Kosmos 523

Kosmos 523, known before launch as DS-P1-Yu No.63, was a Soviet satellite which was launched in 1972 as part of the Dnepropetrovsk Sputnik programme. It was a spacecraft, which was built by the Yuzhnoye Design Bureau, and was used as a radar calibration target for anti-ballistic missile tests.
Kosmos 523 was successfully launched into low Earth orbit at 11:30:00 UTC on 5 October 1972. The launch took place from Site 133/1 at the Plesetsk Cosmodrome, and used a Kosmos-2I 63SM carrier rocket. Upon reaching orbit, the satellite was assigned its Kosmos designation, and received the International Designator 1972-078A. The North American Aerospace Defense Command assigned it the catalogue number 06222.
Kosmos 523 was the fifty-seventh of seventy nine DS-P1-Yu satellites to be launched, and the fifty-first of seventy two to successfully reach orbit. It was operated in an orbit with a perigee of, an apogee of, 71 degrees of inclination, and an orbital period of 91.7 minutes. It remained in orbit until it decayed and reentered the atmosphere on 7 March 1973.