The concept of space security can be extended to include the area of space defence, which is made of two dimensions: “space for defence” and “defence of space”. The former refers to the use of space solutions for the conduct of military activities on Earth. Indeed, Earth observation, telecommunications and position, navigation and timing capabilities provide essential services to the armed forces, from precise intelligence, surveillance and reconnaissance to the possibility of guiding missiles and to communicate securely. For this reason, the integration of space systems into military planning has steadily increased since the 1991 Gulf War. The second dimension, “defence of space”, refers to the protection of assets in orbit, in particular against antisatellite technologies or cyberattacks.

In the past, and still to a major extent today, military space programmes used to rely on exquisite and tailor-made spacecraft, manufactured by a few trusted companies. However, in the recent years, a change has occurred, especially in the United States: military actors have been increasingly eager to adopt the products, services and concepts developed by commercial companies belonging to the New Space ecosystem. As an example, the Space Development Agency, set up in 2019, plans to launch a constellation of hundreds of small satellites to provide different types of services to the armed forces (e.g., data transfer, early warning, ISR). This project is clearly influenced by the idea of large constellations promoted by non-traditional private actors, most notably SpaceX, and aims at reinforcing the resilience of the services essential to the conduct of military operations. Similarly, the U.S. Department of Defense is increasingly interested in the concept of “responsive launch” (launching small satellites at any time, from anywhere) and, for this reason, keeps an eye on the evolution of the micro-launcher sector.

At this moment, this trend remains mostly circumscribed to the United States, as the military space programmes of other major spacefaring nations (e.g., Russia, China) still rely exclusively on their traditional defence sector. Nonetheless, this evolution calls for new approaches in tackling space security and defence issues and, in particular, the role of private actors in these activities.