Cosmos 2550

The russian Pion-NKS (14F139) satellites are the naval component of the next generation ELINT satellite system Liana. As a replacement for both the passive Soviet ELINT US-PM and the Soviet active radar US-A, they carry both ELINT sensors as well as an active radar. The Liana system replaces both the Tselina-2 with Lotos satellites and the naval US-PM and US-A with Pion-NKS (14F139) spacecraft.