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Japanese scientists have developed "wooden" microsatellites to reduce pollution in the sky, which are expected to be launched this summer on American rockets to test whether they can replace metal, and when wooden satellites enter the atmosphere, they will produce only biodegradable ashes.
Recent studies by the National Oceanic and Atmospheric Administration (NOAA) found that 10% of atmospheric aerosols in the stratosphere contain metal particles from spacecraft, including satellites. The long-term effects of these metal fragments are unknown, but scientists are concerned that it could damage the Earth's fragile ozone layer.
For example, satellites, probes and other space vehicles may produce many alumina particles in the process of passing through the atmosphere, affecting the earth's environment.
The intensity from minus 150 to 150 degrees Celsius (-238 to 302 degrees Fahrenheit) has not decreased much, and we confirmed this in our experiments," Murata said. "But a satellite orbiting the Earth has such a huge temperature difference in 90 minutes. We don't know to what extent satellites can withstand this intense, repetitive cycle of temperature differences, so this must be investigated.
For Murata, head of the Space Timber Project at Kyoto University, wood was the obvious choice for spatial structures.
Developed by Kyoto University in collaboration with Sumitomo Forestry, the satellite is reportedly made from magnolia wood and has been considered the most suitable material due to its durability and resistance to breakage after multiple tests, including on the International Space Station.
When you use wood on Earth, you have problems with burning, rotting and deforming, but in space, you don't have these problems: there is no oxygen in space, so it doesn't burn, and no living beings live in it, so they don't rot," he said.
For this satellite, Murata made three types of wood: the Elman birch (commonly found in East Asia), the Japanese cherry, and the magnolia (a tree species native to Japan). While cypress and cedar are the more common types of construction timber, the team "chose materials that could withstand as much detail work as possible" due to the satellite's small size, Murata said.
Ultimately, magnolia won because its cells are small and uniform in size, which makes the wood easier to work with and less likely to break or break.
Samples of magnolia wood were then sent to the International Space Station (ISS), where they underwent environmental exposure experiments for about a year before being brought back to Earth still intact. Professor Murata said this should be because there is no oxygen in space that can cause wood to burn, and there are no organisms that can cause wood to rot.
It is a renewable, environmentally friendly, humane material," Murata said. "I think wood can be used in space development, especially as an interior material and radiation shielding material for small satellites and manned spacecraft.