A team of Japanese scientists has finished constructing the world’s first wooden satellite – with NASA weeks away from launching it – the world’s first fully biodegradable into space.
Known as the LignoSat probe, the satellite was invented by Japanese scientists, who, combined with Japanese forest giant PEFC-certified Sumitomo Forestry, discovered that magnolia wood is the ideal alternative to earth-polluting metals used in satellites.
“Satellites that are not made of metal should become mainstream,” according to Takao Doi, an astronaut and Kyoto University professor, who, with a Sumitomo Forestry representative, spoke to the world’s media today.
“Data will be sent from the satellite to researchers who can check for signs of strain,” the Sumitomo Forestry representative said, adding that a research team “will check whether the satellite can withstand huge temperature changes.”
Already, the material has been tested at the International Space Station, with Wood Central reporting in May that an international team of scientists led by Kyoto University in Japan proved beyond doubt that exposed wood showed negligible deterioration and maintained stability in space.
The push to use biodegradable materials in satellites comes as the global space industry looks for cleaner, greener and more sustainable materials amid a purge of space waste that is now littering the earth.
If successful, the LignoStat will open the door to replace aluminium with timber, creating a space race for timber supply – more than 2,000 space satellites are expected to be launched annually over the coming decade.
“All the satellites which re-enter the Earth’s atmosphere burn and create tiny alumina particles, which will float in the upper atmosphere for many years,” according to Professor Doi, adding that “eventually, it will affect the environment of the Earth.”
To tackle the problem, researchers evaluated various species to determine how well they could withstand space launches and lengthy flights in orbit around the Earth.
The first tests were carried out in laboratories that recreated conditions in space, and wood samples were found to have suffered no measurable changes in mass or signs of decomposition or damage.
“Wood’s ability to withstand these conditions astounded us,” said Koji Murata, head of the project, with timber specimens then dispatched and texted at the International Space Station via the Japanese Experiment Module ‘Kibo.’
After a ten-month journey, where the specimens were subject to radical temperature fluctuations, cosmic radiation, and solar particles, the samples were retrieved by astronaut Koichi Wakata of the Japan Aerospace Exploration Agency (JAXA).
Following their successful retrieval, SpaceX’s CRS-26 Commercial Resupply Service mission returned the specimens to Earth.
Again, they showed little signs of damage, a phenomenon that Professor Murata attributed to the fact that there is no oxygen in space, which could cause wood to burn and no living creatures to cause it to rot.
“One of the missions of the satellite is to measure the deformation of the wooden structure in space. Wood is durable and stable in one direction but may be prone to dimensional changes and cracking in the other direction,” Professor Murata told the Observer.
Why use wood in space?
Wood, particularly for small satellites known as CubeSats, brings several benefits, “First, it eases the design process of satellites because it allows for the penetration of electromagnetic waves,” according to research published by the Kyoto University last year.
This feature facilitates the internal positioning of components, such as antennas. Another critical advantage comes into play when a wooden satellite re-enters the Earth’s atmosphere. Unlike traditional metal satellites, which can release potentially harmful substances like alumina particles, a wooden satellite combusts entirely, preventing the release.
According to Professor Murata, a final decision had still to be made on the launch vehicle, with choices now narrowed down to a flight this summer on an Orbital Sciences Cygnus supply ship to the ISS or a SpaceXDragon mission later in the year.
The probe – the size of a coffee mug –will operate in space for at least six months before it is allowed to enter the upper atmosphere.
