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UR-100 / SS-11 SEGO

The development of the massively deployed UR-100/SS-11 liquid propellant light ICBM was the centerpiece of a major Soviet effort to reach numerical strategic parity with the USA. The SS-ll was the Soviet counterpart of the US Minuteman system in quantity, size and purpose. Initially deployed with a single warhead [with a yield of 1.1 MT according to Russian sources, or 0.6 to 1.2 MT according to Western reports] and a low accuracy [a CEP of 1.4 km according to Russian sources], the missile could be used only against soft targets.

The UR-100 intercontinental ballistic missile is a two-stage, tandem, storable liquid-propellant missile. It is about 64 feet long and 8 feet in diameter. In both stages the oxidizer and fuel tanks had a common bottom which reduced overall dimensions and launch weight of the missile. The bottom of the oxidizer tank of the first stage was placed inside the tank like an inverted truncated cone. The nozzle of the sustainer of the second stage was included in the formed upper volume. The first stage used a new set of four closed-cycle single-chambered rocket motors, while the second stage incorporated a single-chambered sustainer and a four-chambered control motor. Asymmetrical dimethylhidrazine and nitrogen tetraoxide were used as propellants. The missile uses an inertial guidance system consisting of an autonomous guidance/control system with a gyro-stabilized platform of floating gyros. The command structure also provided an automatic checkout of all systems during flight and automatic preparation of launch.

The development of the UR-100 was approved by the government on 30 March 1963. The developer was NPO Mashinostroyenia (OKB-52). The missile was deployed in at least four variants, and was probably tested in several additional configurations. There is some confusion among these variants between recent published Russian sources, which focus on the physical configuration of the rocket, and contemporaneous Western sources, which were limited to intelligence derived from observing flight tests. In the middle of the 1970's the UR-100 was replaced by two modernized versions that received the designations UR-100K (15A20) and UR-100U (15A20U).

The missile was deployed in a silo launcher, with a design that was substantially simplified in comparison with earlier complexes. The silo could be closed for protection with the help of a pneumatic driven sliding roof. This was the first Soviet ICBM to be deployed with a pressurized transport launch canister in which the missile was delivered to the launch complex and from which it was fired. During the storage of the missile the engines were isolated from the propellant components by membrane-valves that provided their safety during extended times of being in a fueled condition.

The SS-11 deployment was assessed by Western intelligence to be similar in concept to the US Minuteman, where a large force was deployed in hardened silos requiring a minimum of support facilities. Silo and launch control center hardness was estimated at 700 and 400 psi overpressure, respectively, from a 1-MT weapon. The sites were deployed in groups of ten unmanned silos with a single launch control center for each group. Reaction time in the normal readiness condition was assessed by the West as 0.5 to 3.0 min. with an unlimited hold time in this alert condition.

The UR-100 missile was the most extensively deployed ICBM within the Strategic Rocket Forces. Between 1966 and 1972 a total of 990 of these missiles were deployed. Between 1973 and 1977 some 420 launchers of the UR-100K/UR-100U missiles were deployed while the UR-100 missiles were phased out. As of 1991 some 326 remained in service, while by the end of 1994 all but 10 of the UR-100 and UR-100U missiles had been removed from combat duty in compliance with the START-1 treaty. By the end of 1996 all SS-11 missiles had been dismantled.

Specifications

 

Mod-1

Mod-2

Mod-3

Mod-4

DIA

SS-11

SS-11

SS-11

SS-11

NATO

Sego

Sego

Sego

Sego

Bilateral

RS-10

RS-10

RS-10M

RS-10M

Service

UR-100/
UR-100M

UR-100K

UR-100U

OKB/Industry

8K84
8K84UTTkh

8K84K

8K84UTTkh 8K84M 15A20U

Design Bureau

OKB-52
Chelomey

OKB-52
Chelomey

OKB-52
Chelomey

OKB-52
Chelomey

Approved

3/30/1963

     

Years of R&D

1951-66

     

Engineering and Testing

1962-66

1969-1971

1971-1973

1971-1973

First Flight Test

4/19/65

7/23/1969

2/2/71 & 9/2/69

6/16/71

IOC

11/24/966

3/1/1970

1973 - 74

[not deployed]

