Robotic spacecraft for Kosmos 3M active removal (ROSKAR): GNC architecture and robotic system concept

Robotic manipulators have been playing an important role in human spaceflight activities since the 1980s. Nevertheless, an unmanned and completely autonomous robotic system, capable of capturing and manipulating a target has yet to become reality, despite several successfuldemonstration missions, such as the Engineering Test Satellite (ETS)-VII, orbital Express and Robotic Refueling Mission (RRM). Moreover, just recently, only a handful of studies have been dedicated to the analysisand design of a robotic system specifically for active debris removal (ADR) purposes, emphasizing their complexity and room for new ideas. To support future robotic ADR missions, DFKI, within the initial raining network (ITN) Stardust, has committed itself since November 2013 upon studying autonomous close range navigation and manipulation of uncooperative targets. Within that context, the following talk will present a new concept of a robotic spacecraft capable of autonomously approaching, capturing and manipulating a Kosmos 3M second stage. The target is assumed to be uncooperative although well known a priori. In particular, in this talk a detailed look at the robotic system and envisioned GNC architecture will be given, having in mind the most critical phases of an ARD mission which are the close range rendezvous, final approach and the capture of the target. Modularity is seen as one of the key features of this GNC architecture given that it is envisioned to be built using the open source Robotic Construction Kit (ROCK) software framework. The main software modules of the GNC architecture are the: navigation module, guidance module, control module and robotics module. Each software module is responsible for a particular function within the GNC system and will be implemented using state of the art algorithms. The preliminary choice of those algorithms will be presented at the talk.

The envisioned automation and robotic (A&R) system consists of a clamping device for capturing the target vehicle, a robotic manipulator, for placing a de-orbiting kit into the nozzle of the target, and the instrument control unit which controls the A&R payload and communications with the on-board computer of the servicer. The clamping device is imagined to be a system composed of multiple individual fingers with adaptive internal structure in order to firmly grasp the target vehicle without relying on a particular structural feature. The robotic manipulator is a 6m long, DOF, agile robotic arm similar to the European Robotic Arm (ERA) and DLR's Light Weight Manipulator, currently being developed for the Deutsche Orbitale Servicing Mission (DEOS). Like the mentioned manipulators it consists of 7 modular, torque controllable joint elements and a special end-effector for handling hybrid propulsion de-orbiting kits. Finally, a future road map of the research related to the Stardust project will be presented to give the audience the general framework to the presented research.