Kosmos 553

Kosmos 553, known before launch as DS-P1-Yu No.55, was a Soviet satellite which was launched in 1973 as part of the Dnepropetrovsk Sputnik programme. It was a 400-kilogram (880 lb) spacecraft, which was built by the Yuzhnoye Design Bureau, and was used as a radar calibration target for anti-ballistic missile tests.

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