Japanese scientists want to send a wooden satellite into space

CNN
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Aluminum rockets and steel skyscrapers; Sleek, high-speed shuttles and glass facades: this is how “the future” has been envisioned for decades.

But this is not what Koji Murata imagines. Murata, a researcher at Kyoto University in Japan, has been exploring how biological materials can be used in space.

Murata wondered if he “could build a wooden house on the Moon or Mars” and decided to test the theory – by creating Wooden satellite.

Recently Research from the National Oceanic and Atmospheric Administration NOAA found that 10% of aerosols in the stratosphere contain metal particles from spacecraft, including satellites. The long-term impact of these metal fragments is unknown, but scientists are concerned that they could damage the Earth’s fragile ozone layer.

Murata says wooden satellites would be better for the planet, while still providing the same functionality as their metal counterparts.

“At the end of their lives, the satellites reenter the atmosphere. The difference is that the wood in the LingoSat will burn and eventually turn into a gas, while the metals become fine particles instead,” says Murata.

It’s not just a pipe dream: Murata and his team have been working on the project for four years and sent wooden samples into space in 2021 to test the material’s resilience to space conditions.

Now, they are Working with the Japan Aerospace Agency (JAXA) and NASA to send the prototype of the satellite, called LingoSat, into orbit early next year.

Magnolia, cherry and birch

For Murata, who heads the space wood project at Kyoto University, wood is an obvious choice for space structures.

“When you use wood on Earth, you have problems with burning, rotting and warping, but in space, you don’t have these problems: there is no oxygen in space, so it doesn’t burn, and there are no organisms living in it, so it doesn’t rot,” he says.

Murata adds that the strength of wood relative to its weight is the same as that of aluminum, which also makes it a compelling choice for space construction, and the team’s tests conducted on the International Space Station found that wood has remarkable flexibility in outer space.

For the satellite, Murata tested three types of wood: Ermann birch, which is birch Commonly found in East Asia – Japanese cherry and Magnolia obovata – a species native to Japan. While cypress and cedar are the most common wood species in construction, the team “chose materials that can withstand the greatest possible amount of detail work,” because of the satellites’ small size, Murata says.

In the end, magnolia wood won, because its cells are small and uniform in size, making the wood easier to work and less likely to split or break. He says.

Humans have launched satellites into orbit since the 1950s, with up to 100 spacecraft launched each year until 2010. But over the past decade, commercial launches have become more accessible, and that number has risen Increased steadily, Exceeded 1,400 new satellites In 2021. With the number of rockets sent into space likely to increase, NOAA research predicts that in the coming decades, up to half of the aerosols in the stratosphere could contain metal particles from spacecraft.

Other organizations are also looking to use wood in space.

Finnish startup Arctic Astronautics has designed WISA Woodsat, a wooden satellite that was supposed to be launched into space in 2021. However, company founder Jari Mäkinen says the launch has been postponed due to bureaucratic hurdles.

“The satellite is ready, waiting to put the pieces back together when the time comes,” Makinen told CNN in an email, adding that once the company receives a space operations license, the satellite will be launched using RocketLab’s private rocket-sharing service.

At Khalifa University in the United Arab Emirates. flight engineer Yerjan Abdel Samad Graphene is seen as a potential material for space objects.

Samad is exploring “nano wood” – low-density wood mixed with graphene to improve its strength. Samad agrees with Murata that wood, as a renewable, low-density material, has the potential not only to build satellites, but also to build future space structures.

“There are many ongoing research (projects) in the field of space agriculture,” says Samad. “If we have space-grown wood, it can be used for manufacturing in space.”

However, there are still many unknowns about wood in space structures, says Tatsuhito Fujita, an engineer at the Japan Aerospace Exploration Agency who was involved in reviewing the Lingosat project.

“Using natural resources for space hardware[makes sense]from the perspective of the Sustainable Development Goals, but since wood has never been used in satellites, we can’t say what kind of benefit we can get at this moment,” says Fujita.

For the Japan Aerospace Exploration Agency (JAXA) and the J-Cube program, the satellite launch initiative, the priority is safety — and LingoSat passed its initial evaluation without any critical concerns, Fujita says. “JAXA also hopes to obtain structural materials that are lighter, stronger and less likely to generate debris, and is conducting research to achieve this goal.”

LingoSat is in the final stages of safety review It is expected to be launched on a joint mission between the Japan Aerospace Exploration Agency (JAXA) and NASA in the summer of 2024.. Murata says they will monitor the satellite for at least six months, to see how it performs in space conditions — such as extreme temperature changes in space.

Researchers will monitor the satellite for at least six months as it orbits Earth, as shown in this presentation. Credit: Kyoto University

“There was no significant drop in strength from -150 to 150 °C (-238 to 302 °F), and we confirmed this in our experiments,” says Murata. “But the satellite orbits the Earth and creates these huge temperature differences over the course of 90 minutes. We don’t know how much the satellite can withstand this intense and repeated cycle of temperature differences, so this needs to be investigated.”

The team will also monitor its reactions to radio waves and magnetic fields, and how the wood veneer protects the satellite’s semiconductors and chip.

In theory, wood should be a cheaper material to manufacture, although as a new technology, Murata says they are still working out costs.

So far, little of the material has been used on space missions and objects, Murata says. He hopes his and LingoSat’s research can demonstrate the possibilities of other low-impact materials.

“It is a renewable, environmentally friendly and people-friendly material,” says Murata. “I believe wood can be used in space development, especially as an interior material and radiation shielding material, for small satellites and manned spacecraft.”