Silvered FEP Teflon Ag/FEP
Laminate of FEP film (tetrafluoroethylene and hexafluoropropylene copolymer), vapour-deposited silver and Inconel, bonded with a pressure-sensitive adhesive
Silvered FEP Teflon is a flexible second-surface mirror: a fluorinated ethylene propylene (FEP) film with silver and Inconel vapour-deposited on its back.
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.
Low solar absorptance to emittance
0.13 to 0.16 outside surface
Operating temperature
-185 to 125 °C (Dunmore)
Atomic-oxygen erosion
more than 0.001 inch lost
Outgassing limits
TML below 1.0%, CVCM below 0.1%
Recipe, share of the weight
- not statedFluorinated ethylene propylene (FEP) film
- Ag not statedSilver
- not statedInconel
- not statedSilicon oxide (SiOx) barrier
- not statedPressure-sensitive adhesive
Best for
Flexible spacecraft thermal control where a low ratio of solar absorptance to emittance is needed, over a published range of -185 to 125 °C (Dunmore)
Weakest at
Atomic oxygen in low Earth orbit: the FEP erodes, and the SiOx barrier only protects where it has not cracked (NASA TM 106146 and NASA TM 104096)
Risk at a glance
- People None found. Low hazard as a finished film; the bulk silver safety data…
- If it fails High. Atomic-oxygen attack through cracks in the SiOx barrier
- Corrosion Severe. In NASA's plasma-asher test the SiOx/FEP/Ag sample darkened and was removed at 1.1x10^22 atoms/cm2.
Quick facts: Ag/FEP
| Property | Value | Basis |
|---|---|---|
| Density | 2.15 g/cm³ | 1 sourced value |
| Tensile strength | 21 MPa | 1 sourced value |
| Thermal conductivity | 0.2 W/(m·K) | 1 sourced value |
| Melting point | 260 to 280 °C | 1 sourced value |
| Specific heat | 1,172 J/(kg·K) | 1 sourced value |
| Maximum service temperature | 125 to 205 °C | 3 sourced values across conditions |
What is the density of Silvered FEP Teflon (Ag/FEP)?
Silvered FEP Teflon (Ag/FEP) has a density of 2.15 g/cm³. The source and test conditions are listed in the properties table on this page.
What is the thermal conductivity of Silvered FEP Teflon (Ag/FEP)?
Silvered FEP Teflon (Ag/FEP) has a thermal conductivity of 0.2 W/(m·K). The source and test conditions are listed in the properties table on this page.
What is the melting point of Silvered FEP Teflon (Ag/FEP)?
Silvered FEP Teflon (Ag/FEP) has a melting point of 260 to 280 °C. The source and test conditions are listed in the properties table on this page.
What is the tensile strength of Silvered FEP Teflon (Ag/FEP)?
Silvered FEP Teflon (Ag/FEP) has a tensile strength of 21 MPa. The source and test conditions are listed in the properties table on this page.
What is the maximum service temperature of Silvered FEP Teflon (Ag/FEP)?
Silvered FEP Teflon (Ag/FEP) has a maximum service temperature of 125 to 205 °C. The range covers 3 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 Silvered FEP Teflon (Ag/FEP) used for?
Uses recorded in the sources include Thermal control blanket on Space Station Freedom power-system radiators (candidate coating in NASA's test, not a flown product in this source); Thermal blanket on LDEF experiment trays; Flexible second-surface mirror in spacecraft thermal control.
Why it exists
Silvered FEP Teflon is a flexible second-surface mirror. The silver sits behind a transparent fluoropolymer film, so the film faces space and the reflective metal is protected from the outside. The construction is used where a low solar absorptance and a high infrared emittance are both needed in a thin, bendable sheet. Vendor pages give a combined value of 0.13 to 0.16 for the outside surface, and NASA reports that the SiOx-coated version is damaged by atomic oxygen in low Earth orbit.
Where it's used
Space Station Freedom radiators (candidate)
NASA tested SiOx-coated silvered Teflon as a candidate coating for Space Station Freedom power-system radiators, along with two white paints and anodised aluminium. The test asked for a 30-year design life.
LDEF experiment trays
NASA's analysis of LDEF material describes silvered FEP blankets that gave thermal protection to experiments on Tray F2 and Trays C5, C8 and A10 on the Long Duration Exposure Facility.
Spacecraft thermal blankets
NASA describes the material as a flexible second-surface mirror thermal control coating used in a variety of space applications where thermal protection is a consideration.
Recipe
Laminate of FEP film (tetrafluoroethylene and hexafluoropropylene copolymer), vapour-deposited silver and Inconel, bonded with a pressure-sensitive adhesive
Silvered FEP is a laminate: a nominally 5 mil fluorinated ethylene propylene film with about 1600 Å of silver and about 400 Å of Inconel vapour-deposited on its back (NASA TM 104096). Silver reflects sunlight, the transparent film protects it, and a SiOx barrier coat sits on the FEP side in the test construction NASA called SiOx/FEP/Ag (NASA TM 106146).
| Ingredient | Share of the weight | What it does |
|---|---|---|
| Fluorinated ethylene propylene (FEP) film | not stated | Transparent outer layer. Sunlight passes through it and is reflected by the silver, which gives a low solar absorptance. |
| Silver Ag | not stated | Specular reflector behind the film. |
| Inconel | not stated | Thin metal layer over the silver. Dunmore calls it a protective layer. |
| Silicon oxide (SiOx) barrier | not stated | Barrier to atomic oxygen on the FEP in the NASA test construction. Its thickness and whether vendor product uses it are not confirmed. |
| Pressure-sensitive adhesive | not stated | Bonds the laminate to the substrate. The adhesive on the vendor product is not stated. |
Weight shares are as printed in the sources.
What it can do
Low solar absorptance to emittance
0.13 to 0.16 outside surface
Dunmore prints a typical outside-surface value of 0.13 to 0.16 for the solar absorptance and emittance pair. The page does not split the two values, so this profile does not state either one alone.
Operating temperature
-185 to 125 °C (Dunmore)
Dunmore prints an operating range of -185 to 125 °C. SatCatalog prints -150 to 125 °C. Both are kept because the vendors do not agree on the lower limit.
Atomic-oxygen erosion
more than 0.001 inch lost
On LDEF, the most exposed film lost more than 0.001 inch of its 0.005 inch thickness in 5 years and 9 months, according to NASA's preliminary estimate.
Outgassing limits
TML below 1.0%, CVCM below 0.1%
SatCatalog quotes ASTM E-595 limits of TML below 1.0% and CVCM below 0.1%. These are qualification limits, not measured results for this product.
