NORAD Catalog Number (NORAD ID)

The NORAD Catalog Number (also called SATCAT number or USSPACECOM object number) is a sequential integer assigned by the US Space Force to every tracked object in Earth orbit. For example, the ISS is 25544 and Sputnik 1 was 00001. The number is permanent — even after an object re-enters, its number is never reused. Orbital Radar uses NORAD IDs as the primary identifier for all tracked objects.