R-7 - SS-6 SAPWOOD - Western Views
The public display of a Soviet SS-6 rocket at the Paris Air Show in 1967 jolted the US scientific astronautics intelligence community into awareness of many weaknesses in its evaluative processes. These revelations were of much greater intelligence significance than the factual information gleaned from inspection of the missile itself. As a result it became possible to identify many shortcomings in the analytical phase of the intelligence cycle.
It was now evident that this approach involved a dangerous assumption, and that Soviet technological approaches in the field of astronautics often differed significantly from those of the United States. Erroneous judgments reached by ignoring available intelligence because it gave answers seemingly inconsistent with "our way of doing things" have unfortunately been common in the scientific intelligence field. The Soviet approach to rocket engine design could be radically different from that of the US, and a direct comparison could be dangerously misleading.
The most surprising feature of the SS-6, the use of multi-chambered engines, was not recognized. This was due to an adverse influence of US design practice on the thinking of intelligence analysts. Although the number of combustion chambers was incorrectly derived, the presence of four engines in the first stage and one engine in the sustainer stage was correctly derived.
A combination of high specific impulse and thrust level of the SS-6 engine, given the 1957 time frame when it was being initially flown, however, should have alerted US analysts to the fact that something was amiss with their interpretation. The strategic system which preceded the SS-6 in research and development flight testing, the SS-4, as well as systems which followed it, such as the SS-5 and SS-7, all used multi-chambered engines. Analysts within the community were reluctant to accept the multi-chambered engine configurations of both the SS-4 and SS-5, even in the light of evidence that such was the case.
In particular, the specific propellant combination employed by the system was incorrectly determined because the volumetric ration of the bi-liquid was derived from a telemetry interpretation which assumed the sustainer tanks were of the same diameter. There was some support for the view that the SS-6 employed a kerosene-base fuel, but the majority view that the oxidizer was liquid oxygen turned out to be correct. It was immediately obvious upon seeing the vehicle in Paris that the propellant combination would logically be kerosene for fuel and liquid oxygen as the oxidizer, consistent with the Soviet announcements at the time.
The specific impulse of the first stage of the system, and the overall energy capability of the stage, were incorrectly derived; both because of the assumption that the area ratio of the first stage engines should be related to the area ratio of the sustainer engine in about the same manner as in engines of US design of the same type. Many intelligence officers within the US intelligence community were correct in their assessment of the specific combination employed, but unfortunately their adversaries, guided by the "divine righteousness of domestic design concepts," overruled their superior technical judgments.
The detailed configuration of the four boosters was improperly interpreted, principally because of the erroneous assumption that liquid propellant tanks for large rocket vehicles would logically be formed from right circular cylinders. Additionally, the general configuration (parallel, or partial), was misinterpreted by many. This argument, incidentally, grew into one of the major intelligence controversies of the decade. Those who turned out to be wrong on this issue based their decisions upon "domestic logic" rather than objectively interpreting available intelligence information such as intercepted radio telemetry. The basic Soviet philosophy of building and handling large rocket vehicles was therefore misunderstood because of the foregoing errors.
|Historical Review - Western Estimates|
|First system flight test||January 30, 1958|
|Operational training flights began||October 1959|
|Initial operational capability||Early 1960|
|Deployed missiles retrofitted with 9000 lb reentry vehicle Late||1960-Early 1961|
|Maximum operational deployment (four missiles) reached||1962|
|Last missile test firing||1966|
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