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2,005 No. 6
6 2,005

The FOBS of War

The Soviet Union wanted a nuclear weapon that could stage a “backdoor” strike on US soil.

In the movie “Space Cowboys,” Clint Eastwood plays a test pilot/engineer who leads a group of aging astronauts on a mission to retrieve a nuclear-armed satellite, which had been put into space by a Soviet Union that then ceased to exist.

It was, at least in small part, a case of art imitating life.

During the Cold War, both superpowers contemplated the deployment of nuclear weapons in space. However, Moscow did more than contemplate. During the 1960s, the USSR had an operational system ready to go into orbit to attack the United States.

This weapon was a combined low-flying missile and nuclear warhead. It was designed to take off from the Soviet Union and de-orbit for an attack. Most importantly, it would not fly over the Arctic to reach US territory. It would, rather, traverse southern polar areas and reach the US via the “backdoor.”

The superpower space competition heated up with the Soviet Union’s successful Oct. 4, 1957, launch of Sputnik. In those days, the mere act of putting an object into orbit was a major achievement. It didn’t take very long for both sides to start worrying about missiles equipped with doomsday payloads.

For several years afterward, Moscow had the lead. Soviet premier Nikita Khrushchev boasted of his country’s superiority in space. On Aug. 9, 1961, Khrushchev bragged, “You [the Americans] do not have 50- or 100-megaton bombs; we have bombs more powerful than 100 megatons. We placed [cosmonauts] in space, and we can replace them with other loads that can be directed to any place on Earth.”

No one had any doubt that the Kremlin leader was talking about nuclear weapons.

In the ensuing years, both the US and USSR spent considerable energy monitoring the nuclear capabilities of the other. To detect incoming Soviet ICBMs, the US developed both ground- and space-based early warning systems.

The Warning Line

One of the earliest detection systems was the Ballistic Missile Early Warning System, BMEWS, a network of high-powered, long-range radars placed on the northern periphery of the Western Hemisphere, facing the Arctic. An approach over the North Pole was deemed the most likely scenario for a Soviet missile or bomber strike, as that was the shortest route from the USSR to the US.

Washington hoped to achieve at least 30 minutes’ advance warning of a Soviet nuclear strike. In that half-hour, Strategic Air Command would flush its bombers from bases in the Midwest, and US leaders could launch land-based and sea-based missiles in a massive retaliatory strike.

The US deterrent scheme only led Moscow to seek some way to strike that would not be detected until it was too late.

The Soviet Union calculated that a missile fired into a depressed trajectory would follow a low orbital path and be difficult for the US system to “see.” The missile would pop above the horizon—and thus become visible to the searching US radar beams—much later than would be the case with an ICBM attack over the Arctic.

The Soviet Union’s first operational ICBM was the SS-6. If launched on a conventional ballistic trajectory, it would rise on a relatively steep path and soar to an altitude 1,200 miles above Earth before turning back and plummeting to Earth. Only minutes after launch, therefore, the ascending missile would clear the radar’s horizon. When it did, US early warning systems would detect it and sound the alert.

By contrast, a weapon launched into low orbital plane would ascend on a relatively flat, depressed trajectory, level off, and never rise more than 150 miles above Earth. It thus would not clear the radar horizon until it had almost reached its target. As Soviet planners saw it, US warning time would be reduced to as few as five minutes.

Even that much warning would be available only if the incoming warhead were to come in over the Arctic. The US in the early 1960s was unprepared to detect intrusion from the south. In that case, time from detection to impact could have been only a few seconds.

In March 1962, Khrushchev stated that the Soviets could launch missiles “not only over the North Pole but in the opposite direction, too.”

The premier warned, “Global rockets can fly from the oceans or other directions where warning facilities cannot be installed. Given global missiles, the warning system in general has lost its importance. Global missiles cannot be spotted in time to prepare any measures against them.”

Three Projects

At least three projects were under way. The first proposed near-orbital missile was a Vladimir N. Chelomei design based on the UR-100 ICBM. The Soviets began work on this two-stage system on March 16, 1961.

The second proposal came from the legendary designer Sergei P. Korolev. He began preliminary work on Global Rocket No. 1 (GR-1) in 1960. The GR-1 was a part of Korolev’s N-1 lunar program booster. (See “The Secret at Complex J,” July 2004, p. 72.) Korolev’s three-stage GR-1 weighed 117 tons and carried a 2.2-megaton-yield warhead.

The third proposal came from Mikhail K. Yangel, whose R-36-O was approved for development on April 16, 1962. This design was based on the SS-9 super-heavyweight ICBM. The three-stage system weighed 180 tons fully fueled. The 3,000-pound re-entry vehicle (RV) packed an explosive yield of two to three megatons of TNT.

