Almaz 5V24/5V27/S-125 Neva/Pechora 
Air Defence System / SA-3 Goa
  Зенитный Ракетный  Комплекс 5В24/5В27/С-125  Нева/Печора

Technical Report APA-TR-2009-0602

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The S-125 Neva/Pechora / SA-3 Goa Surface to Air Missile system was developed to supplement the S-75 Dvina / SA-2 Guideline in Soviet and Warsaw Pact service. The S-75 Dvina / SA-2 Guideline was designed to provide medium to high altitude air defence coverage, primarily against bomber aircraft. As such it was not well suited to the engagement of low flying targets, especially fighter aircraft and cruise missiles.

The design aim of the S-125 Neva/Pechora / SA-3 Goa was thus to produce a system with a low to medium altitude engagement envelope, thus providing for overlapping all altitude air defence coverage of protected airspace. Specifically, targets travelling at speeds of up to 1500 km/h (800 KTAS) and at altitudes from 100 m to 5000 m (~300 ft to 16,500 ft AGL),  at ranges of up to 12 km (~6,5 NMI) were to be engaged and destroyed. Such performance is today characteristic of a point defence weapon, but during the 1950s it was more typical of area defence weapons.

The Soviets sought to build on the experience gained with the S-75 Dvina / SA-2 Guideline, using command link guidance and a proximity fused warhead, but recognised from the outset that a fundamentally new engagement radar design was required with much better clutter rejection performance than the RSNA/SNR-75 / Fan Song series. The requirement for narrower  antenna mainlobes drove the designers into the 9 GHz frequency band, well above the ~6 GHz operating range of the earlier RSNA/SNR-75 Fan Song series. Development was initiated in 1956, aiming for an IOC after 1960.

The resulting weapon was more compact than the S-75 Dvina / SA-2 Guideline, permitting two rail launchers and two round transloaders, and used a solid propellant sustainer, the first in a PVO SAM design. Canard controls were employed. Like its predecessor, the missile used a solid rocket first stage booster. Numerous development problems were encountered throughout the system, but especially with the performance of the radio proximity fuse and command link guidance at very low altitudes.

The Soviets were particularly concerned about US Air Force low altitude penetration trials flown by the B-58 Hustler, which demonstrated the ability to penetrate US SAM belts undetected, by exploiting ground clutter and elevated terrain, a factor which influenced the design of the subsequent F-111/FB-111 series and the B-1A LRCA.

Trials of the V-600P missile round and new radar demonstrated the capability to engage targets at speeds of up to 2,000 km/h (~1,100 KTAS), at altitudes between 200 m and 10,000 m (~600 ft to 33 kft AGL), with the target pulling up to 4G at 5,000 m to 7,000 m (16.6 kft to 23 kft) and up to 9 G below 3,300 ft AGL at transonic speeds. Estimated single shot P_k was 0.82-0.99, deteriorating to 0.49-0.88 if chaff were deployed.

While the new system met the needs of the PVO, its stow and deploy times were similar to the S-75 Dvina / SA-2 Guideline and thus too great for the Army air defence units, who rejected the design, resulting in the development of the high mobility 2K12 Kub / SA-6 Gainful system. The S-125 Neva / SA-3A Goa achieved IOC in 1961, deployed as part of the Moscow region SAM belt.

The first improved variant was the S-125M Neva M / SA-3B Goa, intended to improve the missile's kinematic engagement envelope, low altitude fusing and radar clutter rejection, and used a new four rail launcher. The new missile was designated the V-601P/5V27. IOC was not achieved until early 1964.

The weapon was not deployed to South East Asia as the Soviets feared that the US Air Force would quickly analyse its design and find its weaknesses, and develop effective countermeasures, as they had done so successfully with the S-75 Dvina / SA-2 Guideline. Instead, the Soviets exported the weapon to Egypt, to counter the innovative Israeli air force, who frustrated Soviet instructors during the war of attrition, by flying well below the engagement envelope of Egyptian S-75 Dvina / SA-2 Guideline batteries.

