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Last Updated: Mon Jan 27 11:18:09 UTC 2014

Almaz S-75 Dvina/Desna/Volkhov

  Air Defence System / HQ-2A/B / CSA-1 / SA-2 Guideline

  Зенитный Ракетный  Комплекс С-75 Двина/Десна/Волхов

Technical Report APA-TR-2009-0702

by Dr Carlo Kopp, AFAIAA, SMIEEE, PEng
July 2009
Updated April, 2012
Text, Line Art © 2009 - 2012 Carlo Kopp

The S-75 / SA-2 Guideline was the first SAM to be used in anger, en masse, and changed the character of air warfare forever. Depicted Soviet supplied S-75 / SA-2 Guideline and SM-90 launcher operated by Egypt in 1985 (US DoD)


The S-75 / SA-2 Guideline family of SAM systems remains the most widely exported area defence missile system, and was supplied in large numbers by the Soviets to Warsaw Pact nations, Third World Soviet allies and other non-aligned nations. Over thirty nations deployed one or another variant of the SA-2, and China manufactured indigenous derivatives well after this design was out of production in the Soviet Union.

The basic design qualifies as semi-mobile, requiring several hours to set up or redeploy a battery. Typical battery composition is a single SNR-75 Fan Song series engagement radar, six SM-90 single rail launchers, and multiple PR-11AM transporter/transloader trucks carrying reload rounds for the SM-90s.

Many S-75 operators deploy the system in fixed sites, with revetments using concreted pads and bays, and/or earthwork berms, to protect the missile system components.

The PLA reverse engineered the Soviet V-75/S-75 Dvina / SA-2 Guideline SAM system during the 1960s, including the SNR-75 Fan Song radar, the SM-90 launcher and the PR-11AM transporter/transloader. Since then the PLA developed a significantly improved HQ-2B variant.

RSNA-75/SNR-75 Fan Song Engagement Radar

The Fan Song is the engagement radar for the S-75/SA-2 family of SAMs. First deployed in strength during the Vietnam conflict, and later used extensively in the Middle East and Africa, the SA-2 was the first Soviet SAM to be used in anger and accounted for large numbers of Western aircraft until electronic countermeasures were developed. The system was cloned by PLA and still remains widely in use, even though Russia has replaced it with the SA-10/20 system.

The are at least six known variants, one of which is a PLA clone. Details of PLA modifications to the design are not public knowledge. There are sufficient differences in the PLA designs to regard these as unique derivatives. The antenna configuration of the PLA variants generally follow the Fan Song A arrangement.

The SNR-75 family of radars employ, by modern standards, a complex antenna arrangement which is employed to effect range and angle tracking of the intended target, and of the transponder beacon in the tail of the missile round. The proximity fused missile round is “dumb”  in the sense that it is a pure command link design, which is flown to a collision with the target using a command uplink embedded in the SNR-75 radar.

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

1D (V-750) Guideline Cutaway (via Vestnik-PVO/Tekhnika i Vooruzheniya)
Radio proximity fuse transmit antenna
Shmel radio proximity fuse
V-88 warhead
Radio proximity fuse receive antenna
AK-20F oxidiser1 melange tank
TG-02 propellant tank
Compressed air tank
AP-75 autopilot module
FR-15Yu command link module
Cruciform controls
OT-155 Isonite (isopropyl nitrate) turbopump gas-generator propellant tank
Isayev S2.711 (S5.711) liquid propellant sustainer powerplant
Adaptor fairing
PRD-18 boost powerplant with 2-4 sec burn duration / 14 tubes of NMF-2 propellant
Note 1: Oxidiser to propellant ratio ~3.2:1
AK-20F oxidiser ~80% nitric acid / ~20% N2O4 / fluorine inhibitor additive
TG-02 propellant [GOST 17147-80] 50% isomeric xylidine / 48.5% triethylamine / 1.5% diethylamine

S-75 / SA-2 Guideline engagement envelope (Almaz image).

Early model 1D SA-2 Guideline missile (Almaz image via http://peters-ada.de/).

