Kosmos 311 (Russian: Космос 311 meaning Cosmos 311), known before launch as DS-P1-Yu No.27, was a Soviet satellite which was launched in 1969 as part of the Dnepropetrovsk Sputnik programme. 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.