What is Hubble's satellite catalog number?

Hubble’s satellite catalog number is 20580.

This number is Hubble’s unique identifier in the U.S. Satellite Catalog, commonly associated with the U.S. Space Surveillance Network and its successor tracking systems. Catalog numbers allow operators and researchers to distinguish an object in orbit from every other tracked spacecraft, rocket body, or debris fragment.

Hubble received catalog number 20580 after its launch aboard Space Shuttle Discovery in 1990. The number is not a serial number assigned by the telescope’s manufacturer, nor is it the same as Hubble’s COSPAR ID, 1990-037B. The COSPAR designator describes the launch year and launch sequence; 20580 is the catalog’s numerical object identifier.

Several tempting alternatives belong to other famous spacecraft. 25544 is the International Space Station’s catalog number, while the other choices identify unrelated satellites. Hubble’s catalog entry is useful for orbital tracking, predictions, conjunction screening, and identifying the telescope in satellite databases.