Autonomous formation flying at DLR'S German Space Operations Center (GSOC)

In the upcoming years, significant changes in the profile of satellite missions are expected as scientists and managers want to benefit from multi-satellite missions. Among others, distributed or virtual satellite platforms will create a completely new class of space missions, where not one single spacecraft or payload segment has to be operated but a formation or constellation of satellites. A “formation” designates multiple satellites in close proximity and is typically characterized by demanding guidance, navigation and control requirements. In comparison to perform these tasks by a ground control approach, on-board autonomy can guarantee superior performance with respect to control accuracies and cost efficiency. A dedicated research and development program on “Autonomous Spacecraft Navigation and Formation Flying” was initiated at DLR/GSOC in 1998. Numerous contributions in the area of space-borne GPS receiver technology, precision relative navigation and autonomous orbit control of satellite formations as a prerequisite for spacecraft autonomy have been made. Practical experience in the operations of a two-satellite formation has been gained by the GRACE mission. Next, GSOC is supporting Swedish Space Cooperation (SSC) in the implementation of the PRISMA formation flying demonstration mission, where a fully autonomous, robust and precise formation flying of spacecraft will be conducted by experiment. Finally, the German TerraSAR-X/TanDEM-X radar satellites will be Europe’s first space mission equipped and operated routinely with an autonomous formation flying system.