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The Soviet Fractional Orbital Bombardment System Program

Technical Report APA-TR-2010-0101

by Miroslav Gyűrösi
Updated April, 2012
Text and images © 2009 - 2012 Miroslav Gyűrösi

Yangel R-36-O / SS-9 Scarp Mod.3 FOBS (© Miroslav Gyűrösi)


The Soviets conducted a long running campaign of strategic deception against the West through the whole Cold War period, and the protracted development of the Soviet FOBS nuclear weapon system presents an excellent case study of such.

The Soviet RVSN or Strategic Rocket Forces were involved in a sustained and intensive arms race against the US Air Force Strategic Air Command, the intent being to provide a decisive advantage in ballistic missile exchanges in the event of a full scale nuclear conflict. An important part of this campaign was the deployment of large phased array Ballistic Missile Early Warning (BMEW) radar systems by both sides. The BMEW radars would track incoming ballistic missiles and Re-entry Vehicles (RV) as they rose above the radar horizon and then re-entered the atmosphere, track these, and provide estimated impact points, impact times, and with lesser accuracy, locations of launchers. The systems of BMEW radars deployed by both sides were critical in providing early warning of a nuclear attack in progress, and data to support decisions on what retaliatory strikes should be launched at what targets. Both sides considered launching strikes against empty ICBM silos to be an ineffective strategy.

Soviet RVSN strategists quickly recognised that the first generation of BMEW radars deployed by the US were oriented to track Soviet attacks on direct trajectories, in which ICBMs were launched from sites in European Russia and Siberia, and would reach their apogees over the northern polar regions. Without BMEW coverage through the southern geographical arc, US nuclear warfighting staffs were blind to attacks from other directions. This presented an opportunity for the Soviets, as a wave of strikes on key US facilities without warning could permit defacto decapitation of the US command, control and communications systems, and if sufficient warheads were delivered, key silo fields could be heavily damaged reducing residual US retaliatory capability. Given the nuclear warfighting imperative of “use them or lose them”, the player who could knock out as many opposing ICBMs in the opening round of a nuclear conflict had an important advantage.

The Fractional Orbital Bombardment System (FOBS) as it was known in the West, was a Soviet innovation intended to exploit the limitations of US BMEW radar coverage. The idea behind FOBS was that a large thermonuclear warhead could be inserted into a steeply inclined low altitude polar orbit, such that it would approach the CONUS from any direction, but primarily from the southern hemisphere, and following a programmed braking manoeuvre, re-enter from a direction which was not covered by US BMEW radars. The first warning the US would have of such a strike in progress would be the EMP transients produced by the nuclear devices initiating over their programmed targets in the CONUS.

FOBS Development

Development of the 8K713 GR-1 (Globalnaya Raketa -1 or Global Missile 1) was initiated in 1962 by OKB-1, led by Sergei Pavlovich Korolyov. This was to be the last ballistic missile design produced by Korolyov, best known in the West for his effort in the Soviet space program.

The development effort on the 8K713 GR-1 ceased in 1964, without a single test launch having been performed. Despite, as part of a strategic deception effort, the Soviets displayed this missile as an operational weapon system during their annual Red Square military parade. Western analysts were convinced that this system was in use, and it was allocated the US/NATO designation of SS-10 SCRAG.

What the Soviets did deploy operationally was an entirely different FOBS system, the R-36-O or 8K69 developed by SKB-586, led by Mikhail Kuzmich Yangel’. Based then and since in Dnepropetrovsk, in the Ukraine, the design bureau was co-located with the Yuzhniy Mashinostoryenniy Zavod manufacturing plant.

Strategic Deception - The OKB-1 8K713/GR-1 / SS-10 SCRAG FOBS

Above, below, close-in imagery of the GR-1 FOBS on parade in Moscow during the early 1960s. Development of these missiles was never completed and these examples were used to deceive the West as to actual RVSN capabilities. The real operational Yangel R-36O / SS-9 SCARP Mod.3 did not enter service until much later (via Russian Internet).

Above, below, imagery of the GR-1 FOBS on parade in Moscow during the early 1960s. The transporters are towed by MAZ-535A heavy artillery tractors (via Russian Internet).

Soviet propaganda image of GR-1 missiles being readied for silo loading. These were staged, with RVSN troops used to lend authenticity to a sham (Soviet MoD).

The Yangel R-36 / SS-9 SCARP ICBM

Yangel's R-36 ICBM was the Soviet equivalent to the US Titan series of heavy ICBMs. It formed the basis of the operational R-36-O FOBS, and the subsequent R-36M series (US DoD).

R-36 ICBMs on parade in Moscow during the early 1960s. The transporters are towed by MAZ-535A heavy artillery tractors (via Russian Internet).

