Upravlyaemy Sputnik Kontinentalny Statsionarny (russian: Управляемый Спутник Континентальный Стационарный meaning ''Stationary Continental Controllable Satellite''), or US-KS (russian: УС-КС), also known as Oko-S, was a series of

Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...

, and later Russian, missile detection satellites launched as part of the

Oko OKO ( rus, ОКО, r=, literally means eye, also an abbreviation for Ob'yedinonnyye Kristallom Osnovaniya ( rus, Oбъединённые Кристаллом Oснования, r=, literally means Foundations Bound by a Crystal)) is a complex o ...

(russian: "eye") programme. US-KS was a derivative of the US-K satellite, optimised for operations in

geosynchronous orbit A geosynchronous orbit (sometimes abbreviated GSO) is an Earth-centered orbit with an orbital period that matches Earth's rotation on its axis, 23 hours, 56 minutes, and 4 seconds (one sidereal day). The synchronization of rotation and orbital ...

. Seven were launched between 1975 and 1997, when launches ended in favour of the modernised US-KMO. US-KS had the

GRAU The Main Missile and Artillery Directorate of the Ministry of Defense of the Russian Federation (), commonly referred to by its transliterated Russian acronym GRAU (), is a department of the Russian Ministry of Defense. It is subordinate to the ...

index ''74Kh6''. As of December 2015, the entire Oko programme is being replaced by the new EKS system. Manufactured by NPO Lavochkin, US-KS satellites had a launch mass of , and a dry mass of . Built on a three-axis stabilised cylindrical bus with a diameter of and a length of , the satellites carry infrared telescopes to detect the heat of missile exhausts. US-KS satellites were launched by Proton-K carrier rockets, with

Blok DM Blok D (russian: Блок Д meaning Block D) is an upper stage used on Soviet and later Russian expendable launch systems, including the N1, Proton-K and Zenit. The stage (and its derivatives) has been included in more than 320 launched r ...

and DM-2 upper stages. The first satellite to be launched was a prototype, which was followed by six operational spacecraft. With a spacecraft positioned at a longitude of 24° West, the Soviet Union could continuously monitor missile launches from the United States.

References

Oko Military satellites Military satellites of Russia {{Russia-spacecraft-stub