| 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 |
| 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 |
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]
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]
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