Phenolic Impregnated Carbon Ablator PICA
Carbon-fibre substrate (FiberForm) impregnated with phenolic resin (Durite SC-1008)
PICA (Phenolic Impregnated Carbon Ablator) is a low-density heat shield made from a rigid carbon-fibre preform, called FiberForm, infused with phenolic resin.
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.
Density
224 to 248 kg/m^3
Emissivity
0.8
Specific heat
1200 J/kg-K
Char
0.63 -
Recipe, share of the weight
- - not statedCarbon-fibre preform (FiberForm)
- - not statedPhenolic resin (Durite SC-1008)
Best for
Entry heat shields that need a light carbon-phenolic ablator with flight heritage (Stardust; Mars Science Laboratory in tiled form)
Weakest at
Supply: the rayon precursor has been replaced at least twice in the past 25 years (Gasch et al.), and the sources read here give no hazard, ageing or humidity data
Risk at a glance
- People None found. Not assessed in this run
- If it fails Moderate. Surface recession beyond the design depth
- Corrosion Moderate. In two arc-jet conditions, centerline recession was 2.33 mm at 55 s and 24.72 mm at 400 s.
Quick facts: PICA
| Property | Value | Basis |
|---|---|---|
| Density | 0.14 to 0.28 g/cm³ | 4 sourced values across conditions |
| Tensile strength | 0.3 to 1.7 MPa | 2 sourced values across conditions |
| Thermal conductivity | 0.94 to 1.5 BTU-in/hr-ft2-oF | 2 sourced values across conditions |
| Specific heat | 1,200 J/(kg·K) | 1 sourced value |
What is the density of Phenolic Impregnated Carbon Ablator (PICA)?
Phenolic Impregnated Carbon Ablator (PICA) has a density of 0.14 to 0.28 g/cm³. The range covers 4 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is the thermal conductivity of Phenolic Impregnated Carbon Ablator (PICA)?
Phenolic Impregnated Carbon Ablator (PICA) has a thermal conductivity of 0.94 to 1.5 BTU-in/hr-ft2-oF. The range covers 2 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is the tensile strength of Phenolic Impregnated Carbon Ablator (PICA)?
Phenolic Impregnated Carbon Ablator (PICA) has a tensile strength of 0.3 to 1.7 MPa. The range covers 2 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is Phenolic Impregnated Carbon Ablator (PICA) used for?
Uses recorded in the sources include Stardust sample-return capsule forebody heat shield; OSIRIS-REx sample-return capsule heat shield; Mars Science Laboratory and Mars 2020 entry heat shields (tiled).
Why it exists
Phenolic Impregnated Carbon Ablator (PICA) is a low-density ablative heat shield developed at NASA Ames Research Center. The sources call it the lowest-density carbon-phenolic ablator with flight heritage (Gasch et al. 2019). It is made by infusing a rigid carbon-fibre preform with phenolic resin. Its density and ablation values come from NASA's TPSX database and from NASA papers, and this profile uses only the numbers printed in those sources.
Where it's used
Stardust (launched 1999)
PICA was the forebody heat shield of Stardust, the first sample-return mission from outside the Earth-Moon system. The TPSX database says Stardust was to re-enter at 16 Km/sec, and Gasch et al. describe the heat shield as a single cast piece.
OSIRIS-REx
Gasch et al. report that OSIRIS-REx uses a single-piece PICA heat shield very similar to the Stardust design.
Mars Science Laboratory and Mars 2020 (tiled)
PICA was used on Mars Science Laboratory in a tiled layout, and the Mars 2020 heat shield follows that layout (Gasch et al. 2019).
Orion Crew Module (candidate)
Milos and Chen (2009) call PICA a candidate heat shield material for the Orion Crew Module. The program tested newly manufactured PICA.
Recipe
Carbon-fibre substrate (FiberForm) impregnated with phenolic resin (Durite SC-1008); a composite, not a single compound
PICA is a composite of two parts: a rigid, low-density carbon-fibre preform (FiberForm) and a phenolic resin that fills the open space in the preform. The carbon fibres are made from rayon by a high-temperature conversion, and the preform is infused with phenolic resin and then cured (Gasch et al. 2019; Selvaduray and Cox 1998).
| Ingredient | Share of the weight | What it does |
|---|---|---|
| Carbon-fibre preform (FiberForm) - | not stated | A rigid, porous carbon substrate made from chopped rayon-derived carbon fibres. It sets the low density and the open pore structure. |
| Phenolic resin (Durite SC-1008) - | not stated | Fills the void space between filaments. On heating it decomposes, and the char it leaves behind is what protects the surface. |
Weight shares are as printed in the sources.
What it can do
Density
224 to 248 kg/m^3
measured
The 1998 NASA annual report gives a nominal density of 224 to 248 kg/m^3 for PICA, depending on the phenolic loading. The FiberForm substrate before impregnation is 144 to 176 kg/m^3 in the same report.
Emissivity
0.8
measured
TPSX lists an emissivity of 0.8 for virgin PICA. Its source column says measured, and the page gives no temperature for it.
Specific heat
1200 J/kg-K
measured
TPSX lists a specific heat of 1200 J/kg-K for virgin PICA. The page gives no temperature, and its source column says unknown.
Char
0.63 -
measured
The phenolic resin in PICA leaves about 0.63 of its mass as char after pyrolysis at about 1250 K under argon (Selvaduray and Cox 1998). The report does not say whether 0.63 is a fraction or a percent.
How it compares
No other thermal-protection profile was read in this run, so this paragraph gives no side-by-side number. Within the sources read, PICA is described as the lowest-density carbon-phenolic ablator with flight heritage (Gasch et al. 2019). Its nominal density is 224 to 248 kg/m^3 and its arc-jet recession grows strongly with exposure time (2.33 mm at 55 s, 24.72 mm at 400 s, in different conditions). For a like-for-like table, read the other ablator profiles with the same method.
