An experimental study of low earth orbit atomic oxygen and ultraviolet radiation effects on a spacecraft material - polytetrafluoroethylene

Spacecraft traveling in low earth orbit (LEO) will react with environmental factors, such as atomic oxygen (AO), ultraviolet radiation (UV) and vacuum ultraviolet radiation (VUV), which may severely affect the lifetime of the spacecraft. Teflon, including PTFE (polytetrafluoroethylene) Teflon and FEP Teflon, is a commonly used spacecraft material. Existing studies showed that Teflon could be eroded by AO in LEO but with a lower erosion yield than most of other spacecraft materials. However, its erosion yield increases in long-term flight experiments, which might be caused by synergism of several environmental effects. In this work, experiments were conducted to investigate the erosion effects of atomic oxygen on PTFE Teflon in a ground-based simulation facility. The samples, before and after the experiments, were compared in appearance, mass, surface morphology, optical properties and surface composition. We also analysed the influence of temperature, ultraviolet radiation and vacuum ultraviolet radiation on the atomic oxygen effects. Four conclusions can be drawn: first, PTFE Teflon is eroded severely in the ground-based facility, where the erosion yield is higher than that in the flight experiments and identical to those from other ground-based facilities. Secondly, the erosion yield increases with the sample temperature. Thirdly, ultraviolet radiation has little effect on the mass loss and erosion yield of the Teflon sample in the AO experiment. Lastly, there may be some synergistic effects of atomic oxygen and vacuum ultraviolet radiation, which could be one of the main factors that cause the more severe erosion of Teflon.