[3] These give early warning of ballistic missile launches, mainly from the continental United States.

Oko consists of two types of early warning satellites - US-K and US-KMO.

The older US-K satellites are in highly elliptical molniya orbits which give them coverage of the United States at certain times during the day.

For full coverage of the US missile grounds four US-K satellites need to be operational and the system can have up to nine of them in orbit at once.

[6]: 40 As the eastern control centre it can communicate with geosynchronous satellites in four of the seven reserved locations, those looking over the Pacific.