S-75 Dvina

The S-75 Dvina is a Soviet-designed, high-altitude, command guided, surface-to-air missile (SAM) system. Since its first deployment in 1957, it has become the most widely-deployed and -used air defense missile in history.

This system first gained fame when an S-75 battery shot down a U-2 overflying the Soviet Union in 1960. Later, North Vietnamese forces used the S-75 extensively during the Vietnam War to defend Hanoi and Haiphong. It has also been locally produced in the People's Republic of China using the names HQ-1 and HQ-2. Other nations have produced so many local variants combining portions of the S-75 system with both indigenously-developed components or third-party systems, that it has become virtually impossible to find a pure S-75 system today.

Site layout

Each battalion will typically have six, semi-fixed, single-rail launchers for their V-750 missiles positioned approximately 60 to 100 m (200 to 330 ft) apart from each other in a hexagonal "flower" pattern, with radars and guidance systems placed in the center. It was this unique "flower" shape that led to the sites being easily recognizable in reconnaissance photos. Typically another six missiles are stored on tractor-trailers near the center of the site.

A current example of a site can be seen here just to the west of the junction to Bosra on the M5 motorway in Syria, south of Damascus. This location covers the borders with both Israel and Jordan, so it is of strategic importance.

Missile

The V-750 is a two-stage missile consisting of a solid-fuel booster and a storable liquid-fuel upper stage, which burns red fuming nitric acid as the oxidizer and kerosene as the fuel. The booster fires for about 4–5 seconds and the main engine for about 22 seconds, by which time the missile is traveling at about Mach 3. The booster mounts four, large, cropped-delta wing fins that have small control surfaces in their trailing edges to control roll. The upper stage has smaller cropped-deltas near the middle of the airframe, with a smaller set of control surfaces at the extreme rear and (in most models) much smaller fins on the nose.

The missiles are guided using radio control signals (sent on one of three channels) from the guidance computers at the site. The earlier S-75 models received their commands via two sets of four small antennas in front of the forward fins, while the D model and later models used four much larger strip antennas running between the forward and middle fins. The guidance system at an S-75 site can handle only one target at a time, but it can direct three missiles against it. Additional missiles could be fired against the same target after one or more missiles of the first salvo had completed their run, freeing the radio channel.

The missile typically mounts a 195 kg (430 lb) fragmentation warhead, with proximity, contact, and command fusing. The warhead has a lethal radius of about 65 m (213 ft) at lower altitudes, but at higher altitudes the thinner atmosphere allows for a wider radius of up to 250 m (820 ft). The missile itself is accurate to about 75 m (246 ft), which explains why two were typically fired in a salvo. One version, the SA-2E, mounted a 295 kg (650 lb) nuclear warhead of an estimated 15 Kiloton yield or a conventional warhead of similar weight.

Typical range for the missile is about 45 km (28 mi), with a maximum altitude around 20,000 m (66,000 ft). The radar and guidance system imposed a fairly long short-range cutoff of about 500 to 1,000 m (1,600 to 3,300 ft), making them fairly safe for engagements at low level.

Missiles from SA-2 Guideline (all versions SA-75 / S-75)

