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 303 was launched from Site 133/1 at the Plesetsk Cosmodrome,[2] atop a Kosmos-2I 63SM carrier rocket.

The launch occurred on 18 October 1969 at 10:00:03 UTC, and resulted in the successful deployment of Kosmos 303 into low Earth orbit.

Kosmos 303 was operated in an orbit with a perigee of 259 kilometres (161 mi), an apogee of 426 kilometres (265 mi), 71 degrees of inclination, and an orbital period of 91.4 minutes.

[1][4] It remained in orbit until it decayed and reentered the atmosphere on 23 January 1970.