The world’s first wooden satellite has arrived. Stashed among three tons of cargo, this humble-looking satellite holds the promise of tackling one of space exploration’s most pressing problems: debris.

Developed by Kyoto University and Japanese homebuilding giant Sumitomo Forestry, LignoSat isn’t just an experiment in alternative materials. It’s a pioneering step in space exploration. This small (10 cm³) satellite is crafted from honoki magnolia wood and could offer a cleaner way to design and decommission satellites.

Why wood?

In 2017, Takao Doi, a former NASA astronaut and professor at Kyoto University, started working on an unusual plan. He partnered with forest scientist Koji Murata and asked “Why not make a satellite with wood?”

Wood isn’t the first material you’d think about sending into space but given the lack of water and oxygen in space, it’s more durable than on Earth. Also, wood does have a few distinct advantages.

Firstly, it’s sustainable and biodegradable. Currently, space is littered with defunct satellites, fragments from previous collisions, and discarded rocket parts. This debris can stay in orbit for decades, posing collision risks for active satellites, spacecraft, and even the International Space Station.

Wooden satellites offer a cleaner decommissioning option. Unlike metal, which can leave fragments in orbit or emit harmful particles upon re-entry, wood disintegrates completely with minimal environmental impact. Metal satellites release aluminum oxide when burning up, a substance that can contribute to ozone depletion. In contrast, LignoSat’s honoki wood burns cleanly, leaving no harmful pollutants.

In addition to their environmental benefits, wooden satellites may provide functional advantages in radiation shielding. This is what astronauts are testing now.

No screws nor glue

To select the right wood, Doi and Murata’s team tested three types — honoki (Japanese magnolia), cherry, and birch — on the International Space Station (ISS) for nearly eight months in 2022. These samples were subjected to intense cosmic rays, extreme solar radiation, and temperature swings. All of them performed well but honoki ultimately emerged as the best candidate, retaining its durability and displaying resistance to cracking under these harsh conditions. It’s a type of wood that was used for sword sheaths

The researchers also used a traditional Japanese woodworking technique called sashimono.

This centuries-old Japanese technique uses precise joints instead of screws, glue, or nails. Engineers employed this method to construct LignoSat’s outer casing, underscoring the satellite’s unique blend of tradition and cutting-edge technology.

The wood used in LignoSat is expected to offer natural protection against the high levels of cosmic radiation in space. If confirmed, this could have far-reaching applications beyond satellites. For instance, wood’s shielding properties might be leveraged in data centers to protect sensitive semiconductor equipment from radiation damage. According to Sumitomo Forestry’s research team, this approach could prove invaluable as humanity extends its reach to the Moon, Mars, and beyond.

Now aboard the ISS, LignoSat will be released into orbit in December for a six-month mission to see how well honoki wood holds up in the unforgiving space environment. Circling the Earth at roughly 250 miles above the surface, the wood will experience temperature fluctuations from -100 to 100 degrees Celsius every 45 minutes as it moves between sunlight and shadow. This extreme exposure will test the wood’s resilience, as well as its ability to protect sensitive equipment from cosmic rays and radiation.

The satellite is also equipped with sensors to monitor deformation and determine its impact on onboard equipment measuring geomagnetic fields. These tests all aim to assess whether wood, a naturally insulative and radiation-resistant material, can safeguard the electronic components essential for satellite functions.

Can wood become an important material for space exploration?

LignoSat’s journey may seem like an isolated experiment, but it could serve as a blueprint for more sustainable space exploration.

Traditional satellites, built with metals and synthetic materials, contribute to environmental degradation throughout their lifecycle, from production to decommissioning. If wood satellites turn out to be a viable alternative, it could lead to the development of eco-friendly satellite fleets, built from renewable materials that don’t contribute to atmospheric pollution or long-term orbital debris.

“Satellites that are not made of metal should become mainstream,” Takao Doi said at a press conference earlier this year.

Takao Doi and his team have broader ambitions beyond satellites. They envision a future in which timber could be the building material for space habitats on the Moon and Mars. This would involve a 50-year plan, starting with Earth-based experiments, that could ultimately lead to forests and wooden structures in extraterrestrial environments. By using renewable resources, humanity could theoretically establish a sustainable presence on other planets without excessive reliance on Earth-bound industrial materials.

“With timber, a material we can produce by ourselves, we will be able to build houses, live and work in space forever,” Doi told Reuters.