159. Memorandum Prepared in the Central Intelligence Agency1

    • Recent Tests of the Soviet SS–9

In mid 1968 the Soviets began testing a multiple re-entry vehicle version of their largest ICBM, the SS–9. We have referred to that system as the SS–9 Mod 4. The program consisted of flight tests over their normal test range within the Soviet Union and to longer ranges in the Pacific Ocean. As of April 1970, there had been seventeen tests of the system—[1½ lines not declassified].

[1 paragraph (13½ lines) not declassified]

As a result, the intelligence community has been in agreement that the system, as tested, was a Multiple Re-entry Vehicle (MRV) system rather than a Multiple Independently targetable Re-entry Vehicle (MIRV).

There was a break in the SS–9 Mod 4 testing program from [less than 1 line not declassified]. Since [less than 1 line not declassified] there have been four triple re-entry vehicle tests of the SS–9. At least two of [Page 619]these and possibly a third suggest that development of a MIRV system is under way.2

[4 paragraphs (20 lines) not declassified]

[5½ lines not declassified] Such a system could not be used against widely separated targets, however, as can Minuteman III and Poseidon.

The guidance system employed on the SS–9 Mod 4 through at least April 1970 did not provide the three re-entry vehicles with the accuracy needed to produce a high probability of knocking out hard targets such as Minuteman silos even if they were independently targetable. If the suggestion that testing of a MIRV system is under way is correct, it is possible that the Soviets may also attempt to improve the guidance system. We have not yet determined whether the guidance accuracy has been improved but we are studying all aspects of the problem.

Should the Soviets decide to deploy a MIRV system based on these tests without improving other parts of the system such as the guidance components, it could reach operational status in late 1971. If improvements are made to the guidance system in order to achieve a high probability of killing three hard targets with the three warheads, then the system would probably not be operational until late 1972.3

  1. Source: National Archives, Nixon Presidential Materials, NSC Files, Box 713, Country Files, Europe, USSR, Vol. X. Top Secret; Sensitive. Helms sent the memorandum to Kissinger under a November 10 covering memorandum that begins, “Here is the paper requested on your behalf last evening.” Wayne Smith summarized the CIA memorandum in a November 13 memorandum to Kissinger, who initialed Smith’s memorandum. (Ibid.)
  2. Wayne Smith first alerted Kissinger to the possible outcome of the renewed round of SS–9 tests in a memorandum of November 4. Smith wrote, “if the [less than 1 line not declassified] tests reflect a test of [3 lines not declassified] then the Soviets have begun a new stage of SS–9 Mod 4 flight testing which could lead to a MIRV system.” (Ibid.)
  3. The CIA sent the NSC an Intelligence Memorandum on December 7 reporting that the SS–9 deployment program had slowed and perhaps temporarily stopped. There were also preliminary indications that deployment of the SS–11 and SS–13 had ended. In a December 15 memorandum, Wayne Smith informed Kissinger of this new intelligence regarding the slowdown, which he suggested could be interpreted as a “signal” from the Soviet Union regarding SALT. (Both ibid., Box 714, Country Files, Europe, USSR, Vol. XI)