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 | PICA |
|---|---|
| Thermal behavior and safety | |
| Specific heat, virgin PICA | 1200 J/kg-K3 |
| Thermal conductivity at 100°F, Lyocell-based PICA (PICA-D), average | 0.94 BTU-in/hr-ft2-oF12 |
| Thermal conductivity at 350°F, Lyocell-based PICA (PICA-D), average | 1.32 BTU-in/hr-ft2-oF13 |
| Thermal conductivity at 100°F, heritage rayon-based PICA, range | 1 to 1.5 BTU-in/hr-ft2-oF14 |
| Physical and electrical | |
| Density range, PICA after phenolic impregnation | 224 to 248 kg/m^31 |
| Density range, FiberForm substrate before impregnation | 144 to 176 kg/m^32 |
| Average density, Lyocell-based PICA (PICA-D) | 0.28 g/cc10 |
| Approximate density, PICA (background section of the slides) | 0.27 g/cc11 |
| Temperature behavior | |
| Maximum surface temperature, arc-jet condition 1, model AA-43-209-N | 2033 K8 |
| Maximum surface temperature, arc-jet condition 2b, model AT-007 | 2196 K9 |
| Other measurements | |
| Emissivity, virgin PICA | 0.8 -4 |
| Char yield of the phenolic resin in PICA | 0.63 -5 |
| Centerline recession, arc-jet condition 1, model AA-43-209-N | 2.33 mm6 |
| Centerline recession, arc-jet condition 2b, model AT-007 | 24.72 mm7 |
| In-plane failure stress, Lyocell-based PICA (PICA-D), average | 246 psi15 |
| Through-thickness failure stress, Lyocell-based PICA (PICA-D), average | 44 psi16 |
| Average centerline recession, Lyocell-derived PICA, arc-jet at 1550W/cm2 and 1.3 atm | 4 mm17 |
| Average centerline recession, rayon-derived PICA, arc-jet at 1550W/cm2 and 1.3 atm | 4.2 mm18 |
Why choose it, and why not
Good for
- Entry heat shields that need a light carbon-phenolic ablator with flight heritage: Stardust, and Mars Science Laboratory in tiled form.
- Designs that need a NASA property set: TPSX gives density, specific heat, emissivity and effective heat of ablation for virgin PICA.
Watch out for
- Density depends on phenolic loading: 224 to 248 kg/m^3 nominal in the 1998 report.
- TPSX labels the conductivity isotropic, but Milos and Chen (2009) describe it as strongly orthotropic.
- Recession is large at long exposures: 24.72 mm after 400 s in one arc-jet condition.
- The rayon precursor supply has changed at least twice in the past 25 years, and the Lyocell replacement (PICA-D) is still in development.
PICA is a flight-proven carbon-phenolic heat shield with NASA property values for virgin material. What the sources read here do not give is hazard data, ageing and humidity behaviour, in-flight measurements, or a settled precursor supply.
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 | Density range, PICA after phenolic impregnation | Nominal range stated in the 1998 NASA annual report | phenolic loading depends on the level of phenolic loadingform nominal range for the impregnated preform | Printed as 224 to 248 kg/m^3 (14 to 15.5 lb/ft^3). |
| 2 | Density range, FiberForm substrate before impregnation | Nominal range stated in the 1998 NASA annual report | form FiberForm carbon-fibre substrate, not impregnatedbasis nominal range | Printed as 144 to 176 kg/m^3 (9.0 to 11 lb/ft^3). |
| 3 | Specific heat, virgin PICA | Value listed in the TPSX database; its source column says unknown | temperature not printed on the pagestandard conditions flag TRUE (TPSX column) | Printed as 1.20e+03 J/kg-K. |
| 4 | Emissivity, virgin PICA | Value listed in the TPSX database; its source column says measured | temperature not printed on the pagestandard conditions flag assumed/assumed (TPSX column) | — |
| 5 | Char yield of the phenolic resin in PICA | Specimens cycled to about 1250 K under argon; the report defines char yield as the mass remaining after pyrolysis | atmosphere argon gas flowtemperature about 1250 K, in a tube furnacematerial phenolic resin in PICA | The report defines char yield as a percentage of mass remaining, but prints 0.63 with no unit. The report does not say whether that is a fraction or a percent. |
| 6 | Centerline recession, arc-jet condition 1, model AA-43-209-N | Arc-jet test of a PICA model; centerline recession measured by the authors | condition number 1exposure time 55 sthermocouple option Aheat flux not read: Table 2 is not legible in the extracted text | A second model under the same condition, AA-43-210-N, recessed 2.27 mm. |
| 7 | Centerline recession, arc-jet condition 2b, model AT-007 | Arc-jet test of a PICA model; centerline recession measured by the authors | condition number 2bexposure time 400 sthermocouple option noneheat flux not read: Table 2 is not legible in the extracted text | — |
| 8 | Maximum surface temperature, arc-jet condition 1, model AA-43-209-N | Arc-jet test of a PICA model; maximum surface temperature measured by the authors | condition number 1exposure time 55 sheat flux not read: Table 2 is not legible in the extracted text | A second model under the same condition, AA-43-210-N, reached 2041 K. |
| 9 | Maximum surface temperature, arc-jet condition 2b, model AT-007 | Arc-jet test of a PICA model; maximum surface temperature measured by the authors | condition number 2bexposure time 400 sheat flux not read: Table 2 is not legible in the extracted text | — |
| 10 | Average density, Lyocell-based PICA (PICA-D) | Average value in the Mechanical Property Comparison table of the NASA Ames slides; the slides do not print a test method for density | precursor Lyocell carbon fibre (PICA-D), average of the samples shown | Printed as 0.28 with unit g/cc. |
| 11 | Approximate density, PICA (background section of the slides) | Approximate value given in the background section of the slides | precursor heritage rayon-based PICA, as described in the background sectionbasis approximate | Printed as "~ 0.27g/cm3"; the tilde means approximately and is kept from the slide. |
