Different materials were considered for high-frequency circuit applications
requiring exposure to low Earth orbit (LEO) space environment. The potenti
al candidates were TMM3 which is a ceramic thermoset polymer composite, and
RO4003 which is a glass reinforced hydrocarbon/ceramic laminate, both manu
factured by Rogers Corporation (USA). Various constituents of the space env
ironment can affect these materials' properties. Atomic oxygen is considere
d the most hazardous component since it may cause degradation of these mate
rials by etching and/or changing the chemical composition. The candidate ma
terials were tested by exposure to different equivalent atomic oxygen (ATOX
) fluences of up to 1.9 X 10(21) atoms cm(-2). The effects of the atomic ox
ygen exposures were studied by means of scanning electron microscopy (SEM),
energy dispersive x-ray spectroscopy (EDS), atomic force microscopy (AFM)
and mass loss measurements. Both materials were degraded under ATOX exposur
e, resulting in intensive mass loss as well as changes in surface morpholog
y and chemistry. In order to protect these materials in the LEO environment
several protective coatings were evaluated for TMM3. The protective coatin
gs tested were SiO2, CV1 144-0 (a clear silicone coating) and SG120FD (a wh
ite silicone paint). SG120FD was found to provide the best protection again
st ATOX irradiation attack, while CV 1144-0 provided a sufficient, though s
omewhat inferior protection.