Could wood be the answer for sustainable satellites?

Space travel is notoriously hard on materials. The temperature swing from freezing cold to white-hot on re-entry, the G-force exerted by the launch into orbit, the need to shield against potential impacts from meteorites or satellite fragments all add up to a tough challenge.

But a team of Japanese researchers are banking on an unlikely material to offer a sustainable alternative for space applications: wood. Investigations on Earth have found that wood has a surprising ability to survive at temperatures ranging from -150 to 150 degrees Celsius, and in near-vacuum conditions. 

Now, researchers are planning to test slats of wood on board the International Space Station. "Wood's ability to withstand simulated low earth orbit – or LEO – conditions astounded us," explains Koji Murata, head of the space-wood research effort and member of the Biomaterials Design Lab at Kyoto University's graduate school of agriculture. "We now want to see if we can accurately estimate the effects of the harsh LEO environment on organic materials.”

Murata’s team are working with the Japanese space agency JAXA to send a selection of wooden samples from various plant species to the exposed experiment platform of the Kibo module on the ISS. A frame holding the samples will be sent there by the end of 2021, and then returned to Earth six months later for a detailed analysis. 

"We particularly want to measure the degree of erosion resulting from atomic oxygen collisions with the fibrous material," continues Murata, referring to the fact that LEO is characterised by the presence of free oxygen atoms travelling at high velocity, which over time can cause damage to exposed surfaces. "We also want to see the effects of cosmic rays and the vacuum of space on the mechanical properties of wood."

The work will build towards plans by Kyoto University researchers to build a wooden satellite called ‘LignoSat’ in 2023. 

---