UWE{3 is the third generation of picosatellites developed at the Univerisity of Wurzburg and it is currently being prepared for its launch in 2013. It will demonstrate in-orbit attitude determination and control, of which the accomplishment would be another important cornerstone in the realization of picosatellite formations. In order to prepare the satellite for launch, the attitude determination system had to be integrated into the complete satellite system. This comprises work on the dierent in-satellite communication systems, data storage devices, power saving measures and other important developments, which are described here. During the development of UWE{3 , one major focus of the project was to implement testing facilities for the various subsystems in order for students to participate actively in the program as well as to enhance the satellite's robustness. The attitude determination testbed was further improved during this work and experiments to verify the systems performance are described within this report.