1D/13D/DM/DA/DAM/20D/DP/DSU/5Ya23/15D Surface to Air Missiles

The configuration of the 1D through 5Ya23 missiles is a direct evolution of the earlier SA-25/S-25 / SA-1 Guild, itself evolved from the 1944 German Wasserfall design. Unlike its predecessors, the S-75 / SA-2 family of missiles were two stage designs, using a solid rocket first stage booster for launch and a variable thrust liquid propellant motor sustainer. Midbody cruciform wings were employed to improve range and turning ability, with canard and tail winglets for pitch, roll and yaw control and stability.

By modern standards, the missile design is unusually simple, with most of the complexity in the liquid propellant sustainer and fuel system. The choice of this sustainer for two reasons, the first being immaturity of high impulse solid propellants, the second being in the ability to modulate thrust through the flight profile.

An important consideration is the Soviet philosophy of making the missile round as simple and cheap as possible, and putting the cost and complexity into the engagement radar. The operational economics of this model were to minimise the cost of the expendable component of the weapon system.

The nose of the missile houses the radio proximity fuse. In early variants this was the 5E11 Shmel series, the later Ovod variant, and then the 5E29. Early variants used separate linear transmit and receive antennas flush with the skin of the missile, later variants used a characteristic dielectric band radome. Later variants included programmable ECCM modes, such as alternating emissions between the two hemispheres of antenna coverage.

Immediately aft of the fuse is the V-88 series blast fragmentation warhead, which weighs between 190 kg and 250 kg, depending on missile variant. The large warhead size was intended to produce a large lethal envelope, to offset the accuracy limitations of the command link guidance and proximity fusing. Warhead performance evolved over the life of the missile, the early 11D round producing 8,000 fragments, the 20D 32,000 fragments and the very late 5Ya23 29,000 fragments. Initial fragment velocity was 2,500 m/s. The timing of the proximity fuse trigger point was programmable via the command uplink, with shorter delays for closing versus receding targets. Lethal radius was nominally 60 metres (~400 ft lethal diameter).

Much of the missile's internal volume is occupied with propellant tanks for the sustainer engine.

The 43 kg dry weight Isayev S2.711 (S5.711) liquid propellant powerplant burns a hypergolic propellant mix. The oxidiser is either AK-20F or AK-20K fuming nitric acid melange depending on the motor variant, comprising ~80% nitric acid and ~20% N2O4 with an inhibitor additive. The fuel is TG-02, comprising 50% isomeric xylidine, 48.5% triethylamine and 1.5% diethylamine, this propellant mix was essentially an evolution of the 1944 Wasserfall fuel. The S2.711 used in early variants produced a thrust rating between 2,650 and 3,000 kp (5,800 lbf and 6,600 lbf), the later S2.720 used in the 20D round produced between 2,075 kp and 3,500 kp (4,580 lbf and 7,700 lbf) thrust using a different propellant mix. Specific impulse for the S2.711 was 224 up to 252.7 kp.sec/kg.

The turbopump for the engine was fuelled by a tank of OT-155 Isonite (isopropyl nitrate). The propellant payload permitted a burn duration between 25 and 60 seconds, subject to thrust profile. All propellant tanks were pressurised from a compressed air tank.

This fuel system arrangement as used in the earlier 1D through 11D variants was supplanted in the 20D and later missile rounds. The later variants used the AK-27I oxidiser, comprising  ~73% nitric acid,  ~27% N2O4 and an inhibitor additive. The fuel was TM185 comprising 56% Kerosene and 40% Trikresol. As this fuel did not ignite spontaneously, an additional tank of TG-02 “starter fuel” was employed to ignite the rocket. The later propellant mix was more energetic and provided better storage life, with the TM185 fuel being less toxic, and the primary propellant components safer to fuel and defuel.

The first stage which was used to accelerate the missile at launch used a PRD-18 solid rocket powerplant with 2-4 sec burn duration. This design used 14 tubes of NMF-2 propellant and a variable cross section throat.

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 Fan Song radar.

The command link channel produced four distinct pulse modulated waveforms. The K1 and K2 waveforms carried climb/dive and left/right turn commands, the K3 waveform arms the radio proximity fuse, and the K4 waveform is used to program the proximity fuse delay depending on missile engagement geometry.

In operation, the Fan Song radar would track the target and continuously compute an optimal missile trajectory for intercept, while tracking the missile via its transponder beacon. The uplink would then be used to continuously drive the missile flightpath as close as possible to the intended trajectory, in a closed loop scheme.

Two control laws were employed, the “Treokh Tochek (TT - three point)” and “Polavinoye Spravleniye (PS - half correction)” techniques.

