OVERVIEW: The SO‑50 is a 120 mm short-range infrared/electro-optical decoy munition introduced by Russia in 1990. It is designed to seduce infrared-guided threats by deploying a thermal or optical signature at short stand-off range.

DETAILS: The SO‑50 is compatible with the 120 mm PK‑10 decoy dispenser system used aboard Russian naval vessels. It is launched from deck-mounted multi-barrel PK‑10 launchers to deploy a heated or optically reflective payload that simulates a ship’s infrared signature. Designed for close-in soft-kill defense, SO‑50 operates as part of a layered countermeasure suite alongside radar-distracting rounds like the SR‑50.

FONCTION:
Fired from the PK‑10 launcher upon detection of an IR or electro-optical threat.
Travels to a short stand-off distance before deploying its thermal/optical payload.
Creates a false signature to divert or confuse incoming IR-guided weapons.

SOURCE:
Naval-Technology article on Project 11356 frigates (PK‑10 A3-SO-50 electro-optical decoy round)