It was a 325-kilogram (717 lb) spacecraft, which was built by the Yuzhnoye Design Bureau, and was used as a radar calibration target for anti-ballistic missile tests.

[1] Kosmos 523 was successfully launched into low Earth orbit at 11:30:00 UTC on 5 October 1972.

[2] The launch took place from Site 133/1 at the Plesetsk Cosmodrome,[3] and used a Kosmos-2I 63SM carrier rocket.

[4] The North American Aerospace Defense Command assigned it the catalogue number 06222.

[6] It remained in orbit until it decayed and reentered the atmosphere on 7 March 1973.