Otto Koudelka, Rainer Kuschnig, Manuela Wenger, Andreas Hörmer, Reinhard Zeif
Institute of Communication Networks and Satellite Communications
Graz University of Technology, Austria
CubeSat missions make use of industry-grade instead of radiation-hardened electronics components for cost reasons. The other rationale is that the mission duration is typically short and higher risks can be taken.
In February 2013 the first Austrian satellite TUGSAT-1/BRITE-Austria and its sister satellite UniBRITE were launched. The design lifetime was two years. Now the satellites are successfully in orbit for more than six years and exhibit an excellent health status. The most critical components are the CCD sensors of the telescopes which show natural degradation due to radiation. Due to an image processing technique, well known in astronomy, called chopping, the effects could be minimised and the quality of the science data is still very good. Analyses show that the spacecraft will be able to produce science data meeting the requirements for at least two more years.
The Institute is responsible for two ESA nanosatellite missions: OPS-SAT and PRETTY. OPS-SAT has the goal to demonstrate new operational concepts and to carry out on-board RF and optical communications, camera, attitude control and hardware/software experiments. PRETTY is concerned with altimetry and dosimetry. A special GNSS receiver developed by RUAG and TU Graz is carrying out passive reflectometry. A novel dosimeter measuring the radiation environment is developed by Seibersdorf Laboratories.
For both missions TU Graz developed a high-performance on-board processor and a software-defined radio front-end based on COTS components. They were successfully tested for total dose at the Co60 facility at ESTEC and for SEUs at the Paul Scherrer Institute.
The paper will present performance results of the BRITE mission and discuss design considerations as well as operational procedures to ensure spacecraft safety.