| 12 | Thermal conductivity at 100°F, Lyocell-based PICA (PICA-D), average | Average shown in the Thermal Property Comparison table of the NASA Ames slides; the slides do not print the test method | temperature 100°Fprecursor Lyocell carbon fibre (PICA-D), average | — |
| 13 | Thermal conductivity at 350°F, Lyocell-based PICA (PICA-D), average | Average shown in the Thermal Property Comparison table of the NASA Ames slides; the slides do not print the test method | temperature 350°Fprecursor Lyocell carbon fibre (PICA-D), average | — |
| 14 | Thermal conductivity at 100°F, heritage rayon-based PICA, range | Range shown in the Thermal Property Comparison table of the NASA Ames slides | temperature 100°Fprecursor heritage rayon-based PICA | Printed as 1.0 – 1.5 for rayon PICA at 100°F. |
| 15 | In-plane failure stress, Lyocell-based PICA (PICA-D), average | Average failure stress in the Mechanical Property Comparison table of the NASA Ames slides; the slides do not name the test standard | orientation in-plane (IP)precursor Lyocell carbon fibre (PICA-D), average | The same table prints 160 - 255 for rayon PICA IP properties. |
| 16 | Through-thickness failure stress, Lyocell-based PICA (PICA-D), average | Average failure stress in the Mechanical Property Comparison table of the NASA Ames slides; the slides do not name the test standard | orientation through-thickness (TTT)precursor Lyocell carbon fibre (PICA-D), average | The same table prints 43 to 54 for rayon PICA TTT properties. |
| 17 | Average centerline recession, Lyocell-derived PICA, arc-jet at 1550W/cm2 and 1.3 atm | Average centerline recession of arc-jet runs, as tabulated on the NASA Ames slides; the exposure time is not printed on the slide | heat flux 1550W/cm2pressure 1.3 atmatmosphere air (runs in air, 2017)precursor Lyocell (PICA-D) | Rayon-derived PICA at the same condition is a separate row. |
| 18 | Average centerline recession, rayon-derived PICA, arc-jet at 1550W/cm2 and 1.3 atm | Average centerline recession of arc-jet runs, as tabulated on the NASA Ames slides; the exposure time is not printed on the slide | heat flux 1550W/cm2pressure 1.3 atmatmosphere air (runs in air, 2017)precursor heritage rayon | Lyocell-derived PICA at the same condition is a separate row. |
Corrosion and compatibility
What happens when it meets other materials and environments.
| Environment | Concern | What happens |
|---|---|---|
| Arc-jet aerothermal heating, the test conditions in Milos and Chen (2009) | moderate | In two arc-jet conditions, centerline recession was 2.33 mm at 55 s and 24.72 mm at 400 s.1 |
| Heating of the phenolic resin to about 1250 K under argon (pyrolysis) | low | About 0.63 of the phenolic resin mass remains as char after pyrolysis (printed value, unit not stated).2 |
| # | Environment | Details | Test conditions |
|---|---|---|---|
| 1 | Arc-jet aerothermal heating, the test conditions in Milos and Chen (2009) | Recession is the depth of surface material removed. The two rows come from different test conditions, and the heat flux for each condition is not legible in the extracted text, so the two rows are not a rate for PICA. The maximum surface temperature was 2033 K at 55 s and 2196 K at 400 s. | test arc-jet tests of PICA modelsheat flux not read for each conditiondata Table 4 of the paper |
| 2 | Heating of the phenolic resin to about 1250 K under argon (pyrolysis) | The 1998 report uses this char yield for the phenolic resin in PICA. It gives 0.60 for the silicone resin in SIRCA, the silicone-impregnated ceramic ablator the report also tests. | atmosphere argon gas flowtemperature about 1250 K in a tube furnacematerial phenolic resin in PICA |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
No safety data sheet or PubChem GHS entry for PICA itself was read, so this group has no verdict.
- Gap
- The supplier safety data sheet and the PubChem record for PICA were not read in this run. The phenolic resin in PICA is a different product.
If the heat shield ablates
Ablation is the design mechanism: the surface material is removed in a controlled way. The sources give these values from arc-jet tests, not from flight.
- Recession at 55 s
- In arc-jet test condition 1 of Milos and Chen (2009), a model recessed 2.33 mm in 55 s, with a maximum surface temperature of 2033 K. A second model under the same condition recessed 2.27 mm.
- Recession at 400 s
- In arc-jet test condition 2b, a model recessed 24.72 mm in 400 s, with a maximum surface temperature of 2196 K. The heat flux for each condition is not legible in the extracted text.
Handling and storage
Only test-model preparation is documented in the sources read.
- Test models
- In the arc-jet models, the exposed surface was machined, and the unexposed PICA surfaces were sealed or bonded to adjacent parts (Milos and Chen 2009).
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Surface recession beyond the design depthmoderate severity | Arc-jet exposure of 400 s in test condition 2b (Milos and Chen 2009, Table 4)Centerline recession of 24.72 mm and a maximum surface temperature of 2196 K in that test. |
Supply and geography
How common the raw materials are and where they come from.
Rayon-based carbon precursor for the FiberForm preform
- Recycling
- Not found in any source we hold.
- Substitutes
- Lyocell-based PICA (PICA-D) is in development as a domestic replacement for rayon (Gasch et al. 2019).
Rayon and Lyocell carbon-fibre precursors for PICA
- Recycling
- Not found in any source we hold.
- Substitutes
- Lyocell-based PICA (PICA-D) is the domestic replacement for rayon, with Lenzing as the precursor supplier (Ellerby et al. 2019).
