer country shares for the Beta glass fibre and the Teflon coating were not found. Critical-mineral list status for fluorspar was not read in this run.
  - Recycling and substitutes for Beta cloth were not found in any source read.
  - No flight or vacuum outgassing numbers for Beta cloth were printed; the 2017 and 1975 papers say the fabric met NASA criteria for outgassing, toxicity and odour without giving the numbers.
  - Radiation tolerance is stated qualitatively (ICES 2025 says the glass is resistant to solar and ionizing radiation) but no dose or retention figure was printed.
  - The brief describes Beta cloth as an MLI outer layer; the 1975 report says Beta marquisette was a spacer between aluminised Kapton layers in ITMG superinsulation, so no outer-layer use is stated here.
  - The Ortho Fabric design goals from ICES 2025 (goal weight 10 oz/yd2, breaking strength 180 lbf/in, tear strength 20 lbf/in, flex life 100,000 cycles, quoted from the 1974 ILC recommendation) are goals for the successor shell, not measured Beta properties, so they are not used as values here.
  - Ortho Fabric test results from ICES 2025 (for example tumbler losses) belong to another fabric and are not used as Beta values.
  - Coating level 1 fill breaking strength (X4190B) is not legible in the scanned table and is left out.
  - Fill value for air permeability and Taber abrasion at coating level 2 are not printed in the table as legible text and are left out.
  - Beta cloth flammability at reduced oxygen levels (LOI or pressure test results) was not found; only the 16.5 psia noncombustible statement is printed.
  - Degradation temperature is recorded as degradation_temperature, a name not in property-canon.yaml; the same applies to filament_diameter, noncombustible_pressure_in_oxygen, tongue_tear, elmendorf_tear, stoll_flat_abrasion, taber_abrasion_to_fabric_failure, air_permeability, seam_strength, ignition_loss, thickness, mit_flex_cycles, mullen_burst and yarn_count.
  - Ultimate tensile strength is printed in lbs/in and lbs/inch, not in MPa; the importer must convert these units.
  - No CAS number for Beta cloth was printed in any source read. The Daikin safety data sheet prints CAS 9002-84-0 for POLYFLON PTFE M-532, which is PTFE in general, not the Beta fabric or its coating, so it is not used as the identity CAS.
  - Eight sources are cited. Four are NASA or Wikipedia items read in an earlier pass; this pass added NIOSH, USGS and Daikin, plus Wikipedia Fiberglass for glass type composition only.
  - No images were added to this profile; no licensed Beta cloth image was fetched in this run. The media section is therefore absent.
  - No standard abbreviation for Beta cloth was printed in any source read, so the abbreviation field is absent.
  - The ICES 2025 paper's Ortho Fabric test data (sections on tumbler, dust and temperature) were read and are not included as Beta properties.
sources:
  dillon-cobb-1975:
    title: Research, development and application of noncombustible Beta fiber structures
    id: NTRS 19750021113 (J. J. Dillon and E. S. Cobb, Owens-Corning Fiberglas Corp., 1975)
    url: https://ntrs.nasa.gov/citations/19750021113
    year: 1975
    kind: report
    license: public domain (NASA)
  fire-fibers-2017:
    title: Flame Retardant Fibers for Human Space Exploration - Past, Present, and Future
    id: NTRS 20170008542
    url: https://ntrs.nasa.gov/citations/20170008542
    year: 2017
    kind: report
    license: public domain (NASA)
  ices-2025-jones:
    title: Artemis Suit Material Project Overview
    id: ICES-2025-56, 54th International Conference on Environmental Systems, Prague, 13-17 July 2025; NTRS 20250003726
    url: https://ntrs.nasa.gov/citations/20250003726
    year: 2025
    kind: paper
    license: public domain (NASA)
  wiki-ptfe:
    title: Polytetrafluoroethylene (Wikipedia)
    id: en.wikipedia.org, read 2026-11-01; used for the coating repeat unit only
    url: https://en.wikipedia.org/wiki/Polytetrafluoroethylene
    kind: web
