Europe’s Approach to Space Situational Awareness: A Proposal

According to the “User Expert Group of ESA SSA Requirement Study”, a Space Situational Awareness (SSA) system can be defined as a system which provides “comprehensive knowledge of the population of space objects, of existing threats and risks, and of the space environment”. As distinguished from the notion of “space surveillance” which denotes the routine and operational service of the detection, correlation, characterisation and orbit determination of space objects, the SSA concept “implies more in terms of data processing and use”. An SSA system is normally composed of space and ground segments. The United States is the only country which has so far developed a global SSA system. A European SSA programme could be started by connecting the existing national ground radars and telescopes in a single European network. In a later step, the system could then be completed with ESA space assets. A European SSA system could provide four categories of services that can be grouped into two big families: (1) Space Object Surveillance, including a Surveillance and Monitoring Service, an Imaging (Characterisation) Service; (2) Space Environment Monitoring, including a Space Weather Service, a Near-Earth Object (NEO) Service.