How it compares
Silvered FEP trades atomic-oxygen tolerance for a low solar absorptance. In NASA's 1993 plasma-asher test, the SiOx/FEP/Ag sample was removed at 1.1x10^22 atoms/cm2 after severe degradation, while the white paints Z-93 and YB-71 and the anodised aluminium were carried through the full test fluence in the same asher test (the full value is printed in NASA TM 106146, Exposure in an RF Plasma Asher). The bare FEP film is rated for a continuous service range of -240 to 205 °C, but the silvered product's own published range is -185 to 125 °C (Dunmore) or -150 to 125 °C (SatCatalog).
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 | Ag/FEP |
|---|---|
| Thermal behavior and safety | |
| Melt point of the bare FEP filmValue printed in the Typical Properties table | 260 to 280 °C |
| Specific heat of the bare FEP filmValue printed in the Thermal table | 1172 J/(kg·K) |
| Thermal conductivity of the bare FEP filmValue printed in the Thermal table | 0.195 W/(m·K) |
| Physical and electrical | |
| Film thickness rangeValue printed on the Dunmore product page | 50 to 250 μm |
| Vapour-deposited silver layer | 1600 Å2 |
| Vapour-deposited Inconel layer | 400 Å3 |
| Density of the bare FEP filmValue printed in the Miscellaneous table | 2150 kg/m3 |
| Temperature behavior | |
| Zero strength temperature of the bare FEP filmValue printed in the Typical Properties table | 255 °C |
| Other measurements | |
| Typical outside surface solar absorptance / emittance valueValue printed on the Dunmore product page | 0.13 to 0.16 -1 |
| Operating temperature, upper limit (Dunmore)Value printed on the Dunmore product page | 125 °C |
| Operating temperature, lower limit (Dunmore)Value printed on the Dunmore product page | -185 °C |
| Operating temperature, upper limit (SatCatalog)Value printed on the SatCatalog component page | 125 °C |
| Operating temperature, lower limit (SatCatalog)Value printed on the SatCatalog component page | -150 °C |
| ReflectanceValue printed on the SatCatalog component page | > 90 % |
| Normal emittanceValue printed on the SatCatalog component page | 40 to 80 % |
| Maximum film widthValue printed on the SatCatalog component page | 24 inches |
| FEP film loss in LDEF Rows 8 to 10Preliminary estimate by the authors | > 0.001 inch4 |
| Continuous service temperature, upper limit (bare FEP film) | 205 °C5 |
| Tensile strength at break of the bare FEP filmValue printed in the Mechanical table | 21 N/mm2 |
| Elongation at break of the bare FEP filmValue printed in the Mechanical table | 300 % |
| Dielectric constant of the bare FEP filmValue printed in the Electrical table | 2 -6 |
| Refractive index of the bare FEP filmValue printed in the Miscellaneous table | 1.341 to 1.347 - |
| Solar transmission of the bare FEP filmValue printed in the Miscellaneous table | 96 %7 |
| Total mass loss limit (ASTM E-595) | < 1 %8 |
| Collected volatile condensable material limit (ASTM E-595) | < 0.1 %9 |
Why choose it, and why not
Good for
- Thin, flexible thermal control on spacecraft, where a low solar absorptance and a high emittance are both needed (Dunmore and NASA).
- Use over a published operating range of -185 to 125 °C, according to Dunmore.
Watch out for
- Atomic oxygen in low Earth orbit erodes the FEP. On LDEF, the most exposed film lost more than 0.001 inch.
- A SiOx barrier does not protect the FEP where thermal cycling has cracked it, according to NASA.
- The two published operating ranges disagree on the lower limit: -185 °C (Dunmore) and -150 °C (SatCatalog).
Silvered FEP is a well-documented thermal-control film for the sunward side of a spacecraft. Its low solar absorptance is useful, but its atomic-oxygen tolerance depends on the barrier staying intact, and the published data do not settle the lower operating limit.
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 | Typical outside surface solar absorptance / emittance value | — | product silvered FEP Teflon, outside surfacesplit the page prints one combined pair and does not separate solar absorptance from emittancetest not stated | — |
| 2 | Vapour-deposited silver layer | Value printed in the NASA description of the blanket | basis nominal, as printed for the LDEF blanket materiallayer silver on the back of the FEP film | — |
| 3 | Vapour-deposited Inconel layer | Value printed in the NASA description of the blanket | basis nominal, as printed for the LDEF blanket materiallayer Inconel over the silver | — |
| 4 | FEP film loss in LDEF Rows 8 to 10 | — | exposure 5 years 9 months in low Earth orbit on LDEF, most extreme rows 8 to 10starting thickness 0.005 inch nominal FEP filmnote printed as in excess of 0.001 inch | — |
| 5 | Continuous service temperature, upper limit (bare FEP film) | Value printed in the bulletin description bullets | form bare Teflon FEP film resin, not the silvered blanketbasis continuous service range as printed | — |
| 6 | Dielectric constant of the bare FEP film | — | form bare Teflon FEP film at 25 °Cfrequency 100 Hz to 1 MHztest ASTM D150 | — |
| 7 | Solar transmission of the bare FEP film | — | form bare Teflon FEP film, 1 mil (0.025 mm) basis at 25 °Ctest ASTM E-424note the silvered blanket is opaque to solar transmission because of its silver layer | — |
| 8 | Total mass loss limit (ASTM E-595) | Limit printed on the SatCatalog component page (printed as TML <1.0%) | standard ASTM E-595kind qualification limit printed by the vendor, not a measured result for this product | — |
| 9 | Collected volatile condensable material limit (ASTM E-595) | Limit printed on the SatCatalog component page (printed as CVCM <0.1%) | standard ASTM E-595kind qualification limit printed by the vendor, not a measured result for this product | — |
Corrosion and compatibility
What happens when it meets other materials and environments.
