The history of spaceflight has always been closely linked to the development of missile technology. But does that mean that advances in a country's missile programme also spell success for its space ambitions? And is there a difference between a rocket and a missile? Melissa Hanham, an affiliate with the Stanford Center for International Security and Cooperation, explains why missile developments matter for space, why diplomatic language around this wording can be important, and how space in turn helps us keep track of ballistic missile testing.