The Japanese company Sumitomo Forestry is developing a timber spacecraft for researchers at Kyoto University. Only the approximate launch date of the device is known, 2023, but no more information has been released. The purpose of the project, the technical details, even the type of wood – all this is kept secret.
Nikkei Asia has suggested that this is just another study of the possibilities of wood. For example, in microgravity, this material should expand, but sudden temperature changes in space make this process unpredictable. The influence of solar radiation is also interesting, as well as how the wood processed in different ways will behave. Finally, in the end, the satellite should completely burn up in the atmosphere without the formation of dust and soot, unlike metal structures.
The use of wood for space purposes is extremely difficult due to the fact that in a vacuum moisture begins to appear on the surface and evaporate. This causes corrosion on the metal fasteners and compromises the integrity and tightness of the structure. On the other hand, on the Chinese satellites of the Fanhui Shi Weixing series in the 1970-2000s. white oak insulation was successfully used, which evenly burned out and protected the core of the apparatus upon return to Earth.
Americans were less fortunate in the 1960s. For the Ranger program, stages 3 through 5 were made of balsa spheres with a cavity inside, where seismometers and other sensors were placed. The cavity was filled with liquid, which, together with the wooden shell, was supposed to protect the equipment when it hit the lunar surface. Alas, Ranger 3 and Ranger 5 missed the Moon, and Ranger 4’s transmitters failed immediately after landing, so there is no practical information on the behavior of wooden spheres at NASA got.