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P-70 Ametist

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P-70 Ametist
(NATO reporting name: SS-N-7 'Starbright')
TypeAnti-ship missile
Place of originSoviet Union
Service history
In service1967-1992
Used bySoviet Union, Russia, India, North Korea (unconfirmed)
Production history
DesignerVladimir Chelomey
Designed1958 - 1968
ManufacturerNPO Mashinostroyeniye
Produced1966 - 1987
No. built631
Specifications
Mass3,500 kg (7,700 lb)
Length7 m (23 ft)
Warhead4G66 HEAT Warhead or 200 kt nuclear
Warhead weight1,000 kg (2,200 lb)

PropellantSolid fuel
Operational
range
65 km (35 nmi)
Boost time7 seconds (tube exit to main stage)
Maximum depth30 m (98 ft)
Maximum speed Mach 1.0
Guidance
system
Inertial guidance, terminal active radar homing
Launch
platform
Charlie-I & Papa class SSGNs

The P-70 Ametist (NATO reporting name: SS-N-7 Starbright, GRAU designation 4K66; Russian: П-70 «Аметист» 'Amethyst') was an anti-ship missile carried by Soviet and Indian Project 670 submarines, as well as the Soviet Project 661 Anchar. It was soon succeeded by the P-120 Malakhit (SS-N-9 'Siren').

Fielded on June 3 1968, it was the first missile system in the world to be launched from a submerged submarine. From 1968 to 1987, a total of 631 missiles were built.

Development

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The P-5 Pyatyorka (SS-N-3 Shaddock) missile required the Project 659 submarines carrying them to stay surfaced after firing to send mid-flight guidance updates. This made submarines very vulnerable to enemy attack, so in the 1960s the Soviets started working on a new missile that could be fired whilst submerged, and a submarine would carry it. These became the P-120 Malakhit and Project 670 submarine.

However, problems with the engines of the P-120 Malakhit forced the Soviets to design a sub-launched missile based on the P-15M Termit (SS-N-2C 'Styx') as a stopgap measure for the first batch of Charlie submarines. This became the P-20L, later renamed the P-70 Ametist.

Design

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The P-15M was fitted with an L band active radar homing sensor and a new radar altimeter both developed for the P-120, but there was no room for a datalink in the smaller P-15M. Folding wings were added to reduce the size of the missile, and the missile could be launched at a maximum depth of 30 m (98 ft).

The short range of the P-70 meant it could rely on inertial navigation and radar-homing, and as such did not need mid-course updates from a radar on the submarine. Consequently, along with the addition of the radar-altimeter (which allowed for a much lower cruise altitude than previous missiles), the novel sub-surface launch capability meant that reaction time for surface targets was minimal.

As a result, the ability to deploy in littoral and close-range combat scenarios without necessitating exposure of the launching submarine more than made up for its lack of range compared to the P-5.

Operational history

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The P-70 went into service with the Soviet Navy on the first Project 670, on June 3, 1968.[1] About 200 were produced.

India leased the "Chakra" Project 670 submarine from January 1988 to 1992, to gain experience of operating a nuclear submarine.

Operators

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 Soviet Union
 Russia
 India
 North Korea

References

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  1. ^ "P-70 Ametist" (in Russian). Archived from the original on 2011-07-09. Retrieved 2007-01-06.