Increasing system performance and flexibility: Distributed computing and routing of data within the fast formation flying mission

In 2007, the Tsinghua University, China, and the Delft University of Technology, The Netherlands, have agreed to jointly define, develop and operate the Formation for Atmospheric Science and Technology demonstration (FAST) mission. FAST will allow for a synoptic evaluation of global aerosol data and altitude profiles of the cryosphere with two cooperating micro-satellites flying in formation in 2011. One of the many technology demonstrations planned for the FAST mission involves the use of distributed space-based computing. This technique can be used to maximize the computational power available in a formation of small satellites, as well as reducing downlink budgets by processing data in flight. Its implementation on FAST is discussed in the paper. The formation flying and distributed computing demonstrations call for a communication link between the two FAST spacecraft. Important to the design of the link is that it does not necessarily need to be a direct link. In fact, during a part of the mission, such a direct link will be impossible due to the relative orbit geometry of the satellites. This requires an alternative routing of the inter-satellite communications via ground stations or via commercial satellite communication constellations. This flexible solution is explored, with special emphasis paid to the issues related with communication with a commercial satellite communication constellation.