The use of space technologies has become a sine qua non condition for the well-being of people around the globe, resulting in a strong imperative to defend the space assets in orbit, and related infrastructure on Earth. Thus, the concept of space security is implying per se a military security dimension, however limited by the principle of peaceful purposes stipulated by the 1967 Outer Space Treaty. Nevertheless, the concept of space security is evolving, including aspects related to space economy, space debris mitigation and space sustainability. Overall, the terms “space for security” and “security in space” are different but complementary. The use of space technologies to ensure security on Earth and the operation of space assets without incoming threats implies space security policies.
Intentional collisions of objects in outer space (ASAT) imply a military activity which results in the destruction of the targeted object in orbit by colliding with it. ASAT were performed by top spacefaring nations, the United States (U.S.), China, India and Russia, by using direct-ascent intercontinental ballistic missiles against their own satellites located in Low Earth Orbit (LEO). Examples from recent years include the ASAT performed by China in 2007 at an altitude of about 863 km, India in 2019 at an altitude of about 283 km and Russia in 2021 at an altitude of about 480 km. Two major consequences result from ASAT. The immediate outcome is the deliberate creation of space debris, the collision in orbit generating thousands of pieces of trackable debris which start floating in space in an uncontrolled manner. The space debris could further increase in number because of the cascading effect and could even spread in higher orbits, therefore posing important threats to the safety of space operations in different orbits. Another consequence of ASAT is the threat to security in outer space. Thus, the ASAT can harmfully interfere with the operations of space objects pertaining to other countries, or even limiting the other countries options to accessing and using space. An assessment of the legality of ASAT implies a comparison between hard law and soft law provisions. The UN Space Treaties, including the Outer Space Treaty (OST), do not contain specific provisions regarding ASAT, whether this is allowed or prohibited. However, because ASAT negatively impacts the space environment and the operations of other actors in orbit, it could be considered a violation of the principles stipulated in Article IX OST. Moreover, the UN Space Debris Mitigation Guidelines have clear provisions against the creation of space debris, which is one of the consequences of ASAT. Therefore, even if these guidelines are voluntary in nature, there is a political and diplomatic consensus that States should avoid the creation of space debris. This is one of the reasons behind the implementation of these guidelines at national level, and imposing obligations to private companies to limit the creation of space debris. Overall, the concern at international level for reducing space threats, including ASAT, reiterates the relevance of negotiations on norms of behaviour in outer space. Among the most significant initiatives at international level regarding sustainability of outer space, it could be identified the UNCOPUOS Guidelines on the Long-term Sustainability of Outer Space Activities, the UNGA First Committee Resolution on norms of behaviour and the ongoing push for an international Space Traffic Management (STM).
Space security requires a holistic approach, which will also consider the limits of the orbital environments and sustainability. Outer space security depends on its environment and sustainability. Emerging space technologies and activities have a potential to destabilise global security. The growing problem of space debris elevates the increased risk of orbital collisions and poses challenges for accurate space situational awareness (SSA) and space traffic management (STM). With existing and proposed large constellations more new satellites are deployed in low Earth Orbit (LEO). While there are no specific international agreements on STM and space sustainability, we need both, a new interpretation and systemisation of existing laws, as well as creative thinking for the future of the interconnected Earth System-outer space. Space sustainability is necessary for ensuring safe and responsible actions in LEO. This requires international cooperation and consultation. Without a sustainable and safe space, the ability to use it for other essential purposes can be jeopardised. These include national security, telecommunications, navigation, or scientific exploration, Earth observation and climate change mitigation, as well as economic development and achievement of the broader Sustainable Development Goals (SDGs). Treating the Earth’s orbit as a vulnerable environment is necessary for space security. Some of the variables that require monitoring include space debris, the impact of space weather, and the impact of greenhouse gas emissions (GHGs) on space debris deorbiting, as well as the impact of launches on the Earth’s atmosphere. This means that both Earth System-orbit and interplanetary environments are of importance. The interaction of a space system with its orbital environment is a major consideration as natural environmental factors and interactions, in addition to anthropogenic activities, contribute to various hazards. Low altitude orbiting satellites usually experience fewer charging effects than high altitude geosynchronous (GEO) satellites, except for low altitude polar orbiting satellites which cross the auroral oval. Environmental factors include trapped and transient radiation, solar and galactic cosmic rays. Anthropogenic space debris consists of all non-functional, artificial objects, including fragments and elements thereof, in Earth orbit or re-entering into Earth’s atmosphere. Human-made space debris dominates over the natural meteoroid environment, except around millimetre sizes. The international legal framework needs to respond to both human needs, and the physics of the space environment. The Guidelines for the Long-term Sustainability of Outer Space Activities, 2019, as adopted in June 2019 provide us with important architecture. For instance, it specifies the need for addressing a risk to people, property, public health, and the environment associated with the launch, in-orbit operation, and re-entry of space objects; and promote regulations and policies that support the idea of minimizing the impacts of human activities on Earth as well as on the outer space environment. Hence the process of developing regulatory frameworks governing space activities need to avoid unintended consequences of anthropogenic environmental pollution, which imperil the present and long-term future of space security.
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.