The detection and cataloguing capability for objects in orbit, whose resolution determines what an underwriter can actually measure of collision risk.
Space situational awareness covers the radars, telescopes and processing that detect, identify and track objects in orbit in order to maintain a catalog and predict close approaches. Its practical limit is a size threshold: objects of a few centimeters escape routine tracking although they carry more than enough energy to destroy a satellite, so the catalog lists tens of thousands of objects while statistical models estimate several hundred thousand. That gap is not a technical footnote, it is the reason collision risk is priced off an environment model rather than off observation. Governance adds its own difficulty, since a large share of tracking data comes from military assets whose true accuracy is not public, leaving operators and their insurers dependent on a source they cannot audit. The European Union has built its own civil framework, and the general trend is to move the service toward civil authorities, a precondition for the data ever serving as evidence in a claim.
The European Union established a space surveillance and tracking support framework by Decision No 541/2014/EU of 16 April 2014, pooling member states' observation assets and providing collision warning services to operators.
SSA, space situational awareness, space surveillance and tracking, SST, catalogue orbital