s a result of the 1960s doctrine of mutual assured destruction the United States possesses antiaircraft missile defences were dismantled in the 1970s and an antiballistic missile system was built, but activated for only one day. Its earth-spanning electronic early-warning system, examined later, is a means of giving sufficient warning to offensive forces to make the structure of deterrence work. The essence is ability to survive. However destructive the effects of a strike suicidal. That is why in the mid-1950s the so-called triad of US strategic systems began to evolve land-based intercontinental ballistic missiles, submarine-based ballistic missiles and manned, penetrating bombers.
It was partly a result of inter-service competition, but each had relative advantages and disadvantages in accuracy, ability to survive, range and cost, and from these basics, a set of deterrent strategies could be constructed.
This combination was enough until the mid-1970s when the new technologies available to both sides began to diminish the credibility of the triad. It was apparent that Soviet air defence would be increasingly able to destroy the USAFs B-52 bombers and that the new Soviet ICBMs would be accurate and powerful enough in a counterforce strike to devastate the Minuteman force sitting in its silos. Meanwhile, the United States own weapon research was providing technology and developing prototypes for new delivery systems and new warheads, which would themselves render the existing triad forces obsolete.
Thus it was that when the Reagan administration took office in 1980 with a commitment to spend a trillion dollars on defence, US strategic forces stood on the brink of replacement and modernization, with new systems available in prototype form. They are the MX mobile land-based ICBM, the Trident I and Trident II SLBM, the B-1B manned bomber, and the cruise missile in its air, land and sea-launched variants. In addition, there are improvements to the tanker force and the all-important Command, Control and Communications (C3) system.
Looking further ahead, research continues on the ATB or stealth bomber, supersonic cruise missiles and space-based antiballistic missile defence. This chapter considers first US strategic forces, offensive and defensive, as they are now, and ten the planned programmes for new systems in Chapter Four.
All this, moreover, is taking place against a background of sporadic US-Soviet diplomacy in the Strategic Arms Reduction Talks (START), inter-nuclear weapons in Europe and, equally important, US domestic politics, as each step of the modernization plan inches its way through the US Congress, where the pursestrings are ultimately controlled. In April 1983 the bipartisan Presidential Commissions on Strategic Forces chaired by Lt General Brent Scowcroft, USAF (Ret), with a brief of review and assess the multiple strands of the strategic force modernization programme against the background of international attempts at arms control, made its report and its recommendations are looked at later. The modernization plan that went in is not the one that will finally emerge.
The long-range strategic systems of the United States are operated by the USAFs Strategic Air Command (SAC, universally referred to as Sack), which controls intercontinental ballistic missiles and strategic bombers, and the US Navy, which operates ballistic-missile launching submarines. The US Army has tactical nuclear weapons the Pershing 1A intermediate-range ballistic missile in Europe. The USAF controls ground and air-launched nuclear cruise missiles and the US Navy will operate their sea-launched counterparts. The US Army will operate the Pershing II missile, which is technically capable of striking Soviet soil from forward NATO bases.
SAC maintains nearly 70% of all US delivery vehicles, 1045 ICBMs and 316 land-based bombers. Virtually all the missiles and 30% of the bombers are on constant alert. From its headquarters at Offutt AFB Omaha, Nebraska, SAC also commands the USAF tanker fleet of 600 KC-135s, now being equipped with new engines, the EC-135s Looking Glass command posts, the E-4A and B National Emergency Airborne command posts, RC-135 electronic intelligence aircraft, and U-2, TR-1 and SR-71 strategic reconnaissance aircraft. A proportion of the reconnaissance and tanker assets and some of the older B-52s are based, rotationally, in the United Kingdom.
The total number of US land-based missiles was fixed in 1967 : 1000 Minuteman solid-fuelled ICBMs and 54 liquid-fuelled Titan IIs. (Subsequently two Titans have been lost in silo accident and phaseout began in 1982.)
There are 550 Minuteman IIIs operational, each tipped with a triple-RV warhead, and 450 single warhead Minuteman IIs. In 1983 50 Minuteman IIs were replaced with Minuteman IIIs, thus increasing the number of warheads by 100.
Some of the Minuteman IIs are committed to emergency rocket communications (ERCS). Once launched they broadcast an alert via Universal Attack Order satellites to other SIOP forces, in particular insurance against the fear of decapitation.
The Minuteman III was the first US system operational with an MIRV warhead. The result of deploying the Minuteman III, along with the Poseidon SLBM, which also has an MIRV warhead, increased the total number of warheads from 1054 land-based and 656 submarine-based in 1970 to a total of 7274 individual warheads a decade later.
Strategic Air Command
The Minuteman III is a three-stage ICBM with a MIRV warhead of three individual RVs. The first two stages are the same as in Minuteman II but the third stage has improved directional guidance. The Minuteman III has greater range than its silo mate (13,000 km compared with 11,250 km), but is more accurate in spite of flying further. Its circular error probable (the radius of a circle in which half the rounds launched will land) is about 400 m.