In Egypt, the sandy desert terrain proved problematic for wheeled vehicles, which were often replaced with tracked AT-S artillery tow tractors. The Soviet instructors shot down several Israeli aircraft during the War of Attrition, mostly F-4E Phantoms and at least one A-4 Skyhawk. The US ALQ-101 jamming pods were effective against the S-75 Dvina / SA-2 Guideline, but not the S-125 Neva / SA-3 Goa, possibly due to different operating bands and antenna scan frequencies. The good low altitude capability of the weapon frustrated Israeli low altitude penetration tactics. In the subsequent 1973 Yom Kippur war, the S-125 Neva / SA-3 Goa repeated its earlier achievement, outperforming the S-75 Dvina / SA-2 Guideline.

Operational experience from the Middle East led to the development of the S-125M1 Neva M1 upgrade package, intended to improve countermeasures resistance and performance. The 9Sh33A Karat 2 television telescope was added to provide for optical angle tracking under daylight conditions, and a new heavier and faster 5V27D missile round was designed. The heavier missile resulted in the 5P73 launcher loadout being limited to three missiles. IOC was achieved in 1978.

The S-125 Neva / SA-3 Goa was also used extensively by Iraq during the Iran-Iraq war, but reliable statistics do not exist, given that both sides in the conflict had a well established habit of grossly overstating kills in combat.

The S-125 Neva / SA-3 Goa did not perform well during the Desert Storm campaign, as it had been completely compromised due to the Israeli capture of SNR-125 Low Blow radars in 1973, and good countermeasures were available. Nevertheless, the weapon is usually credited with the handful of Iraqi SAM kills against Coalition aircraft.

The last two documented kills credited to the S-125 Neva / SA-3 Goa are the F-117A Nighthawk and an F-16 lost during Operation Allied Force in 1999.

The basic S-125 Neva / SA-3 Goa qualifies as semi-mobile, requiring several hours to set up or redeploy a battery. Typical battery composition is a single SNR-125 Low Blow  series engagement radar, four dual rail 5P71 or four rail 5P73 launchers, and multiple PR-14 series dual round  transporter/transloader trucks carrying reload rounds. Most S-125 operators deploy the system in fixed sites, with revetments using concreted pads and bays, and/or earthwork berms, to protect the missile system components.

SNR-125/125M Low Blow Engagement Radar

A more detailed discussion can be found under Engagement and Fire Control Radars.

5V27 (V-601P) Goa Cutaway (via Vestnik-PVO/Aviatsiya i Kosmonavtika No12/2002)
1	Proximity fuse transmit antenna
2	5E18 radio proximity fuse
3	Canard controls
4	5P18 72 kg fragmentation warhead (4,500 fragments)
5	Receive antenna
6	Transducer
7	Splitter/converter box
8	Battery
9	5A22/APS-600 autopilot
10	5U42/UR-20A Command link control module
11	Aileron control
12	Aileron drive
13	Sustainer powerplant with 151 kg of 301-K solid propellant providing 20 sec burn duration
14	Compressed air tank
15	Initiator for sustainer powerplant
16	Adaptor destabilising fins
17	5S45/PRD-36 boost powerplant with 2-4 sec burn duration / 14 tubes of NMF-3K propellant
18	Stabiliser pivot

Early model 5V24 SA-3A Goa missile (Almaz image via Vestnik PVO).



  Late model 5V27 SA-3B Goa missile (Almaz image via Vestnik PVO).

The nose of the missile houses the radio proximity fuse. In early variants this was the 5E15 Proliv series, in later variants the 5E18. The transmit antenna is in the nose, the receive antennas aft of the cruciform canard controls and their actuator module. The canards are used for pitch/yaw control inputs, with a pair of ailerons on the cruciform wing used for roll stabilisation.

The truncated conically shaped  fragmentation warhead is mounted aft of the canard controls. In early variants this was the 5B15, with ~33 kg of high explosive and a prefragmented casing designed to produce 3,560-3,570 high velocity fragments. Later variants used the 72 kg 5P18  producing 4,500 fragments. A 5B72 self destruct mechanism is mounted behind the warhead.

