End-to-End Simulation and Verification of Rendezvous and Docking/Berthing Systems using Robotics

The rendezvous and docking/berthing (RvD/B) phase is one of the most complex and critical parts of future on-orbit servicing missions. Especially the operations during the final approach (separation distance < 20m) have to be verified and tested in detail. Such tests involve on-board systems, communication systems and ground systems. In the framework of an end-to-end simulation of the final approach to and capture of a tumbling client satellite, the necessary components are developed and the entire chain will be tested and verified. Concerning the on-board system, this involves the robotic arm for grasping the client, a stereo camera for visual servoing mounted on the robotic arm, the rendezvous sensors (CCD camera and LiDAR), and the on-board navigation and control software. A software satellite simulator is employed which emulates the physical environment of the two spacecraft. Two robotic test facilities, the European Proximity Operations Simulator (EPOS 2.0) at DLR-GSOC and the OOS Grasping Simulator (OOS-Sim) at DLR-RMC are used. The hardware components are mounted on the robots of the two facilities. The robots move according to the resulting relative position and orientation of the two satellites computed by the numerical satellite simulator. The communication infrastructure is simulated, and the ground infrastructure is established including three consoles: a standard satellite bus console, a rendezvous console and a robotic console. Finally, a series of end-to-end tests will be conducted; different approaches will be simulated. The first part, the approach to the final hold point will be performed using the EPOS facility. Then a switch to the OOS-Sim facility will be done, followed by a capture of the target