AbstractTo assess the resistance of polymer nanocomposites to the effects of atomic oxygen in low Earth orbits, we study the effect of oxygen plasma on the structural and optical properties of an epoxy resin with the addition of graphene and Taunit-M carbon nanotubes. Introducing carbon fillers to epoxy resin increases the weight loss and erosion depth when exposed to oxygen plasma. The weight erosion coefficient at an atomic-oxygen fluence of 30 × 1020 cm–2 is 0.82 × 10–23 g/at for pure epoxy resin and 0.86 × 10–23 and 1.06 × 10–23 g/at for samples with graphene and Taunit-M, respectively. In the case of the sample with the Taunit-M filler, a greater weight loss and erosion depth are observed as a result of irradiation in oxygen plasma in comparison with the sample with the graphene filler. The treatment of carbon nanocomposites in oxygen plasma significantly decreases the reflectance coefficients in the spectral range of 0.2–2.5 µm. The lowest diffuse (less than 1%) and specular (less than 0.02%) reflectance coefficients are registered for the irradiated polymer with Taunit-M.