This subsection is responsible for the entire mechanical construction of the satellite. A central issue here is, of course, the housing, which stabilises the individual components of the satellite, protects them from radiation and dissipates any heat that arises. The positioning of all components on the surface and within the small housing is another task. In addition, we are involved in the development of the antenna and the reflectors for the mission.
The enclosure is subject to strict guidelines regarding external dimensions, weight, material and load capacity.
- A 1U cubesat may be a maximum of 113.5x100x100mm and weigh 1.33kg. The material must not radiate even under cosmic influences, must withstand the vibrations during launch in a rocket, and must be able to withstand temperature fluctuations of approximately 200°C. To ensure the latter, we work closely with thermal control.
- A special aspect of the enclosure is an integrated ejection mechanism. This is provided by Cubesat standards and ensures that several satellites launched into orbit at the same time leave the launch vehicle with sufficient distance between them.
- For our mission to passively track the satellite, unique patterns of retro-reflectors are required on each side surface. These must neither overlap with the solar cells nor exceed the outer dimensions of the casing. The reflective properties are also related to the mechanical integration and must be taken into account.
We are currently working on MADDI („Model for exhibition and design test with detailed interior“), a prototype which will provide a vivid impression of the future satellite and serve for tests of the structure and later developed components.
Development of the CubeSat structure
In order to develop the housing for the real satellite, some research into designs that have already been flown is first necessary. Based on this, 3D drawings are created on the computer (CAD), which can be used to simulate the mechanical and thermal properties of the construction. In order to check these results and to ensure the functionality, the later constructed housing is subjected to various tests, such as being exposed to various strong vibrations in a shaker.
Research is also done for the material of the enclosure. Although there are frequently used alloys that have proven themselves, there are also ideas for new materials with different properties that can offer new possibilities. For example, we are working on shape-memory alloys, which take on a predetermined shape through changes in temperature without the need for electronic control.
The tasks of this subsection already provide a rough work plan. The concrete work on subsections is organised freely according to mutual agreement.
The basis for our work are the Cubesat standards, which limit the scope. Therefore, these, as well as our own research results, should be clearly summarised in the TUDSaT’s own Wiki.
As soon as a (preliminary) decision can be made for an enclosure design, it will be drawn in CAD, unless there is already a freely available model for download. Depending on the results of the simulations and the requirements of other subsections, the model is iteratively improved.
In parallel, we will work on the development of the reflectors and the solar cells on the one hand, and the positioning of the electronics inside and the antenna on the other hand, and the unification of these with the housing construction.
Finally, we will be heavily involved in the assembly of prototypes and the satellite.
Then just drop by one of our meetings. Our weekly meeting takes place every Monday at 6 pm on our Discord server in the voice channel cs_structure. If you have any questions, feel free to contact the team leaders of the structure team, Christian Ehrt or Julian Olbrich.