The prohibition of the use of force is a universally applicable rule that applies in outer space and is a key element for the pursuit and achievement of space security. While space security is not the main focus of international space regulations in general nor of the Outer Space Treaty in particular, the prohibition of the use of force —set out in Article 2(4) of the UN Charter and also reflected in customary international law— is implicit in the references in articles I and III of the OST to the applicability of international law.
There are uncertainties about how to apply the prohibition of the use of force to space, many of which are not exclusive to outer space; rather, the unique nature of space brings these uncertainties to the fore.
In the context of multilateral debates, States have the opportunity to increase clarity on the interpretation of Article 2(4) of the UN Charter in its application to outer space. As the definition of prohibited force can help to clarify regulation of space capabilities and space behaviours and already applies to all States, the prohibition of the use of force can serve as a useful basis for advancing common understandings for Preventing an Arms Race in Outer Space.
Citation: Erin Pobjie & Almudena Azcárate Ortega. “Space Security Legal Primer 1 – Outer Space & Use of Force”, UNIDIR, Geneva, 2024. https://doi.org/10.37559/WMD/24/Space/02