Yantar-4K1

Yantar-4K1, named Oktan, was a Soviet reconnaissance satellite and the second of the Yantar series, run by the GRU, the Soviet military intelligence agency, to supplement and eventually replace the Zenit spacecraft. It was a modification of Yantar-2K that kept the other systems of that type but carried a better camera, the Zhemchug-18, and stayed in orbit for 45 days rather than 30. Its first launch was Kosmos 1097 on 27 April 1979 and its last was Kosmos 1511 on 11 November 1983, twelve launches in all. It was in military service only from 1982 to 1983 and had the GRAU index 11F693. Launches from Plesetsk flew at inclinations of about 67 degrees, one from Baikonur flew at 64.9 degrees, and one in April 1983 flew at 70.4 degrees. The type was replaced by the Yantar-4K2, named Kobalt, which first flew in August 1981 and made its first operational flight in 1984.