Fleet ballistic missile submarine operations

 

Unlike the USAF and the specified command of SAC, the US Navy’s strategic missile force is not under one single designated command, but comes under the operational control of Atlantic Command (LANTCOM), European Command (EUCOM) and Pacific Command (PACOM), answerable through the Joint Chiefs of Staff to the National Command Authority who alone can authorize a launch. Four hundred Poseidon warheads are allotted to NATO’s Supreme Allied Command Europe (SACEUR) to cover targets in eastern Europe and the western Soviet Union outside the full US SIOP.

            A launch order would arrive as a coded Emergency Action Message. Only by mating it with its counterpart in the submarine’s special safe would the captain begin a firing sequence.

            In June 1981 Admiral Powell Carter, communications director of US strategic and theatre nuclear warfare, revealed that there is no ‘voting’ system for launches in the US ballistic missile submarine fleet as there is for bomber and missile crews, who need correlations from outside sources to remove interlocks. In certain circumstances a submarine commander could arm and fire his weapons without coded instructions, even though such as launch would need the co-operation of most of the crew.

 

 

 

 

 

 

            Like the first-generation jet bombers, the first Polaris SSBNs to get within range of their targets needed forward bases at Rota in Spain, Guam in the Pacific, and Holy Loch in Scotland to mount their and 30 days in port, with transit time to alunch areas of between two and ten days, depending of the base location. But, in fact, there is little difference in time on station between a Poseidon patrol mounted from Kings Bay, Georgia, the US Atlantic SSBN fleet base, or from Holy Loch. The advent of the Trident I will cause further changes. The Rota base was closed in 1980 and its squadron withdrawn for refitting with the new missile. Holy Loch to recent reports, and a new base for Ohio-class operations is under construction at Bangor, on the northwest Pacific coast of the United States.

            Strategic-missile submarines are designed to run deep, run alone and come to the surface as infrequently as possible – yet they must be in contact with the National Command Authority and launch missiles from uncharted start points to hit specific targets over distances of thousands of kilometers – inertial navigation (INS). This system relies on an onboard reference of time elapsed, distance covered and changes of direction from a known, fixed starting point. A submarine, therefore, functions like an underwater guided missile, with the SINS (submarine inertial navigation system) constantly fixing the ship’s location in relation of the start point. When necessary, satellite and radio fixes can update the plans.

            Targeting data in a variety of strategic plans is carried aboard each operational submarine. This data, together with a fix from the SINS, is fed electronically through the submarine’s fire-control system into the Poseidon or Trident missiles’ own inertial guidance system. On launch, therefore, each missile ‘knows’ where it is and where it is going.

            Using a small solid-fuel motor which generates gas and steam in a water boiler, the missile is punched out of its launch tube underwater, boiling and dubbling its way to the surface, where the first-stage motor ignites. As seawater pours into the vacated tube, ballast is provided, steadying the ship to fire the next round. The whole operation takes some 50 seconds.

            However self-contained an SSBN’s fire control system, it must be covered by the strategic command, control and communication net. The problem is how to communicate with a submerged submarine, for which very large and unusual shore installations are required, and which themselves become an extremely vulnerable target. The US Navy currently relies on satellites and shore transmitters to make emergency contact with submarines trailing antennae some 25 to 30 ft below the surface, to which depth a very low-frequency wavelength can penetrate. There are also now 18 TACAMO (Take Charge and Move Out) EC-130Q aircraft based on C-130 airframes which act as airborne communications centers with survival ability five miles long. One is constantly aloft over the Atlantic and, from 1983, over on the Boeing 707 airframe, is under development and will eventually take over the TACAMO mission.

            Using VLF transmissions, radio contact is not constant and may be broken off for several hours. Moreover, because the submarine has to come to periscope, speed is limited. However, extremely low frequency (ELF) transmissions are capable of being propagated through seawater to the depths in which SSBNs operate. The US Navy has been experimenting with ELF for a long time, but previous programmes (called ‘Sanguine’, ‘Seafarer’ and ‘Shelf’) all came to dead ends. Then, as part of the strategic force modernization plan (to be looked at later) proposals for an operational ELF transmitter and for receivers aboard every nuclear-powered submarine were implemented by the administration and approved by Congress.

 

Poseidon and Trident I

The Poseidon missile or UGM-73A became operational in March 1971, first supplanting, then replacing the Polaris. It had the same range (4000 km), but carried a much bigger payload, with a 10 MIRV front end, and could deliver it more accurately using inertial guidance and onboard digital electronics. Trident I is basically a Poseidon with a third stage. Its longer range (7400 km) vastly increases the area of sea in which the launch submarine can hide. It can carry 8 re-entry vehicles, or 14 over a reduced range.

            Range is the imperative behind the development of the Trident I but, although it has nearly double the Poseidon’s reach. It has similar accuracy at the target with a CEP of around half a mile (0·8 km).

            The Trident’s Mk 5 guidance system is similar to the Poseidon’s inertial system, but has a sensor able to take a star shot during the post-boost phase of flight, comparing what it sees of the heavens with an onboard computer map.

 

 

Strategic aerospace defence

 

The North American Air Defense Command (NORAD) was formed in 1955 in response to the threat of Soviet bomber attack on the United States and Canada. It remains a two-nation command, but the nature of the threat has changed completely – as has the response to it. Gone are surface to air missiles and the directly assigned interceptor fighter squadrons of the US Air Defense Command (ADCOM). NORAD and Space Command, established in 1982 under a joint commander, now control a global network of electronic warning systems stretching far into space, which is designed to give warning of an attack and make the retaliatory forces on which deterrence depends credible.

            The warning systems feed into central command and control facilities based at Colorado Springs on the edge of the Rocky Mountains. There NORAD and SPADOC (Space Defense Command and Control System) have a massive battle headquarters carved out of the solid granite of Cheyenne Mountain, where the staff can ‘button up’ at the first hint of an alert. Space Command has a back-up facility (BUF) at Petersen AFB a few miles east of Colorado Springs.

            In peacetime NORAD’s sensors and computers are linked to the National Command Center at the Pentagon, SAC headquarters at Omaha and, through that, to the Looking Glass airborne command posts of Strategic Air Command.

 

Above: Poseidon C-3 test round breaks surface. Poseidon was the first SLBM to carry a MIRV warhead.

 

Above: The missile control panel of a British Polaris submarine Britain relies on US technology for the missile propulsion guidance and fire control. The captain and his officers can launch a missile if they have reason to believe that national authorities cannot transmit launch orders to them. The same is technically true of US missile-firing submarines.

 

 

The essence of ballistic missile submarine operations is isolation – SSBNs must run deep, rune alone and come to the surface as infrequently as possible. To function as an effective deterrent, however, they must be able to receive emergency action messages and thus they are as vulnerable to C3 decapitation as any land-based system. US submarines communicate by means of a variety or systems and on a span of frequencies, all ultimately reaching back to the National Military Command Center and its Alternative via the most secure routes of the Defense Communications System. Message nay be routed by the FLSATCOM, AFSATCOM and Defence Satellite Communications System satellites, via shore stations transmitting on ultra high, high, very low and extremely low frequencies, via TACAMO aircraft trailing long airborne aerials, via surface ships, direct from the Presidential ‘Kneecap’ aircraft or through the missile-borne Emergency Rocket Communication System (ERCS) which is the last ditch retaliatory launch order system. The diagram also shows radio antenna limitation on submarine speed and depth at various frequencies.

 

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