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R-9 - SS-8 SASIN

The R-9/SS-8 Sasin intercontinental ballistic missile is a two-stage, tandem, cryogenic liquid-propellant missile. According to Western assessements it was capable of delivering a 3500 lb reentry vehicle to a maximum operational range of 6000 nm with a CEP of about 1.0 nm.

The R-9 was the last Soviet ICBM using cryogenic propellant. This two-stage ICBM had sequential stages that were connected by a truss. The first stage was equipped with a closed cycle engine with four combustion chambers that used a liquid cryogenic propellant developed by NPO Energomash Imeni V.P. Glushko (OKB-456). For the second stage an open-cycle four combustion chamber engine developed by KB Khimavtomakiki (OKB-154) was employed. The flight control during the first stage flight used a new system of gimbaled combustion chambers of the sustainer stage. The flight control of the second stage was provided through control nozzles using exhaust gas from the turbopump unit. As the separation of the first stage occurred at an altitude where the influence of aerodynamic forces was still essential, the application of stabilizers was necessary. To maintain aerodynamic stability during the first seconds of flight of the second stage four aerodynamic fins were placed on its aft bay. They opened after the separation from the first stage. Several seconds afterwards the aft bay of the second stage was also separated. The R-9 was the first Soviet ICBM to incorporate pressurization of the main propellant in the fuel tanks, which obviated the need for special bottles with a pressuring gas.

The original missile had a combined command structure with a radio engineering channels. The inertial system provided flight control during almost all the active trajectory except for the last ten seconds which were controlled by a radio-correction-system. Subsequently however, the use of a radio engineering channel was discarded, and the command system of the missile allowed to execute autonomous monitoring of missile flight parameters. .

The missile could be equipped with two different nose cones according to different payloads: a light nose cone capable of containing a warhead with a yield of 1.7 MT and a heavier one with a warhead of 2.09 MT.

The original missile was intended to be surface launched, but in 1960 the development of a silo-launched version was begun. In total three different launch complexes were developed: Two ground-launch complexes (Desna-N/Valley) and a silo-launch complex ("Desna-V").were developed. Two launchers, a command center, missile and propellant depots and radio command guidance system formed part of the "Desna-N" launch complex. The "Valley" complex had a similar structure, but was equipped with an automatic system that could carry out a launch within 20 minutes. Within this time the missile could be transported from the depot to the launch-complex, installed, fueled prepared and targeted. The minimal interval for the next missile firing lasted from nine minutes for the next launcher up to 2.5 hours for a repeat launch from one pad.

The silo-launch complex "Desna-V" consists of three silos, located in a straight line close to each other an underground command center, underground depots of propellant components and compressed gases and a radio control complex. The silos were 36 m deep with a minimum diameter of 7.8 m and a canister diameter of 5.5 m. For the first time a hot launch of a missile from the silo was accomplished through the use of oxygen that was previously cooled to –186° C. The missile could be held in readiness up to 1 year, and in the fueled condition up to 24 hours.

The proposals of the chief designers for the development of a new ICBM with an oxygen-kerosene propellant and an initial weight of about 100 tons (i.e. almost three times less than that of the R-7) were submitted to the government in April 1958. The order of the ministerial council to build the R-9 missile was issued on 13 May 1959 and the designated head developer was S. P. Korolev's OKB-1. The flight tests of a missile were conducted at the Baikonur cosmodrome. They were first carried out on 09 April 1961 at a modified launch complex, then proceeded on an experimental ground-launch launch complex "Desna-N" until 14 February 1963. The test of the ground-launched version were finished on the "Valley" battle complexes and tests of the silo-launched version were finished on 02 February 1964. Due to serious engine problems 15 of the first 32 launches terminated in emergencies. In total 54 missile tests were carried out.

The SS-8 system was deployed at both soft and hard sites.On July 21, 1965 the deployment of SS-8 missiles began. They were capable of ground and silo-launch from the "Valley" and "Desna-V" launch complexes. The "Desna-N" complex was not deployed, since launch preparation took at least 2 hours. According to Western assessments, the reaction time for soft systems in the normal readiness condition was one to three hours, and for hard systems from 30 to 45 minutes. Because of the cryogenic oxidizer, the allowable hold time in the highest degree of pre-launch alert (reaction time equals five to ten minutes) was assessed at about one hour.

According to Western intelligence, soft-site initial operational capability was achieved in November, 1963, and hard-site IOC followed in April 1964. In fact, Russian sources suggest that the first missile regiments equipped with missiles R-9A, were put on alert in December 1964 (4 regiments with surface-based missiles and one regiment with missiles of silo basing). The maximum operational launcher inventory of 23 was reached in 1963 and 1964. Soft-site phase out began in 1971, and in 1976 the R-9A missiles were phased out entirely.

Sources and Resources

• Russian Strategic Nuclear Weapons, Pavel Podvig, ed., IzdAT, Moscow, 1998, 492 pp. (in Russian). Authors: Oleg Bukharin, Timur Kadyshev, Eugene Miasnikov, Pavel Podvig, Igor Sutiagin, Maxim Tarasenko, Boris Zhelesov
• SS-8 Sasin @ US Naval Institute Military Database
• "A History of Strategic Arms Competition 1945-1972" (U), Volume 3, A Handbook Of Selected Soviet Weapon and Space Systems, United States Air Force, June 1976. pg 152

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