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Yantar-4KS1 (Terilen, 11F694)

Yantar-4KS1 [TsSKB]

The Terilen or Yantar-4KS1 satellites were the first series of soviet elctro-optical reconnaissance satellites. They transmitted the data via Potok (Geizer) relay satellites.

The Yantar-2K (Feniks) was not capable of providing strategic warning of attack and fast reaction due to the need to return the film. Therefore additional variants were developed, one of them the detailed electro-optical and operational reconnaissance satellite Yantar-4KS. The spacecraft was designed to relay visual and infrared band images via a digital data link to the planned Potok-Luch GKRSS relay satellite system.

There were two phases to the project plan. The first phase spacecraft, the Yantar-4KS1 (Terilen), would be launched by the Soyuz-U launch vehicle, begin flight trials of system components in 1979, with the system to be accepted into the military by 1981. Phase 2 would be the more capable Yantar-4KS2, launched by the more powerful Zenit-2 launch vehicle, with flight trials to begin in 1983.

Soviet digital electronics technology hampered a fast development. The structure and wire harnesses for the first spacecraft were completed in 1978, but delays in the electronics meant that the first flight could not begin until the end of 1982. But the very first trials flight, in conjunction with the first Potok communications relay satellite, proved the worth of the system, with immediate operational use of the imagery. Yantar-4KS1 was accepted into military service in 1985.

On 1 June 1983 the Yantar-4KS2 was cancelled and it was decided to modernise the Yantar-4KS1 instead forming the Yantar-4KS1M (Neman).

Typical orbital profile of the satellites was: inclination 64.9 degrees with an altitude of 230-280 km or 180-270 km.

Nation: USSR
Type / Application: Reconnaissance, photo (data transmitting)
Operator: GRU
Contractors: TsSKB
Configuration: Yantar Bus
Power: 2 deployable solar arrays, batteries
Satellite COSPAR Date LS Launch Vehicle Remarks
Kosmos 1426 (Yantar-4KS1 #1, Terilen #1) 1982-120A 28.12.1982 Ba LC-31/6 Soyuz-U
Kosmos 1552 (Yantar-4KS1 #2, Terilen #2) 1984-045A 14.05.1984 Ba LC-31/6 Soyuz-U
Kosmos 1643 (Yantar-4KS1 #3, Terilen #3) 1985-026A 25.03.1985 Ba LC-1/5 Soyuz-U
Kosmos 1731 (Yantar-4KS1 #4, Terilen #4) 1986-013A 07.02.1986 Ba LC-1/5 Soyuz-U
Kosmos 1770 (Yantar-4KS1 #5, Terilen #5) 1986-060A 06.08.1986 Ba LC-1/5 Soyuz-U
Kosmos 1810 (Yantar-4KS1 #6, Terilen #6) 1986-102A 26.12.1986 Ba LC-1/5 Soyuz-U
Kosmos 1836 (Yantar-4KS1 #7, Terilen #7) 1987-033A 16.04.1987 Ba LC-1/5 Soyuz-U
Kosmos 1881 (Yantar-4KS1 #8, Terilen #8) 1987-076A 11.09.1987 Ba LC-1/5 ? Soyuz-U
Kosmos 1936 (Yantar-4KS1 #9, Terilen #9) 1988-027A 30.03.1988 Ba LC-1/5 Soyuz-U
Kosmos (1958) (Yantar-4KS1 #10, Terilen #10) 1988-F02 09.07.1988 Ba LC-1/5 F Soyuz-U
Kosmos (1979) (Yantar-4KS1 #11, Terilen #11) 1988-F05 11.11.1988 Ba LC-1/5 ? F Soyuz-U
Kosmos 2007 (Yantar-4KS1 #12, Terilen #12) 1989-024A 23.03.1989 Ba LC-1/5 Soyuz-U
Kosmos 2049 (Yantar-4KS1 #13, Terilen #13) 1989-088A 17.11.1989 Ba LC-1/5 Soyuz-U
Kosmos 2072 (Yantar-4KS1 #14, Terilen #14) 1990-033A 13.04.1990 Ba LC-1/5 Soyuz-U
Kosmos 2113 (Yantar-4KS1 #15, Terilen #15) 1990-113A 21.12.1990 Ba LC-1/5 ? Soyuz-U