Nomex
misse2-pppa-nomexIn short
On the International Space Station's forward-facing side, oxygen atoms ate away 119 µm of Nomex in 3.95 years, about 30 µm a year. A standard 25 µm film of it would last about 10 months there. It resists atomic oxygen 2.1 times better than Kapton H, the reference film.
Benchmarks
The benchmarks that matter for this material's applications, each compared with the reference engineers use.
| Benchmark | Result | Compared with reference |
|---|---|---|
| Atomic oxygen erosionHow fast low-orbit oxygen eats the surface. Lower is better. | 1.41×10⁻²⁴ cm³/atomLow Earth orbit, 3.95 years in flight | 0.47× Kapton HResists 2.1× better |
Not measured yet (6): darkening under UV and particles (Δα); flammability (crewed vehicles); toxic offgassing (crewed vehicles); outgassing, total mass loss (TML); thermal cycling survival; dust abrasion wear.
Applications
Where materials like Nomex are considered, the benchmarks that decide each use, and what the measured data says so far.
| Application | Deciding benchmarks | What the data says |
|---|---|---|
| External surfaces in low Earth orbit1 of 2 deciding benchmarks measured |
| Atomic oxygen resistance is good (0.47×). Still needed: darkening under UV and particles (Δα). |
| Crewed cabins, habitats and suits0 of 2 deciding benchmarks measured |
| None of the deciding benchmarks are measured yet. |
"What the data says" is Space Mushroom's reading of the measured values, not a flight qualification. Deciding benchmarks come from the Benchmark Framework.
What it went through
| Where | ISS, MISSE 2, PEC 2 tray 1 (outside the Quest airlock) |
|---|---|
| When | 2001-08-16 to 2005-07-30 (3.95 years) |
| Atomic oxygen dose | 8.43×10²¹ atoms/cm² |
| Sunlight | 5,000–6,700 equivalent sun hours |
| Temperature | Cycled between −30 °C and 40 °C |
| Also exposed to | Solar UV and charged particle radiation, in vacuum |
How it compares
Materials flown on the same tray, ranked from least to most eroded. Nomex is number 14 of 40.
| Rank | Material | Compared with Kapton H | Lost in 3.95 years |
|---|---|---|---|
| 5 | FEPFluorinated ethylene propylene | 0.067× | 17 µm |
| 12 | ZylonPoly(p-phenylene-2 6-benzobisoxazole) | 0.45× | 115 µm |
| 13 | PANPolyacrylonitrile | 0.47× | 119 µm |
| 14 | NomexPolyphenylene isophthalate | 0.47× | 119 µm |
| 15 | PUPolyurethane | 0.52× | 132 µm |
| 16 | HalarEthylene-chlorotrifluoroethylene | 0.60× | 151 µm |
| 25 | Kapton HPolyimide (PMDA) | 1.00× | 253 µm |
How the numbers are calculated
- Erosion yield is NASA's measurement: volume of material removed per oxygen atom.
- Thickness lost = erosion yield × oxygen dose = 1.41×10⁻²⁴ cm³/atom × 8.43×10²¹ atoms/cm² = 0.0119 cm = 119 µm.
- Compared with Kapton H = erosion yield ÷ 3.00×10⁻²⁴ (Kapton H's value on the same flight).
- Film life = 25 µm ÷ 30 µm per year, for the same exposure.
Full record
The complete spore, as stored. Free to reuse under CC-BY-4.0.
spore: passport
id: misse2-pppa-nomex
spore_version: 0.1
status: measured
org: nasa
dataset: misse2-peace
material:
name: "Polyphenylene isophthalate"
abbreviation: "PPPA (Nomex)"
family: Other polymer
category: polymers
type: aramids
tags:
environments: [low-earth-orbit]
stresses: [atomic-oxygen, uv, total-radiation-dose, thermal-cycling, vacuum-and-outgassing]
applications: []
exposures:
- environment: low Earth orbit
platform: ISS, MISSE 2, PEC 2 tray 1 (outside the Quest airlock)
start: 2001-08-16
end: 2005-07-30
duration_years: 3.95
atomic_oxygen_fluence: {value: 8.43e21, unit: atoms/cm2}
solar_exposure: {value: "5000-6700", unit: equivalent sun hours}
thermal_cycling: {min_c: -30, max_c: 40, note: nominal base-plate range}
results:
- property: atomic oxygen erosion yield
value: 1.41e-24
unit: cm3/atom
lower_bound: false
sources:
- title: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit
id: NASA/TM-2008-215490 (Banks, Backus and de Groh, December 2008)
url: https://ntrs.nasa.gov/citations/20090011780
where: Table I; exposure details in section 2.1
license: CC-BY-4.0
Sources
- Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit. NASA/TM-2008-215490 (Banks, Backus and de Groh, December 2008), Table I; exposure details in section 2.1.