The Post-Boost Vehicle is a mini spacecraft equipped with control motors to propel it on military mission dispensing warheads in a computer predicted footprint on ground targets. The normal payload for a Minuteman III is three Mk 12 thermonuclear warheads, along with chaff and decoys (penaids) to confound antiballistic missile defences.
The Minuteman improvement programme centers on both its destructive potential and its own ability to survive. The destructive power of a nuclear weapon is a function of its reliability, accuracy and yield or explosive power. Great efforst are being made to maintain the operational potential of the Minuteman force on each count. Replacement of Mk 12 re-entry vehicles with the new Mk 12A is in progress on 300 Minuteman IIIs and the entire force is scheduled to receive computer technology.
The Mk 12A has been under development by General Electric since 1974. There was s protected political fight over funding because of the counter-force potential of the system afforded by its yield and high accuracy. Miniaturizations of the arming and fusing electronic circuit means that it can carry a W-78 nuclear weapon with a yield increased from the Mk 12s 170 kiloton to 330 kilotons. The length of the Mk 12A is 1813 mm and the base diameter is 543 mm. Because the Mk 12A is approximately 16 kg heavier than the Mk 12 the range and MIRV footprint are slightly reduced. Thus, only 300 out of 550 nose cones will be equipped with the Mk 12A. completion is scheduled for the mid-1980s, the changeover being effected when missiles fall due for periodic inspection and maintenance.
Above: The 100-ton door is open and a Minuteman ICBM is erady for launch. In its nose is the NS-20 guidance computer that can be electrically reprogrammes to take its multiple warheads to different targets within the Single Integrated Operational Plan. The launch sequence begins with strategic alert, then passes through warhead armed to launch in progress. After missiles away there is no recall three 330-kiloton warheads are on their way to the Soviet Union.
The ability to survive of the Minuteman force was to be achieved by wide dispersion and silo basing. The force is organized in flight of ten-launch silos, each ten-missile flight having its own launch control centre (LCC). Five such flights make a squadron and three squadrons make a wing. The Minuteman Wings of SAC are deployed as follows:
I 341 Strategic Missile Wing (SMW) Malstrom,
Montana 150 M II/50 M III
II 44 SMW, Ellsworth, south Dakota 150 M III
III 91 SMW, Minot, North Dakota 150 M III
IV 351 SMW, Whiteman, Missouri 150 M II
V 90 SMW, F.E. Warren, Wyoming 200 M III
VI 321 SMW, Grand Forks, North Dakota 150 M III
Each wing can be dispersed over a very wide area the biggest Minuteman field is over 18,000 sq mi. while individual missiles are placed in silos with a fenced-off surface area of two acres strewn with sensors. The silo is 25 m deep and 4 m in diameter, protected by a six-sided steel and concrete carapace weighing 100 tons. The flight-launch control centre, over 5 km from the silo, is 15 m underground and contains a blast-resistant, shock-mounted capsule occupied by two SAC officers who control a flight of ten missiles. Inside the launch control centre the first warning of an attack would be an oscillating note on the loudspeaker, at which the crew immediately close the blast doors and go on to emergency air. If it is a real attack the speaker will announce, Gentlemen, you have received an authorized launch instruction from the National Command Authority, and simultaneously a printed code of letters and numbers comes through a telex machine. The crew open a strongbox on the wall and check the code inside against the code they have received. If they match, the launch command is valid.
The crew sit in chairs at right-angles to each other, 15 feet apart, and set their individual codes (unknown to each other) to gain access to the firing circuits, then turn keys within two seconds of each other and hold them in place for two seconds. A second crew in another capsule has to go through the same operations, voting simultaneously for the launch command to be effected. These centers be knocked out, and a single centre can override another individual centres launch command, acting independently of the squadrons. But, once a missile is fired, there is no recall.
From the very start of the Minuteman programme, great emphasis was laid on ensuring the survival of no just the weapons in their silos but also of the command and control system that linked them together and transmitted the orders that would allow the Single Integrated Operational Plan to be put into effect.
In 1962 work on the Minuteman Ground Electronics System (GES) was begun by the Sylvania Systems Group. Called WS-133B, the system has been continually upgraded. Sylvania installed 2000 km of cable and buried radio antennae at each launch facility to provide a double route system of cable and radio, with a third redundant radio backup.
Recent work has been concentrated on hardening the GES and achieving remote rapid targeting. Hardening entails increasing the resistance of the system to shock, vibration, radiation and the phenomenon of electromagnetic pulse. One answer is to construct cable communications from optical fibres.
Remote targeting is another priority. Target information is stored in the missiles guidance computer as a tape. To re-target the missile the tape has to be changed manually. The missile launch sites are unmanned in their normal alert state, but the missile guidance equipment power is on continuously while the missiles own computer carriers out routine readiness chacks. The new programme allows re-targeting to be achieved from the launch control facility, which is at least 5½ km from the silo. Much more significantly, re-targeting and launch can be achieved by a flying control centre virtually immune to destruction in a first-strike.
Above: Minuteman III launch from a test silo at the Air force Missile Test Centre.
Below: Minuteman silos are hardened up to twelve times atmospheric pressure but have been judged vulnerable to the new generation of Soviet land-based strategic missiles.