Prior launching a satellite to space, many tests have to be done. Most of the tests are simulations and repeated use of the satellite and its systems in laboratory or even office environments, but the most rigorous tests are done at the special test laboratories that mimic the launch and space conditions as closely as possible.
The best place for these tests is ESTEC, the technical centre of the European Space Agency located in the Netherlands. Most of the European famous space probes and satellites have been tested at ESTEC.
WISA Woodsat was invited by ESA to conduct the tests also at ESTEC, and it was an honour to be there aside JUICE, the ambitious spacecraft that will be launched to Jupiter next year. While JUICE was in a huge space simulator, our little wooden satellite encountered a vibration test with a special shaker that can recreate the vibrations of a rocket ride.
The model used for the tests was an exact copy of the actual satellite to be launched to space. The satellite went through a violent vibration test, mimicking a ride to space atop of a rocket shaken by the engines. The satellite must also withstand loud roar from the engines and the hard acoustic noise originating from the aerodynamic forces around the fairing.
The structure and the plywood panels resisted the forces as expected and are now ready for the spaceflight from the vibration point of view. The plywood panels will be studied afterwards to find out possible hidden damages.
However, a problem occurred with the screws of the “selfie stick”, i.e. the additively manufactured (AM) deployable camera boom, which extends from the satellite once in orbit.
Two screws from the scissor mechanism came undone during the shaking, and further analysis is needed. The camera and its boom are vital for the mission, because the camera will be used to survey the satellite and its plywood panels during the mission.
“This is certainly a small disappointment, but also extremely interesting as we are a scientific and educational project”, said the WISA Woodsat mission manager Jari Mäkinen afterwards.
"We want to show how a space mission is done, and missions typically proceed with setbacks and highlights. Flying to space and operating a satellite is still far away from an everyday activity!"
Our team will now go through the data gathered and decide on the next steps soon. Right now the issue seems to be very trivial and can be corrected easily.
Up to now, the design, construction and testing of the WISA Woodsat and its systems has been a success considering that satellite projects usually take years to implement and often face significant delays.
“The mistakes or design faults can’t be repaired in space, and in that sense the test failure of the WISA Woodsat is a relief. The problem will be addressed promptly and won’t endanger the mission later”, says Mäkinen.
“This shows how difficult getting to space really is”, states Kevin Vainio, project manager at Huld for the AM deployable boom.
“Every component has to be 110%, even simple components like screws. But It’s great to see that even with this issue all AM components stayed safely in place and withstood the forces from the vibration. AM components are tough.” Vainio adds.