Missile	Factory index	Character
V-750	1D	Firing range 7–29 km; Firing altitude 3,000–23,000 m
V-750V	11D	Firing range 7–29 km; Firing altitude 3,000–25,000 m; Weight 2,163 kg; Length 10,726 mm; Warhead weight 190 kg; Diameter 500 mm / 654 mm
V-750VK	11D	Modernized missile
V-750VM	11DM	Missile for firing to aircraft - jammer
V-750VM	11DU	Modernized missile
V-750VM	11DА	Modernized missile
V-750M	20ТD	No specific information available
V-750SM	-	No specific information available
V-750VN	13D	Firing range 7–29 km / 7–34 km; Firing altitude 3,000–25,000 m / 3,000–27,000 m; Length 10,841 mm
-	13DА	Missile with new warhead weight 191 kg
V-750АK	-	No specific information available
V-753	13DM	Missile from naval SAM system M-2 Volkhov-M (SA-N-2 Guideline)
V-755	20D	Firing range 7–43 km; Firing altitude 3,000–30,000 m; Weight 2,360–2,396 kg; Length 10,778 mm; Warhead weight 196 kg
V-755	20DP	Missile for firing on passive flight-line, Firing range 7–45 km active, 7–56 km passive; Firing altitude 300–30,000 m / 300–35,000 m
V-755	20DА	Missile with expired guarantee period and remodeled to 20DS
V-755OV	20DO	Missile for taking air samples
V-755U	20DS	Missile with selective block for firing to target in low altitude (under 200 m); Firing altitude 100–30,000 m / 100–35,000 m
V-755U	20DSU	Missile with selective block for firing to target in low altitude (under 200 m) and shortening time preparation missile to fire; Firing altitude 100–30,000 m / 100–35,000 m
V-755U	20DU	Missile with shortening time preparation missile to fire
V-759	5Ja23 (5V23)	Firing range 6–56 km / 6–60 km / 6–66 km; Firing altitude 100–30,000 m / 100–35,000 m; Weight 2,406 kg; Length 10,806 mm; Warhead weight 197–201 kg
V-760	15D	Missile with nuclear warhead
V-760V	5V29	Missile with nuclear warhead
V-750IR	-	Missile with pulse radiofuse
V-750N	-	Test missile
V-750P	-	Experimental missile - with rotate wings
V-751	KM	Experimental missile - flying laboratory
V-752	-	Experimental missile - boosters at the sides
V-754	-	Experimental missile - with semi-active homing head
V-757	17D	Experimental Missile - with scramjet
-	18D	Experimental Missile - with scramjet
V-757Kr	3M10	Experimental Missile - version for 2K11 Krug (SA-4 Ganef)
V-758 (5 JaGG)	22D	Experimental Missile - three-stage missile; Weight 3,200 kg; Speed 4.8 mach (1,560 m/s, 5,760 km/h)
Korshun	-	Target missile
RM-75MV	-	Target missile - for low altitude
RM-75V	-	Target missile - for high altitude
Sinitsa-23	5Ja23	Target missile

S-75 Dvina Radar

The S-75 typically uses the Spoon Rest early warning radar which has a range of about 275 km (171 mi). The Spoon Rest provides early detection of incoming aircraft, which are then handed off to the acquisition Fan Song radar. These radars, having a range of about 65 km (40 mi), are used to refine the location, altitude, and speed of the hostile aircraft. The Fan Song system consists of two antennas operating on different frequencies, one providing elevation (altitude) information and the other azimuth (bearing) information. Regimental headquarters also include a Spoon Rest, as well as a Flat Face long-range C-band radar and Side Net height-finder. Information from these radars is sent from the regiment down to the battalion Spoon Rest operators to allow them to coordinate their searches. Earlier S-75 versions used a targeting radar known as Knife Rest, which was replaced in Soviet use, but can still be found in older installations.

Major variants

Upgrades to anti-aircraft missile systems typically combine improved missiles, radars, and operator consoles. Usually missile upgrades drive changes to other components to take advantage of the missile's improved performance. Therefore, when the Soviets introduced a new S-75, it was paired with an improved radar to match the missile's greater range and altitude.