    license: CC BY-SA 4.0 (Wikipedia)
  niosh-npg-fibrous-glass:
    title: NIOSH Pocket Guide to Chemical Hazards, fibrous glass entry
    id: CDC/NIOSH npgd0288, read 2026-11-01
    url: https://www.cdc.gov/niosh/npg/npgd0288.html
    kind: handbook
    license: public domain (US government)
  usgs-mcs2026-fluorspar:
    title: Mineral Commodity Summaries 2026, Fluorspar
    id: USGS, DOI 10.3133/mcs2026, read 2026-11-01
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-fluorspar.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  daikin-ptfe-sds:
    title: Safety data sheet, POLYFLON PTFE M-532 (Daikin Chemicals)
    id: article 532, CAS 9002-84-0, printed 20.01.2011, read 2026-11-01
    url: https://www.daikinchemicals.com/library/pb_common/pdf/sds/Fluoropolymer/PTFE-M/sds-m-532-E_20110120.pdf
    year: 2011
    kind: datasheet
    license: manufacturer safety data sheet, used for the printed facts only
  wiki-fiberglass:
    title: Fiberglass (Wikipedia)
    id: en.wikipedia.org, read 2026-11-01; used for glass fibre type composition only
    url: https://en.wikipedia.org/wiki/Fiberglass
    kind: web
    license: CC BY-SA 4.0 (Wikipedia)
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 21
  unreachable: 0
  caveats: 3
  note: Written by an AI assistant on 2026-11-01. Values come from the NASA reports and paper and from Wikipedia for the coating repeat unit (read earlier). The hazard, supply and NIOSH and Daikin SDS facts were read in the 2026-11-01 deepen pass from NIOSH, USGS MCS 2026 and the Daikin SDS. Scanned-table values were checked visually where the text layer was unclear. Not checked against a second reader.
story:
  recipe:
    line: Beta cloth is a woven glass fabric, made from Beta fibre filaments of 3.5 to 3.8 microns, and coated with PTFE (Teflon). The coating repeat unit is (CF2-CF2)n, built from tetrafluoroethylene. The composition of the Beta glass is not printed in any source read. For glass fibre types in general, Wikipedia describes E-glass as "alumino-borosilicate glass with less than 1% w/w alkali oxides"; that describes E-glass, not Beta fibre.
    parts:
      - name: Beta glass fibre
        symbol: glass
        share: not printed in any source read
        role: The load-bearing textile. Fine filaments give the fabric drape and flexibility, and the glass itself is inorganic.
      - name: PTFE coating (Teflon)
        symbol: CF2-CF2
        role: Applied to the yarns or the woven surface to ease weaving and improve abrasion resistance. Repeat unit per the Wikipedia Production section; the coating processes are described in the 1975 report.
  risk_groups:
    - title: For people
      lead: The sources read do not give a hazard classification for the woven fabric, and no safety data sheet was read in this run.
      points:
        - label: Fibres
          line: The glass fibres are fragile. They crack when sewn and flexed, so the fabric is handled with care during garment work.
        - label: Fire in oxygen
          line: Beta cloth was noncombustible in 100 percent oxygen up to 16.5 psia, the condition of the Apollo capsule.
        - label: Dust
          line: Lunar dust was embedded in the Apollo-era weave, according to post-flight inspection.
    - title: In service
      lead: These results come from Apollo-era inspections and from a laboratory rotary tumbler test, not from incidents in service.
      points:
        - label: Lunar surface
          line: Post-Apollo inspection found fibres frayed and broken by lunar dust and abrasion after short use. The fabric was not durable enough for a sustained lunar presence.
        - label: Laboratory abrasion
          line: Beta cloth failed the NASA rotary tumbler abrasion test and was excluded from the 2025 trade study as a benchmark.
    - title: Handling and manufacture
      points:
        - label: Assembly
          line: Chalk bags were used to mark patterns, and seam edges were coated with cement, to keep the fabric from degrading during garment work.