| Environment | Concern | What happens |
|---|---|---|
| Atomic oxygen in low Earth orbit, simulated in an RF plasma asher | severe | In NASA's plasma-asher test the SiOx/FEP/Ag sample darkened and was removed at 1.1x10^22 atoms/cm2.1 |
| Low Earth orbit in flight, LDEF, 5 years 9 months | severe | Silvered FEP on LDEF lost more than 0.001 inch of its 0.005 inch film in the most exposed rows.2 |
| Ultraviolet and vacuum-ultraviolet radiation in orbit | moderate | NASA's review says UV can embrittle FEP, degrade transmittance and cause mass loss over long exposure.3 |
| Thermal cycling and micrometeoroid or debris impact | moderate | Cracks from thermal cycling let atomic oxygen reach the FEP, and impacts can delaminate the film.4 |
| Outgassing in vacuum | low | The SatCatalog page quotes ASTM E-595 limits of TML below 1.0% and CVCM below 0.1%.5 |
| # | Environment | Details | Test conditions |
|---|---|---|---|
| 1 | Atomic oxygen in low Earth orbit, simulated in an RF plasma asher | At that fluence the sample's solar absorptance rose and its thermal emittance fell sharply. The sample turned into a black, tar-like film that began at its unprotected edges, where the silver and silicone adhesive oxidised. NASA states that atomic oxygen oxidises FEP, causing mass loss and surface texturing, and that the asher gives a random-direction attack, unlike the directed beam in orbit. | facility RF oxygen plasma asher with intense VUVfluence 1.1x10 22 atoms/cm2 at removalcaveat the test is not a direct lifetime prediction, because the asher attack is random |
| 2 | Low Earth orbit in flight, LDEF, 5 years 9 months | Atomic-oxygen erosion roughened the coating surface, and some pieces changed from specular to diffuse reflectors. XPS, infrared and thermal analysis found no significant change at the molecular level. The authors call the erosion extent unanticipated, and note that it was not uniform across the film. | exposure 5 years 9 months on LDEF, Rows 8 to 10 (most extreme cases)note the film-loss figure is a preliminary estimate |
| 3 | Ultraviolet and vacuum-ultraviolet radiation in orbit | The review states that ultraviolet radiation may cause embrittlement, transmittance degradation and mass loss over a long exposure duration. It notes that atomic oxygen and UV act together on FEP, and that a SiOx coating does not stop UV that reaches the FEP through cracks. | basis statement in the NASA review; no UV dose or number is printed for this laminate |
| 4 | Thermal cycling and micrometeoroid or debris impact | NASA notes that cracks in the SiOx coating caused by thermal cycling let atomic oxygen and UV reach the FEP, changing its optical properties. LDEF showed delamination of FEP from the silver around impact sites, and exposed silicone adhesive at an impact site can form a dark contaminant with atomic oxygen and UV. | thermal cycling in test 10 cycles between -93 °C and +49 °C in vacuum, before plasma-asher exposure |
| 5 | Outgassing in vacuum | These are qualification limits printed by the vendor catalog, not measured results for this product. The page does not give the test lot, date or specimen. | standard ASTM E-595basis limits as printed on the SatCatalog page |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
The finished film has no safety data sheet read in this run. The bulk silver safety data sheet classifies silver as very toxic to aquatic life with long-lasting effects.
- The silver metal
- The bulk silver sheet classifies silver as H400 and H410 (very toxic to aquatic life) and prints an oral LD50 in rat of more than 5,000 mg/kg. It prints an OSHA limit of 0.01 mg/m3 and an ACGIH limit of 0.1 mg/m3.
- The FEP film
- The Chemours bulletin describes the polymer as chemically inert to virtually all chemicals. No hazard statement for the film was found in a page read in this run.
If the film is damaged in orbit
These results come from ground tests and one flight sample, not from incidents.
- Atomic oxygen
- In NASA's plasma-asher test, the SiOx/FEP/Ag sample was removed at 1.1x10^22 atoms/cm2 after severe darkening. On LDEF, the most exposed film lost more than 0.001 inch of 0.005 inch.
- Impacts
- NASA reports that FEP delaminated from the silver around impact sites on LDEF, and that exposed silicone adhesive can form a dark deposit on nearby surfaces.
Handling and storage
- Storage of the silver metal
- The bulk silver sheet says the metal is air sensitive, so it should be stored under inert gas and kept dry. This does not describe the finished film.
- Flammability of the film
- The bulletin rates the bare FEP film VTM-0 under UL 94, with an oxygen index of 95%.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Atomic-oxygen attack through cracks in the SiOx barrierhigh severity | Cracks from thermal cycling in the SiOx coating, exposing the FEPAtomic oxygen and UV reach the FEP, changing its optical properties and the integrity of the coating (NASA TM 106146) |
| Darkening and oxidation of unprotected edgeshigh severity | Plasma-asher exposure to 1.1x10^22 atoms/cm2, with unprotected sample edgesSolar absorptance rose and emittance fell sharply, and the silver and silicone adhesive oxidised into a black, tar-like film (NASA TM 106146) |
| Delamination around micrometeoroid or debris impactsmoderate severity | Impacts in orbitFEP delaminated from the silver around impact sites on LDEF, and exposed silicone adhesive can form a dark deposit (NASA TM 106146) |
| Erosion and roughening of the FEP surfacehigh severity | Long exposure in low Earth orbit (LDEF, 5 years 9 months)Film lost more than 0.001 inch of 0.005 inch in the most exposed rows, and some pieces changed from specular to diffuse reflectors (NASA TM 104096) |
Side effects on surrounding parts
| Affects | Effect |
|---|---|
| Nearby spacecraft surfaces | Atomic oxygen and UV acting together with silicones can produce a dark-coloured contaminant deposit on nearby surfaces (NASA TM 106146). |
Handling and storage
- Bulk silver: air sensitive; store under inert gas and keep in a dry place (safety data sheet, storage section). This applies to the silver metal, not to the finished film.
- Teflon FEP film is rated VTM-0 under ANSI/UL 94 with an oxygen index of 95% (ASTM D2863), per the bulletin, for the bare film at 1 mil.
Mitigations
- A SiOx barrier coat reduces atomic-oxygen attack on the FEP, but thermal-cycling cracks leave gaps in it (NASA TM 106146).
Supply and geography
How common the raw materials are and where they come from.
Silver
- Top producers (2025)
- Mexico 24.2%, Peru 13.8%, China 13.1%, Bolivia 5.8%, Chile 5.4%
- Critical mineral lists
- US: listed, EU: not listed
- Recycling
- USGS: about 1,000 tons of silver was recovered from new and old scrap in 2025, about 11% of apparent consumption.
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.
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spore: profile
id: silvered-fep-teflon
spore_version: 0.2
family: fluoropolymer-mirror
name: Silvered FEP Teflon
abbreviation: Ag/FEP
role: second-surface mirror thermal control film
category: coatings
type: optical-solar-reflectors
summary: |
Silvered FEP Teflon is a flexible second-surface mirror: a fluorinated ethylene propylene (FEP) film with silver and Inconel vapour-deposited on its back. Dunmore prints a typical outside-surface value of 0.13 to 0.16 for the solar absorptance and emittance pair, without splitting them, and an operating range of -185 to 125 °C. SatCatalog prints an operating range of -150 to 125 °C. In a NASA plasma-asher test, the SiOx-coated version darkened and was removed after an atomic-oxygen fluence of 1.1x10^22 atoms/cm2. Film flown on LDEF lost more than 0.001 inch of its nominal 0.005 inch thickness in its most exposed rows.
