The SpaceX SPX27 space transporter will fly to the International Space Station (ISS) on March 15, 2023 (CET). Among others, the transporter will carry an experimental setup that the student small satellite group KSat e.V. of the University of Stuttgart will use to conduct three experiments on ferrofluids. The setup is held securely in place by super-light and extremely stable structural components that were additively manufactured at the Fraunhofer IPT.
Mechanical components such as ball bearings, pistons or pumps have a limited service life: they wear out over time and then have to be replaced. Such wear parts cause a major problem because they cannot simply be replaced in space. If such a component were to break on the James Webb Space Telescope, which has been orbiting the Earth since the end of 2021, the success of the $10 billion mission could be put in jeopardy. One promising solution for increasing the durability of mechanical components is superparamagnetic fluids known as ferrofluids.
In their experiments, the young researchers from KSat in Stuttgart aim to test in weightlessness the extent to which mechanical components can be optimized through the use of ferrofluids. For example, a bearing control system supported by ferrofluid will be tested with long-term goal of completely replacing ball bearings with ferrofluids. The other two experiments involve a thermal switch that controls the transfer of heat and an electrical switch that opens and closes an electric circuit.
The three experiments are held securely in place on aluminum plates measuring only 10x20 centimeters and bolted to the floor with threaded rods. Special support structures were also required to stabilize the construction. The team of students asked the Fraunhofer IPT to design and manufacture four such structural components for the experimental setup.
The requirements were demanding: The structural components had to be extremely stable to protect the experimental setup against the strong vibrations during flight – especially during launch and re-entry – and to prevent the experimental planes from shifting. At the same time, they had to be particularly light: less than 400 grams in total. In addition, the parts had to be designed to be as open as possible to ensure air circulation for cooling the experiments.
The Fraunhofer IPT team manufactured the structural components from stainless steel using laser powder bed fusion (LPBF). The process lent itself well to the project because the component design developed in Aachen included open areas for air circulation as well as hollow structures for weight reduction. Since LPBF builds up component the layer-by-layer, the component could be designed and built easily and quickly.
The Fraunhofer team's strategy worked: The support structures weigh only 141 grams in total. The Fraunhofer IPT team thus remained well below the specifications. Despite the extremely low weight, the components passed the subsequent "vibration test," which tested their stability at the German Aerospace Center (DLR) in Cologne.