The TT control law is essentially a Soviet implementation of Command to Line of Sight (CLOS), where the missile flightpath is continously adjusted so that it follows the line of sight between the radar and the target. While this technique does attempt to minimise flightpath length, it does not maximise missile range per propellant payload, and tends to subject the missile, in some geometries, to large transverse accelerations. The latter facilitated defeat of the missile by high G manoeuvres.

The PS control law was more sophisticated and used against manoeuvring targets. An earth bias was often included in the control law when firing against low altitude targets, to preclude unwanted proximity fuse initiation, or inadvertent ground collision caused by autopilot inputs.

The command link guidance scheme and need to carefully select control laws and radar modes resulted in a need for high levels of operator skill and a good understanding of engagement geometries. The combat effectiveness of the S-75 / SA-2 Guideline varied widely as a result, with Warsaw Pact instructors and their Vietnamese students typically performing much better in combat compared to their counterparts in the Middle East.

Production and Exports

The S-75 / SA-2 Guideline was manufactured by the Soviets from the mid-1950s through to the 1980s, with spare part manufacture to support exported installations continuing since then. The Chinese reverse engineered the missile system during the 1960s, as the HQ-1, and then produced indigenous improved HQ-2 variants thereafter. The Soviets and Chinese have exported the weapon globally, and it would appear that this system has been built in more variants and exported more widely than any other SAM system.

Attempting to survey current global deployments of this system is a challenging task. While Russia retired the system, it remains deployed in large numbers by China, by many former Soviet Republics, some former Warsaw Pact nations, and many former Soviet client nations in the developing world. Much of Iran's air defence system comprises Chinese supplied HQ-2s.

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

S-75 Technical Data

SA-2 Guideline Variant Specifications
Industry Designation
SA-75 S-75 S-75M     S-75V S-75V     S-75M
Military Designation
SA-75 S-75 S-75 S-75M1 S-75M1 S-75M S-75M S-75M2 S-75M4 S-75
NATO Designation
Fan Song Variant
RSNA-75 RSN-75 RSN-75M RSN-75V1 RSN-75V1 RSN-75V RSN-75V RSNA-75M RSN-75M4 RSN-75M
Max Range
m 29000 34000 43000 34000 43000 43000 45000 56000 76000  
Min Range
m 8000 8000 8000   7000 7000 7000 6000 6000  
Max Alt
m 22000 27000 30000 27000 30000 30000 30000 30000 30000  
Min Alt
m 3000 3000 1000 500 300 1000 1000 100 50 5000
Vmax appr tgt
m/s 417 417 639 556 639 639   1000 1000  
Vmax reced tgt
m/s       417 417 417   417    
Missile Type
1D 13D 13DM 13DA 13DAM 20D 20DP 20DSU 5Ya23 15D
mm 10726 10841 10841 10841 10841 10778 10778 10778 10798 11200
Max speed
m/s   650 650 650 650 885 885 885    
kg 2163 2283 2283 2289 2289 2391 2391 2397 2406 2450
Warhead Weight
kg 190 190 190 196 196 190 190 196 197 250
1st Stage
mm 654 654 654 654 654 654 654 654 654  
2566 2566 2566 2566 2566 2566 2566 2566  
kg 1135 1032 1032 1032 1032 1011 1011 1011 1007  
2nd Stage
mm 500 500 500 500 500 500 500 500 500  
mm   1691 1691 1691 1691 1691 1691 1691 1691  
kg 1028 1251 1251 1257 1257 1380 1380 1386 1399  
Source: http://www.rzeszow.mm.pl/~jowitek/S-75.html / Vestnik PVO

S-75 Battery Components

S-75M Battery Components
SNR-75 PV Cabin / Fan Song
Radar head van
SNR-75 UV Cabin
Radar operator van
SNR-75 AV Cabin
Radar electronics van
Launcher, Single Rail
PR-11BM/D (20D round)
Training Emulator (OdAZ-828 semitrailer) Towed
P-12M/P-18 Spoon Rest
Acquisition Radar
1L22 Parol 4 / 75E6 Parol 3
IFF Interrogator
PRV-10 Konus  / PRV-11 Vershina / Side Net
Heightfinding Radars Towed
ESP-90 (3 x 5E93)
Power generator
5Ya61/62/63 Tsikloida
Radio relay van (OdAZ-828 semitrailer)
Chemical decontamination van
Fuel Tank (TG-02)
Oxidiser Tank (AK-27P)

S-75 Optional Battery Components
RD-75 Amazonka
Rangefinding radar
P-15/19 Flat Face
UHF-Band Acquisition Radar Ural-375
P-15M Squat Eye
UHF-Band Acquisition Radar Towed

S-75 Battery Deployment

US DoD rendering of fixed revetted SA-2 site circa 1966.

