The Right of Self-Defence in Outer Space Law: Legal Issues and Way Forward

Space has never been so important as it is today. Modern societies depend on satellites for the provision of vital services, such as telecommunication, navigation, internet access, banking, etc . Also, the military apparatus of the most advanced countries relies on space assets to perform national defence tasks as well as to enhance the effectiveness of military operations.
The increasing relevance of space, both from an economic and military perspectives, inevitably, puts satellites at risk of being targeted in the event of conflict among nations. Unsurprisingly, thus, recent years have witnessed numerous developments intended to protect valuable space assets and give States the means to respond to a threat to their space objects. For example, a few countries have established military branches specifically designed to operate in outer space, the so-called ‘space forces’, and have developed and tested various counterspace capabilities.
In such a dynamic scenario, it seems logical to reflect upon the applicability of the right of self-defence in outer space, particularly on the circumstances triggering recourse to this right and the circumstances according to which such a right can be exercised. As this chapter will explain, the way in which the right of self-defence applies to outer space remains largely controversial . This is mostly due to two factors: 1) the international treaties governing activities in outer space contain no provisions on the exercise of the right of self-defence therein; 2) the existing public international law rules on self-defence were designed to be applied in relation to events occurring on Earth, either on the ground, sea, or air, not in outer space. Furthermore, due to peculiar characteristics of the space environment and space objects, it is simply not possible to take those rules as they stand, as well as their interpretation, and apply them to events happening in outer space; instead, in the majority of cases, it is necessary to adapt those rules or to perform an effort of creative interpretation.
After a section briefly outlining the relevance of self-defence in outer space in today’s geopolitical environment, this chapter will then analyse the right of self-defence, first, from an international law perspective, and then in the specific context of outer space. In order to do so, the chapter will end by envisioning a series of scenarios intended to demonstrate the challenges that one faces when attempting to exercise the right of self-defence in outer space and possible approaches to address them.