Satellite technology: wooden boxes orbiting the earth

It’s the size of a coffee cup and looks like a small birdhouse, but looks are deceptive. This box made of light wood is scheduled to be sent into orbit in September this year – as a satellite. And there is no longer any doubt that this is a good idea, says Kenji Kariya: “We have been testing our wooden satellite in space for ten months starting in 2022. We were able to confirm that wood remains stable in space.«

Kenji Kariya works for Sumitomo Ringyou, a Japanese construction company that specializes in wood. Together with the University of Kyoto, the engineer, who has a doctorate, has been researching the possibility of using wood in space since 2020. Now he is excited: “We are currently preparing the final steps.” In space, the wooden satellite will first prove that it can stay there at all, and it will also be accessible to amateur radio operators. And then pave the way to a more sustainable future?

Not long ago, developing a satellite out of wood would have sounded like a dream. The devices on which humanity has depended for decades for television images, weather forecasts and all kinds of GPS signals have so far been made of plastic and metal. However, satellites also cause a lot of electronic waste. When they re-enter the atmosphere at the end of their useful life, they also produce harmful gases. The expectation is that this would not be the case with wood.

Idea of ​​an astronaut

“The idea of ​​building a satellite out of wood originally came from the Japanese astronaut Takao Doi, who now works at Kyoto University,” explains Kenji Kariya, whose employer has been cooperating with the university for two decades and has worked on various other wood-related topics has. »We therefore know that wood has a positive effect on people’s well-being. In addition, it is of course a sustainable material that grows again.«

The timber construction company was immediately enthusiastic about the idea of ​​working on a satellite. But what do mental well-being, satellites and wood have to do with each other? Possibly a lot. More and more work is being done around the world to ensure that space could become a space inhabitable by humans in the not too distant future. Much-discussed scenarios range from tourism to colonies of people living there. Sumitomo Ringyou therefore sees a future market in space.

»Wood has always been used as a building material for residential buildings in Japan. But for a long time it wasn’t intended for larger buildings,” says Rin Fukunaga, who is responsible for communications at the company. Reservations about wood also had to do with the high risk of earthquakes in Japan, which could often cause fires in combination with short circuits or stoves. »After the turn of the millennium, regulations and habits changed because we now understand wood better.«

We want to use that now. A research project in space is particularly suitable for testing the potential of wood. There is hardly any place where the conditions for materials from Earth are so unfavorable: temperatures vary greatly, there is practically no oxygen, but there is plenty of cosmic radiation. It was previously assumed that wood would suffer severe deformations and cracks in space.

The ten-month experiment that began in 2022 and tested magnolia wood on the International Space Station is now causing the research team to be optimistic. Kenji Kariya sums it up: »Wood actually contains around 15 percent water. But in space this is lost. And we were surprised that the wood suffered no damage at all afterward.” It is hardly a coincidence that wood and space are thought of together in Japan, of all places. Not only does the country have a long tradition of using wood as a building material.

The idea of ​​sustainability is also prominent in Japan’s space research. “The removal of scrap objects is a topic that is also high on the national agenda in Japan,” says Chiara Manfletti, professor of space propulsion and mobility at the Technical University of Munich. And space debris is a serious problem: “We already have some objects in space that can no longer be controlled. This can lead to collisions, which shatter parent objects.”

Incineration still needs to be researched

Wooden satellites can, in turn, help prevent new scrap from being created. Because at the end of their lifespan they would simply burn up when they re-entered the atmosphere. Chiara Manfletti warns that science is only just beginning: “We don’t yet fully know what the interactions are between the particles that then remain in the atmosphere. What is the difference between metal and wood burning up in the atmosphere? We do not know that.”

For the Japanese research team, the new satellite called LignoSat3 should still help make space technology more sustainable in the future. So far it only consists of around 20 percent wood. “We would have preferred to make everything out of wood, but so far we still need aluminum in some places,” says Kenji Kariya. »The computer in the case is also made of plastic. Maybe in 30 years there could be a satellite made almost entirely of wood.”

Another finding from the research project is that wood could also serve as a housing for electronics because it protects well from external influences. According to Kenji Kariya, it could also be used in the construction of supercomputers, data centers, semiconductors or smartphones. However, such activities are not currently planned in the construction company. Instead, people are interested in life in space. The next step will be to research the conditions under which trees could grow in space.