The first generation R-36 being loaded into a silo. Later variants used storable liquid propellant, and encapsulated storage to permit rapid silo reloads (US DoD).

Development of a FOBS derivative of the existing R-36 heavy ICBM design was authorised in 16th April, 1962, leading to approval and assignment of the 8K69 designation in December, 1962, and subsequently, initial prototypes in the third quarter of 1964.

In January, 1965, the government authority directed that the missile be redesigned for an “encapsulated” launch system. Until then, Soviet ICBMs were stacked in situ in a silo, and then fuelled for operation with the toxic and corrosive liquid propellant mix. The new encapsulated packaging scheme would see the ICBMs stacked, and then installed in a hermetic launch container, which was inserted into a silo for long duration standby operation. Prior to sealing, the missile was pumped full of the inhibited propellant mix, which would allow it to sit in a silo for 7.5 years, ready for launch at five minutes notice, before it needed to be extracted, defueled, and overhauled.

In introduction of this scheme was intended to increase the operational readiness of the RVSN ICBM force, which was at that time largely equipped with liquid fuelled missiles. ICBMs could sit in silos ready for immediate launch, within minute of a launch order arriving at the hardened Launch Control Centre for the silo.

Design bureau test launches of the R-36-0 / 8K69 commenced in December, 1965, from the Baikonur LC-160 and LC-162 silo complexes. The R-36-O / 8K69 FOBS was accepted into operational service on the 19th November, 1968, and remained operational until January, 1983.

The R-36-O was designated in the US/NATO system as the SS-9 Mod 3 SCARP or “SS-9 FOBS”, and is sometimes labeled the R-36orb. The principal difference compared to the basic R-36 was redesigned terminal stage, with a liquid propellant de-orbit engine, designed to decelerate the RV.

The missile’s flight profile comprised four phases – boost phase, orbital phase, braking phase and finally, the re-entry phase. The weapon’s 1,700 kg orbital stage was designated the 8F021 OGCh, which comprised a fuselage, an instrument section with an inertial guidance system, the de-orbit engine section, and an 8F673 ~5 Megatonne nuclear warhead section.

The 8F021 would, as it neared the de-orbit manoeuvre entry point, start the AT/UDMH liquid fuelled de-orbit engine turbopump using a solid propellant gas generator. Exhaust gasses from the turbine were used for vehicle attitude control, using a 4 + 4 thruster arrangement. This de-orbit engine design later formed the basis of the Tsiklon 3 ELV S5.23/RD-861 third stage orbital engine, rated at 78.710 kN / 17,695 lbf. The cited CEP for the RV was 1.1 km.

Conceived at the peak of the Cold War, the Soviet FOBS effort showed the extreme lengths to which the Soviets were prepared to go in order to gain a decisive advantage over the West in a nuclear confrontation.

The usefulness of the FOBS declined very rapidly, as the US deployed early warning satellites capable of tracking missile launch signatures, and the expanded coverage BMEWS network, with the new phased array AN/FPS-115 PAVE PAWS detection and precision tracking radars.
Counterclockwise from top: display model of 8K69 FOBS; detail of orbital stage; detail of warhead section (© Miroslav Gyűrösi).

While the FOBS had unlimited range and could attack targets anywhere on the globe, the loss of the element of surprise due to improved early warning systems relegated it to the position of an expensive single warhead missile with limited 5 Megatonne yield with 1,100 metre CEP, and longer flight time, compared to later MRV/MIRV ICBM variants of the R-36. Eighteen silos at Baikonur were loaded with these weapons until 1983, when they were decommissioned under the terms of the SALT-2 treaty.

The Soviet FOBS program was devised to exploit the limited geographical coverage of the first generation US BMEWS system, which provided coverage only in the northern sector. The advent of the FOBS and more capable Soviet SLBMs saw the deployment of AN/FPS-115 PAVE PAWS phased array BMEW radars at Beale AFB in California, and Otis AFB in Massachussetts, expanding angular coverage of CONUS and rendering the FOBS unusable in its original role (diagrams US Air Force).

Above, PAVE PAWS at Otis AFB, below, recently upgraded BMEWS at Thule AB in Greenland (US Air Force).


  1. Mark Wade, Tsiklon, Encyclopedia Astronautica, URI: http://www.astronautix.com/lvs/tsiklon.htm
  2. Anatoliy Zak, R-36 family tech dossier, Russian Space Web, URI: http://www.russianspaceweb.com/r36.html
  3. Dneprovskiy Raketno-Kosmicheskiy Tsentr, Dnepropetrovsk, PO YuMZ KBYu , 1994.
  4. RKK Energiya 1946-1996.
  5. Oruzhie Rossii, Katalog Vooruzheniye RVSN, Moskva 1997.

Technical Report APA-TR-2010-0101

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