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: pica
spore_version: 0.2
family: carbon-phenolic
name: Phenolic Impregnated Carbon Ablator
abbreviation: PICA
role: Ablative heat shield for atmospheric entry (carbon-fibre preform infused with phenolic resin)
category: thermal-protection
type: ablators
summary: |
PICA (Phenolic Impregnated Carbon Ablator) is a low-density heat shield made from a rigid carbon-fibre preform, called FiberForm, infused with phenolic resin. The 1998 NASA annual report gives a nominal density of 224 to 248 kg/m^3 for PICA, depending on phenolic loading. PICA was the forebody heat shield of the Stardust sample-return capsule, launched in February 1999, and was used in a tiled layout on Mars Science Laboratory.
best_for: Entry heat shields that need a light carbon-phenolic ablator with flight heritage (Stardust; Mars Science Laboratory in tiled form)
weakest_at: 'Supply: the rayon precursor has been replaced at least twice in the past 25 years (Gasch et al.), and the sources read here give no hazard, ageing or humidity data'
identity:
formula: Carbon-fibre substrate (FiberForm) impregnated with phenolic resin (Durite SC-1008); a composite, not a single compound
source: selvaduray1998
where: Materials section (PICA uses FiberForm and the phenolic resin Durite SC-1008)
tags:
environments:
- re-entry
stresses:
- extreme-heat
applications:
- heat-shields
properties:
- benchmark: density
label: Density range, PICA after phenolic impregnation
value: 224
value_high: 248
bound: range
unit: kg/m^3
scope: material
conditions:
phenolic_loading: depends on the level of phenolic loading
form: nominal range for the impregnated preform
method: Nominal range stated in the 1998 NASA annual report
status: ground
note: Printed as 224 to 248 kg/m^3 (14 to 15.5 lb/ft^3).
source: selvaduray1998
where: Materials section, paragraph on the nominal density of PICA
- benchmark: density
label: Density range, FiberForm substrate before impregnation
value: 144
value_high: 176
bound: range
unit: kg/m^3
scope: material
conditions:
form: FiberForm carbon-fibre substrate, not impregnated
basis: nominal range
method: Nominal range stated in the 1998 NASA annual report
status: ground
note: Printed as 144 to 176 kg/m^3 (9.0 to 11 lb/ft^3).
source: selvaduray1998
where: Materials section, first density sentence
- benchmark: specific_heat
label: Specific heat, virgin PICA
value: 1200
unit: J/kg-K
scope: material
conditions:
temperature: not printed on the page
standard_conditions_flag: TRUE (TPSX column)
method: Value listed in the TPSX database; its source column says unknown
status: ground
note: Printed as 1.20e+03 J/kg-K.
source: tpsx-pica
where: Properties at Standard Conditions table, Specific Heat row
- benchmark: emissivity
label: Emissivity, virgin PICA
value: 0.8
unit: '-'
scope: material
conditions:
temperature: not printed on the page
standard_conditions_flag: assumed/assumed (TPSX column)
method: Value listed in the TPSX database; its source column says measured
status: ground
source: tpsx-pica
where: Properties at Standard Conditions table, Emissivity row
- benchmark: char_yield
label: Char yield of the phenolic resin in PICA
value: 0.63
unit: '-'
scope: material
conditions:
atmosphere: argon gas flow
temperature: about 1250 K, in a tube furnace
material: phenolic resin in PICA
method: Specimens cycled to about 1250 K under argon; the report defines char yield as the mass remaining after pyrolysis
status: ground
note: The report defines char yield as a percentage of mass remaining, but prints 0.63 with no unit. The report does not say whether that is a fraction or a percent.
source: selvaduray1998
where: Charring paragraph, char yield V of the phenolic resin in PICA
- benchmark: centerline_recession
label: Centerline recession, arc-jet condition 1, model AA-43-209-N
value: 2.33
unit: mm
scope: material
conditions:
condition_number: '1'
exposure_time: 55 s
thermocouple_option: A
heat_flux: 'not read: Table 2 is not legible in the extracted text'
method: Arc-jet test of a PICA model; centerline recession measured by the authors
status: ground
note: A second model under the same condition, AA-43-210-N, recessed 2.27 mm.
source: milos2009
where: Table 4, condition 1, model AA-43-209-N
- benchmark: centerline_recession
label: Centerline recession, arc-jet condition 2b, model AT-007
value: 24.72
unit: mm
scope: material
conditions:
condition_number: 2b
exposure_time: 400 s
thermocouple_option: none
heat_flux: 'not read: Table 2 is not legible in the extracted text'
method: Arc-jet test of a PICA model; centerline recession measured by the authors
status: ground
source: milos2009
where: Table 4, condition 2b, model AT-007
- benchmark: max_surface_temperature
label: Maximum surface temperature, arc-jet condition 1, model AA-43-209-N
value: 2033
unit: K
scope: material
conditions:
condition_number: '1'
exposure_time: 55 s
heat_flux: 'not read: Table 2 is not legible in the extracted text'
method: Arc-jet test of a PICA model; maximum surface temperature measured by the authors
status: ground
note: A second model under the same condition, AA-43-210-N, reached 2041 K.
source: milos2009
where: Table 4, condition 1, model AA-43-209-N
- benchmark: max_surface_temperature
label: Maximum surface temperature, arc-jet condition 2b, model AT-007
value: 2196
unit: K
scope: material
conditions:
condition_number: 2b
exposure_time: 400 s
heat_flux: 'not read: Table 2 is not legible in the extracted text'
method: Arc-jet test of a PICA model; maximum surface temperature measured by the authors
status: ground
source: milos2009
where: Table 4, condition 2b, model AT-007
- benchmark: density
label: Average density, Lyocell-based PICA (PICA-D)
value: 0.28
unit: g/cc
scope: material
conditions:
precursor: Lyocell carbon fibre (PICA-D), average of the samples shown
method: Average value in the Mechanical Property Comparison table of the NASA Ames slides; the slides do not print a test method for density
status: ground
note: Printed as 0.28 with unit g/cc.
source: stackpoole2018
where: Mechanical Property Comparison table, Density column, Average Lyocell PICA row
- benchmark: density
label: Approximate density, PICA (background section of the slides)
value: 0.27
unit: g/cc
scope: material
conditions:
precursor: heritage rayon-based PICA, as described in the background section
basis: approximate
method: Approximate value given in the background section of the slides
status: ground
note: Printed as "~ 0.27g/cm3"; the tilde means approximately and is kept from the slide.
