In the communication subsection we design and develop all systems needed for communication with and on the CubeSat. Current projects include the construction of an own ground station and a fail-safe bus system, which will be used on our satellite. In our hardware related projects we mainly work with the programming languages MicroPython and C(++), in many projects Python is also used. If something is designed in CAD, this is done in OpenSCAD and then printed in 3D.
When developing a communication system, it is important to focus on the reliability of the system in order to maintain constant control over the satellite. To ensure this we have decided to use CCSDS standards for radio transmission and for command and data processing, which are used in commercial spaceflight, at ESA and NASA.
The communication system comprises the ground station, the communication board in the satellite, the self-developed on-board bus and the transmission of data from the ground station to the mission control centre. We work closely with the on-board computer subsection in order to define requirements and to design uniform interfaces.
The different subsystems of a CubeSat need a reliable and fail-safe way to communicate and exchange commands. Since there is no common solution for this at the moment we have developed the SpaceCAN together with LibreCube. It is based on the CAN bus which is widely used in automation and automotive applications. By adding a redundant line and mechanisms to restore operational capability in case of failure, a critical “single point of failure” is eliminated and the probability of success of the entire mission of the satellite is increased.
To keep the costs for the development of the ground station low and to be able to build prototypes quickly, Software Defined Radio (SDR) and higher programming languages such as Python are used. We use GNU Radio, an open source framework for SDR development and simulation. Since our CubeSat will move several times a day over our ground station, the station must be able to follow it with its antennas with the help of a rotator. We develop this rotator ourselves with 3D printing, stepper motors and Arduinos.
No matter if you come from electrical engineering, physics or a completely different field of study, you are always welcome to join us, because the tasks are manifold and we can learn, tinker and create something great together. Did you get interested or do you have any further questions? Then just send a mail to Milenko Starcik, the head of this subsection. Our meetings take place regularly on Friday at 14:30 in room S3|06 509, so please register in advance if you want to come by.