Legenda, or the MKRC Legenda system, is a Sovietsatellite targeting system mated to the SS-N-19 missile. It consisted of the US-PSIGINT satellites and the US-A Radar Oceanreconnaissance satellites, which were nuclear powered.[1]
The Legenda system consists of 37 ELINT satellites named US-P [2] and 32 US-A nuclear powered radar satellites [3] to provide global coverage.
Legenda is now non-functional after the US-A and US-P satellites were deactivated. It is being replaced by the Liana system with 4 operational satellites as of July 2021.[4]
^Brian Harvey The Rebirth of the Russian Space Program: 50 Years After 2007 "The US-P ("P" for "passive"; industry code 11F120) program began with Cosmos 699 in 1974, becoming operational as the Legenda system in 1978. US-P5 are built by the Arsenal Design Bureau in St. Petersburg. Thirty-six were launched."