source: stackpoole2018
where: Background section, first bullet
- benchmark: thermal_conductivity
label: Thermal conductivity at 100°F, Lyocell-based PICA (PICA-D), average
value: 0.94
unit: BTU-in/hr-ft2-oF
scope: material
conditions:
temperature: 100°F
precursor: Lyocell carbon fibre (PICA-D), average
method: Average shown in the Thermal Property Comparison table of the NASA Ames slides; the slides do not print the test method
status: ground
source: stackpoole2018
where: Thermal Property Comparison table, Average Lyocell PICA row, 100°F column
- benchmark: thermal_conductivity
label: Thermal conductivity at 350°F, Lyocell-based PICA (PICA-D), average
value: 1.32
unit: BTU-in/hr-ft2-oF
scope: material
conditions:
temperature: 350°F
precursor: Lyocell carbon fibre (PICA-D), average
method: Average shown in the Thermal Property Comparison table of the NASA Ames slides; the slides do not print the test method
status: ground
source: stackpoole2018
where: Thermal Property Comparison table, Average Lyocell PICA row, 350°F column
- benchmark: thermal_conductivity
label: Thermal conductivity at 100°F, heritage rayon-based PICA, range
value: 1
value_high: 1.5
bound: range
unit: BTU-in/hr-ft2-oF
scope: material
conditions:
temperature: 100°F
precursor: heritage rayon-based PICA
method: Range shown in the Thermal Property Comparison table of the NASA Ames slides
status: ground
note: Printed as 1.0 – 1.5 for rayon PICA at 100°F.
source: stackpoole2018
where: Thermal Property Comparison table, Rayon PICA row, 100°F column
- benchmark: ultimate_tensile_strength
label: In-plane failure stress, Lyocell-based PICA (PICA-D), average
value: 246
unit: psi
scope: material
conditions:
orientation: in-plane (IP)
precursor: Lyocell carbon fibre (PICA-D), average
method: Average failure stress in the Mechanical Property Comparison table of the NASA Ames slides; the slides do not name the test standard
status: ground
note: The same table prints 160 - 255 for rayon PICA IP properties.
source: stackpoole2018
where: Mechanical Property Comparison table, Average failure stress column, IP properties row
- benchmark: ultimate_tensile_strength
label: Through-thickness failure stress, Lyocell-based PICA (PICA-D), average
value: 44
unit: psi
scope: material
conditions:
orientation: through-thickness (TTT)
precursor: Lyocell carbon fibre (PICA-D), average
method: Average failure stress in the Mechanical Property Comparison table of the NASA Ames slides; the slides do not name the test standard
status: ground
note: The same table prints 43 to 54 for rayon PICA TTT properties.
source: stackpoole2018
where: Mechanical Property Comparison table, Average failure stress column, TTT properties row
- benchmark: centerline_recession
label: Average centerline recession, Lyocell-derived PICA, arc-jet at 1550W/cm2 and 1.3 atm
value: 4
unit: mm
scope: material
conditions:
heat_flux: 1550W/cm2
pressure: 1.3 atm
atmosphere: air (runs in air, 2017)
precursor: Lyocell (PICA-D)
method: Average centerline recession of arc-jet runs, as tabulated on the NASA Ames slides; the exposure time is not printed on the slide
status: ground
note: Rayon-derived PICA at the same condition is a separate row.
source: ellerby2019
where: PICA-D Arc Jet Testing, Recession Comparison table, Lyocell PICA row, first column
- benchmark: centerline_recession
label: Average centerline recession, rayon-derived PICA, arc-jet at 1550W/cm2 and 1.3 atm
value: 4.2
unit: mm
scope: material
conditions:
heat_flux: 1550W/cm2
pressure: 1.3 atm
atmosphere: air (runs in air, 2017)
precursor: heritage rayon
method: Average centerline recession of arc-jet runs, as tabulated on the NASA Ames slides; the exposure time is not printed on the slide
status: ground
note: Lyocell-derived PICA at the same condition is a separate row.
source: ellerby2019
where: PICA-D Arc Jet Testing, Recession Comparison table, Rayon PICA row, first column
corrosion:
- environment: Arc-jet aerothermal heating, the test conditions in Milos and Chen (2009)
headline: In two arc-jet conditions, centerline recession was 2.33 mm at 55 s and 24.72 mm at 400 s.
effect: Recession is the depth of surface material removed. The two rows come from different test conditions, and the heat flux for each condition is not legible in the extracted text, so the two rows are not a rate for PICA. The maximum surface temperature was 2033 K at 55 s and 2196 K at 400 s.
rating: moderate
conditions:
test: arc-jet tests of PICA models
heat_flux: not read for each condition
data: Table 4 of the paper
source: milos2009
where: Table 4 (test conditions, centerline recession and maximum temperature)
- environment: Heating of the phenolic resin to about 1250 K under argon (pyrolysis)
headline: About 0.63 of the phenolic resin mass remains as char after pyrolysis (printed value, unit not stated).
effect: The 1998 report uses this char yield for the phenolic resin in PICA. It gives 0.60 for the silicone resin in SIRCA, the silicone-impregnated ceramic ablator the report also tests.
rating: low
conditions:
atmosphere: argon gas flow
temperature: about 1250 K in a tube furnace
material: phenolic resin in PICA
source: selvaduray1998
where: Charring paragraph, char yield V
risks:
hazards:
- text: Phenol, the monomer used to make phenolic resins, is classed in PubChem's aggregated GHS record (ECHA C&L notifications) as toxic if swallowed (H301), toxic in contact with skin (H311), causing severe skin burns and eye damage (H314), toxic if inhaled (H331), suspected of causing genetic defects (H341), and causing damage to organs through prolonged or repeated exposure (H373). Serious eye damage (H318) and toxicity to aquatic life (H411) appear in some notifications. This is a different substance from the phenolic resin in PICA (Durite SC-1008, per Selvaduray and Cox 1998). No safety data sheet for PICA or for that resin was read in this run, so this entry describes phenol only.
