Survivability of carbon nanotubes in space

Carbon nanotube (CNT) yarns were exposed to the space environment on the international space station (ISS) at low Earth orbit (LEO) of around 400 km altitude. Ground-based comparison tests, including irradiation of atomic oxygen (AO), electron beam (EB) and ultraviolet (UV) individually for different sets of samples, were performed. Significant deterioration of the outer surface and substantial reduction in tensile strength were found for AO irradiated CNT yarns among the ground-based comparison tests. Transmission electron microscopic observation revealed that crystal structure of CNT was physically damaged showing sharp graphene edges. As to the space exposure tests, quite similar damages and decrease in tensile strength were observed on the CNT yarns. We found that high kinetic energy impacts of the AO at LEO cause severe damages on carbon crystal materials.