Arctic Astronautics / ESA
Satellites orbiting Earth generally end their lives in a fiery reentry, but a small CubeSat scheduled to be launched by the European Space Agency later this year could have a warm glow than most in its final moments.
That’s because WISA-Woodsat is made primarily of plywood.
It is not such a crazy idea: since was widely available about a century ago, plywood has long been prized for its strength, rigidity, and durability – three things that are good on a spaceship.
WISA Woodsat is the brainchild of Jari Mäkinen, a writer and broadcaster from Finland who co-founded a company called Arctic astronautics, which markets fully functional replicas of CubeSats ready for orbit.
“I have always liked to make model airplanes, with many pieces of wood … [This] It has me wondering; Why don’t we blow up any wood material in space? “he said in a ESA press release.
Plywood could be a cheaper alternative to traditional materials
Believe it or not, small satellite plywood “could be a great low-cost alternative to traditional materials and is absolutely doable with the right testing and modifications,” says Michelle Johnson, associate researcher in materials and process engineering at Lockheed. Martin Space. NPR.
Modern spacecraft are often made of carbon fiber composites “which is essentially an engineering improvement on nature’s original composite, namely wood,” he explains.
Sarbajit Banerjee, a chemistry professor at Texas A&M University, agrees that wood in space is not a completely crazy idea.
But using wood in spaceflight has its challenges
“Wood is an amazing structural material; it performs very well compared to other materials in terms of strength-to-weight ratios,” he tells NPR.
“However, there are several challenges to using wood in high-performance applications such as space flight,” he admits.
Due to the grain and the way trees grow, wood can be weaker in some dimensions than others, Banerjee points out, although plywood is specifically designed to minimize that. It is also difficult to mold without losing strength and does not easily dissipate energy from impacts.
And then there is the space environment itself. Satellites in orbit “inevitably suffer radiation damage, which in the case of wood can significantly degrade mechanical strength,” he says.
Samuli Nyman, the project’s chief engineer and also co-founder of Arctic Astronautics, says: “The base material for plywood is birch, and we are using basically the same thing that you would find in a hardware store or to make furniture.”
“The main difference is that ordinary plywood is too wet for space uses, so we put our wood in a thermal vacuum chamber to dry it,” it says in the ESA press release.
Nyman says the Woodsat team will also test varnishes and lacquers aboard the spacecraft.
Researchers will use high-tech tools to monitor plywood in orbit
An array of on-board sensors, including two cameras, one mounted on a small retractable selfie stick (made of metal), will be used to monitor the performance of the plywood (and finishes) in the space.
An ultra-thin layer of aluminum oxide, commonly used to coat electronic devices (and ironically, to make sandpaper), will be added to the CubeSat to minimize any “outgassing” of wood fumes into space. Such degassing “could cloud spacecraft optical instruments,” says Lockheed Martin’s Johnson.
Woodsat, which ESA says will launch from New Zealand at the end of the year, is being announced as the first wooden satellite. But it may not be the first spaceship made in part of wood, nor the last.
A type of cork is being tested as thermal protection in parts of the central stage of NASA’s Newest SLS Rocket, which is currently in development. Cork has also been used in thermal shielding on other CubeSats. And china reportedly used white oak to make a heat shield for recoverable satellites in some of his early space efforts.
And a Japanese company and the University of Kyoto are supposedly working together in a prototype of a wooden satellite for launch in 2023. They hope it will help it burn out completely on re-entry, without leaving toxic substances in the atmosphere or debris returning to Earth.