Munitions / Surface to surface missiles / P-70 Ametist

P-70 Ametist

General Facts

  • TYPE
    Anti-ship missile

  • ORIGIN
    USSR

  • NICKNAMES
    SS-N-7 Starbright (NATO reporting name)
    4K66 (GRAU designation)
    P-20L (early project name)

  • DESIGNED
    1960's

  • DESIGNER
    OKB-52 Chelomei design bureau

  • PRODUCTION
    1966 - 1987

  • PRODUCERS
    USSR - NPO Mashinostroyeniye

  • QUANTITY
    A total of 631 missiles built, production complete.

  • UNIT COST
    Unknown

  • CHARACTERISTICS
    Can be launched from submerged submarines
    Low level flight profile
    Powerful warhead
    Limited range put launch platform at risk
    Single mode seeker

Introduction

The P-70 Ametist is late Cold War era subsonic anti-ship missile of Soviet origin. It was developed in the 1960's for underwater launch by guided missile submarines, significantly improving chances of survival for the launch platform. In the West the P-70 is known by its NATO reporting name SS-N-7 Starbright.

Design

The P-70 is a longer and sleeker missile than the older Soviet P-15 Termit. The guidance section and warhead are located in the nose. The main wings are folded within the launch container. Two booster engines on each side provides initial velocity upon launch. They are discarded when depleted and the solid fuel sustainer engine takes over. Flight altitude is about 60 meters above sea level.

Guidance

The P-70 is fitted with an active radar seeker. The first stage of flight uses inertial naviation. In the terminal phase the seeker switches on. There is no secondary seeker type.

Firepower

The P-70 is fitted with either a 500 kg shaped charge warhead or a 200 kT nuclear warhead. The maximum range is about 65 km. Various sources report a maximum range of 80 km. Possibly the latter range can be achieved when the launch platform is surfaced. The sustained flight speed is Mach 0.9. Flight altitude is about 60 meters above sea level.

Platforms

The P-70 was used as the primary armament on two types of nuclear powered attack submarines. The first and foremost being the Project 670 Skat (NATO: Charlie I) class with 8 launch tubes. The second being the sole Project 661 Anchar (NATO: Papa) class which carried 10 missiles. The submarines that launch the P-70 have forward angled launch tubes. These are flooded just before launch. Maximum depth of launch is 30 to 40 meters. Reportedly P-70 missiles can also be launched from P-120 launch tubes.

Users

The main user of the P-70 was the USSR. A small number of P-70 was included in the lease of a Charlie I submarine to India. When the USSR dissolved all remaining P-70 missiles were inherited by Russia. They were never in active service and in 1992 all launch platforms were out of service. Some sources indicate an official out of service date of 1995.

Variants

P-70 Ametist

The P-70 Ametist is a subsonic sea skimming anti-ship missile of which only one model was produced. The missile is fitted with either a conventional shaped charge warhead of 200 kt nuclear warhead. The P-120 Malakhit (NATO: SS-N-9 Siren) is a further development of the P-70 and looks rather similar. The P-70 can be distinguished from the later P-120 by being shorter, lacking the infrared seeker pod and having four booster rockets instead of two.

TypeAnti-ship missile
Diameter0.55 m body
Length7.0 m
Weight2.9 t without boosters, 3.65 t with boosters
GuidanceInertial first phase, active radar homing in terminal phase
Warhead530 kg 4G66 shaped charged warhead or 200 kt nuclear warhead
PropulsionModel 239P single-stage solid propellant rocket motor, four booster rockets
SpeedMach 0.9
Range65 or 80 km
Altitude-
Engagement envelope-
Remarks60 m flight altitude, can be launched from depth of 30 to 40 meters.

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