A Soyuz-2-1B rocket lifted off from the Plesetsk Cosmodrome in Northern Russia, at 0633 GMT on 25 May. The mission carried the second EKS spacecraft (Edinaya Kosmicheskaya Sistema – Unified Space System), these satellites provide Russia’s missile early-warning system from a highly elliptical Molniya orbit. The spacecraft are sometimes referred to as “Tundra”.
The EKS satellites are the replacements for the Soviet-era OKO spacecraft which were launched from the 1970s up until 2010. The system is reported to require eight spacecraft to provide global coverage, however due to the characteristics of the Molniya orbit the satellites spend most of their time over the Northern Hemisphere.