DLR's robotics technologies for on-orbit servicing

The paper outlines the long-term space robotics projects as well as recent results in DLR's robotics laboratory. The driving force behind all the efforts made in hardware and software development is to design highly integrated robot systems which can be utilized in space, especially for extravehicular activities. Our envisaged field of application reaches from servicing satellites in low Earth and geostationary orbit to space stations as well as planetary exploration robots, all of them fully ground controlled from Earth. The ground control concept is based on the MARCO architecture, which was verified in a few space robotics projects over recent years. It includes task-oriented programming capabilities for autonomous robot control at the remote site as well as methods for direct telemanipulation by means of virtual reality and telepresence techniques, which allows a realistic feeling for the ground operator via visual and haptic feedback devices. In addition to the control techniques, a new generation of ultra-lightweight robot arms with articulated hands is required to give the space robot systems the necessary dexterity. A number of experiments will verify and consolidate the usage of space robots. First, the ROKVISS experiment aims at the verification of DLR's lightweight robotics components under realistic mission conditions. Second, the TECSAS experiment will show the feasibility of autonomous as well as telepresence methods for further satellite servicing tasks. Third, a strong cooperation with industry will create the first business case in on-orbit-servicing: by attaching a tugboat to a satellite, whose propellant is declining, the lifetime of valuable telecommunication satellites could be prolonged for several years.