"SA-8" redirects here. For the Apollo flight, see A-104 (SA-8)
The 9K33 Osa (English: wasp) is a highly mobile, low-altitude, short-range tactical surface-to-air missile system. "9K33" is its GRAU designation. Its NATO reporting name is SA-8 Gecko. Its export version name is Romb.
The SA-8 was the first mobile air defense missile system incorporating its own engagement radars on a single vehicle.
All versions of the 9K33 feature all-in-one 9A33 transporter erector launcher and radar (TELAR) vehicles which can detect, track and engage aircraft independently or with the aid of regimental surveillance radars. The six-wheeled transport vehicles BAZ-5937 are fully amphibious and air transportable. The road range is about 500 km.
The 1S51M3-2 radar system on the SA-8 TELAR received the NATO codename Land Roll. It was derived from the naval `Pop Group' radar system but is smaller since it does not require the elaborate stabilisation system. An improved system designated the SA-8B `Gecko' Mod 1, was first seen in Germany in 1980. It had improvements added to the launcher configuration, carrying six missiles in ribbed containers. The system is reported to be of the frequency-agile monopulse type. It consists of an elliptical rotating surveillance antenna mounted on top of the array, operates in H band (6 to 8 GHz) and has a 30 km acquisition range against most targets. The large pulsed J band (14.5 GHz) engagement antenna is mounted below it in the centre of the array and has a maximum tracking range of about 20 km.
Mounted on either side of the tracking radar antenna is a small J band parabolic dish antenna to track the missile. Below that is a small circular antenna which emits an I band uplink capture beam to gather the missile shortly after launch. The final antennas in the array are two small white rectangular ones, one on either side of the array mounted alongside the I band. These are used for command uplink to the missile. This twin antenna system permits the 'Land Roll' radar to control up to two missiles simultaneously against a single target. Furthermore, the two missiles can be guided on different frequencies to further complicate ECM. There is also a tubular device fitted to and above the tracking radar; this is a 9Sh33 electro-optical tracker. It can be used to track the target when the main tracking radar is jammed by ECM.
A 9K33 battery comprises four 9A33B TELAR vehicles and two 9T217 transloader vehicles on BAZ-5939 chassis with reload missiles and a crane. A reload time of five minutes has been reported per TELAR.
In addition to the TELARs, each regiment is also assigned a single radar collimation vehicle 9V914 (initially on the BAZ-5938 chassis but more often found on the ZiL-131 truck). This vehicle assists in the alignment of the TELAR's radar systems, ensuring accurate target tracking and engagement.
- 9K33 "Osa" (US DoD designation SA-8A "Gecko") began development in 1960 and was introduced in 1971-1972 with four exposed 9M33 missiles per TELAR 9A33B and a maximum range of 12 km (7.5 mi).
- 4K33 "OSA-M" (NATO reporting name SA-N-4 "Gecko") was introduced in 1972 and is the naval version of the system with two 9M33M missiles on a Zif-122 retractable rotating launcher and improved performance. It has been installed on Gepard class frigate, Kara class guided missile cruisers, Kiev class VTOL cruisers and also the Kirov, Slava and Krivak classes.
- 9K33M2 "Osa-AK" (US DoD designation SA-8B "Gecko Mod-0") with TELAR 9A33BM2 was introduced in 1975 with the new six-missile box launcher, each 9M33M2 missile being a sealed round.
- 9K33M3 "Osa-AKM" (US DoD designation SA-8B "Gecko Mod-1") with TELAR 9A33BM3 and missiles 9M33M3 was introduced in 1980 with the maximum range extended to 15 km (9.3 mi) and maximum altitude to 12 km (40,000 ft) as explained above. Most OSA-AKM systems also feature an IFF antenna.
- Saman and Saman-M (Russian Саман – adobe) is a development of the Osa\Osa-M system into target drones, used for testing and training with air defense systems, including SAMs.
The 9K33M3 is also able to utilize the 9A33BM3 missiles which are wire-guided, presumably for use in an ECM-heavy environment where the radio command guidance may not operate properly.