Missile OTR-23 Oka (SS-23 Spider)

Development of the OTR-23 Oka began in 1972 to replace the R-17 Elbrus. The project addressed limitations of earlier liquid-fueled systems, such as slow launch preparation times and hazardous fuel handling. The system entered service in 1980.

The OTR-23 is a mobile theatre ballistic missile system utilizing a single-stage solid propellant motor with four exhaust nozzles. The missile is launched from a 9P71 transporter erector launcher based on an 8x8 BAZ-6944 amphibious chassis, which provides NBC protection and maintains the missile in a temperature-controlled, enclosed environment. Guidance is provided by an inertial platform integrated with an onboard digital computer and millimeter-wave active radar homing. The system is designed to engage stationary hardened targets, such as command centers and airfields, as well as moving targets. The missile can be readied for launch in less than 30 minutes. Warhead options include high explosive fragmentation, chemical, and cluster munitions containing 95 submunitions. The nuclear-armed variant is designated 9M714B and utilizes the 9M63 warhead. Documentation also indicates the availability of an earth-penetrating warhead for both conventional and nuclear applications.

The Soviet Union deployed the system during the final decade of the Cold War. The system was also transferred to several Warsaw Pact states, including Bulgaria, Czechoslovakia, and East Germany. These transfers became a point of diplomatic contention during the negotiation of the Intermediate-Range Nuclear Forces (INF) Treaty, as the Soviet Union informed the United States in 1990 of the covert transfer of at least 120 missiles to these states. While the missiles were transferred with conventional warheads, the equipment required to load nuclear warheads was retained. The system was phased out of Soviet service as directed by the INF Treaty. Successor states and former Warsaw Pact members retired their inventories in subsequent years; East Germany and the Czechia decommissioned the system in the 1990s, followed by Slovakia in 2000 and Bulgaria in 2002.