best_for: Flexible spacecraft thermal control where a low ratio of solar absorptance to emittance is needed, over a published range of -185 to 125 °C (Dunmore)
weakest_at: 'Atomic oxygen in low Earth orbit: the FEP erodes, and the SiOx barrier only protects where it has not cracked (NASA TM 106146 and NASA TM 104096)'
identity:
formula: Laminate of FEP film (tetrafluoroethylene and hexafluoropropylene copolymer), vapour-deposited silver and Inconel, bonded with a pressure-sensitive adhesive
source: nasa-tm104096
where: Introduction, description of the blanket material; monomers from the Wikipedia FEP article (composition only)
tags:
environments:
- low-earth-orbit
stresses:
- atomic-oxygen
- ultraviolet
- vacuum-and-outgassing
applications:
- thermal-control
properties:
- benchmark: alpha_epsilon_outside_surface
label: Typical outside surface solar absorptance / emittance value
value: 0.13
value_high: 0.16
bound: range
unit: '-'
scope: material
conditions:
product: silvered FEP Teflon, outside surface
split: the page prints one combined pair and does not separate solar absorptance from emittance
test: not stated
method: Value printed on the Dunmore product page
status: ground
source: dunmore-silver-fep
where: Product page, typical outside surface values line
- benchmark: max_service_temp
label: Operating temperature, upper limit (Dunmore)
value: 125
unit: °C
scope: material
conditions:
product: silvered FEP Teflon
basis: operating temperature range as printed
method: Value printed on the Dunmore product page
status: ground
source: dunmore-silver-fep
where: Product page, operating temperature line (-185 °C to 125 °C)
- benchmark: min_service_temp
label: Operating temperature, lower limit (Dunmore)
value: -185
unit: °C
scope: material
conditions:
product: silvered FEP Teflon
basis: operating temperature range as printed
method: Value printed on the Dunmore product page
status: ground
source: dunmore-silver-fep
where: Product page, operating temperature line (-185 °C to 125 °C)
- benchmark: max_service_temp
label: Operating temperature, upper limit (SatCatalog)
value: 125
unit: °C
scope: material
conditions:
product: silvered FEP Teflon
basis: operating temperature range as printed
method: Value printed on the SatCatalog component page
status: ground
source: satcatalog-silver-teflon
where: Overview section, operating temperature range (-150 °C to 125 °C)
- benchmark: min_service_temp
label: Operating temperature, lower limit (SatCatalog)
value: -150
unit: °C
scope: material
conditions:
product: silvered FEP Teflon
basis: operating temperature range as printed; differs from the Dunmore lower limit of -185 °C
method: Value printed on the SatCatalog component page
status: ground
source: satcatalog-silver-teflon
where: Overview section, operating temperature range (-150 °C to 125 °C)
- benchmark: reflectance
label: Reflectance
value: 90
bound: lower
unit: '%'
scope: material
conditions:
basis: printed as Reflectance >90%; wavelength and reflectance type not stated
method: Value printed on the SatCatalog component page
status: ground
source: satcatalog-silver-teflon
where: Overview section, Optical Performance
- benchmark: normal_emittance
label: Normal emittance
value: 40
value_high: 80
bound: range
unit: '%'
scope: material
conditions:
basis: printed as 40-80% depending on film thickness; the page does not pair each value with a thickness
method: Value printed on the SatCatalog component page
status: ground
source: satcatalog-silver-teflon
where: Overview section, Optical Performance
- benchmark: film_thickness
label: Film thickness range
value: 50
value_high: 250
bound: range
unit: μm
scope: material
conditions:
product: silvered FEP Teflon film
basis: range as printed; not a single thickness
method: Value printed on the Dunmore product page
status: ground
source: dunmore-silver-fep
where: Product page, film thickness line
- benchmark: maximum_film_width
label: Maximum film width
value: 24
unit: inches
scope: material
conditions:
basis: printed as maximum film width under Customization
method: Value printed on the SatCatalog component page
status: ground
source: satcatalog-silver-teflon
where: Overview section, Customization
- benchmark: silver_layer_thickness
label: Vapour-deposited silver layer
value: 1600
unit: Å
scope: material
conditions:
basis: nominal, as printed for the LDEF blanket material
layer: silver on the back of the FEP film
method: Value printed in the NASA description of the blanket
status: ground
source: nasa-tm104096
where: Introduction, description of the blanket (approximately 1600A of vapor deposited silver)
- benchmark: inconel_layer_thickness
label: Vapour-deposited Inconel layer
value: 400
unit: Å
scope: material
conditions:
basis: nominal, as printed for the LDEF blanket material
layer: Inconel over the silver
method: Value printed in the NASA description of the blanket
status: ground
source: nasa-tm104096
where: Introduction, description of the blanket (approximately 400A of vapor deposited inconel)
- benchmark: ao_erosion_depth
label: FEP film loss in LDEF Rows 8 to 10
value: 0.001
bound: lower
unit: inch
scope: material
conditions:
exposure: 5 years 9 months in low Earth orbit on LDEF, most extreme rows 8 to 10
starting_thickness: 0.005 inch nominal FEP film
note: printed as in excess of 0.001 inch
method: Preliminary estimate by the authors
status: ground
source: nasa-tm104096
where: Discussion of LDEF film erosion, paragraph beginning Preliminary estimates
- benchmark: melting_point
label: Melt point of the bare FEP film
value: 260
value_high: 280
bound: range
unit: °C
scope: material
conditions:
form: bare Teflon FEP film, 1 mil (0.025 mm) basis, not the silvered blanket
test: ASTM D3418 (DTA)
method: Value printed in the Typical Properties table
status: ground
source: chemours-fep-bulletin
where: Typical Properties table, Thermal section, Melt Point (printed 260–280 °C)
- benchmark: zero_strength_temperature
label: Zero strength temperature of the bare FEP film
value: 255
unit: °C
scope: material
conditions:
form: bare Teflon FEP film, 1 mil basis
load: temperature at which a film supports 0.14 N/mm2 (20 psi) for 5 sec, per the bulletin footnote
method: Value printed in the Typical Properties table
status: ground
source: chemours-fep-bulletin
where: Typical Properties table, Thermal section, Zero Strength Temperature
- benchmark: max_service_temp
label: Continuous service temperature, upper limit (bare FEP film)
value: 205
unit: °C
scope: material
conditions:
form: bare Teflon FEP film resin, not the silvered blanket
basis: continuous service range as printed
method: Value printed in the bulletin description bullets
status: ground
source: chemours-fep-bulletin
where: Description bullets, continuous service temperature (–240 to 205 °C)
