This subsection is responsible for the entire mechanical construction of the satellite. A central issue is of course the housing, which stabilizes the individual components of the satellite, protects them from radiation and dissipates any heat generated. The positioning of all components on the surface and within the small housing is another task. In addition, we participate in the development of the antenna and the reflectors for the mission.
- The housing is subject to strict guidelines regarding external dimensions, weight, material and load capacity. A 1U-Cubesat may have a maximum size of 113.5x100x100mm and weigh 1.33kg. The material must not radiate even under cosmic influences, must withstand the vibrations during the launch in a rocket and temperature fluctuations of about 200°C. To ensure the latter, we work closely with the thermal control.
- A special aspect of the housing is an integrated ejection mechanism. This is provided for by Cubesat standards and ensures that several satellites that have been thrown into orbit simultaneously leave the launcher with sufficient distance between each other.
- For our mission to passively track the satellite, clear patterns of retro-reflectors on each side surface are required. These must neither overlap with the solar cells nor exceed the outer dimensions of the housing. The reflection properties are also related to the mechanical integration and must be taken into account.
Currently we are working on MADDI (abbreviation for “Model for exhibition and design test with detailed interior”, only makes sense in german), a prototype, which should give a vivid impression of the future satellite and serve for tests of the structure and later developed components.
Development CubeSat structure
To develop the housing for the real satellite, some research on already flown constructions is necessary first. 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 verify these results and to ensure the functionality of the housing, which is built later, it is subjected to various tests, such as exposure to various strong vibrations in a shaker.
Research is also being conducted into the material of the housing. Although there are frequently used alloys which have proven their worth, there are also ideas for new materials with other properties which may offer new possibilities. For example, we are working on shape-memory alloys, which take on a predetermined shape through temperature changes without the need for electronic control.
How we work
The tasks of this subsection already provide a rough work plan. The concrete processing of subsections is organized freely according to mutual agreement.
Basis for our work are the Cubesat standards, which limit the room for manoeuvre. Therefore, these standards, as well as our own research results, should be clearly summarized in TUDSaT’s own Wiki.
As soon as a (preliminary) decision for a housing design can be made, it will be drawn in CAD, unless a freely available model is already available for download. Depending on the results of the simulations and requirements of other subsections, the model is iteratively improved.
Parallel to this, 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, will be collaborated and the combination of this with the housing construction will be done.
Finally, we will be heavily involved in the assembly of the prototype and the satellite.
Then just drop by one of our meetings at our office in S3|06 509 (Hans Busch Institute). As our weekly team meeting takes place at different times, please write an email to the team leaders of the Structure team, Christian Ehrt and Julian Olbrich.