General Facts

TYPE
Self-propelled SAM system

ORIGIN
USSR

NICKNAMES
SA-8 Gecko (NATO reporting name)

DESIGNED
1960 - 1971

DESIGNER
OKB-2 Fakel

PRODUCTION
1972 - 1975 (9M33)
1975 - 1980 (9M33M2)
1980 - 1989 (9M33M3)

PRODUCERS
USSR - Almaz Antei

QUANTITY
Over 1.150 launch vehicles

UNIT COST
Unknown

CHARACTERISTICS
All in one system
Good accuracy and speed
Amphibious and good mobility
All weather system
Limited range
Engages single target at a time

Introduction

The 9K33 Osa is a point defense SAM system of Soviet origin. It was developed in the late 1960s and is operational since the early 1970s. In the West the Osa is known by the NATO reporting name SA-8 Gecko. The Osa replaced the 57mm S-60 towed anti-aircraft guns and is being supplemented by the new 9K330 Tor (SA-15 Gauntlet).

Missile

The missiles used in the Osa system feature a conventional design. Most of the missile is made up of the dual thrust solid rocket motor. The booster provides initial velocity and the sustainer maintains that speed. The HE-frag warhead is located at the front. There are four large control vanes at the rear and four smaller ones at the front. The missiles use radar command guidance and feature a contact and proximity fuze.

Layout

The Osa was the first self-propelled SAM system that incorporated both the missiles and the radar system. Both the launcher and transloader are based on the large amphibious BAZ-5937 6x6 chassis. The launch vehicle is fitted with a rotating parabolic through search radar and a tracking radar with a small missile guidance radar on each side. On either side of the radar assembly three missile canisters can be fitted.

Guidance

The search radar has an acquisition range of 30 km against most targets. The tracking range is 20 km. The Osa may operate autonomously but is usually supplied with data longer range radars such as the 175 km range P-40 (Long Track) early warning radar or the 250 km range P-15 (Long Track) acquisition radar.

Firepower

The Osa is able to launch two missiles at a single target. Targets can be engaged out to 10 km and at altitudes up to 5 km. The kill probability is quoted as being 0.35-0.85 for the original Osa and 0.55-0.85 for the later versions.

Mobility

The BAZ-5937 chassis provides a good all terrain performance and good mobility on road. The Osa is powered by a 300 hp diesel engine. The maximum road speed is 60 km/h and 30 km/h on dirt roads. It has an amphibious capability with speeds up to 8 km/h.

Users

The main user of the Osa was the Soviet military and it was widely exported to Warsaw pact nations and Soviet allies in the Middle East, Africa and Asia. Although the Osa is a dated design it is still a potent weapon system today. In Russian service it has been supplemented by the more capable Tor (SA-15 Gauntlet) which is also much more useful against cruise missiles and incoming missiles.

9K33 Osa system

9K33 Osa: Original Osa system introduced in 1972. Comprises of 9A33 launch vehicle with four 9M33 missiles out in the open. NATO reporting name SA-8A Gecko.
9K33M2 Osa-AK: Improved Osa system introduced in 1975. Based on the 9A33B launch vehicle with six 9M33M2 missiles in ribbed launch canisters. NATO reporting name SA-8B Gecko Mod 0.
9K33M3 Osa-AKM: Improved Osa-AK system introduced in 1980. Uses the 9A33BM launch vehicle with 9M33M3 missiles and IFF antennas. NATO reporting name SA-8B Gecko Mod 1.

Specifications:
Osa-AKM

Type	Self-propelled SAM system
Crew	5 (commander, driver, 3 operators)
Length	9.14 m
Width	2.80 m
Height	1.85 m (hull top), 4.2 m (search radar lowered), 4.86 m (firing position)
Ground clearance	0.42 m
Weight	17.6 t combat load (Osa-AK), 18.8 t combat load (Osa-AKM)
Ground pressure	?
Wheelbase	Wheeled chassis, 6x6, 3.08 + 2.79 m wheelbase
Turn radius	?
Engine	5D20 B-300 diesel, 300 hp at 2.000 rpm

Power ratio	17.1 hp/t (Osa-AK), 16.0 hp/t (Osa-AKM)
Transmission	?
Speed	60 km/h on road, 30 km/h on dirt road, 10 km/h cross country, 8 km/h in water
Fuel	350 L
Range	500 km on road
Wall	0.5 m
Trench	1.2 m
Gradient	?
Fording	Amphibious
Armor	No
NBC equipment	?

