US-KS

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, and later Russian, missile detection satellites launched as part of the Oko (Russian: "eye") programme.[1] US-KS was a derivative of the US-K satellite, optimised for operations in geosynchronous orbit. Seven were launched between 1975 and 1997, when launches ended in favour of the modernised US-KMO.[2] US-KS had the GRAU index 74Kh6. As of December 2015, the entire Oko programme is being replaced by the new EKS system.[3]

US-KS

Manufacturer	NPO Lavochkin
Country of origin	Soviet Union  Russia
Operator	VKS
Applications	Missile defence
Specifications
Bus	Upravlyaemy Sputnik
Launch mass	2,400 kilograms (5,300 lb)
Regime	Geosynchronous
Dimensions
Production
Status	Retired
Launched	7
Operational	0
Retired	7
Failed	None known
Lost	0
Maiden launch	Kosmos 775 8 October 1975
Last launch	Kosmos 2345 14 August 1997
Related spacecraft
Derived from	US-K
Derivatives	US-KMO

Manufactured by NPO Lavochkin, US-KS satellites had a launch mass of 2,400 kilograms (5,300 lb), and a dry mass of 1,250 kilograms (2,760 lb). Built on a three-axis stabilised cylindrical bus with a diameter of 1.7 metres (5 ft 7 in) and a length of 2 metres (6 ft 7 in), the satellites carry 50 centimetres (20 in) infrared telescopes to detect the heat of missile exhausts.[4]

US-KS satellites were launched by Proton-K carrier rockets, with Blok DM 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.[4]