Abstract
Six different types of carbon and carbon-boron nitride composites were exposed to low Earth orbit (LEO) aboard Space Shuttle flight STS-46. The samples received a nominal atomic-oxygen fluence of 2.2 × 1020 atoms/cm2 in 42 h of exposure. Pyrolytic graphite and highly oriented pyrolytic graphite showed significant degradation, and the measured erosion yield was within a factor of 2 of published values. The erosion yield of pyrolytic boron nitride was found to be 2.6 × 10-26 cm3/atom in plasma asher exposure, over 42 times lower than that of pyrolytic graphite. This low erosion yield makes graphite-boron nitride mixtures quite resistant to LEO exposure. Evidence suggests that the graphitic component was preferentially etched, leaving the surface boron nitride rich. Atomic-oxygen resistance increases with boron nitride composition. Carbon-fiber-carbon composites eroded in LEO, and the carbon pitch binder was found to etch more easily than the graphite fibers, which have much higher atomic-oxygen resistance.
Original language | English (US) |
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Pages (from-to) | 1015-1017 |
Number of pages | 3 |
Journal | Journal of Spacecraft and Rockets |
Volume | 32 |
Issue number | 6 |
DOIs | |
State | Published - 1995 |
ASJC Scopus subject areas
- Aerospace Engineering
- Space and Planetary Science