Night vision	?
Smoke	No
Remarks	APU
Armament	9M33 missile (6x)
Weapon1	SA-8 Gecko missile on turret 6 rounds, all ready to fire non-stabilized
Weapon2	-
Weapon3	-
Weapon4	-
Weapon5	-
Weapon6	-

9M33 missile

9M33: Original missile without launch canister as used with the 9K33 system.
9M33M: Original 9M33 missile modified for naval use. NATO reporting name SA-N-4. The 9M33M1 might be an improved naval Osa missile.
9M33M2: 9M33 with reduced minimum range and extended maximum range. First Osa missile to be carried in a launch canister. Used in the 9K33M2 system.
9M33M3: A 9M33M2 missile with extended range and larger warhead for increased effectiveness against helicopters. Used in the 9K33M3 system.

Specifications:
9M33
9M33M2
9M33M3

Type	Surface to air missile
Diameter
Length	3.158 m
Weight

Guidance	Radio command guidance
Warhead	13 kg
Propulsion
Speed

Range	2 to 9 km
Altitude	50 m to 5 km
Engagement envelope	420 m/s maximum target speed
Remarks	Pk aircraft: 0.35-0.85, Pk helicopters: 0.3-0.4, Pk cruise missile: 0.4

Type	Surface to air missile
Diameter
Length	3.158 m
Weight

Guidance	Radio command guidance
Warhead	13 kg
Propulsion
Speed

Range	1.5 to 10 km
Altitude	25 m to 5 km
Engagement envelope	500 m/s maximum target speed
Remarks	Pk aircraft: 0.5-0.85, Pk helicopters: 0.45, Pk cruise missile: 0.4

Type	Surface to air missile
Diameter	0.210 m body, 0.65 m wingspan
Length	3.158 m
Weight	126 kg, 161 kg with container

Guidance	Radio command guidance
Warhead	13 kg
Propulsion	Single-stage solid propellant rocket motor plus booster
Speed	1.850 km/h average

Range	1.5 to 10 km
Altitude	25 m to 5 km
Engagement envelope	500 m/s maximum target speed
Remarks	Pk aircraft: 0.5-0.85, Pk helicopters: 0.6-0.85, Pk cruise missile: 0.6

9T217 transloader

The 9T217 transloader is based on the same chassis as the launch vehicle. It carries 12 missiles and is fitted with a crane to load them onto the launch vehicles. Additionally it carries extra fuel. The missiles and crane are stored under a tarpaulin cover. The later 9T217B transloader is modified to accept the 9M33M2 and M3 missiles that are stored in ribbed canisters. The 9T217BM2 is used with the Osa-AK system and the 9T217BM3 with the Osa-AKM.

Specifications:
9T217BM2

Type	Transloader
Crew	3 (commander, driver, operator)
Length	9.23 m
Width	2.78 m
Height	3.10 m
Ground clearance	?
Weight	16.6 t combat load
Ground pressure	?
Wheelbase	Wheeled chassis, 6x6, 3.08 + 2.79 m wheelbase
Turn radius	?
Engine	5D20 B-300 diesel, 300 hp at 2.000 rpm

Power ratio	18.1 hp/t
Transmission	?
Speed	70 km/h on road, 15 km/h cross country, 8 km/h in water
Fuel	330 L + 640 L auxiliary
Range	?
Wall	0.5 m
Trench	1.2 m
Gradient	?
Fording	Amphibious
Armor	No
NBC equipment	?

Night vision	?
Smoke	No
Remarks	610 kg crane with 6.65 m heigh limit, refueling capability
Armament	-
Weapon1	-
Weapon2	-
Weapon3	-
Weapon4	-
Weapon5	-
Weapon6	-

9M33M naval system

The 9M33M Osa-M is the naval version of the Osa system. It was developed at the same time as the land based Osa system. In the naval version the ZIF-122 retractable pop-up two round launcher is used. The below deck magazine holds 20 missiles. The guidance systems are similar to the vehicle mounted set but are independent from the launcher and feature a stabilization system.

Osa-M: Original naval version of the Osa system. Introduced in 1972. NATO reporting name SA-N-4a Gecko.
Osa-MA: Improved version for export introduced in 1979 which reduces the minimum altitude from 60 to 25 meters.
Osa-2M: Final naval version that uses the 9M33M3 missiles. Operational since 1980. NATO reporting name SA-N-4b Gecko.