Kosmos 818 (Russian: Космос 818 meaning Cosmos 818), also known as DS-P1-Yu No.78, was a Soviet satellite which was launched in 1976 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.

[2] The launch occurred at 11:00 UTC on 18 May 1976, and resulted in the successfully insertion of the satellite into low Earth orbit.

[4] The North American Aerospace Defense Command assigned it the catalogue number 08851.

Kosmos 818 was the seventy-eighth and penultimate DS-P1-Yu satellite to be launched,[1] and the seventy-first to successfully reach orbit.