(6) 宇宙環境下における材料劣化現象

抄録

Space materials used in space degradate their physical/chemical propertuies by exposing to space environemnts. There exists many environmental factors in space, i.e., radiation, ultraviolet, atomic oxygen, thermal cycling, space debris, and contamination. Degradations were observed in STS or ISS components and, thus, a number of on-orbit exposure experiments have been conducted using ISS as an in-orbit platform such as MISSE and ExHAM. Many results have been observed by these exposure experiments. However, mechanistic aspect on erosion phenomena is difficult to study by in-orbit exposures. On the other hand, ground-based simulation techniques have also been developed for many years using electron and proton beams, UV source and laser detonation atomic oxygen beam source. They are used as pre-flight assessment of materials as well as mechanistic studies for interaction of materials and space environment. In-orbit and ground-based experiments have complementary nature, and both of them are important for improving the reliability of space system. In this commentary article, space environment in low Earth orbit and its effect on materials are described based on the observed phenomena. A brief description of ground-based simulation techniques are included as well.