Deployment Date

7/21/1967

12/28/72

9/26/1974

[not deployed]

Type of Warhead

Single

Single

MRV

MRV

Warheads

1

1

3

6

Yield per Warhead (Mt)
(Russian Sources)

0.5 or
1.0 -1.1

1.2

0.35

0.35-1.3

Yield per Warhead (Mt)
(Western Sources)

0.6 to 1.2

0.6 to 1.2

0.2 to 0.8

Payload (t)

0.76 - .08

0.9-1.2

1.208

1.2

Total length (m)

16.925

18.9 - 19.0

18.9

19.1 - 19.8

Total length w/o
Warhead (m)

16.45-16.69

16.5

17

17

Missile Diameter (m)

2

2.

2

2

Launch Weight (t)

39.4 - 42.3

50.1

50.09 - 50.1

50.1 - 51.24

Fuel Weight (t)

40.4?

45.3

45.3

45.3

Range (km)

11,000-12,000 or
5,000

11,000-13,000

10,600-12,000

10,600-12,000

CEP (m)
(Russian Sources)

1,400

1,400

900-1,350

900-1,350

CEP (m)
(Western Sources)

1,400-1,500

1,100-1,400

1,000-1,100

 

Number of Stages

2

Canister length (m)

19.5

Canister length w/o
Front meters (m)

 

Canister diameter (m)

2.9

Booster guidance system

Inertial, autonomous

 

1st stage (8S816)

2nd stage (8S817)

 

Mod-1

Mod-2

Mod-3/4

Mod-1

Mod-2

Mod-3/4

Length (m)

12.5

13.3

13.4

2.9

3.2

3.8

Body diameter (m)

2

2

Fueled weight (t)

34

38-40

40

     

Dry weight (t)

           

Engine

Designation

RD-0216 / RD-0217
(15D2)

RD-0235 / RD-0236
(8D13, 8D419, 15D14)

Design Bureau

OKB-154, Acad. S. A. Kosberg

OKB-117, Acad. V. Klimov

Configuration

Cluster of four engines

One engine

Years of R & D

1963-1966

 

Propellants

Liquid

Liquid

Fuel

UDMH

UDMH

Oxidizer

Nitrogen Tetroxide

Nitrogen Tetroxide

Burning time (sec)

103?

164?

Verniers Thrust Sea Level/Vacuum (Tonnes)

N/A

1.565 ?1.6

Main Engines Thrust Sea Level/Vacuum (Tonnes)

79.95/86.275 - 89.33

13.665 - 15.195 - 24.5 Vacuum

Total Thrust Sea Level/Vacuum (Tonnes)

319.8/357.6

20.0651 - 22.3 - 30.9 Vacuum

Main engine Specific Impulse Sea Level/Vacuum (sec.)

262/313 Vacuum

320 Vacuum

Verniers Specific Impulse Sera Level/Vacuum (sec.)

N/A

293 Vacuum

Basing Mode

Silo

Hardness

Silo at 700-750 psi
LCC at 360-400 psi

Launching Technique

Hot

Deployed boosters

 

Test Boosters

 

Deployment Sites

 

Training Launchers

 

Space Booster Variant

No

Deployment Sites

START

Locale US-Designation

Bershet?

Perm

Drovyanaya

Drovyanaya

 

Itatka

Kostroma

Kostroma

Kozelsk

Kozelsk

Krasnoyarsk

Gladkaya

Pervomaysk

Pervomaysk

 

Shadrinsk

Svobodny

Svobodny

Teykovo

Teykovo

 

Tyumen

Yasnaya

Olovyannaya

Historical Review - Western Estimates

First flight test
Mod 1 April 19, 1965
Mod 2 July 23, 1969
Mod 3 September 12, 1969
Operational system production probably began
Mod 1 1965
Mod 2 ?
Mod 3 1971
First penaids flight testing September 20, 1967
Short-range flight testing . began July 1968
First launch from operational site November 11, 1970
Maximum operational launcher deployment 1971

SS-11/RS-10  in Launch Canister 
SS-11/RS-10 Outside Launch Cannister
SS-11/RS-10 Stage 1

SS-11/RS-10
Emplacement
Equipment
SS-11/RS-10
Emplacement
Equipment 2

Sources and Resources



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