ICBM BASING II

RT-23UTTKh Molodets (SS-24 Scalpel Mod.1)

Alternative Basing Schemes

Although most of their ICBMs were always sited in silos, both the USA and the USSR repeatedly examined alternatives, both to increase survivability and, perhaps of greater importance in the USA than in the USSR, to reduce costs. In the USA, environmental factors also became an increasingly important consideration.

One of the US schemes was called Multiple Protective Structures (MPS) and consisted of a number of ‘racetracks’, each about 45 km in circumference and equipped with twenty-three hardened shelters. One mobile ICBM, mounted on a large wheeled TEL, would have moved around each racetrack at night in a random fashion, with decoy TELs and missiles adding to the adversary’s uncertainties. Basic MPS involved 200 missiles moving between 4,600 shelters covering an area of some 12,800 km2, but a more grandiose version envisaged 300 missiles moving around 8,500 shelters.

An enhanced version of MPS was proposed in the early 1980s, in which a new Small ICBM (SICBM) would have been deployed in fixed, hardened silos distributed randomly among the 200 racetracks of the MPS system, thus adding to the aiming points for the Soviet ICBM force. It was intended that the SICBM would be 11.6 m long and weigh 9,980 kg, have a range of 12,000 km, and carry a single 500 kT warhead; it would have been launched by an airborne launch-control centre. SICBM would have been housed in a tight-fitting container placed in a vertical silo hardened to approximately 530 kgfcm2, and it would have required an exceptionally accurate incoming warhead to destroy such a target. Various other launch methods were also considered for SICBM, including a road vehicle, normal silos, airborne launch from a transport aircraft, and (possibly the only time this was ever considered for an ICBM) from a helicopter.

Another scheme was based on the racetrack principle of MPS, but this time with the TELs running inside shallow tunnels, 4 m in diameter. The TELs would simply have kept moving, thus avoiding the need for shelters, and would have had large plugs fore and aft to protect against nuclear blast within the tunnel. If required to launch, the TEL would have halted and used hydraulic jacks to drive the armoured roof upwards, breaking through the surface until the missile was raised to the vertical.

Deep Basing (DB) involved placing the ICBMs either singly or in groups deep underground, where they would ride out an attack and then emerge to carry out a retaliatory strike. One of the major DB schemes was the ‘mesa concept’, in which the missiles, crews and equipment were to be placed in interconnecting tunnels some 760–915 m deep under a mesa or similar geological formation. 

Following an enemy nuclear strike, the crews would have used special machines to dig a tunnel to the surface and then brought the launcher to the open to initiate a retaliatory strike. This scheme’s disadvantage lay in its poor reaction time and the difficulty it posed for arms-control verification. From the practical point of view it would have been necessary to find rock which was both fault-free and sufficiently strong to resist a Soviet nuclear attack, but which could nevertheless be drilled through in an acceptable time and without the machinery becoming jammed by debris. On top of all that, a second incoming nuclear strike when the drilling machine was near to the surface would have caused irreparable damage. A related project (Project Brimstone) examined existing deep mines, but also proved unworkable.

A totally different approach, known as Closely Based Spacing or ‘Dense Pack’, was also considered. This suggested that, instead of spacing missile silos sufficiently far apart to ensure that not more than one could be destroyed by one incoming warhead, 100 MX missiles should be sited in superhardened silos placed deliberately close together. The idea was that this would take advantage of the ‘fratricide’ effect in which incoming warheads would be deflected or destroyed by the nuclear explosions of the previous warheads. A spacing of the order of 550 m was suggested, and it was claimed that in such a scheme between 50 and 70 per cent of the ICBMs would have survived.

Mobile basing

All the basing methods discussed above were either static or involved limited movement in a closed circuit, but the question of mobile basing was often considered as well. As described earlier, the German A-4 was designed as a road-mobile system, but an alternative rail-based option was also considered, and a similar scheme was designed and tested during the development phase of the Minuteman I. The plan was to have fifty trains, each of some fourteen vehicles, which would have included up to five TEL cars, each carrying a single missile, together with command-and-control, living-accommodation, and power facilities. The scheme was examined in great detail, and a prototype ‘Mobile Minuteman’ train was tested on the public railway. Although the scheme proved feasible, it was dropped in favour of silo deployment.

A similar proposal was considered during the long development of the Peacekeeper (MX) system, and very nearly became operational. This version would have consisted of twenty-five missile trains, each carrying two missiles. Each train would have consisted of the locomotive and six cars: two missile launch cars; a launch-control car, a maintenance car, and two security cars. In peacetime the trains would have been located in a ‘rail garrison’ sited on an existing Strategic Air Command base, which would have contained four or five shelters (known as ‘igloos’), each housing one train. These garrisons would each have covered an area of some 18–20 hectares, with tracks leading to the USA’s 240,000 km national rail network. On receipt of strategic warning the trains would have deployed on to this national network, where they would have rapidly attained a high degree of survivability. This scheme was under active development from 1989 until its cancellation in 1991.

As we have seen, the Soviet SS-24 Mod 1 was actually fielded in the rail-mobile mode. There were three rail garrisons, all in Russia, with four trains at two sites and three trains at the third. The trains had one launcher each, with two further cars for launch control, maintenance, and power supply.

The Soviets also fielded a road-mobile ICBM, the SS-25, which was also the last Soviet ICBM to enter service during the Cold War. This single-warhead missile was carried on a fourteen-wheeled TEL, which was raised on jacks for stability during the launch. The TEL and its missile were normally housed in a garage with a sliding roof which would be opened for an emergency launch. Given the necessary warning, however, the TELs deployed to pre-surveyed sites in forests.

One US proposal was the ‘continuous patrol aircraft’, in which a packaged missile was carried inside a large, fuel-efficient aircraft. On receipt of verified launch instructions, the missile would have been extracted by a drogue parachute, and once it was descending vertically its engine would have fired automatically, enabling the missile to climb away on a normal trajectory. Tests were carried out using a Minuteman I missile transported by a C-5 Galaxy and were completely successful. Large numbers of aircraft would have been needed to maintain the number required on simultaneous patrol. It would have been very difficult for a potential enemy to track them and even more difficult to guarantee the destruction of every airborne aircraft in a pre-emptive strike, but the main weaknesses of the scheme were the vulnerability of the airfields, the enormous operating costs, and, to a lesser degree, the decreased accuracy of the missile.