        - label: Coating
          line: Teflon on the woven surface reduced tear strength. Coating the yarns before weaving fixed that but was costly.
  why: Beta cloth is a PTFE-coated glass textile. It was made from Beta fibre, an extra-fine glass filament (3.5 to 3.8 microns) that Owens-Corning developed under NASA contract. Its fibre fineness gave the fabric drape and flexibility. The glass is inorganic, so it does not burn in pure oxygen up to 16.5 psia, which made it the choice for the Apollo spacecraft and spacesuit. Its main weakness is abrasion, and a 1974 NASA contract sought a replacement shell layer for it.
  uses:
    - where: Apollo spacesuit outer layer
      line: Woven Beta fabrics were selected for the outer layer of Apollo space suits and flight suits, for the interior liner of the Apollo command module, and for several crew equipment items and fire protective covers.
    - where: Space Shuttle cargo bay cover
      line: The largest use of Beta fabric in the Shuttle Orbiter was the contamination control cover of the cargo bay. Between 1967 and 1990 approximately 10450 lb of Beta fabrics were used across Apollo, Skylab, Apollo-Soyuz, Shuttle and Spacelab.
    - where: Insulation spacer
      line: Beta marquisette was used as a spacer between aluminised Kapton layers in the ITMG superinsulation, according to the 1975 report.
  can_do:
    - label: Heat in oxygen
      value: 16.5 psia
      line: In a 100 percent oxygen atmosphere, Beta fibre was noncombustible up to 16.5 psia (Dillon and Cobb, 1975). It kept its service range from -184 °C to 482 °C (NASA, 2017).
    - label: Weight
      value: 6.6 oz/sq yd
      line: The Teflon-coated style X4190B weighed 6.6 oz/sq yd at coating level 1 and 7.8 oz/sq yd at coating level 2 (Dillon and Cobb, 1975). The X4484 fabric, woven from Teflon-coated yarn, weighed 6.18 oz/sq yd.
    - label: Fine fibre
      value: 3.5 to 3.8 microns
      line: The Beta filament is 3.5 to 3.8 microns in diameter, which the NASA 2017 paper says makes it a microfiber in modern textile terms.
  compare: Beta cloth is a fine glass textile, while the later Ortho Fabric is a two-layer blend of Gore-Tex, Nomex and Kevlar. The 2025 ICES paper says Beta cloth was noncombustible in oxygen and resisted atomic oxygen when tightly woven, but it failed the NASA rotary tumbler abrasion test. Ortho Fabric, by contrast, survived the same test with measurable degradation. The numbers in this profile are from the 1975 Owens-Corning report and the 2017 NASA paper, not from the Ortho Fabric data.
  compare_rows:
    - label: Maximum service temperature
      benchmark: max_service_temp
    - label: Breaking strength, X4190B warp
      benchmark: ultimate_tensile_strength
    - label: Taber abrasion to fabric failure
      benchmark: taber_abrasion_to_fabric_failure
  handling:
    - Beta cloth is a glass textile, and its fibres crack when sewn and flexed. Handle it with care and mark patterns with chalk.
    - Coat the yarns before weaving if tear strength matters; coating the woven surface reduced tear strength.
    - 'Do not rely on it for lunar abrasion: the fabric was degraded by dust after short use.'
  good_for:
    - Oxygen-rich spacecraft and spacesuit layers where non-combustibility matters, as shown by the 16.5 psia statement.
    - Fine, flexible glass textiles for covers and liners, as used on the Shuttle cargo bay.
  watch_out:
    - 'Abrasion: the fabric frayed and broke under lunar dust in Apollo suits and failed the NASA rotary tumbler test.'
    - 'Fragile glass fibres: they crack when sewn and flexed, and weaving needed silicone oil.'
    - 'The coating changes the handling: Teflon on the woven surface reduced tear strength.'
  verdict: Beta cloth is a proven noncombustible glass textile for Apollo and Shuttle use, but its abrasion resistance made NASA design a successor shell for lunar surface work.