World's First Wooden Satellite Aims to Mitigate Growing Space Junk Problem

Researchers in Japan have finished building the world’s first wooden satellite. Called LignoSat—a reference to lignin, wood’s chief organic polymer—the satellite represents a potential solution to the space industry’s growing debris problem.

Space junk is such a pervasive problem that it’s becoming more space junk and tricking people into believing they’ve seen UFOs. The Federal Communications Commission (FCC) recommended in 2022 that space agencies deorbit unused satellites within five years of retirement to mitigate waste accumulation, but agencies aren’t legally required to do so. What doesn’t re-enter Earth’s atmosphere—intentionally or otherwise—is left to float among the stars, until private firms figure out a way to snatch trash out of space. 

What does re-enter Earth’s atmosphere is a problem, too. In October, the National Oceanic and Atmospheric Administration (NOAA) found that spacecraft that burn upon atmospheric re-entry release aerosolized metals, which linger indefinitely in the stratosphere by attaching to sulfuric acid particles. Our atmosphere is polluted enough already; if the 7,800-plus satellites currently in low Earth orbit (LEO) were to deorbit right now, they’d fling metal onto half of the stratosphere’s total sulfuric acid. 

Replacing some metal components with wood ones could reduce the amount of metal that hovers in space or becomes one with the stratosphere. At the top of the decade, researchers at Kyoto University began collaborating with Sumitomo Forestry, a Japanese logging and wood processing company, to test the strength of different wood types. They began by measuring samples’ ability to withstand extreme temperatures and near-vacuum conditions here on Earth. Then, in 2021, the Japan Aerospace Exploration Agency (JAXA) sent wood samples to the International Space Station, where they endured ten months of LEO’s harsh conditions on the exposed experiment platform of the Kibo module.

The lack of oxygen and moisture in space allowed all of the samples to survive LEO remarkably well, even after prolonged exposure to “intense cosmic rays and dangerous solar particles,” Kyoto University shared in a follow-up release. However, magnolia wood was their best option for its dimensional stability and impressive workability. The team set about constructing a hand-size satellite out of magnolia lumber. Now they’re busy figuring out how to get LignoSat to space. 

According to the BBC, LignoSat will likely hitch a ride on Cygnus, a collaborative cargo spacecraft made by Orbital Sciences and Northrop Grumman, when it brings supplies to the ISS later this year. If that doesn’t work out, the wooden cubesat might also join a SpaceX Dragon mission.