Wikipedia
US-KMO , is a series of Russian, previously Soviet, satellites which are used to identify ballistic missile launches. They provide early warning of missile attack and give information for the Moscow A-135 anti-ballistic missile system. They were run by the Russian Space Forces and its successor the Aerospace Defence Forces.
These satellites are part of the Oko programme and are in geosynchronous orbit 35,750 km above the Earth's equator. This means that they are always in the same place with the same field of view. Western locations give Russia coverage of missile launches in the United States whereas more eastern ones give coverage of China and the Middle East. They complement ground based early warning radars and the US-K satellites which are in molniya orbits.
The first prototype satellite was launched on 8 October 1975, atop a Proton-K/ DM-2 carrier rocket from Baikonur Cosmodrome. The most recent, and last of the series, was launched on 30 March 2012. As of December 2015, the entire Oko programme is being replaced by the new EKS system.