- benchmark: density
label: Density of the bare FEP film
value: 2150
unit: kg/m3
scope: material
conditions:
form: bare Teflon FEP film, 1 mil basis
test: ASTM D1505
method: Value printed in the Miscellaneous table
status: ground
source: chemours-fep-bulletin
where: Miscellaneous table, Density
- benchmark: ultimate_tensile_strength
label: Tensile strength at break of the bare FEP film
value: 21
unit: N/mm2
scope: material
conditions:
form: bare Teflon FEP film, 1 mil (0.025 mm) basis at 25 °C
test: ASTM D882
method: Value printed in the Mechanical table
status: ground
source: chemours-fep-bulletin
where: Mechanical table, Tensile Strength at Break (3000 psi)
- benchmark: elongation
label: Elongation at break of the bare FEP film
value: 300
unit: '%'
scope: material
conditions:
form: bare Teflon FEP film, 1 mil (0.025 mm) basis at 25 °C
test: ASTM D882
method: Value printed in the Mechanical table
status: ground
source: chemours-fep-bulletin
where: Mechanical table, Elongation at Break
- benchmark: dielectric_constant
label: Dielectric constant of the bare FEP film
value: 2
unit: '-'
scope: material
conditions:
form: bare Teflon FEP film at 25 °C
frequency: 100 Hz to 1 MHz
test: ASTM D150
method: Value printed in the Electrical table
status: ground
source: chemours-fep-bulletin
where: Electrical table, Dielectric Constant
- benchmark: refractive_index
label: Refractive index of the bare FEP film
value: 1.341
value_high: 1.347
bound: range
unit: '-'
scope: material
conditions:
form: bare Teflon FEP film
test: ASTM D542
method: Value printed in the Miscellaneous table
status: ground
source: chemours-fep-bulletin
where: Miscellaneous table, Refractive Index
- benchmark: solar_transmittance
label: Solar transmission of the bare FEP film
value: 96
unit: '%'
scope: material
conditions:
form: bare Teflon FEP film, 1 mil (0.025 mm) basis at 25 °C
test: ASTM E-424
note: the silvered blanket is opaque to solar transmission because of its silver layer
method: Value printed in the Miscellaneous table
status: ground
source: chemours-fep-bulletin
where: Miscellaneous table, Solar Transmission
- benchmark: specific_heat
label: Specific heat of the bare FEP film
value: 1172
unit: J/(kg·K)
scope: material
conditions:
form: bare Teflon FEP film
method: Value printed in the Thermal table
status: ground
source: chemours-fep-bulletin
where: Thermal table, Specific Heat (0.28 Btu/(lb·°F))
- benchmark: thermal_conductivity
label: Thermal conductivity of the bare FEP film
value: 0.195
unit: W/(m·K)
scope: material
conditions:
form: bare Teflon FEP film
method_printed: Cenco-Fitch
method: Value printed in the Thermal table
status: ground
source: chemours-fep-bulletin
where: Thermal table, Coefficient of Thermal Conductivity
- benchmark: total_mass_loss
label: Total mass loss limit (ASTM E-595)
value: 1
bound: upper
unit: '%'
scope: material
conditions:
standard: ASTM E-595
kind: qualification limit printed by the vendor, not a measured result for this product
method: Limit printed on the SatCatalog component page (printed as TML <1.0%)
status: ground
source: satcatalog-silver-teflon
where: Qualification and Testing section
- benchmark: collected_volatile_condensable_material
label: Collected volatile condensable material limit (ASTM E-595)
value: 0.1
bound: upper
unit: '%'
scope: material
conditions:
standard: ASTM E-595
kind: qualification limit printed by the vendor, not a measured result for this product
method: Limit printed on the SatCatalog component page (printed as CVCM <0.1%)
status: ground
source: satcatalog-silver-teflon
where: Qualification and Testing section
corrosion:
- environment: Atomic oxygen in low Earth orbit, simulated in an RF plasma asher
headline: In NASA's plasma-asher test the SiOx/FEP/Ag sample darkened and was removed at 1.1x10^22 atoms/cm2.
effect: At that fluence the sample's solar absorptance rose and its thermal emittance fell sharply. The sample turned into a black, tar-like film that began at its unprotected edges, where the silver and silicone adhesive oxidised. NASA states that atomic oxygen oxidises FEP, causing mass loss and surface texturing, and that the asher gives a random-direction attack, unlike the directed beam in orbit.
rating: severe
conditions:
facility: RF oxygen plasma asher with intense VUV
fluence: 1.1x10 22 atoms/cm2 at removal
caveat: the test is not a direct lifetime prediction, because the asher attack is random
source: nasa-tm106146
where: Damage Mechanisms to Coatings; Exposure in an RF Plasma Asher; RF Plasma Asher Effects on Coatings
- environment: Low Earth orbit in flight, LDEF, 5 years 9 months
headline: Silvered FEP on LDEF lost more than 0.001 inch of its 0.005 inch film in the most exposed rows.
effect: Atomic-oxygen erosion roughened the coating surface, and some pieces changed from specular to diffuse reflectors. XPS, infrared and thermal analysis found no significant change at the molecular level. The authors call the erosion extent unanticipated, and note that it was not uniform across the film.
rating: severe
conditions:
exposure: 5 years 9 months on LDEF, Rows 8 to 10 (most extreme cases)
note: the film-loss figure is a preliminary estimate
source: nasa-tm104096
where: Abstract; Discussion of LDEF film erosion
- environment: Ultraviolet and vacuum-ultraviolet radiation in orbit
headline: NASA's review says UV can embrittle FEP, degrade transmittance and cause mass loss over long exposure.
effect: The review states that ultraviolet radiation may cause embrittlement, transmittance degradation and mass loss over a long exposure duration. It notes that atomic oxygen and UV act together on FEP, and that a SiOx coating does not stop UV that reaches the FEP through cracks.
rating: moderate
conditions:
basis: statement in the NASA review; no UV dose or number is printed for this laminate
source: nasa-tm106146
where: Damage Mechanisms to Coatings, paragraph on SiOx/FEP/Ag
- environment: Thermal cycling and micrometeoroid or debris impact
headline: Cracks from thermal cycling let atomic oxygen reach the FEP, and impacts can delaminate the film.
effect: NASA notes that cracks in the SiOx coating caused by thermal cycling let atomic oxygen and UV reach the FEP, changing its optical properties. LDEF showed delamination of FEP from the silver around impact sites, and exposed silicone adhesive at an impact site can form a dark contaminant with atomic oxygen and UV.
rating: moderate
conditions:
thermal_cycling_in_test: 10 cycles between -93 °C and +49 °C in vacuum, before plasma-asher exposure
source: nasa-tm106146
where: Damage Mechanisms to Coatings; Vacuum Thermal Cycling Exposure
- environment: Outgassing in vacuum
headline: The SatCatalog page quotes ASTM E-595 limits of TML below 1.0% and CVCM below 0.1%.
