Space Situational Awareness programme (SSA) The Space Situational Awareness (SSA) initiative of the European Space Agency (ESA) is aimed at providing independent information and services regarding the environment, threats (man-made as well as natural) and sustainable exploitation of the region of space surrounding planet Earth, including the Lagrangian points. The main objectives of the future European SSA System include: Space Surveillance and Tracking of man-made objects in Earth orbit maintain a catalogue of man-made objects in Earth orbit, detection, tracking, correlation and cataloguing of all objects above a given size threshold for a given orbit region, prediction and warning of collisions and re-entry events, detection of on-orbit explosions, collisions and manoeuvres. Space Weather Monitoring and Forecasting detection and forecasting of Space weather and its effects, monitoring of the Sun, solar wind, radiation belts, magnetosphere, ionosphere and ground based effects, support services relating to effects, including: radiation and spacecraft charging hazards, spacecraft drag; ionospheric perturbations, aircraft radiation hazards, geomagnetic disturbances, and current induced in large conductive networks, such as power lines and pipelines. Near Earth Objects (NEOs) Surveillance, Tracking and risk assessment solar system objects with orbits that bring them into close proximity with the Earth. They include a few thousand Near Earth Asteroids, Near Earth Comets and larger meteoroids, identification and ranking of NEO collision risk with Earth, monitoring and tracking of natural space objects and determination of orbit state and physical parameters of trackable objects, warnings and mitigation support. The European SSA System will be highly federated, integrating new and pre-existing assets that may be owned and operated by diverse private, national and international organisations. A network of ground- and space-based sensors will provide input data to a set of SSA Service Centers that will be specific to each of the main functions.