Isayev S-125 Neva/Pechora

The Isayev S-125 Neva/Pechora is Soviet surface-to-air missile system was designed to complement the S-25 and S-75. It has a shorter effective range and lower engagement altitude than either of its predecessors and also flies slower, but due to its two-stage design it is more effective against more maneuverable targets. It is also able to engage lower flying targets than the previous systems, and being more modern it is much more resistant to ECM than the S-75. The 5V24 (V-600) missiles reach around Mach 3 to 3.5 in flight, both stages powered by solid fuel rocket motors. The S-125, like the S-75, uses radio command guidance. The naval version of this system has the NATO reporting name SA-N-1 Goa and original designation M-1 Volna (Russian Волна – wave).

The S-125 is somewhat mobile, an improvement over the S-75 system. The missiles are typically deployed on fixed turrets containing two or four but can be carried ready-to-fire on ZIL trucks in pairs. Reloading the fixed launchers takes a few minutes.

Missile

The S-125 system uses 2 different missiles versions. The V-600 (or 5V24) had the smallest warhead with only 60 kg of High-Explosive. It had a range of about 15 km.

The later version is named V-601 (or 5V27). It has a length of 6.09 m, a wing span of 2.2 m and a body diameter of 0.375 m. This missile weighs 953 kg at launch, and has a 70 kg warhead containing 33 kg of HE and 4,500 fragments. The minimum range is 3.5 km, and the maximum is 35 km (with the Pechora 2A). The intercept altitudes are between 100 m and 18 km.

Radars

The launchers are accompanied by a command building or truck and three primary radar systems:

• P-15 "Flat Face" or P-15M(2) "Squat Eye" 380 kW C-band target acquisition radar (also used by the SA-6 and SA-8, range 250 km/155 miles)
• SNR-125 "Low Blow" 250 kW I/D-band tracking, fire control and guidance radar (range 40 km/25 miles, second mode 80 km/50 miles)
• PRV-11 "Side Net" E-band height finder (also used by SA-2, SA-4 and SA-5, range 28 km/17 miles, max height 32 km/105,000 ft)

"Flat Face"/"Squat Eye" is mounted on a van ("Squat Eye" on a taller mast for better performance against low-altitude targets also an IFF [Identifies Friend or Foe]), "Low Blow" on a trailer and "Side Net" on a box-bodied trailer.

Isayev S-125 Variants and upgrades

Naval version

Work on a naval version M-1 Volna (SA-N-1) started in 1956, along with work on a land version. It was first mounted on a rebuilt Kotlin class destroyer (Project 56K) Bravyi and tested in 1962. In the same year, the system was accepted. The basic missile was a V-600 (or 4K90) (range: from 4 to 15 km, altitude: from 0.1 to 10 km). Fire control and guidance is carried out by 4R90 Yatagan radar, with five parabolic antennas on a common head. Only one target can be engaged at a time (or two, for ships fitted with two Volna systems). In case of emergency, Volna could be also used against naval targets, due to short response time.

The first launcher type was the two-missile ZIF-101, with a magazine for 16 missiles. In 1963 an improved two-missile launcher, ZIF-102, with a magazine for 32 missiles, was introduced to new ship classes. In 1967 Volna systems were upgraded to Volna-M (SA-N-1B) with V-601 (4K91) missiles (range: 4–22 km, altitude: 0.1–14 km).

In 1974 - 1976 some systems were modernized to Volna-P standard, with an additional TV target tracking channel and better resistance to jamming. Later, improved V-601M missiles were introduced, with lower minimal attack altitude against aerial targets (system Volna-N).

Some Indian frigates also carry the M-1 Volna system.

Modern upgrades

Since Russia replaced most of its S-125 sites with SA-10 and SA-12 systems, they decided to upgrade the S-125 systems being removed from service to make them more attractive to export customers. Released in 2000, the Pechora-2 version features better range, multiple target engagement ability and a higher probability of kill (PK). The launcher is moved onto a truck allowing much shorter relocation times. It is also possible to fire the Pechora-2M system against cruise missiles.

In 1999, a Russian-Belarusian financial-industrial consortium called Oboronitelnye Sistemy (Defense Systems) was awarded a contract to overhaul Egypt's S-125 SAM system. These refurbished weapons have been reintroduced as the S-125 Pechora 2M.

In 2001, Poland began offering an upgrade to the S-125 known as the Newa SC. This replaced many analogue components with digital ones for improved reliability and accuracy. This upgrade also involves mounting the missile launcher on a T-55 tank chassis (a TEL), greatly improving mobility and also adds IFF capability and data links. Radar is mounted on an 8-wheeled heavy truck chassis (formerly used for Scud launchers). Serbian modifications include terminal/camera homing from radar base.

Later the same year, the Russian version was upgraded again to the Pechora-M which upgraded almost all aspects of the system - the rocket motor, radar, guidance, warhead, fuse and electronics. There is an added laser/infra-red tracking device to allow launching of missiles without the use of the radar.

There is also a version of the S-125 available from Russia with the warhead replaced with telemetry instrumentation, for use as target drones.

In October, 2010, Ukrainian Aerotechnica announced a modernized version of S-125 named S-125-2D Pechora.

Isayev S-125
Type	Surface-to-air missile
Place of origin	Soviet Union
Production history
Variants	V-600, V-601
Specifications (V-601)
Weight	953 kg
Length	6.09 m
Diameter	375 mm
Warhead	Frag-HE
Warhead weight	60 kg
Detonation mechanism	Command
Wingspan	2.2 m
Propellant	Solid propellant rocket motor
Operational range	35 kilometres (22 mi)
Flight altitude	18,000 metres (59,000 ft)
Guidance system	RF CLOS