With the launch on 22 May of the fourth Tundra-series satellite into long-dwell orbit, deployment was completed of the minimum capability in the Russian early warning missile defence system.
Tundra satellites operate as part of the Kupol integrated space system (formerly known as EKS), which is designed to track ballistic missile launches.
The satellite constellation is equipped with telescopes designed to detect the launch of enemy ballistic missiles by their powerful IR emissions, which can be observed from space. Early warning satellites are launched either into highly elliptical orbit (with a 40,000-50,000km apogee) or geosynchronous orbit that allows the satellite