The Right of Self-defence in the Earth’s Orbit

The increasing presence of non-State actors in space raises a plethora of legal questions, including those related to the use of force, especially in the context of the right of self-defence. The first aim of this article is to explain the legal basis for resorting to force in the exercise of self-defence in space, specifically in the Earth’s orbit. The second goal is to contribute to the legal framework concerning how States may exercise self-defence against attacks committed by non-State actors in space. In this regard, the author distinguishes between the rules of attribution of the use of force to a State and the “unwilling or unable” doctrine. It is suggested that the latter may be transposed into the space domain, mutatis mutandis, by a re-conceptualisation of the notion of a State’s “territory”, shifting from its sovereignty-based foundation towards State jurisdiction. Further on, in the realm of the rules of attribution of conduct to a State, the author compares the ARSIWA rules of State responsibility with the strict responsibility regime of the Outer Space Treaty (OST), to clarify which system applies when addressing State responsibility for the use of force by non-State actors in space. Three solutions are offered in this regard. The first rests on the premise that space law, specifically Article VI OST, may be seen as lex specialis in relation to ARSIWA. The second supports the view that the general rules of State responsibility in ARSIWA should apply, as they are secondary rules of international law, whereas Article VI OST encompasses primary rules. The third approach offers a combined reading of Article VI OST and ARSIWA, based on a systematic interpretation of the norms contained therein, to preserve the purpose of the secondary rules on State responsibility.