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

The launch occurred on 27 June 1970 at 07:39:55 UTC, and resulted in the successful deployment of Kosmos 351 into low Earth orbit.

[5] It was operated in an orbit with a perigee of 261 kilometres (162 mi), an apogee of 429 kilometres (267 mi), 70.9 degrees of inclination, and an orbital period of 91.43 minutes.

[1][6] It remained in orbit until it decayed and reentered the atmosphere on 13 October 1970.