The 5A22/APS-600 autopilot and 5U42/UR-20A Command link control module are mounted aft of the warhead in the main control section. A UR-80M turbogenerator is mounted in this section, together with the 5P54 power converter. A spherical 300 atm compressed air tank is used to power the controls.

The V-600P missile used a 5B83 solid propellant rocket sustainer, constructed with a 375 mm dia steel cylindrical casing and filled with 125 kg of NM-4Sh nitrocellulose based propellant charge, in an annular arrangement. A 5B93 igniter was used, initiating the burn from the central cylindrical cavity. An external cable duct routed signal cables around the engine section.

The missile guidance system is relatively simple, comprising an autopilot and a command link receiver, with a missile beacon in the tail to facilitate tracking by the Low Blow radar.

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Production and Exports

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The S-125 Neva / SA-3 Goa was manufactured by the Soviets from the mid-1960s through to the 1980s, with spare part manufacture to support exported installations continuing since then. The Soviets exported the weapon globally, and it would appear at this time that it is the mostly widely used of the legacy SAM systems. As the S-125 Neva / SA-3 Goa does not require the stockpiling and handling of problematic hypergolic liquid fuels, and is much simpler to operate and maintain than its PVO-SV contemporary, the 2K12 Kvadrat / SA-6 Gainful, it has been a very popular weapon in the developing world.

Surveying the exact status of current global deployments of this system is problematic, since many operators do not disclose the state of their air defence systems. Russia retired the system during the 1990s, but it remains in use with many former Soviet Republics, some former Warsaw Pact nations, and many former Soviet client nations in the developing world, especially Africa.

A number of electronics and mobility upgrades have been developed, a more detailed discussion can be found under Legacy Air Defence System Upgrades.

S-125 Launch Footage

US DoD rendering of fixed revetted S-125 / SA-3 Goa site. Site design followed a similar practice to that followed in the construction of S-75 / SA-2 Guideline sites.

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AT-S Tow Tractor

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The AT-S tracked tow tractor was often used as a substitute for wheeled tractors in Middle Eastern deployments, due to soft surface conditions (Russian internet image).

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Almaz SNR-125 Low Blow Engagement Radar

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PR-14A , P-15 Flat Face and P-15M Squat Eye. Note the antenna mast tether on the P-15M (Soviet MoD).

Early model PRV-10 heightfinder (Vestnik PVO image).

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The SNR-125M Low Blow operated at the core of the most successful S-125M battery ever used in combat is depicted here. This system, formerly of the 3rd battery of the 250th Missile Brigade of the Yugoslav Federal Air Force (3. raketni divizion 250. raketne brigade PVO (Protivvazdusne otbrane)), is credited with two confirmed kills during the Allied Force air campaign of 1999, while under the command of then LtCol and later Col Zoltán Dani. The first claimed kill was Vega 31, F-117A AF 82-0806, lost on the 27th March, 1999. The second claimed kill was F-16CG AF 88-0550, lost on 2nd May, 1999. The Serbians are also claiming a B-2A Spirit bomber, on 20th May 1999, but no physical evidence exists to support the latter claim. The SNR-125M Low Blow in question has since 1999 been upgraded to the SNR-125M1T configuration, with a thermal imager and laser rangefinder, and some electronics upgrades like the TVK (television coordinator equipment), and was recently photographed at Jakovo, near Belgrade International Airport. It currently belongs to the 2nd Missile Battalion of the Serbian Air Force. All images  © 2009, Miroslav Gyűrösi.

SNR-125M1T Low Blow UNV radar head and UNK operator van.

SNR-125M1T Low Blow UNV radar head, above and below.

SNR-125M1T Low Blow UNK operator van, above, and stencils denoting claimed kills, below.

5P73 launcher with four 5V27D Goa rounds loaded.

Technical Report APA-TR-2009-0602

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