GRALS Testbed

This robotic arm, attached to a 33 m track is ESA's GNC Rendezvous, Approach and Landing Simulator. Part of the Agency's Orbital Robotics and Guidance, Navigation and Control Laboratory, GRALS is used to simulate close approach and capture of uncooperative orbital targets, such as drifting satellites or to rendezvous with asteroids. It can also be used to test ideas for descending to surfaces, such as a lunar or martian landing.

The moveable arm can be equipped with cameras to test vision-based software on a practical basis to close on a scale model of its target. Image-processing algorithms recognise various features on the surface of the model satellite seen here, and uses those features to calculate the satellite’s tumble, allowing the chaser to safely come closer. Alternatively, the robotic arm can be fitted with a gripper, to test out actually securing a target, or with altimeters or other range sensors.

The Orbital Robotics and GNC Lab is located at ESA’s ESTEC technical centre in the Netherlands.