This paper examines the legality of using Rendezvous and Proximity Operations (RPO) as a counterspace weapon. RPO enables a satellite to approach, inspect, or manoeuvre in proximity to another object, allowing kinetic or non-kinetic attacks, electronic interference, or intelligence gathering, sometimes pretending to be engaged in civilian activity. While the weaponization of space has been widely discussed, the legality of specific technologies such as RPO remains underexplored. Under Article 2(4) of the UN Charter, employing RPO as a kinetic or non-kinetic weapon may constitute a ‘use of force’, This would apply even if it only partially damages the target, given the irreversibility and high value of space assets. RPO’s unique features should also be considered: its ability to image and exert pressure on another satellite during its proximity operation even prior to any actual attack. While imaging alone, similarly to cyber espionage, may not violate international law, proximity operations intended to intimidate may amount to a ‘threat of force’. This paper concludes that legal analysis, involvement of technical experts, and tailored governance frameworks focusing on RPO’s distinctive challenges are essential.
Air and Space Law