SA-9 GASKIN (9K31 Strela-1) SURFACE-TO-AIR MISSILE
The SA-9 Gaskin (Russian name 9K31 Strela-1) is a highly mobile, short-range, low altitude infra-red guided surface-to-air missile system mounted on the wheeled armoured vehicle BRDM-2. The first Strela-1 (SA-9/`Gaskin') launchers were produced in 1966 with the system attaining operational status in 1968.
The system consists of a 9P31 BRDM-2 based Transporter-Erector-Launcher (TEL) with the normal turret and chain-driven belly wheels removed and replaced with a turret having four ready to launch SA-9 container-launcher boxes. Reloading is performed manually and usually takes approximately 5 minutes. The missile boxes are lowered for transport to lower the total height of the vehicle. The missiles fold down to the sides of the turret which greatly reduces the height of the vehicle whilst traveling.
The vehicle crew of three comprises the commander, driver and gunner. An air-filtration and overpressure NBC system are standard. The driver and commander have periscopes for viewing outside the vehicle when the hatches are closed as well as infra-red vision systems. The vehicle is fitted with the standard NBC (Nuclear, Biological and Chemical) protection including overpressure.
One SA-9 TEL vehicle in each battery, usually the battery commander, is fitted with 9S16 Flat Box-A radar detection antenna. The antenna are fitted either side of the hull above the front wheel housings, one under the left launch canisters pointing forward and one mounted on a small frame above the rear engine deck plate pointing rearwards. The azimuth scan sector for the system is 360º, the elevation capability 40º and the maximum detection range 30 km. The BTR-60PU-12 command vehicle of the Strela-1 unit is usually alerted by the Divisional Air Defence Regiment's command post as to a potential target's azimuth, range and altitude. This information is assessed with additional data from the unit's own visual observer network and any microwave transmissions picked up by the Strela-1 `Flat Box' TEL. The commander then instructs the unit as to which target should be engaged by which vehicle and orders the engagement(s) to commence.
The original version of the Strela-1 missile was known as the 9M31 (Gaskin' Mod 0) and used a 9E41 uncooled first-generation lead sulphide (PbS) infra-red seeker operating in the 1 to 3 µm waveband region. This was supplemented by the 9M31M variant (Strela-1M/SA-9b/`Gaskin' Mod 1) which entered service in 1970 and has an improved 9E41 PbS seeker operating in the 1 to 5 µm waveband region to provide greater target sensitivity and lock on ability. When engaging a head-on target the system has a considerably reduced range. The 1-5 µm waveband cooled lead sulfide (PbS) passive Infra Red homing seeker missile weighs 30 kilograms, is 1.8 meters long and 0.12 meters in diameter with a wing span of 0.375 meters. The speed of the missile is Mach 1.5 (1.5 times the speed of sound) and is fitted with a 3kg High Explosive fragmentation warhead with proximity fuze. The warhead has a lethal shrapnel radius of 5 m and damage radius of 7.6 m
The Strela-1 was deployed in short-range Air Defence Batteries of FAPLA motor rifle and tank regiments. The battery consisted of an anti-aircraft gun platoon and a SAM platoon with four Strela-1 vehicles. In combat the missiles are usually sequentially fired (two per target) to increase the kill probability with a time between rounds of about 5 seconds. Reloading is performed manually and takes about 5 minutes to accomplish. Operating in the visual and near IR regions the Strela-1 can home in on any air target from any direction in daytime since its tracking ability relies on a contrast (either positive or negative) with the background