An essential subtask for performing autonomous on-orbit servicing is the relative navigation between the approaching spacecraft and the target spacecraft. Camera based solutions can be cheap and lightweight and have low power consumption, but they need adequate estimation algorithms. In mobile robotics many approaches for camera based autonomous navigation have been developed so far. We present an approach for vision based autonomous relative spacecraft rendezvous navigation between a chaser and an uncooperative and unknown target based on simultaneous localization and mapping algorithms (SLAM) concepts. The paper outlines the general concept and details the mathematical formulation for stereo image observables. Performance results are shown based on simulation experiments.