Why would anyone build a satellite out of wood?
Kyoto University and Sumitomo Forestry put a wooden satellite into orbit. The strange part is that there were some quite sensible reasons for doing it.
On 9 December 2024, a 10-centimetre satellite was released from the International Space Station.
Built by Kyoto University and Sumitomo Forestry, LignoSat contained the electronics and other hardware you would expect inside a CubeSat. But its outer structure used 4-millimetre panels of honoki, a Japanese magnolia traditionally used for things such as sword scabbards.
The panels were fitted together using a traditional Japanese dovetail joint, without screws or glue in the wooden enclosure.
Japan had put wood into orbit.
First, they left some wood outside the ISS
Before building the satellite, the researchers did something arguably even stranger.
They attached samples of three Japanese hardwoods: honoki, yamazakura and dakekanba.
The samples went outside the International Space Station on 4 March 2022. They came back inside on 23 December.
The experiment tested how the woods handled vacuum, ultraviolet radiation, atomic oxygen and other conditions in low-Earth orbit.
It didn't go entirely to plan. An equipment problem meant the samples were mounted facing the opposite direction from the one intended, so they received much less atomic-oxygen exposure than expected.
None of the three species showed measurable mass loss, and the researchers found no visible surface erosion from atomic oxygen.
But the wood did change.
Brightness fell in all three species, meaning they became darker. Colour saturation also increased in honoki and dakekanba. Researchers found a thin film on the aluminium cover holding the samples and suggested a similar film may have formed on the wood itself, contributing to the darkening.
Honoki was eventually selected for LignoSat because of its combination of workability, dimensional stability and strength.
Why wood at all?
One argument concerns what happens at the end of a satellite's life.
Satellites in low-Earth orbit eventually re-enter the atmosphere. Research has raised questions about aluminium oxide and other material deposited in the upper atmosphere as spacecraft burn up.
The LignoSat project argues that replacing some conventional metal structure with wood could reduce those metal-derived re-entry products.
LignoSat did not prove that environmental benefit. It still contained aluminium, stainless steel and electronics, and the project did not measure its own re-entry emissions.
The other idea may be more interesting: putting the antenna inside the satellite.
CubeSats have to fit within strict dimensions during launch and deployment, so communications antennas are commonly deployed once the satellite reaches space. That adds another mechanical system capable of going wrong.
Because wood is much more transparent to radio waves than metal, the LignoSat team wants to place a flat antenna inside the wooden structure instead.
There is an unfortunate relevance to that idea given what happened to the first satellite.
It made it to orbit. Then it went silent
LignoSat was launched to the International Space Station in November 2024 and released from the Japanese Kibo module on 9 December.
It then orbited Earth for about four months.
But the team never established reliable communication with it.
That matters because LignoSat carried sensors intended to measure things such as strain in the wooden panels, internal temperature, the geomagnetic field and radiation effects. The wooden structure made it into space, but much of the data intended to show researchers exactly how it behaved there never came home.
The project has since said suspected causes of the communications failure include software and a malfunction in the antenna-deployment mechanism.
So the first wooden satellite produced an incomplete result.
The team successfully built and deployed a wooden CubeSat. It did not get the detailed in-orbit evidence it wanted.
Then traditional joinery entered the picture
The wooden enclosure wasn't produced by an aerospace company.
It came from Kuroda Kobo, a woodworking workshop in Shiga whose craftsmen have also worked on the restoration of Nijo Castle in Kyoto.
The satellite's panels were joined using tomegata kakushi arikumi-tsugi, a concealed dovetail technique. Kyoto University says the craftsmen were working to tolerances of around 0.1 millimetres.
But the joinery still had to survive modern aerospace constraints.
During development, NASA raised a problem. Wood loses moisture and shrinks in vacuum. An early design sandwiched the wooden box between metal frames, creating the possibility that shrinkage would leave the satellite loose inside dimensions that have to remain extremely precise.
The team redesigned it, adding shafts through the structure to hold everything in place.
The eventual spacecraft therefore combined wooden panels with aluminium frames and stainless-steel shafts.
LignoSat was never literally a satellite made only from wood.
The result was a hybrid: traditional joinery redesigned around CubeSat tolerances, electronics and the inconvenient fact that wood changes size in vacuum.
They are trying again
The project hasn't ended with the communications failure.
A LignoSat-1R is planned for launch through the ISS in Japan's FY2027, which runs from April 2027 to March 2028. An April 2026 IARU filing gives the target more narrowly as sometime in 2027.
Its telemetry is intended to help researchers understand what happens to the wooden structure in space while the team also tries to fix the communications problems encountered by the first satellite.
Further down the roadmap is LignoSat-2, a larger spacecraft intended to add attitude control and place a flat communications antenna inside the wooden structure.
The internal antenna may turn out to be the more consequential experiment.
If wood eventually becomes useful in satellites, it may not be because anyone particularly wants wooden spacecraft. It may be because wood lets engineers do something awkward to do with metal.
The rabbit hole
Long before LignoSat went into orbit, pieces of the wood that would lead to it spent 294 days bolted to an experiment platform outside the International Space Station.
Even that experiment contains a useful reminder of how real research differs from the clean version presented afterwards.
The samples ended up facing the wrong direction.
Atomic oxygen was one of the things the researchers specifically wanted to study, but the unexpected mounting position meant the samples received much less of it than planned. Their eventual peer-reviewed paper states the limitation openly.
Wood went to space. The satellite went to space. Neither experiment produced quite the dataset the researchers originally hoped for.
So the next satellite is, in part, a repeat experiment: another tiny wooden box sent into orbit to answer questions the first one couldn't.
And further down the roadmap is the stranger possibility: using the wood not merely as structure, but as something radio waves can pass through.
That is where LignoSat stops being a wooden-satellite curiosity and starts becoming an engineering experiment worth following.
Sources & Further Reading
Government of Japan — LignoSat retrospective
The clearest recent account of what happened to the first satellite, the communications failure and the current LignoSat-1R and LignoSat-2 plans.
Kyoto University — LignoSat student-team interview
Excellent detail on Kuroda Kobo, traditional joinery, the 0.1 mm tolerances and the redesign prompted by wood shrinkage.
Journal of Wood Science — Space exposure test of hardwood specimens
The peer-reviewed account of the 294-day ISS experiment, including the colour changes, lack of measurable mass loss or erosion, and the unexpected mounting orientation.
JAXA — LignoSat mission overview
The planned measurements aboard the first satellite, including strain, temperature, geomagnetism and radiation effects.
NASA — LignoSat deployment
Useful photographs showing how the wooden panels sit alongside aluminium frames and stainless-steel shafts.
Geophysical Research Letters — Satellite re-entry and aluminium oxide
Independent research into the possible atmospheric consequences of aluminium oxide produced during satellite re-entry.
Kyoto University Space Wood Project — second satellite plans
The development plan describing the larger satellite, internal patch antenna and attitude-control experiment.
IARU — LignoSat-1R filing
The April 2026 technical filing for the 1U follow-up satellite and its planned JAXA/ISS launch in 2027.
A note on the name
Kyoto University's January 2024 English release referred to the then-planned flight satellite as LignoSat2. Later official material calls the spacecraft released in December 2024 LignoSat, with LignoSat-1R and LignoSat-2 used for the subsequent spacecraft. This article follows the later naming.
