The missile was high, in diameter and weighed 37.1 tons. It was based on two solid-fuel fibre-glass clad stages of the RT-21 Temp 2S, so it was also known as the RT-21M Pioneer. The missile's range was from initially; the final model had a maximum range of possibly. Initially the missile was fitted with a single 1 Mt, 1.6 ton warhead, later models could take one warhead or two and from 1980 three, 150 kt MIRV devices. The CEP was also reduced from to. The missile was the first Soviet missile equipped with solid fuel instead of liquid fuel, which meant that it could be launched once the order had been given instead of requiring hours doing the dangerous work of pumping the missile with liquid fuel. The missile used a MAZ-547A/MAZ-7916 transporter erector launcher produced in the Belarusian SSR by the Minsk Automobile Plant. The TEL was originally designed for the RT-21 Temp 2S intercontinental ballistic missile. On 10 August 1979 testing of the modernized "Pioneer"-UTTKh began at the Kapustin Yar test site. It continued through 14 August 1980, and on 17 December 1980 the missile designated as SS-20 Mod3 was deployed. This variant had the same propulsion system as earlier versions, but due to upgrading of a command structure and instrumentation-service unit it was possible to improve accuracy from 550 to 450 meters, to increase maximum range by 10%, and to increase the area covered by the warheads. This latest RSD-10 variant subsequently received NATOreporting nameSS-28 Saber 2.
Development
It was intended to replace, or augment, the R-12 Dvina and R-14 Chusovaya missiles deployed from 1958 and 1961 respectively in the USSR and Warsaw Pact states. It entered the development stage in 1966 and a design concept was approved in 1968 with the task given to the Moscow Institute of Thermal Technology and Alexander Nadiradze, who also developed the RT-21 Temp 2S in the same period. Flight testing began in 1974 and deployment commenced on 11 March 1976, with the first supplied units becoming operational in August of that year. Up to 1986, a total of 48 launch sites including a site at Pavschino, were equipped with 405 RSD-10 missiles under control of the Strategic Missile Forces. There were several theories as to why the Soviet Union developed the SS-20:
Some in the United States such as Richard Perle saw the SS-20 as a part of a bid for global power on the part of the Soviet Union.
Another popular theory held that the SALT treaties, by placing quantitative limits on long-range missiles, had encouraged the Soviets to place more emphasis on medium-range missiles, which were not covered by SALT.
Another theory held that the SS-20 was the "son" of the failed SS-16 ICBM project. Following the failure of the SS-16, the Soviets simply used the technology and parts that had been developed for the SS-16 for the SS-20.
Others argued that the SS-20 was part of an attempt on the part of the Soviet military to develop a more sophisticated nuclear strategy that did not call for an all out nuclear first strike as soon as World War III began by giving the Soviets a second strike capability that they had previously lacked.
During the 1960s, Soviet missile procurement was dominated by the ideas of Defence Minister, Marshal Andrei Grechko who was opposed to the idea of nuclear weapons as a weapon of last resort, and planned that if World War III began to begin that conflict with an immediate nuclear strike on the NATO nations. By the early 1970s, Grechko's views had caused opposition within the military and the political leadership, who wanted the Soviet Union to have a second strike capacity in order to prevent a war with the United States from going nuclear immediately as Grechko preferred. More importantly, the increasing influence of Marshal Dmitriy Ustinov heralded a shift in Soviet thinking about nuclear weapons. Ustinov was a man closely connected with the various Soviet design bureaus, and who generally sided with demands of the design bureaus against the military regarding weapons procurement. The decision to order and introduce the Pioneer in the mid-1970s was in large part due to Ustinov's wishes to shift military procurement out of the hands of the military and into the design bureaus, who in turn pressed for more and varied weapons as a way of increasing orders. The British historian James Cant wrote that it was the triumph of the Soviet version of the military-industrial complex over the military as regarding weapons procurement that was the most important reason for the Pioneer.
Deployment
While the Warsaw Pact arguably enjoyed a massive conventional superiority over NATO in Central Europe, Soviet leaders assumed that NATO would use tactical nuclear weapons to stop a massive Warsaw Pact offensive. The RSD-10 provided the Soviet Union with an in-theater "selective" targeting capability that it previously had lacked. The RSD-10 had the capacity to destroy all NATO bases and installations with negligible warning. Thus, the Soviet Union acquired the capability to neutralise NATO's tactical nuclear forces with surgical nuclear strikes. In 1979 NATO decided to deploy US Pershing II and BGM-109G Ground Launched Cruise Missile missiles in Western Europe in attempt to counter the RSD-10. In 1979, when the NATO decision was taken, the Soviet Union had 14 SS-20 launch sites.
