Astronauts Deploy the First Wooden Satellite into Orbit

Wood has been a mainstay of human machines and construction for millennia. Its physical properties offer capabilities that are unmatched by almost any synthetic replacements. However, it has only very rarely been used in space. That might change based on the results of a new test run by Japan’s Space Agency (JAXA). LignoSat, one of the world’s first wooden satellites, was deployed from the ISS in December. 

We previously reported on the satellites’ history and launch. Matt’s article here provides an in-depth look at LignoSat’s path to eventual deployment.

Now that LignoSat has officially been deployed, what is it trying to measure? Stress and strain are two big ones that go hand in hand with temperature. Wood can warp with temperature changes, and there is probably still some water left in the honoki magnolia wood panels used for LignoSat’s construction. Understanding those effects on the satellite’s structure is one of the metrics of LignoSat’s makers at the University of Kyoto.

The effect of radiation is another. Wood, though an organic substance, is typically housed under the protective umbrella of the ozone layer, protecting it from most of the Sun’s radiation. Several samples of different kinds of wood were exposed to the space environment outside the ISS to test for these effects. However, testing them in full force without shielding the ISS is another of LignoSat’s challenges.

Finally, it will test for geomagnetic interference. Typical satellites are large metal boxes. In electrical engineering terms, we would call that a “Faraday cage,” named after Michael Faraday, the father of modern electrical engineering. Faraday cages are essential to keeping signals either inside or outside the cage and now allowing signals to pass either in or out. That’s why old-style radios used to have antennas that extended outside of their metal housings.

However, a wooden box doesn’t create a Faraday cage, so any electronics inside would be subjected to various geomagnetic interferences. LignoSat’s other job is to determine how severe those interferences are.

To be fair, the satellite isn’t entirely made of wood—it has aluminum frames and internal steel shafts holding the wood panels in place. However, it is still intended to burn up in Earth’s atmosphere upon reentry in around six months, steel struts and all.

Interestingly, LignoSat uses a traditional Japanese wood joinery technique that will allow the panels to flex during temperature changes, whereas metal fasteners would be much more restrictive and possibly damage the panels. If nothing else, it makes for a beautifully designed box, the outside of which looks more like home decoration than a satellite.

As LignoSat begins collecting data, researchers at the University of Kyoto are already working hard on LignoSat2. It’s scheduled to be launched in 2026, and it promises to add even more aesthetic appeal to the satellite industry while hopefully overcoming some of its technical challenges.

Learn More:
NASA – JAXA’s First Wooden Satellite Deploys from Space Station
UT – Japan Launches the First Wooden Satellite to Space
UT – Japan to Launch ‘Wooden Satellite’ in 2023
UT – Building a Satellite out of Wood? Use Magnolia

Lead Image:
Internal view of LignoSat’s structure shows the relationship among wooden panels, aluminum frames, and stainless-steel shafts.
Credit: Kyoto University