Russian rendering of an SA-2 site with Fan Song E radar vans in protected excavations (Almaz image).

An S-75 / SA-2 SAM site photographed by a US reconnaissance aircraft during the Cuban Missile Crisis (US Air Force).

An operational S-75 / SA-2 SAM site photographed from low altitude by a US reconnaissance aircraft early during the Vietnam conflict. Note the large number of radar and generator vans, reduced in later variants of the system (US Air Force).

SM-90 Launcher

Late model 5Ya23 / SA-2D Guideline on SM-90M launcher. Note the concrete pad (Almaz image via http://peters-ada.de/).

Early model 1D / SA-2A Guideline on an SM-63 launcher. Note the blast deflector (Image © Miroslav Gyűrösi).

SM-90 Launcher elevated (via Vestnik PVO).

Stowed SM-90 configured for towing (
image via http://peters-ada.de/).

Loading the SM-90 from a PR-11AM transloader.

PR-11A/AM Towed Transporter/Transloader

PR-11A transloader and late model V-759/5Ya23  round of the Slovakian Army (Image © Miroslav Gyűrösi).

Reverse engineered PLA PR-11AM transporter/transloader, with a late model tractor.

A Soviet supplied S-75 Guideline and early model PR-11AM  transporter/transloader, operated by Egypt in 1985 (US DoD).

Almaz RSNA/SNR-75M Fan Song E Engagement Radar

SNR-75M3 PV van with antenna head elevated at ~15° and rotated on the base turntable (Image © Miroslav Gyűrösi).

Aft view of PV van with antenna head levelled (Image © Miroslav Gyűrösi).

SNR-75M3 UV and AV vans - these contain the operator stations and system electronics respectively  (Image © Miroslav Gyűrösi).

NITEL P-18-2/P-18M  Spoon Rest D/E  Acquisition Radar

Slovakian Army P-18 (Image © Miroslav Gyűrösi).

PRV-10 Konus  / PRV-11 Vershina / Side Net Heightfinding Radars

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

RD-75 Amazonka Rangefinding Radar

The RD-75 Amazonka was a rangefinding radar incorporated often in late model S-75 / SA-2 Guideline missile batteries. It was slaved in azimuth and elevation to the boresight of the SNR-75M3 Fan Song and was employed to perform precision rangefinding when the rangefinding channel in the Fan Song was degraded or compromised by jamming. (Image © Miroslav Gyűrösi).

S-75 / SA-2 Guideline Combat Imagery

US Air Force F-105D Thunderchief evading an SA-2 missile over North Vietnam (US Air Force image).

SA-2 missile in flight over the NVAF airfield at Kep (US Air Force image).

Above, proximity fused SA-2 round explodes beneath a US Air Force RF-4C Phantom flown by Capts. Edwin Atterberry and Thomas Parrott near Hanoi, 12th August, 1967. Below, the RF-4C breaks up as a result of fatal structural damage. Both crew survived the ejection, but Capt Atterberry was later killed in captivity by the PAVN (US Air Force image).

A damaged F-105D after a near miss by a proximity fused SA-2 round (US Air Force image).

The lethality of the SA-2 was so high that it forced the development of specialised aircraft and systems to hunt it. Above, the F-105F Wild Weasel, below the F-105G (US Air Force images).

A late model 20D SA-2 Guideline of the PAVN (image via http://peters-ada.de/).

The SA-75 Desna system SM-63 launcher used to fire the 13D missile, which downed Gary Powers' U-2, is on display at the Zvezda Air Defence Museum in Russia (image © Miroslav Gyűrösi).


  1. Said Aminov, Vestnik PVO, URL: http://pvo.guns.ru
  2. Peter Skarus, Peter's ADA - Theorie und Grundlagen  der Fla, URL: http://peters-ada.de/

Technical Report APA-TR-2009-0702

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