• SA-2A; S-75 Dvina (Двина - Dvina River) with Fan Song-A guidance radar and V-750 or V-750V missiles. Initial deployment began in 1957. The combined missile and booster was 10.6 m (35 ft) long, with a booster having a diameter of 0.65 m (26 in), and the missile a diameter of 0.5 m (20 in). Launch weight is 2,287 kg (5,040 lb). The missile has a maximum effective range of 30 km (19 mi), a minimum range of 8 km (8,000 m), and an intercept altitude envelope of between 450 and 25,000 m (1,480 and 82,000 ft).
• SA-N-2A; S-75M-2 Volkhov-M (Russian Волхов - Volkhov River): Naval version of the A model fitted to the Sverdlov Class cruiser Dzerzhinski. Generally considered unsuccessful and not fitted to any other ships.
• SA-2B; S-75 Desna (Russian Десна - Desna River). This version featured upgraded Fan Song-B radars with V-750VK and V-750VN missiles. This second deployment version entered service in 1959. The missiles were slightly longer than the A versions, at 10.8 m (35 ft), due to a more powerful booster. The SA-2B could engage targets at altitudes between 500 and 30 km (1,600,000 and 98,000 ft) and ranges up to 34 km (21 mi).
• SA-2C; S-75M Volkhov. Once again, the new model featured an upgraded radar, the Fan Song-C, mated to an improved V-750M missile. The improved -2B was deployed in 1961. The V-750M was externally identical to the V-750VK/V-750VN, but it had improved performance for range up to 43 km (27 mi) and reduced lower altitude limits of 400 m (1,300 ft).
• SA-2D; Fan Song-E radar and V-750SM missiles. The V-750SM differed significantly from the A/B/C versions in having new antennas and a longer barometric nose probe. Several other differences were associated with the sustainer motor casing. The missile is 10.8 m (35 ft) long and has the same body diameters and warhead as the SA-2C, but the weight is increased to 2,450 kg (5,400 lb). The effective maximum range is 43 km (27 mi), the minimum range is 6 km (3.7 mi), and the intercept altitude envelope is between 250 and 25,000 m (820 and 82,000 ft). Improved aircraft counter measures led to the development of the Fan Song-E with its better antennas which could cut through heavy jamming.
• SA-2E: Fan Song-E radar and V-750AK missiles. Similar rocket to the D model, but with a bulbous warhead section lacking the older missile's forward fins. The SA-2E is 11.2 m (37 ft) long, has a body diameter of 0.5 m (20 in), and weighs 2,450 kg (5,400 lb) at launch. The missile can be fitted with either a command-detonated 15 kt nuclear warhead or a 295 kg (650 lb) conventional HE warhead.
• SA-2F: Fan Song-F radar and V-750SM missiles. After watching jamming in Vietnam and the Six-Day War render the SA-2 completely ineffective, the existing systems were quickly upgraded with a new radar system designed to help ignore wide-band scintillation jamming. The command system also included a home-on-jam mode to attack aircraft carrying strobe jammers, as well as a completely optical system (of limited use) when these failed. Fs were developed starting in 1968 and deployed in the USSR later that year, while shipments to Vietnam started in late 1970.
• SA-2 FC: Latest Chinese version. It can track six targets simultaneously and is able to control 3 missiles simultaneously.
• S-75M Volga (Russian С-75М Волга - Volga River). Version from 1995.

As previously mentioned, most nations with S-75s have matched parts from different versions or third-party missile systems, or they have added locally produced components. This has created a wide variety of S-75 systems which meet local needs.

• HQ-1 (Hong Qi, Red Flag): Chinese version of SA-2 with additional ECCM electronics to counter the System-12 ECM aboard U-2s flown by the Republic of China Air Force Black Cat Squadron.
• HQ-2: Upgraded HQ-1 with additional ECCM capability to counter the System-13 ECM aboard U-2s flown by Republic of China Air Force Black Cat Squadron. Upgraded HQ-2s remain in service today, and the latest version utilizes passive phased array radar designated SJ-202, which is able to simultaneously track and engage multiple targets at 115 km (71 mi) and 80 km (50 mi), respectively. The adoption of multifunction SJ-202 radar has eliminated the need to have multiple, single-function radars, and thus greatly improved the overall effectiveness of the HQ-2 air defense system. A target drone version is designated BA-6.

S-75 Dvina, V-750
Type	Surface-to-air missile
Place of origin	Soviet Union
Production history
Variants	V-750, V-750V, V-750VK, V-750VN, V-750M, V-750SM, V-750AK
Specifications
Weight	2,300 kg (5,100 lb)
Length	10,600 mm (420 in)
Diameter	700 mm (28 in)
Warhead	Frag-HE
Warhead weight	200 kg (440 lb)
Detonation mechanism	Command
Propellant	Solid-fuel booster and a storable liquid-fuel upper stage
Operational range	45 km (28 mi)
Flight altitude	20,000 m (66,000 ft)
Boost time	5 s boost, then 20 s sustain
Speed	Mach 3.5
Guidance system	Radio control guidance
Accuracy	65 m
Launch platform	Single rail, ground mounted (not mobile)