Since Sputnik 1 was launched in 1957, satellites have been made with metals. A group of Japanese scientists thinks it has a viable alternative: wood.
A SpaceX rocket launched Monday night from the Kennedy Space Center in Florida carrying the world’s first satellite model with wooden components, marking a potential shift in space engineering that marries cutting-edge technology with traditional craftsmanship.
The satellite, a wooden cube with four-inch-wide panels and small plastic and silicon parts, will be sent to the International Space Station carrying an array of electronics. The plan is to put it into orbit in early December, according to Koji Murata, a professor of forest and biomaterials science at Kyoto University in Japan who worked on the satellite.
If successful, the invention, named LignoSat after the Latin word for wood, lignum, could open the door to other uses for wood in space. The idea originated in 2017 from a question posed by Takao Doi, a Japanese engineer and former NASA astronaut: Could a human society living in space grow trees as renewable building material?
“We were trying to think about how to build something on the moon with wood,” Mr. Murata said in an interview. But they needed to verify whether wood could be used in space. The following year, Mr. Doi began talking about how, about a hundred years ago, airplanes had been built with wood. “So why not make a satellite with wood, too?” Mr. Murata said.
What began as an impulsive idea evolved into a serious scientific endeavor, he said. Mr. Doi and a group of scientists at Kyoto University and Sumitomo Forestry, one of Japan’s oldest timber companies, set out to determine the best wood to send to space.
They tested three types: birch, cherry and magnolia. The samples were sent in 2022 to the International Space Station, where they spent nearly eight months and were exposed to extreme temperatures, “intense cosmic rays and dangerous solar particles.”
“Tests confirmed no decomposition or deformations, such as cracking, warping, peeling or surface damage,” the researchers wrote in January.
The team selected magnolia for its lightweight properties and resistance to cracking. The wood was processed using a centuries-old Japanese woodworking technique called “sashimono,” which uses intricate joints instead of screws, nails or glue to assemble furniture and wooden buildings.
Two master carpenters in Kyoto, who usually restore historical buildings like Nijo Castle, were enlisted to work on the satellite, Mr. Murata said. Using traditional tools, like saws and chisels, they crafted the wooden components that would eventually orbit Earth.
“Nobody had ever thought about using wood for rocket science before,” Mr. Murata said. “Many engineers thought wood was old technology and couldn’t be applied to cutting-edge technology.”
A group of researchers in Finland said in 2021 that it was on a similar mission to launch a wooden satellite, using birch plywood. But their satellite has not yet been sent to space.
The Japanese project wasn’t without its challenges, either. Wood’s tendency to shrink and deform unevenly when it loses moisture required careful engineering considerations. The final design also needed to be approved by both the Japan Aerospace Exploration Agency and NASA, which was involved in launching the satellite.
“There was a lot of debate because this material had never been used before,” Mr. Murata said.
Once in orbit, LignaSat’s wood will be tested for six months before it burns up in Earth’s atmosphere, he said. Scientists will monitor how much the wood expands and contracts in space and how accurately the geomagnetic field can be measured inside a wooden structure.
The project could also help address a growing problem in space exploration: environmental impact. When metal satellites burn up in the atmosphere, they release pollutants like aluminum oxide that damage the ozone layer. But burning wood simply produces water vapor and carbon dioxide, a cleaner byproduct, Mr. Murata said.
A lot can go wrong while the satellite is in space. Its solar panels may stop operating, and the batteries may overheat or freeze in an environment where temperatures can fluctuate from 212 degrees to minus 148 degrees Fahrenheit every hour or so.
But as far as the wood is concerned, Mr. Murata isn’t worried. He said that tests had already shown that wood does not deteriorate in space.
Looking ahead, Mr. Murata said the team envisioned larger wooden satellites. Farther in the future, he said his ambitions extended beyond Earth’s orbit.
“I am hoping to grow wood on Mars,” he said.
The goal appears far-fetched today. But he is no stranger to achieving the implausible.
“I used to think it was impossible to send anything made of wood to space,” he said.
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