effect: These are qualification limits printed by the vendor catalog, not measured results for this product. The page does not give the test lot, date or specimen.
rating: low
conditions:
standard: ASTM E-595
basis: limits as printed on the SatCatalog page
source: satcatalog-silver-teflon
where: Qualification and Testing section
risks:
hazards:
- text: The bulk silver safety data sheet (Stanford Advanced Materials, product Silver, brand SAM, revision 09/04/2017) classifies silver as acute aquatic toxicity Category 1 (H400) and chronic aquatic toxicity Category 1 (H410), with signal word Warning and precautionary statement P273, avoid release to the environment.
ghs:
- H400
- H410
source: sds-silver-sam
where: Sections 2.1 and 2.2
- text: The same sheet prints an oral LD50 for silver in rat of more than 5,000 mg/kg (male), and 'No data available' for inhalation and dermal toxicity.
ghs: []
source: sds-silver-sam
where: Section 11.1
- text: The same sheet prints silver exposure limits of TWA 0.01 mg/m3 (OSHA Table Z-1) and TWA 0.1 mg/m3 (ACGIH TLV).
ghs: []
source: sds-silver-sam
where: Section 8.1, control parameters
- text: The Chemours FEP bulletin says the polymer is chemically inert and solvent resistant to virtually all chemicals, except molten alkali metals, gaseous fluorine and certain complex halogenated compounds at elevated temperatures and pressures.
ghs: []
source: chemours-fep-bulletin
where: Chemical compatibility paragraph
failure_risks:
- mode: Atomic-oxygen attack through cracks in the SiOx barrier
trigger: Cracks from thermal cycling in the SiOx coating, exposing the FEP
consequence: Atomic oxygen and UV reach the FEP, changing its optical properties and the integrity of the coating (NASA TM 106146)
severity: high
source: nasa-tm106146
where: Damage Mechanisms to Coatings
- mode: Darkening and oxidation of unprotected edges
trigger: Plasma-asher exposure to 1.1x10^22 atoms/cm2, with unprotected sample edges
consequence: Solar absorptance rose and emittance fell sharply, and the silver and silicone adhesive oxidised into a black, tar-like film (NASA TM 106146)
severity: high
source: nasa-tm106146
where: RF Plasma Asher Effects on Coatings
- mode: Delamination around micrometeoroid or debris impacts
trigger: Impacts in orbit
consequence: FEP delaminated from the silver around impact sites on LDEF, and exposed silicone adhesive can form a dark deposit (NASA TM 106146)
severity: moderate
source: nasa-tm106146
where: Damage Mechanisms to Coatings
- mode: Erosion and roughening of the FEP surface
trigger: Long exposure in low Earth orbit (LDEF, 5 years 9 months)
consequence: Film lost more than 0.001 inch of 0.005 inch in the most exposed rows, and some pieces changed from specular to diffuse reflectors (NASA TM 104096)
severity: high
source: nasa-tm104096
where: Abstract; Discussion of LDEF film erosion
side_effects:
- text: Atomic oxygen and UV acting together with silicones can produce a dark-coloured contaminant deposit on nearby surfaces (NASA TM 106146).
affects: Nearby spacecraft surfaces
source: nasa-tm106146
where: Damage Mechanisms to Coatings
handling:
- text: 'Bulk silver: air sensitive; store under inert gas and keep in a dry place (safety data sheet, storage section). This applies to the silver metal, not to the finished film.'
source: sds-silver-sam
where: Section 7
- text: Teflon FEP film is rated VTM-0 under ANSI/UL 94 with an oxygen index of 95% (ASTM D2863), per the bulletin, for the bare film at 1 mil.
source: chemours-fep-bulletin
where: Mechanical and Flammability rows of the Typical Properties table
mitigations:
- text: A SiOx barrier coat reduces atomic-oxygen attack on the FEP, but thermal-cycling cracks leave gaps in it (NASA TM 106146).
source: nasa-tm106146
where: Damage Mechanisms to Coatings
uses:
- application: thermal-control
device: Thermal control blanket on Space Station Freedom power-system radiators (candidate coating in NASA's test, not a flown product in this source)
example: NASA tested SiOx-coated silvered Teflon with white paints and anodised aluminium as candidate radiator coatings for Space Station Freedom, against a 30-year design life.
source: nasa-tm106146
where: Introduction; Materials Tested
- application: thermal-control
device: Thermal blanket on LDEF experiment trays
example: Silvered FEP thermal blankets provided thermal protection for experiments on LDEF Tray F2 and Trays C5, C8 and A10.
source: nasa-tm104096
where: Section 1, Introduction
- application: thermal-control
device: Flexible second-surface mirror in spacecraft thermal control
example: NASA describes the blanket material, also known as flexible second-surface mirror thermal control coating, as used in a variety of space applications where thermal protection is a consideration.
source: nasa-tm104096
where: Section 1, Introduction
supply:
- subject: Silver
producers:
- country: Mexico
share_percent: 24.2
year: 2025
- country: Peru
share_percent: 13.8
year: 2025
- country: China
share_percent: 13.1
year: 2025
- country: Bolivia
share_percent: 5.8
year: 2025
- country: Chile
share_percent: 5.4
year: 2025
critical_lists:
- list: USGS 2025 Final List of Critical Minerals (silver added)
listed: true
- list: EU critical raw materials list
listed: false
recycling: 'USGS: about 1,000 tons of silver was recovered from new and old scrap in 2025, about 11% of apparent consumption.'
substitutes: []
source: usgs-mcs2026-silver
where: World Mine Production and Reserves table, 2025e (world total rounded 26,000 t). Shares calculated by Space Mushroom as printed tons divided by the rounded world total. Critical list change in the opening paragraph. Recycling paragraph.
documents:
- title: 'Dunmore: Silver FEP film product page'
type: datasheet
url: https://www.dunmore.com/products/silver-fep-film.html
year: 2026
- title: 'SatCatalog: Silver Teflon FEP tape component page'
type: database
url: https://www.satcatalog.com/component/silver-teflon-fep-tape
year: 2026
- title: 'NASA TM 106146: The Effects of Simulated Low Earth Orbit Environments on Spacecraft Thermal Control Coatings (Dever et al., 1993)'
type: report
url: https://ntrs.nasa.gov/api/citations/19930017830/downloads/19930017830.pdf
year: 1993
- title: 'NASA TM 104096: An Analysis of LDEF-Exposed Silvered FEP Teflon Thermal Blanket Material (Young and Slemp, 1992)'
type: report
url: https://ntrs.nasa.gov/api/citations/19920005971/downloads/19920005971.pdf
year: 1992
- title: Teflon FEP Fluoropolymer Film Properties Bulletin (copy hosted by PolymerFilms)
type: datasheet
url: https://polymerfilms.com/wp-content/uploads/2023/06/Chemours-Teflon_FEP-Datasheet-cobranded-pf.pdf
year: 2022
- title: 'USGS Mineral Commodity Summaries 2026: Silver'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silver.pdf
year: 2026
- title: 'Safety Data Sheet: Silver (Stanford Advanced Materials, brand SAM, version 3.0)'
type: sds
url: https://www.sputtertargets.net/wp-content/uploads/2018/05/Silver-Ag-sds.pdf
year: 2017
gaps:
- 'No flight-heritage details are verified: SatCatalog prints Heritage Yes without listing missions. The brief''s Hubble and ISS use is not confirmed by any page read in this run, so it is not in uses.'
