The 9K33 Osa, codenamed SA-8 Gecko by Nato, is a highly mobile, low-altitude, short-range tactical surface-to-air defence missile system designed in the Soviet Union.
The development of Osa began in 1960 in the Soviet Union in response to the US’ Mauler air missile defence system. Osa entered service with the Soviet Army in 1971, while Osa-M (SA-N-4 Gecko), the naval version of the system, was fielded in 1972.
The upgraded versions of the missile system include Osa-AK (SA-8B Gecko Mod-0) and Osa-AKM (SA-8B Gecko Mod-1).
The export versions of the missile system were marketed as the 9K33 Romb. The missile system and its variants were exported to Algeria, Angola, Armenia, Azerbaijan, Belarus, Bulgaria, Croatia, Cuba, Czech Republic, Ecuador, Georgia, Greece, India, Iraq, Jordan, Libya, Poland, Romania, Russia, South Africa, Syria, Tajikistan, Turkmenistan, Ukraine, and Serbia.
A number of countries have modernised the 9K33 Osa to improve its detection capabilities and firing range following its entry into service. Its Belarusian upgrade is known as Osa-1T, while the Polish upgrade is called Osa-AKM-P1 Zadlo.
Russian news agency TASS reported that the Osa-AKM missile system destroyed 115 aerial targets in combat missions in Ukraine in August 2022.
9K33 Osa missile system design and features
The 9K33 Osa missile system has a length of about 9.1m, a width of 2.78m, and a weight of up to 18,000t.
The surface-to-air missile system is mounted atop a six-wheeled BAZ-5937 fully-amphibious and air-transportable transporter erector launcher and radar (TELAR) vehicle.
The vehicle can carry up to five crew members and is fitted with a nuclear, biological and chemical (NBC) protection system.
The system carries its engagement radars on the same vehicle. The radar system on the vehicle is codenamed Land Roll by Nato. The all-in-one TELAR vehicles can detect, track and engage aircraft either independently or with the regimental surveillance radars’ assistance.
The system can’t launch missiles on the move, but can be prepared for engagement within four minutes of stopping. It takes 26 seconds from target detection to launch.
The BAZ-5937 TELAR features a turret fitted with four elevating missile launch rails, each armed with a 9K33A round and two radars, including an identification friend and foe (IFF) system and missile capture and uplink antennas.
The anti-aircraft system carries missiles with a length of 3.2m, a diameter of 0.21m and a weight of up to 126kg.
The missile can carry 14.5kg of high explosive fragmentation (HE FRAG) warhead. The missiles of the initial production version had a maximum range of 10km and a maximum altitude of 5km.
The second variant, 9K33M2 Osa AK, features the improved 9A33VM2 TELAR with more accurate fire control computers and an increased payload of six folding fin missiles in sealed container tubes.
The improved missile round can engage targets up to a maximum range of 12km. The missile features a two-channel proximity fuse designed to compensate for ground clutter and engage targets at lower altitudes. 9K33 Osa is always placed in the ready-to-launch position.
The missile system’s Land Roll engagement radar package provides a completely autonomous acquisition and engagement capability. The vehicle is also installed with a tracking radar and missile guidance component.
The antenna system allows Osa to launch two missiles against a single target simultaneously.
An electro-optical tracker provides the ability to track the target when electronic countermeasures jam the main tracking radar.
The missile system is powered by a turbocharged diesel engine, which provides an output of 300hp. It is also equipped with an auxiliary gas turbine power unit to power all systems when the main engine is turned off.
Osa-AKM missile system design and features
The 9K33M3 Osa-AKM anti-aircraft missile system, loaded on a self-propelled launcher, can be used to safeguard protecting troops on the march and in mobile combat. It is capable of defending troops and assets from manned and unmanned aerial attacks at low and medium altitudes and can strike enemy aircraft, cruise missiles, helicopters, drones and other adversary air attack weapons up to an altitude of 5km, at a range of 1.5km to 10.3km and a target speed of up to 500m/s.
The system carries six missiles in ribbed containers and features improved kill probability against low-flying helicopters.
The frequency-agile monopulse type Osa-AKM missile system is fitted with an elliptical rotating surveillance antenna placed on top of the array.
The H band (6GHz to 8GHz) radar has an acquisition range of 30km against most targets. The large-pulsed J band (14.5 GHz) engagement radar located in the centre of the array provides a maximum tracking range of about 20km.