ghs:
- H301
- H311
- H314
- H318
- H331
- H341
- H373
- H411
source: pubchem-phenol
where: GHS Classification section, aggregated ECHA C&L data (CID 996)
failure_risks:
- mode: Surface recession beyond the design depth
trigger: Arc-jet exposure of 400 s in test condition 2b (Milos and Chen 2009, Table 4)
consequence: Centerline recession of 24.72 mm and a maximum surface temperature of 2196 K in that test.
severity: moderate
source: milos2009
where: Table 4, condition 2b
side_effects: []
handling: []
mitigations: []
uses:
- application: heat-shields
device: Stardust sample-return capsule forebody heat shield
example: PICA was selected as the forebody heat shield for the Stardust Discovery Class Mission, which launched in February 1999 and was to re-enter at 16 Km/sec.
source: tpsx-pica
where: Description (summary) on the TPSX Material page
- application: heat-shields
device: OSIRIS-REx sample-return capsule heat shield
example: Gasch et al. (2019) report that OSIRIS-REx uses a single-piece PICA heat shield very similar to the Stardust design.
source: gasch2019
where: Introduction
- application: heat-shields
device: Mars Science Laboratory and Mars 2020 entry heat shields (tiled)
example: PICA was used as the Mars Science Laboratory heat shield in a tiled configuration, and the Mars 2020 heat shield design follows that layout with PICA in a tiled arrangement.
source: gasch2019
where: Introduction
- application: heat-shields
device: Orion Crew Module heat shield (candidate)
example: Milos and Chen (2009) describe PICA as a candidate heat shield material for the Orion Crew Module, and the Orion program tested newly manufactured PICA.
source: milos2009
where: Abstract and Section II (Material Properties)
supply:
- subject: Rayon-based carbon precursor for the FiberForm preform
producers: []
note: Fiber Materials Inc. (Biddeford, Maine) makes FiberForm and PICA. No production share by country was found in the sources read.
critical_lists: []
recycling: Not found in any source we hold.
substitutes:
- Lyocell-based PICA (PICA-D) is in development as a domestic replacement for rayon (Gasch et al. 2019).
source: gasch2019
where: Introduction, paragraphs on the supply chain issues and the PICA-D development plan. The rayon supply has been replaced at least twice in the past 25 years.
- subject: Rayon and Lyocell carbon-fibre precursors for PICA
producers: []
note: Lenzing makes the Lyocell precursor at sister plants in the US, Austria and UK, which the slides call multiple supply routes. Heritage rayon came from Liberty (US, production ceased in the 1990s) and from Sniace (an international source, production ceased in about 2017). Mars 2020 uses the last of the heritage Sniace rayon-based PICA.
critical_lists: []
recycling: Not found in any source we hold.
substitutes:
- Lyocell-based PICA (PICA-D) is the domestic replacement for rayon, with Lenzing as the precursor supplier (Ellerby et al. 2019).
source: ellerby2019
where: Challenges with PICA Sustainability table (slide 4) and the Lyocell supply slide
media: []
documents:
- title: 'NASA Ames Thermal Protection Materials Database (TPSX): PICA [virgin], Material id 43'
type: database
url: https://tpsx.arc.nasa.gov/Material?id=43
year: 2006
- title: Ablation and Thermal Response Property Model Validation for Phenolic Impregnated Carbon Ablator (AIAA-2009-0262)
type: paper
url: https://ntrs.nasa.gov/api/citations/20110012891/downloads/20110012891.pdf
year: 2009
- title: Development of Domestic Lyocell Based Phenolic Impregnated Carbon Ablator (PICA-D) for Future NASA Missions
type: report
url: https://ntrs.nasa.gov/api/citations/20190031963/downloads/20190031963.pdf
year: 2019
- title: Thermal Protection Materials Development, 1997-1998 Annual Report (NASA/CR 208331)
type: report
url: https://ntrs.nasa.gov/api/citations/19980235586/downloads/19980235586.pdf
year: 1998
- title: Sustaining PICA TPS for Future NASA Robotic Science Missions (slides)
type: report
url: https://ntrs.nasa.gov/api/citations/20180006865/downloads/20180006865.pdf
year: 2018
- title: Sustaining Phenolic Impregnated Carbon Ablator (PICA) for Future NASA Missions Including Discovery and New Frontiers (IPPW 2019 slides)
type: report
url: https://ntrs.nasa.gov/api/citations/20190028929/downloads/20190028929.pdf
year: 2019
- title: PubChem compound summary, phenol (CID 996), GHS Classification
type: database
url: https://pubchem.ncbi.nlm.nih.gov/compound/996
gaps:
- No flight-measured recession, surface temperature or in-flight data for PICA was found in the sources read; all recession and temperature values are arc-jet ground tests.
- The heat flux for each Milos and Chen (2009) Table 4 condition is not legible in the extracted text (Table 2 is garbled), so the recession rows give no heat flux.
- The Gasch et al. (2019) PICA-D tension, compression, shear, CTE and conductivity results are in figures only; no numbers were read from text, so none are listed.
- Virgin PICA gas permeability values in the 1998 report are garbled by OCR in the extracted text, so none are listed.
- No safety data sheet or PubChem GHS record for PICA itself was read in this run. The only hazard entry is for phenol, the monomer of phenolic resins, from PubChem; it is not the Durite SC-1008 resin used in PICA, and no SDS for that resin was read.
- The Ellerby et al. (2019) recession rows are arc-jet runs in air; the slide does not print the exposure time, so they are not a recession rate.
- No handling, storage or workplace guidance for PICA was read in this run.
- No humidity, UV, heat-ageing or radiation data for PICA was found in the sources read.
- No production share by country and no critical-mineral list status was found for the rayon precursor or FiberForm; the supply entry gives producers only by name.
- No licensed image was fetched, so the media list is empty.
- Eight sources are now read. The Stackpoole 2008 Stardust post-flight paper and the Tran 1994 and 1996 PICA papers were cited by the sources but not opened.
