The international responsibility of states for planetary defence activities

Among the legal issues raised by space missions related to NEOs, this chapter focuses on the international responsibility of states for planetary defence activities, describing the particularities of responsibility under international space law and analysing its application to planetary defence. It also refers to the difference between responsibility and liability, which has been dealt with in two previous chapters and addresses the applicability of circumstances precluding wrongfulness to planetary defence missions. The topic of the involvement of private actors, which is discussed in the next chapter, is mentioned here only as far as it regards the attribution of conducts of individuals to a state as source of international responsibility. From a general standpoint, the topic is treated with the aim of analysing whether the international responsibility of states for planetary defence activities presents any peculiarities with regard to the international responsibility of states under international law at large and under international space law as a part of international law.