A wooden satellite sounds like a joke, but from the very beginning, WISA Woodsat was a serious endeavour.
The goal was to make spaceflight more affordable and environmentally friendly, and also to spread the word of the possibilities and benefits of space technology. We consider ourselves missionaries of sustainable space. The serious scientific studies around the use of wood in space are now looking at many different kinds of applications – but we're not talking about those now.
Today we look back to 12 April 2021, when the project was revealed. As you may imagine, the project started well before that.
We have been working on wooden satellites since 2017, but considered it merely an interesting, but a too crazy idea. We launched a test satellite on a stratospheric flight in the summer of 2017 and made countless tests with different materials and ways to attach these together. Finally, the best solution seemed to be a simple birch plywood panel in a combination of wooden and/or metal structures.
Anyhow, this was just a funny sidekick project until the end of December 2021. Then BBC published an article about a Japanese wooden satellite project. We saw right away that the plan – according to photos in the article – wasn't very optimal and we were able to make a better wooden satellite.
And in fact, we could make it quite fast by combining our experiences with the wooden structures to Kitsat, the educational satellite that is the core of our business.
Kitsat is a fully functional 1U CubeSat, but made with affordable parts and designed for use in classrooms and space education. It can be upgraded very easily to a space-worthy spacecraft.
Wooden satellite is of course very catchy, but for us, this was much more from the beginning. This was a material science mission for studying the behaviour of the biomaterials in space conditions and evaluating the characteristics of the wood (plywood) when building a "real" satellite. We're recording the procedure and will finally compare the environmental impact of our project with a traditional CubeSat mission.
After the initial studies and evaluations, we considered the project feasible and rushed to search for partners.
Huld, an engineering company with long space history and our partner helping with the development of Kitsat, expressed right away their interest and they took a massive task: designing and building the selfies stick, that is needed for taking photos of the satellite in space. That's the best way to see how the plywood is doing in extreme conditions of space.
The deployable camera boom was designed in just a couple of months and it was much better than anticipated. It is lightweight and robust, made by 3D printing metal and connected to the satellite structure with a similarly 3D printed metal. The whole satellite can't be wooden, but we can limit the amount of metals used with 3D printing.
This will be the first Europan 3D printed primary structure part in space, along with the first wooden primary structure parts in the history of spaceflight. Plywood meets 3D printed metal!
Then we needed more data and hard facts about the plywood. So, we contacted UPM Plywood, a Finnish plywood manufacturer and a leader of high-quality plywoods in the world. They were interested in cooperation almost immediately because the only place and environment they have not studied plywood yet was space and satellites.
The next problem was getting good, interesting and precise measurements of the plywood; the photos are not enough. Therefore we contacted the Materials and Component Technology Division of the European Space Agency. They were eager to join the mission, study the materials we chose for the satellite and finally, they asked if they could add a mini-laboratory aboard. Of course – it was just perfect.
After that also Captain Corrosion, a spinoff from Tartu University, offered an experimental atomic oxygen sensor for our mission. And again we were more than happy to welcome them aboard because atomic oxygen (loose oxygen atoms in orbit well) is an important factor in the ageing of the materials in space. Tartu University is also taking case of the coating of the camera boom parts.
Finally, we secured a launch with Rocket Lab's Electron small launch vehicle.
What an year!
Finally, on 12 April 2021, the project was ready for the reveal. The satellite was designed, the camera boom was about ready, the instruments drafted and the first parts were already in production.
Then, on 12 May 2021, the first prototype was presented in an event, that unfortunately because of the COVID restrictions was just made online.
Details were polished, more parts manufactured, tests were done, and on 12 June 2021, the first functional prototype was sent on a stratospheric flight from Heureka Science Centre near Helsinki. The flight was just perfect and we received via radio images taken by the selfie camera from the edge of space.
At the Heureka event, we also presented a new partner: Tikkurila paint company, who provided colour test cards for the satellite. They are vital when studying the colour changes of the plywood surface. The original idea was also to use Tikkurila's varnish for protecting the plywood, but that wasn't a good idea: varnish has a little bit too much so-called outgassing in space. In earthly conditions, Tikkurila Temadur is a perfect product, but in our case, not optimal.
Therefore we needed another solution: ALD, Atomic Layer Deposition, developed by Picosun. The final satellite plywood parts are now ALD coated with a nanometre-thick aluminium oxide layer. Another first in the world and an invention offering many possibilities in future.
The next step was the vibration test at ESTEC, ESA's technical centre in the Netherlands. The tests are made for finding issues with the design or other problems, and we had one with some of the screws in the camera boom. Otherwise, the satellite came out with flying flags.
We needed a fastener for the screws, and luckily Henkel came with a very good solution. It's trusted in the space business and perfect also for us: Locktite.
Then, in November, we had a big setback, when The International Amateur Radio Union announced that they are not supporting our application for a radio amateur bandwidth for communicating with the satellite. This meant designing some parts of the satellite again and modifications to the antennae.
In February 2022 the modifications were done and the satellites are waiting for a final assembly. We'll de a flight model and a backup copy that is used for testing. The parts for the satellites are now waiting until we have more information about the licences and the launch opportunity with Electron; it will take only a week to put everything together and the last tests will be done right after.
So, now we're in waiting mode – and in good company, because practically all space projects are faced with delays.
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