Choice of suitable target for developing proposals for an ADR flight demonstration experiment

A concept for a flight demonstration experiment for active debris removal is presented. It is based on the exploitation of the launch of a payload in its desired orbit, then followed by the active debris removal demonstration experiment using the leftover resources of the upper stage, in terms of remaining propellant and electric battery residual lifetime, and a specialized piggy-back payload for the far guidance and acquisition of the selected target, the engagement and docking with it, the stabilization of the docked complex and, finally, its controlled de-orbiting. The basic components of the system will consist of a Transport and Docking Module (TDM), with its own autonomous propulsion, guidance, control and docking mechanism, and a retractable tether system, with a controllable drum for deployment and retraction, connecting the upper stage of the launcher with TDM. Concerning the choice of the target for the active debris removal demonstration experiment, ideal candidates are represented by the Russian Kosmos-3M second stages. In fact, there are a lot of them in low Earth orbit, concentrated in two narrow inclination bands and quite evenly distributed in right ascension of the ascending node, then offering a wide range of targeting opportunities. Moreover, their simple shape and symmetry around the longitudinal axis, their known characteristics and the presence of a nozzle ideally suited for a docking with a pin probe render these abandoned stages extremely attractive from an active debris removal point of view, as also confirmed by an evaluation of their environmental criticality ranking.