- The TPSX reference page (Reference id 74) returned HTTP 404, and a Wikipedia article for PICA does not exist, so neither was used.
- The NASA Stardust mission page does not mention PICA, and no value in this profile is taken from it. The NASA MSL page does not mention the heat shield.
- Orion candidate status comes from a 2009 paper; no current status was found.
- 'TPSX values read in this run but removed from properties: the value check cannot match the exponent notation the page prints, so they are kept here as printed. Density 2.36e+02 kg/m^3 (uncertainty 12.0, no unit printed); thermal conductivity 3.05e-01 W/m-K (labelled isotropic, temperature not printed; Milos and Chen 2009 call PICA strongly orthotropic); effective heat of ablation 1.15e+08 J/kg (uncertainty 5.77e+06, no unit printed; description ties it to heat fluxes of 300 to 1500 W/sqcm); pyrolysis gas enthalpy -9.02e+06 J/kg; tensile strength 1.34e+06 Pa in-plane and 2.41e+05 Pa through-thickness; tensile modulus 1.10e+08 Pa in-plane and 2.36e+07 Pa through-thickness; tensile strain to failure 1.20e-03 m/m in-plane and 8.50e-03 m/m through-thickness; volume fraction of resin 6.46e-02.'
- 'Property names not in spores/property-canon.yaml and used here: emissivity, char_yield, centerline_recession and max_surface_temperature.'
- The TPSX page prints no temperature for its specific heat and emissivity values.
license: CC-BY-4.0
updated: '2026-11-01'
review:
status: draft
method: assistant
checked_values: 18
unreachable: 1
caveats: 2
note: Read by an AI assistant on 2026-11-01 from the TPSX page (raw HTML checked against the WebFetch summary) and three NASA PDFs (text-extracted with pdftotext). The value check could not match 11 TPSX values printed in exponent notation, so they are listed in gaps rather than in properties. One TPSX reference page returned 404 and was not used.
story:
recipe:
line: 'PICA is a composite of two parts: a rigid, low-density carbon-fibre preform (FiberForm) and a phenolic resin that fills the open space in the preform. The carbon fibres are made from rayon by a high-temperature conversion, and the preform is infused with phenolic resin and then cured (Gasch et al. 2019; Selvaduray and Cox 1998).'
parts:
- name: Carbon-fibre preform (FiberForm)
symbol: '-'
share: The rest of the volume after the phenolic resin share (TPSX)
role: A rigid, porous carbon substrate made from chopped rayon-derived carbon fibres. It sets the low density and the open pore structure.
- name: Phenolic resin (Durite SC-1008)
symbol: '-'
share: Volume share of phenolic resin (TPSX)
role: Fills the void space between filaments. On heating it decomposes, and the char it leaves behind is what protects the surface.
risk_groups:
- title: For people
level: 0
verdict: Not assessed in this run
lead: No safety data sheet or PubChem GHS entry for PICA itself was read, so this group has no verdict.
points:
- label: Gap
line: The supplier safety data sheet and the PubChem record for PICA were not read in this run. The phenolic resin in PICA is a different product.
- title: If the heat shield ablates
lead: 'Ablation is the design mechanism: the surface material is removed in a controlled way. The sources give these values from arc-jet tests, not from flight.'
points:
- label: Recession at 55 s
line: In arc-jet test condition 1 of Milos and Chen (2009), a model recessed 2.33 mm in 55 s, with a maximum surface temperature of 2033 K. A second model under the same condition recessed 2.27 mm.
- label: Recession at 400 s
line: In arc-jet test condition 2b, a model recessed 24.72 mm in 400 s, with a maximum surface temperature of 2196 K. The heat flux for each condition is not legible in the extracted text.
- title: Handling and storage
lead: Only test-model preparation is documented in the sources read.
points:
- label: Test models
line: In the arc-jet models, the exposed surface was machined, and the unexposed PICA surfaces were sealed or bonded to adjacent parts (Milos and Chen 2009).
why: Phenolic Impregnated Carbon Ablator (PICA) is a low-density ablative heat shield developed at NASA Ames Research Center. The sources call it the lowest-density carbon-phenolic ablator with flight heritage (Gasch et al. 2019). It is made by infusing a rigid carbon-fibre preform with phenolic resin. Its density and ablation values come from NASA's TPSX database and from NASA papers, and this profile uses only the numbers printed in those sources.
uses:
- where: Stardust (launched 1999)
line: PICA was the forebody heat shield of Stardust, the first sample-return mission from outside the Earth-Moon system. The TPSX database says Stardust was to re-enter at 16 Km/sec, and Gasch et al. describe the heat shield as a single cast piece.
- where: OSIRIS-REx
line: Gasch et al. report that OSIRIS-REx uses a single-piece PICA heat shield very similar to the Stardust design.
- where: Mars Science Laboratory and Mars 2020 (tiled)
line: PICA was used on Mars Science Laboratory in a tiled layout, and the Mars 2020 heat shield follows that layout (Gasch et al. 2019).
- where: Orion Crew Module (candidate)
line: Milos and Chen (2009) call PICA a candidate heat shield material for the Orion Crew Module. The program tested newly manufactured PICA.
can_do:
- label: Density
benchmark: density
line: The 1998 NASA annual report gives a nominal density of 224 to 248 kg/m^3 for PICA, depending on the phenolic loading. The FiberForm substrate before impregnation is 144 to 176 kg/m^3 in the same report.
- label: Emissivity
benchmark: emissivity
value: '0.8'
line: TPSX lists an emissivity of 0.8 for virgin PICA. Its source column says measured, and the page gives no temperature for it.
- label: Specific heat
benchmark: specific_heat
value: 1200 J/kg-K
line: TPSX lists a specific heat of 1200 J/kg-K for virgin PICA. The page gives no temperature, and its source column says unknown.
