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.