- Solar absorptance (alpha) and infrared emittance (epsilon) are not given separately. Dunmore prints one combined pair (0.13 to 0.16), and SatCatalog prints normal emittance of 40-80% by thickness without alpha.
- The two operating ranges disagree on the lower limit (Dunmore -185 °C, SatCatalog -150 °C). Both are kept, each with its source. Neither is tied to a test standard.
- The Dunmore page names an Inconel protective layer over the silver but does not print a SiOx layer, its thickness, the FEP thickness on the product, or the adhesive. SiOx and the Permacel P223 adhesive come from the NASA test samples only.
- No atomic-oxygen erosion yield or solar absorptance and emittance change values for this material were read as numbers. NASA's test results are shown in figures only, so no value was taken from them.
- The Wikipedia article says FEP contains about 5% of the 'propylene component'. The term is ambiguous, so the share was not used.
- The FEP film's own thermal decomposition products and hazard statements were not found. PubChem's silver record was blocked by a reCAPTCHA and could not be read.
- The silver safety data sheet is for bulk silver metal (brand SAM, revision 09/04/2017). The silvered film has no safety data sheet read in this run.
- Silver abundance in the Earth's crust was not found in a page read in this run.
- No supply data for FEP resin producers or feedstock was read. The supply section covers silver only.
- The EU critical raw materials list status for silver was not checked.
- No substitute for silvered FEP in thermal control was found in a page read in this run.
- No standard grade designations apply to this coating. The bulletin's 'Teflon FEP' trade name is not listed as a designation.
- No image with a confirmed licence was fetched, so media is not included.
- Thermal-cycling and UV effects are described in NASA's text, but no numeric change for this laminate was read from the text.
- The ASTM E-595 limits are quoted from SatCatalog and were not checked against the ASTM standard.
sources:
dunmore-silver-fep:
title: Dunmore, Silver FEP film product page
id: Dunmore product page, silver-fep-film
url: https://www.dunmore.com/products/silver-fep-film.html
year: 2026
kind: datasheet
license: vendor web page, cited not reproduced
satcatalog-silver-teflon:
title: SatCatalog, Silver Teflon FEP tape component page (vendor SQUID3 Space)
id: SatCatalog component silver-teflon-fep-tape
url: https://www.satcatalog.com/component/silver-teflon-fep-tape
year: 2026
kind: database
license: catalog web page, cited not reproduced
nasa-tm106146:
title: The Effects of Simulated Low Earth Orbit Environments on Spacecraft Thermal Control Coatings (NASA TM 106146, SAMPE 1993)
id: NASA TM 106146; NTRS 19930017830
url: https://ntrs.nasa.gov/api/citations/19930017830/downloads/19930017830.pdf
year: 1993
kind: report
license: public domain (NASA)
nasa-tm104096:
title: An Analysis of LDEF-Exposed Silvered FEP Teflon Thermal Blanket Material (NASA TM 104096)
id: NASA TM 104096; NTRS 19920005971
url: https://ntrs.nasa.gov/api/citations/19920005971/downloads/19920005971.pdf
year: 1992
kind: report
license: public domain (NASA)
chemours-fep-bulletin:
title: Teflon FEP Fluoropolymer Film Properties Bulletin (Chemours name; copy hosted by PolymerFilms, footer names Polymershapes)
id: Teflon FEP film bulletin, 1 mil basis for typical values
url: https://polymerfilms.com/wp-content/uploads/2023/06/Chemours-Teflon_FEP-Datasheet-cobranded-pf.pdf
year: 2022
kind: datasheet
license: manufacturer bulletin, cited not reproduced
usgs-mcs2026-silver:
title: Mineral Commodity Summaries 2026, Silver
id: USGS MCS 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silver.pdf
year: 2026
kind: report
license: public domain (USGS)
sds-silver-sam:
title: 'Safety Data Sheet: Silver (Stanford Advanced Materials, brand SAM, version 3.0, revision 09/04/2017)'
id: CAS 7440-22-4; revision 09/04/2017
url: https://www.sputtertargets.net/wp-content/uploads/2018/05/Silver-Ag-sds.pdf
year: 2017
kind: datasheet
license: supplier document, linked not reproduced
wikipedia-fep:
title: Fluorinated ethylene propylene (Wikipedia), used for monomers and composition only
id: Wikipedia article, Fluorinated ethylene propylene
url: https://en.wikipedia.org/wiki/Fluorinated_ethylene_propylene
year: 2026
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: 25
unreachable: 1
caveats: 3
note: Written by an AI assistant on 2026-11-01 from pages read in this run. PubChem was blocked by a reCAPTCHA. Values are copied as printed; the Dunmore pair is not split into alpha and epsilon.
story:
recipe:
line: 'Silvered FEP is a laminate: a nominally 5 mil fluorinated ethylene propylene film with about 1600 Å of silver and about 400 Å of Inconel vapour-deposited on its back (NASA TM 104096). Silver reflects sunlight, the transparent film protects it, and a SiOx barrier coat sits on the FEP side in the test construction NASA called SiOx/FEP/Ag (NASA TM 106146).'
parts:
- name: Fluorinated ethylene propylene (FEP) film
share: nominally 5 mil, Type A film (NASA TM 104096)
role: Transparent outer layer. Sunlight passes through it and is reflected by the silver, which gives a low solar absorptance.
- name: Silver
symbol: Ag
share: approximately 1600 Å, vapour-deposited (NASA TM 104096)
role: Specular reflector behind the film.
- name: Inconel
share: approximately 400 Å, vapour-deposited (NASA TM 104096)
role: Thin metal layer over the silver. Dunmore calls it a protective layer.
- name: Silicon oxide (SiOx) barrier
share: thickness not found
role: Barrier to atomic oxygen on the FEP in the NASA test construction. Its thickness and whether vendor product uses it are not confirmed.
