Since the beginning of space exploration, dating back to the launch of Sputnik 1 in 1957, a new sector called Space Economy has simultaneously developed. Among the many activities that are growing in this field, In-Orbit Servicing is emerging. This one includes a set of operations on satellites already in orbit, such as: Life Extension, Relocation, De-Orbiting, Robotics, Space Situational Awareness, Active Debris Removal and Last Mile Delivery. These are becoming more and more interesting, especially because the number of satellites already in orbit, space debris and collisions is increasing dramatically: it is therefore convenient to think about extending the life of satellites already in orbit, especially for the most distant orbits hosting larger satellites.