Threats awaiting Earth observation satellites

The space environment imposes risks on the space assets and the services provided by or depending on satellites, such as communication, navigation, and intelligence. Space assets are vulnerable and protection means are very limited. Therefore SSA is the basis for the safe usage of space and protection of valuable space assets. With the advances in space technology, wider availability and use of space and satellite technologies, increased reliance on satellite systems in civil and military applications, and increased number of actors the need for the protection of space assets and for this purpose Space Situational Awareness (SSA) has continuously gained importance. This paper gives examples of threats awaiting Earth observation satellites and mitigation of risks through collision avoidance. The first requirement for collision avoidance is awareness of the threats, i.e., space debris and other satellites - generally Space Situation Awareness (SSA). After giving an overview of typical components of an SSA system and examples it discusses current SSA developments and opportunities in building space situation awareness.