Space Situational Awareness

What is Space Situational Awareness?

Space Situational Awareness (SSA) is an essential component of the EU Space Programme. By providing comprehensive knowledge and understanding about space hazards, SSA plays a key role in ensuring the safety and security of the European economies, societies and citizens who rely on space-based capabilities and applications such as communication, navigation and observation applications.  

SSA covers three areas:

  • Space Surveillance and Tracking (SST): a system of networked sensors to survey and track space objects together with processing capabilities to provide data, information and services on objects that orbit the Earth.
  • Near-Earth Objects (NEO): capabilities to monitor the risk of natural space objects approaching the Earth, such as asteroids and comets.
  • Space Weather Events (SWE): capabilities to monitor space weather and solar activity.

What is Space Surveillance and Tracking?

More than 1 million pieces of ‘space debris’ are orbiting the Earth. With 20,000 new satellites expected to be launched over the next decade, this number will increase – as too will the risk of collision in space. 

Such collisions can create hundreds of new debris, increasing the risk against space activities and could severely damage an active satellite, or even destroy it, resulting in significant disruptions of services. 

To mitigate the risk of a collision between space assets – such as GalileoEGNOSCopernicus and GOVSATCOM satellites – and other spacecraft and debris, in-orbit fragmentations and uncontrolled re-entries of space objects, the EU established the Space Surveillance and Tracking (SST) sub-component of the EU Space Programme.

EU SST is the European operational capability that safeguards the space assets of the EU, especially the satellites involved in the EU Space Programme, its Member States and other space operators. It uses a network of ground-based sensors capable of surveying and tracking artificial space objects, together with processing capabilities aiming to provide data, information and services on space objects orbiting the Earth. EU SST currently provides three services:

  • Collision Avoidance (CA): risk assessment of collision between satellites or between satellites and space debris and generates collision avoidance alerts. 
  • Re-entry Analysis (RE): risk assessment of uncontrolled re-entry of artificial space objects into the Earth’s atmosphere and generates related information.
  • Fragmentation Analysis (FG): detection and characterisation of in-orbit fragmentations, break-ups or collisions, and analyses of all the available information regarding the object(s) involved in the event. 

Download the EU SST Leaflet

Download the EU SST Facts and figures




More than 200 organisations currently receive these services and more than 400 satellites are safeguarded from the risk of collision.

EUSPA’s role 

Following the European Commission’s decision from 3 June 2022, EUSPA has taken responsibility for the Programme’s SST Front Desk operations  starting from 1 July 2023. The responsibility was transferred from the European Union Satellite Centre (SatCen) to EUSPA’s Galileo Security Monitoring Centre (GSMC) in Madrid. 

The operational information is built by the SST Partnership made of EU Member States, from the SSA assets and national operations centres that are owned by the Member States.

The Front Desk is the main interface to deliver SST information and services between the SST Partnership and the users’ community, including activities related to user coordination, service performance, engagement and communication. 

In addition to its SST Front Desk responsibilities, EUSPA is contributing to the system’s security monitoring, particularly establishing the security requirements needed to shape the SST network in support of the European Commission and the EU SST Partnership. 

More here

Updated: Nov 30, 2023