Kyoto University and Sumitomo Forestry Co., Ltd. will start the "Space Exposure Experiment on Wood at the International Space Station (ISS)".This is the world's first wood exposure experiment in outer space. In September 2021, the wood of the test piece was handed over to the Japan Aerospace Exploration Agency (JAXA), and experiments will be conducted at the International Space Station for about half a year from December.
In April 2020, Kyoto University and Sumitomo Forestry signed a joint research agreement for "Basic Research on Tree Growth and Wood Utilization in Space" and started the "LignoStella Project". Development is underway with the aim of launching a wooden artificial satellite (LignoSat) in 4.Since electromagnetic waves and magnetic waves pass through wood, antennas and attitude control devices can be installed inside the satellite, and the structure can be simplified.After the operation is completed, it will be completely burned out when it enters the atmosphere, so no minute substances (alumina particles) will be generated, which will lead to the development of a cleaner and environmentally friendly artificial satellite.
In the experiment, several types of wood specimens will be exposed to outer space on the outboard exposure platform of the Japanese Experiment Module "Kibo" on the International Space Station.After about half a year, it will be collected and subjected to physical property tests on the ground, tissue structure observation with a microscope, and crystal structure analysis by X-rays.We will work to elucidate the existence, situation, and mechanism of wood deterioration in extreme environments such as outer space, and from the findings obtained here, we will examine predictions and countermeasures for wood deterioration in outer space.
When wood is exposed overboard in the orbit of the International Space Station, the surface disappears slightly due to the collision of atomic oxygen.Although no exposure experiments using wood have been conducted so far, similar studies and theoretical considerations suggest that the surface layer that disappears even after one year of exposure is at most less than 1 mm.In addition, considering examples such as gamma-ray irradiation experiments on wood, it is expected that it can be used as a structural material for artificial satellites without a sharp decrease in strength even when exposed to galactic cosmic rays and solar energy particles for one year. ..By elucidating the mechanism of wood deterioration, we will develop deterioration control technology in extreme environments and aim to apply it to the expansion of wood applications.
