A laboratory test bed is introduced, which enables the hardware-in-the-loop simulation of the autonomous approach and docking of a chaser spacecraft to a target spacecraft of similar mass. The test bed consists of a chaser spacecraft and a target spacecraft simulators floating via air pads on a flat floor. The prototype docking interface mechanism of Defense Advanced Research Projects Agencyﾒs (DARPAﾒs) Orbital Express mission is integrated on the spacecraft simulators. Relative navigation of the chaser spacecraft is obtained by fusing the measurements from a single-camera vision sensor and an inertial measurement unit, through Kalman filters. The target is collaborative in the sense that a pattern of three infrared Light Emitting Diodes is mounted on it as reference for the relative navigation. Eight cold-gas on-off thrusters are used for the translation of the chaser vehicle. They are commanded using a non-linear control algorithm based on Schmitt triggers. Furthermore, a reaction wheel is used for the vehicle rotation with a proportional derivative linear control. Experimental results are presented of both autonomous proximity maneuver and autonomous docking of the chaser simulator to the non-floating target. Further analytical and experimental studies are currently on-going on the navigation and control of a multi-spacecraft system for on-orbit assembly and reconfiguration.