A NORAD ID is the catalogue number given to every tracked object in orbit — the ISS is 25544 and India's Cartosat-3 is 44804.
Thousands of objects circle the Earth: working satellites, dead ones, spent rocket stages and broken pieces. To keep them apart, each tracked object gets a number in one public list, the satellite catalogue. Trackers, including this one, usually call that number the NORAD ID.
The name is historical. A 1980 US report on orbit prediction describes NORAD (the North American Aerospace Defense Command) as the body that kept orbital data on every object in space. Today NASA describes the US Space Force's 18th Space Defense Squadron as the unit that runs the Space Surveillance Network, keeps the space catalogue and hosts the Space-Track.org website.
Every satellite page on this site is addressed by its NORAD ID. Cartosat-3 lives at /satellite/44804, and its Satellite Information table repeats the number in the NORAD ID row. The search box on the globe accepts a NORAD ID as well as a name, and every pass card's Track live link points to `/satellite/` followed by the number.
Why a number and not a name? Names change and repeat. EOS-05 is also catalogued as GISAT-1A; there are many objects called simply ‘R/B’ (rocket body). The number never changes, so it is the safest way to ask a database for one object. When this site downloads fresh orbital data, it matches each record to the right satellite by this number.
The address bar ends in 44804, and the same number appears in the NORAD ID row of the Satellite Information table. Open Cartosat-3
The catalogue number sits in columns 3–7 of both lines of a two-line element set (TLE), and the two copies must match. Five columns can only hold numbers up to 99999, which is why CelesTrak states plainly that TLE formats will not support catalogue numbers above 99999.
CelesTrak's answer is to move users to the CCSDS Orbit Mean-Elements Message (OMM), which it serves as XML, KVN, JSON and CSV. Its query interface already accepts a catalogue number of 1 to 9 digits, and its SATCAT documentation notes that all newly catalogued objects now get six-digit numbers of 100000 and above.
Not everything the radars see gets a catalogue number at once. NASA's conjunction-assessment FAQ explains that objects the 18th Space Defense Squadron tracks but cannot tie to a launch are not officially catalogued; they get a temporary SatID in the 80,000 range.
Worked example: ask CelesTrak's SATCAT service for number 44804 and it returns OBJECT_NAME CARTOSAT-3, OBJECT_ID 2019-081A, LAUNCH_DATE 2019-11-27, LAUNCH_SITE SRILR, an orbit of 500 × 516 km at 97.41° inclination and a period of 94.78 minutes. The NORAD ID is the key; everything else hangs off it. Objects also stay in the catalogue after they fall: number 1 still has its record, with a decay date of 1957-12-01.
25544. It was catalogued from the station's first module, Zarya, launched in 1998.
Because, according to CelesTrak, the five-digit catalogue numbers ran out on 11 July 2026, before its launch on 3 September 2026. New objects now get numbers of 100000 and above.
The US Space Force's 18th Space Defense Squadron, which publishes it on Space-Track.org.