- name: Pressure-sensitive adhesive
share: Permacel P223 on the NASA test samples
role: Bonds the laminate to the substrate. The adhesive on the vendor product is not stated.
risk_groups:
- title: For people
level: 0
verdict: Low hazard as a finished film; the bulk silver safety data…
lead: The finished film has no safety data sheet read in this run. The bulk silver safety data sheet classifies silver as very toxic to aquatic life with long-lasting effects.
points:
- label: The silver metal
line: The bulk silver sheet classifies silver as H400 and H410 (very toxic to aquatic life) and prints an oral LD50 in rat of more than 5,000 mg/kg. It prints an OSHA limit of 0.01 mg/m3 and an ACGIH limit of 0.1 mg/m3.
- label: The FEP film
line: The Chemours bulletin describes the polymer as chemically inert to virtually all chemicals. No hazard statement for the film was found in a page read in this run.
- title: If the film is damaged in orbit
lead: These results come from ground tests and one flight sample, not from incidents.
points:
- label: Atomic oxygen
line: In NASA's plasma-asher test, the SiOx/FEP/Ag sample was removed at 1.1x10^22 atoms/cm2 after severe darkening. On LDEF, the most exposed film lost more than 0.001 inch of 0.005 inch.
- label: Impacts
line: NASA reports that FEP delaminated from the silver around impact sites on LDEF, and that exposed silicone adhesive can form a dark deposit on nearby surfaces.
- title: Handling and storage
points:
- label: Storage of the silver metal
line: The bulk silver sheet says the metal is air sensitive, so it should be stored under inert gas and kept dry. This does not describe the finished film.
- label: Flammability of the film
line: The bulletin rates the bare FEP film VTM-0 under UL 94, with an oxygen index of 95%.
why: Silvered FEP Teflon is a flexible second-surface mirror. The silver sits behind a transparent fluoropolymer film, so the film faces space and the reflective metal is protected from the outside. The construction is used where a low solar absorptance and a high infrared emittance are both needed in a thin, bendable sheet. Vendor pages give a combined value of 0.13 to 0.16 for the outside surface, and NASA reports that the SiOx-coated version is damaged by atomic oxygen in low Earth orbit.
uses:
- where: Space Station Freedom radiators (candidate)
line: NASA tested SiOx-coated silvered Teflon as a candidate coating for Space Station Freedom power-system radiators, along with two white paints and anodised aluminium. The test asked for a 30-year design life.
- where: LDEF experiment trays
line: NASA's analysis of LDEF material describes silvered FEP blankets that gave thermal protection to experiments on Tray F2 and Trays C5, C8 and A10 on the Long Duration Exposure Facility.
- where: Spacecraft thermal blankets
line: NASA describes the material as a flexible second-surface mirror thermal control coating used in a variety of space applications where thermal protection is a consideration.
can_do:
- label: Low solar absorptance to emittance
value: 0.13 to 0.16 outside surface
line: Dunmore prints a typical outside-surface value of 0.13 to 0.16 for the solar absorptance and emittance pair. The page does not split the two values, so this profile does not state either one alone.
- label: Operating temperature
value: '-185 to 125 °C (Dunmore)'
line: Dunmore prints an operating range of -185 to 125 °C. SatCatalog prints -150 to 125 °C. Both are kept because the vendors do not agree on the lower limit.
- label: Atomic-oxygen erosion
value: more than 0.001 inch lost
line: On LDEF, the most exposed film lost more than 0.001 inch of its 0.005 inch thickness in 5 years and 9 months, according to NASA's preliminary estimate.
- label: Outgassing limits
value: TML below 1.0%, CVCM below 0.1%
line: SatCatalog quotes ASTM E-595 limits of TML below 1.0% and CVCM below 0.1%. These are qualification limits, not measured results for this product.
compare: Silvered FEP trades atomic-oxygen tolerance for a low solar absorptance. In NASA's 1993 plasma-asher test, the SiOx/FEP/Ag sample was removed at 1.1x10^22 atoms/cm2 after severe degradation, while the white paints Z-93 and YB-71 and the anodised aluminium were carried through the full test fluence in the same asher test (the full value is printed in NASA TM 106146, Exposure in an RF Plasma Asher). The bare FEP film is rated for a continuous service range of -240 to 205 °C, but the silvered product's own published range is -185 to 125 °C (Dunmore) or -150 to 125 °C (SatCatalog).
compare_rows:
- label: Operating range, upper limit
benchmark: max_service_temp
- label: Melt point of the bare FEP film
benchmark: melting_point
- label: Density of the bare FEP film
benchmark: density
handling:
- The bulk silver metal is classed as very toxic to aquatic life. Avoid releasing it to the environment.
- Keep the silver metal under inert gas and dry. This does not describe the finished film.
- The film is rated VTM-0 under UL 94 for the bare FEP at 1 mil.
good_for:
- Thin, flexible thermal control on spacecraft, where a low solar absorptance and a high emittance are both needed (Dunmore and NASA).
- Use over a published operating range of -185 to 125 °C, according to Dunmore.
watch_out:
- Atomic oxygen in low Earth orbit erodes the FEP. On LDEF, the most exposed film lost more than 0.001 inch.
- A SiOx barrier does not protect the FEP where thermal cycling has cracked it, according to NASA.
- 'The two published operating ranges disagree on the lower limit: -185 °C (Dunmore) and -150 °C (SatCatalog).'
verdict: Silvered FEP is a well-documented thermal-control film for the sunward side of a spacecraft. Its low solar absorptance is useful, but its atomic-oxygen tolerance depends on the barrier staying intact, and the published data do not settle the lower operating limit.
References
Every number above carries a reference number. Click one to see the source and where in it the value comes from.
| # | Source | Type | Year | Used for |
|---|---|---|---|---|
| Dunmore, Silver FEP film product page | datasheet | 2026 | 4 values | |
| SatCatalog, Silver Teflon FEP tape component page (vendor SQUID3 Space) | database | 2026 | 8 values | |
| The Effects of Simulated Low Earth Orbit Environments on Spacecraft Thermal Control Coatings (NASA TM 106146, SAMPE 1993) | report | 1993 | 9 values | |
| An Analysis of LDEF-Exposed Silvered FEP Teflon Thermal Blanket Material (NASA TM 104096) | report | 1992 | 8 values | |
| Teflon FEP Fluoropolymer Film Properties Bulletin (Chemours name; copy hosted by PolymerFilms, footer names Polymershapes) | datasheet | 2022 | 13 values | |
| Mineral Commodity Summaries 2026, Silver | report | 2026 | 1 value | |
| Safety Data Sheet: Silver (Stanford Advanced Materials, brand SAM, version 3.0, revision 09/04/2017) | datasheet | 2017 | 4 values | |
| Fluorinated ethylene propylene (Wikipedia), used for monomers and composition only | web | 2026 | 0 values |
Updated