- label: Char
benchmark: char_yield
line: The phenolic resin in PICA leaves about 0.63 of its mass as char after pyrolysis at about 1250 K under argon (Selvaduray and Cox 1998). The report does not say whether 0.63 is a fraction or a percent.
compare: No other thermal-protection profile was read in this run, so this paragraph gives no side-by-side number. Within the sources read, PICA is described as the lowest-density carbon-phenolic ablator with flight heritage (Gasch et al. 2019). Its nominal density is 224 to 248 kg/m^3 and its arc-jet recession grows strongly with exposure time (2.33 mm at 55 s, 24.72 mm at 400 s, in different conditions). For a like-for-like table, read the other ablator profiles with the same method.
compare_rows:
- label: Density, nominal PICA
benchmark: density
- label: Specific heat, virgin PICA
benchmark: specific_heat
- label: Char yield of phenolic resin
benchmark: char_yield
handling:
- 'Handle as a composite. The sources document only the test-model preparation: the exposed face was machined, and other faces were sealed or bonded.'
- No storage or workplace handling guidance for PICA was read in this run.
- Plan for the precursor supply. The rayon source has been replaced at least twice in the past 25 years (Gasch et al. 2019).
good_for:
- 'Entry heat shields that need a light carbon-phenolic ablator with flight heritage: Stardust, and Mars Science Laboratory in tiled form.'
- 'Designs that need a NASA property set: TPSX gives density, specific heat, emissivity and effective heat of ablation for virgin PICA.'
watch_out:
- 'Density depends on phenolic loading: 224 to 248 kg/m^3 nominal in the 1998 report.'
- TPSX labels the conductivity isotropic, but Milos and Chen (2009) describe it as strongly orthotropic.
- 'Recession is large at long exposures: 24.72 mm after 400 s in one arc-jet condition.'
- The rayon precursor supply has changed at least twice in the past 25 years, and the Lyocell replacement (PICA-D) is still in development.
verdict: PICA is a flight-proven carbon-phenolic heat shield with NASA property values for virgin material. What the sources read here do not give is hazard data, ageing and humidity behaviour, in-flight measurements, or a settled precursor supply.
sources:
tpsx-pica:
title: 'NASA Ames Thermal Protection Materials Database (TPSX): PICA [virgin], Material id 43'
id: TPSX Material id 43; manufacturer Fiber Materials Inc.; point of contact F.S. Milos
url: https://tpsx.arc.nasa.gov/Material?id=43
year: 2006
kind: database
license: NASA public database (cited, not reproduced)
milos2009:
title: Ablation and Thermal Response Property Model Validation for Phenolic Impregnated Carbon Ablator
id: AIAA-2009-0262 (47th AIAA Aerospace Sciences Meeting); NTRS 20110012891; F.S. Milos and Y.-K. Chen, NASA Ames
url: https://ntrs.nasa.gov/api/citations/20110012891/downloads/20110012891.pdf
year: 2009
kind: paper
license: NASA NTRS public record (cited, not reproduced)
gasch2019:
title: Development of Domestic Lyocell Based Phenolic Impregnated Carbon Ablator (PICA-D) for Future NASA Missions
id: NTRS 20190031963; M. Gasch et al., NASA Ames and Fiber Materials Inc.
url: https://ntrs.nasa.gov/api/citations/20190031963/downloads/20190031963.pdf
year: 2019
kind: report
license: NASA NTRS public record (cited, not reproduced)
selvaduray1998:
title: Thermal Protection Materials Development, 1997-1998 Annual Report
id: NASA/CR 208331; NTRS 19980235586; G. Selvaduray and M. Cox, San Jose State University
url: https://ntrs.nasa.gov/api/citations/19980235586/downloads/19980235586.pdf
year: 1998
kind: report
license: NASA NTRS public record (cited, not reproduced)
nasa-stardust:
title: 'NASA Science: Stardust mission page'
id: science.nasa.gov/mission/stardust
url: https://science.nasa.gov/mission/stardust/
year: 2026
kind: web
license: NASA web page (cited, not reproduced)
stackpoole2018:
title: Sustaining PICA TPS for Future NASA Robotic Science Missions (slides)
id: NTRS 20180006865; M. Stackpoole, E. Venkatapathy and M. Gasch, NASA Ames; S. Violette, Fiber Materials Inc.
url: https://ntrs.nasa.gov/api/citations/20180006865/downloads/20180006865.pdf
year: 2018
kind: report
license: NASA NTRS public record (cited, not reproduced)
ellerby2019:
title: Sustaining Phenolic Impregnated Carbon Ablator (PICA) for Future NASA Missions Including Discovery and New Frontiers
id: NTRS 20190028929; International Planetary Probe Workshop, 2019; D. Ellerby et al., NASA Ames
url: https://ntrs.nasa.gov/api/citations/20190028929/downloads/20190028929.pdf
year: 2019
kind: report
license: NASA NTRS public record (cited, not reproduced)
pubchem-phenol:
title: PubChem compound summary, phenol (CID 996), GHS Classification
id: PubChem CID 996
url: https://pubchem.ncbi.nlm.nih.gov/compound/996
kind: database
license: PubChem public record (cited, not reproduced)
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 |
|---|---|---|---|---|
| NASA Ames Thermal Protection Materials Database (TPSX): PICA [virgin], Material id 43 | database | 2006 | 3 values | |
| Ablation and Thermal Response Property Model Validation for Phenolic Impregnated Carbon Ablator | paper | 2009 | 7 values | |
| Development of Domestic Lyocell Based Phenolic Impregnated Carbon Ablator (PICA-D) for Future NASA Missions | report | 2019 | 3 values | |
| Thermal Protection Materials Development, 1997-1998 Annual Report | report | 1998 | 5 values | |
| NASA Science: Stardust mission page | web | 2026 | 0 values | |
| Sustaining PICA TPS for Future NASA Robotic Science Missions (slides) | report | 2018 | 7 values | |
| Sustaining Phenolic Impregnated Carbon Ablator (PICA) for Future NASA Missions Including Discovery and New Frontiers | report | 2019 | 3 values | |
| PubChem compound summary, phenol (CID 996), GHS Classification | database | 1 value |
Updated