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UR-100MR / SS-17 SPANKER

The UR-100MR / SS-17 intercontinental ballistic missile is a two-stage, tandem, storable liquid-propellant missile intended to replace the light UR-100 SS-11 missile. It was a competing design with the SS-19 Stiletto, though in fact both were deployed. It was the first Soviet ICBM to have a Multiple Independently targetable Reentry Vehicle (MIRV) and the first to use a cold launch system. The UR-100MR / SS-17 intercontinental ballistic missile was assessed as being capable of delivering a throw-weight of 6,000 lb to a range of 5,500 nm. The throw-weight consists of a post-boost vehicle and either one or four reentry vehicles.

The overall dimensions of the SS-17 were determined by the characteristics of the SS-11 UR-100 silos in which the UR-100MR missile was planned for deployment. The diameter of both stages was increased in relative to that of the UR-100, and is 2.25 m for the first and 2.1m for the second stage. The UR-100MR uses asymmetrical dimethylhydrazine and nitrogen tetraoxide propellants. The first stage uses a closed-cycle single-chambered sustainer engine and a four-chambered open-cycle control motor. The second stage is equipped with a single-chamber open-cycle sustainer, placed inside the lower part of the fuel tank. The flight control during the first stage uses deflecting the control motor chambers, while the second stage uses gas injected into the diverging part of the nozzles. Solid propellant retrorockets are used to separate the stages.

The rocket MR UR-100 was placed in previously hardened SS-11 UR-100 silos. The missiles in their transport-launch canister were inserted into the silo with the use of two shock-absorption belts. The SS-17 uses a sabot cold launch or pop-up launch system that facilitated modifying existing SS-11 facilities.

• SS-17 Mod-1 - This initial version of the SS-17 carried 4 MIRV warhead with a yield of 0.3-0.75 Mt each, an instrument module with a command structure and solid-propellant rocket motor comprise the post-boost vehicle. According to Western estimates each RV weighed about 900 lbs. The missile had an inertial guidance system with an estimated CEP of 0.34 nm for 1975 and a potential CEP of 0.28 nm in 1980. Its development was approved in September 1970 and conducted by KB Yuzhnoye (OKB-586) which was headed by V. F. Utkin. Pop-up tests which improved the mortar launch technique began in May 1971. The full scale flight-design tests of Mod1 and 2 were conducted at the Baikonur cosmodrome test site from 26 December 1971 and 17 December1974. Flight testing was first detected by the West on 15 September 1972. The first regiment with MR UR-100 missiles was put on alert on 06 May 1975 and its deployment began on 30 December 1975.

• SS-17 Mod-2 - The Mod-2 missile carries only a single warhead with a yield of 4-6 MT.

• SS-17 Mod-3 - On 16 August 1976 a governmental order to improve the UR-100MR performance characteristics was issued. The preliminary design of this MR UR-100UTTh missile known as SS-17 Mod3 was completed by KB Yuzhnoye (OKB-586) in December 1976, receivingthe industrial index number 15A16. Like the SS-17 Mod-1 it carries four MIRV warheads, but it incorporated enhanced survivability and was equipped with an improved commando system and a modernized nose cone. The flight-design tests began on 25 October 1977 and were finished on 15 December 1979. The Mod-3 reached its IOC in 1978 and its deployment started on 17 December 1980 (simultaneously with the R-36MUTTh).

Specifications
	Mod-1	Mod-2	Mod-3
DIA	SS-17	SS-17	SS-17
NATO	Spanker	Spanker	Spanker
Bilateral	RS-16A	RS-16A	RS-16B
Service	MR-UR-100	MR-UR-100	MR-UR-100 UTTKh or MR-UR-100U
OKB/Industry	15A15	15A15	15A16
Design Bureau	OKB-586 Acad. V. F. Utkin	OKB-586 Acad. V. F. Utkin	OKB-586 Acad. V. F. Utkin
Approved	9/1970	9/1969	8/16/1976
Years of R&D	1964-70	1964-70
Engineering and Testing	1971-74	1970-75	1977-79
First Flight Test	09/15/1972 failure 12/26/71 success	12/26/1971	10/25/1977
IOC	05/06/1975	1975	10/17/1978
Deployment Date	12/30/1975	12/30/1975	12/17/1980
Type of Warhead	MIRV	Single	MIRV
Warheads	4	1	4
Yield (Mt)	0.350-0.750	3.5-6.0	0.550 - 0.750
Payload (t)	2.550	2.550	2.550
Total length (m)	22.52	21.6 ? 22.52	23.9
Total length w/o Warhead (m)	20.9	20.9	20.9
Missile Diameter (m)	2.25	2.25	2.25
Launch Weight (t)	71.1	71.1	71.1 - 72
Fuel Weight (t)	63.2	63.2	63.2
Range (km)	10,200 -10,320	10,100 -10,320	10,200 -11,000
CEP (m) (Russian Sources)	1,080	1,080	920
CEP (m) (Western Sources)	440-500	420-450	220-400

Number of Stages	2
Canister length (m)	21.6
Canister length w/o Front meters (m)
Canister diameter (m)	2.5
Booster guidance system	Inertial, autonomous

	1st stage	2nd stage
Length (m)	14.3, 14.9	3.2
Body diameter (m)	2.25	2.15
Fueled weight (t)	59.0
Dry weight (t)
Engine Designation	RD-268 Main Engine	RD-262 (15D169)
Engine Designation	RD-263 Vernier Engine	N/A
Design Bureau	Acad. V. P. Glushko (OKB-456)	Yuzhnoye (OKB- 586)
Configuration	One Main Engine, One Four Chamber Verniers Engine	One Chamber
Year of R & D main engines	1969-1973	1969-1972
Year of R & D Vernier engine	1970-1973	N/A
Propellants	Liquid	Liquid
Fuel	UDMH	UDMH
Oxidizer	Nitrogen Tetroxide	Nitrogen Tetroxide
Burning time (sec.)	130	195
Main Engine Thrust Sea Level/Vacuum (Tonnes)	117/126	14.5 44 Vacuum
Verniers Thrust Sea Level/Vacuum (Tonnes)	28.230 /?	N/A
Main Engine Specific Impulse Sea Level/Vacuum (sec.)	?/319	331 Vacuum
Vernier engine Specific Impulse Sea Level/Vacuum (sec.)	259/301	N/A

Basing Mode	Silo
Hardness
Launching Technique	Mortar Launch
Deployed boosters
Test Boosters
Warheads Deployed
Training Launchers
Space Booster Variant	No

Deployment Sites

START	Locale US-Designation
Kostroma	Kostroma
Vypolzovo	Yedrovo

SS-17/RS-16  in Launch Canister

SS-17/RS-16 Missile

SS-17/RS-16 Stage 1

SS-17/RS-16 and SS-19/RS-18 Emplacement Equipment

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-17 Spanker @ 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. pgs 234 and 238

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