Materials/Polymers/High-performance

Zylon

misse2-pbo-zylon

In short

On the International Space Station's forward-facing side, oxygen atoms ate away 115 µm of Zylon in 3.95 years, about 29 µm a year. A standard 25 µm film of it would last about 10 months there. It resists atomic oxygen 2.2 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.

BenchmarkResultCompared with reference
Atomic oxygen erosionHow fast low-orbit oxygen eats the surface. Lower is better. 1.36×10⁻²⁴ cm³/atomLow Earth orbit, 3.95 years in flight 0.45× Kapton HResists 2.2× better

Not measured yet (3): darkening under UV and particles (Δα); outgassing, total mass loss (TML); thermal cycling survival.

Applications

Where materials like Zylon are considered, the benchmarks that decide each use, and what the measured data says so far.

ApplicationDeciding benchmarksWhat the data says
External surfaces in low Earth orbit1 of 2 deciding benchmarks measured
  • Atomic oxygen erosion
  • Darkening under UV and particles (Δα)
Atomic oxygen resistance is good (0.45×). Still needed: darkening under UV and particles (Δα).

"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

WhereISS, MISSE 2, PEC 2 tray 1 (outside the Quest airlock)
When2001-08-16 to 2005-07-30 (3.95 years)
Atomic oxygen dose8.43×10²¹ atoms/cm²
Sunlight5,000–6,700 equivalent sun hours
TemperatureCycled between −30 °C and 40 °C
Also exposed toSolar UV and charged particle radiation, in vacuum

How it compares

Materials flown on the same tray, ranked from least to most eroded. Zylon is number 12 of 40.

RankMaterialCompared with Kapton HLost in 3.95 years
5 FEPFluorinated ethylene propylene 0.067× 17 µm
10 ABSAcrylonitrile butadiene styrene 0.36× 92 µm
11 KynarPolyvinylidene fluoride 0.43× 109 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
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 = 1.36×10⁻²⁴ cm³/atom × 8.43×10²¹ atoms/cm² = 0.0115 cm = 115 µm.
  • Compared with Kapton H = erosion yield ÷ 3.00×10⁻²⁴ (Kapton H's value on the same flight).
  • Film life = 25 µm ÷ 29 µm per year, for the same exposure.