European Proximity Operations Simulator (EPOS)
Since the launch of the first Sputnik satellite in 1957, more than 8,000 satellites have been launched into space, of which around 5,000 are still in orbit today, but only 2,000 are still active (as of 2018). The rest have re-entered the Earth's atmosphere from low-Earth orbits at the end of their service life and burnt up. The remaining 3000 artificial earth satellites are still in various orbits as so-called space debris, but are no longer in operation, i.e. they can no longer be controlled from Earth.
Such non-operational satellites pose a threat both to other satellites and to manned spaceflight, as a collision could have devastating consequences. Such an incident already occurred in 2009 when two satellites (Iridium 33 and Kosmos 225) collided at an altitude of 790 kilometres, releasing a huge number of uncontrollable small pieces of space debris.
The entire rendezvous process during an on-orbit servicing mission can be simulated with the robotic test facility EPOS 2.0. Furthermore, the developed GNC procedures are verified by hardware-in-the-loop simulations. The system consists of two industrial robots, each with six degrees of freedom, which simulate the translational and rotational movement of two satellites, and a 25 metre long rail to move one of the two robots from a distance of 25 metres to 0 metres.