The ecological satellite LignoSat resembles a toy that has been taken out of a box of wooden blocks.
Researchers at Kyoto University and logging company Sumitomo Forestry created it. Their goal is to build a spacecraft from biodegradable materials such as wood and see whether it could be an eco-friendly alternative to metal. Until now, satellites have been made from metal.
The LignoSat probe, the size of a coffee cup, is made from magnolia wood. In experiments conducted on the International Space Station (ISS), this material proved stable and resistant to cracking. The team is finalizing preparations for a launch that could happen as early as this summer.
Although no launch vehicle has been finalized, a summer liftoff is still possible. The cargo supply ship Orbital Sciences Cygnus may be canceled; if that happens, LignoSat would fly a bit later on a SpaceX Dragon.
Tiny A wooden satellite could protect the environment
“All satellites that re-enter the Earth’s atmosphere burn up and create tiny alumina particles that float in the upper layers of the atmosphere for many years,” said Takao Doi, a Japanese astronaut, co-developer of LignoSat, and a PhD in space engineering.
To tackle this, Kyoto researchers first tested various woods, including cherry, to find which would best withstand harsh space conditions, The Guardian reported. The team ran initial tests in labs that replicated those conditions and were surprised to find that samples showed no significant change in mass or signs of decay or damage.
Space debris in low Earth orbit
“The tree’s ability to withstand these conditions amazed us,” said project leader Koji Murata.
Then the samples went to the ISS, where astronauts exposed them to space conditions for about a year before returning them to Earth. Again, they showed no damage. Murata said that, because there’s no oxygen in space to cause burning and no organisms to cause decay, the wood held up.
Of all the tree species, magnolia proved the strongest and was used to build LignoSat, the world’s first wooden satellite. Soon it will undergo a series of experiments in orbit to test its performance, Murata noted.
Can wood replace metal in satellites?
The next step for the researchers is to answer that question. “One of the satellite’s tasks is to measure the deformation of wooden structures in space. Wood is durable and stable in one direction, but it can be prone to changes in size and cracking in another direction,” explained the project leader.
LignoSat is expected to operate in space for at least six months before re-entering the upper atmosphere.
If the device performs well in orbit, researchers can consider using wood more widely as a satellite building material. Experts forecast that more than 2,000 spacecraft will be launched from Earth each year in the near future, and the aluminum they leave in the upper atmosphere when they burn up will cause growing environmental problems.
Recent research at the University of British Columbia found that aluminum left behind by satellites contributes to serious ozone depletion—the layer that protects Earth from ultraviolet radiation.
But that could change if satellites like LignoSat replace metal ones. After completing their missions, they would produce only small amounts of biodegradable ash.