As 1965 dawned, all three designers had produced required hardware, but none of the systems had yet flown. The Strategic Rocket Forces selected the Yangel article as the most promising system and stopped the other two programs.

Yangel was soon under pressure to produce. The system was tested at the Tyuratam missile range and from launch silos. Operationally, the missile was to be silo-based. At Tyuratam, the 2nd Testing Directorate led a series of test launches beginning in December 1965.

The SS-9 used its first and second stages to reach an orbital plane, with each stage being discarded as it used up its fuel. The flight generally followed a southerly near-polar path. The payload, after passing over the polar region, would fly northward over the Southern Hemisphere, putting the warhead on track to hit targets in the central US. A slightly higher inclination would get the warhead to West Coast targets; a little lower would hit the East Coast.

During the coasting phase, just before de-orbit, the vehicle would initiate a pitch maneuver to reorient itself for re-entry. The retro-rocket would fire for one minute, changing the plane of flight from orbital to ballistic. The warhead would then separate from the RV and continue on its trajectory until impact.

The test launches were monitored by the CIA and matched US expectations. There was a period in 1965-66 to get the system configured, followed in 1967 by a robust firing program, which prepared crews for operations. The orbital missile was first deployed in 1968.

By that time, however, the United Nations had passed Resolution 1884 and the Outer Space Treaty, which called upon the world’s nations to keep nuclear weapons and other weapons of mass destruction out of Earth orbit.


Moscow saw this mainly as a problem of semantics. It promptly dubbed its orbital weapon system the “Fractional Orbital Bombardment System” or FOBS. It claimed that the system would never complete a full orbit and thus would be in compliance with the letter of the international accords. The Kremlin continued developing FOBS to deliver thermonuclear bombs via a low-trajectory, low-visibility route.

The Soviet Union constructed 18 operational FOBS silos at a site west of Tyuratam and activated its first operational unit on Aug. 25, 1969. Two more battalions joined the first. Together, they comprised the 98th Missile Brigade.

FOBS certainly was not a precision weapon. Its circular error probable (the radius of a circle within which at least 50 percent of the warheads would be expected to hit) was more than three miles. Therefore, FOBS wouldn’t be used to destroy hardened ICBM silos or other protected sites requiring a direct hit.

Instead, US strategic planners and policy-makers thought FOBS would be used as a pathfinder. The system could be used to take out numerous command and control centers around Washington, D.C.—the White House, Pentagon, and so forth.

The idea was that effective use of FOBS might well rob the US of its capacity to carry out a launch-under-attack counterstrike which would be possible if a Soviet attack were detected soon enough.

The FOBS threat didn’t last long. Soon, Soviet designers were developing advanced submarine-launched ballistic missiles to equip its undersea vessels. SLBMs emerged as an even stealthier way to launch a disarming strike on the United States. By the time of the SALT II weapons limitation negotiations of the late 1970s, FOBS was nearing its end.

American Nuclear Weapons in Space

In the 1950s and early 1960s, the Air Force pushed to be the space force for America. As part of that drive, the service proposed building a reusable spaceplane, the X-20 DynaSoar.

The X-20 was conceived as an operational system to conduct space missions of reconnaissance, satellite inspection and repair, orbital resupply, and bombardment.

The third version was to use a Titan IIIC rocket booster and have an orbital capability. This variant would contain a bomb bay for delivering nuclear warheads requiring precise targeting and would offer the ability to approach a target from any direction.

Eventually deciding against placing nuclear weapons in space, the Defense Department canceled the first test version of the X-20—less than a year before testing was to have begun in 1964.

US officials preferred smaller, more accurate warheads, unlike their Soviet counterparts, who had a “bigger is better” philosophy. For US leaders, the prospect of a gigantic nuclear weapon coming down accidentally was highly worrisome.

That, plus America’s ability to rely on a large, highly versatile fleet of manned bombers, kept the United States from seriously pursuing an orbital nuclear weapon.

SALT II was signed in 1979, but the Senate never ratified it. Even so, both superpowers informally followed SALT II provisions. The treaty specifically mentioned the SS-9 FOBS as one system marked for deactivation. According to the agreement, 12 of the 18 silos had to be destroyed and the others converted to other uses.

Things moved slowly in the Soviet empire. It was not until 1982 that the USSR began dismantling the FOBS installations and retiring the missiles. By February 1983, the last missile was taken off duty. In May 1984, the Soviets began to remove missiles from the silos, ending the prospect of Soviet nuclear weapons in orbit.

Air Force Lt. Col. Braxton Eisel is assigned as an air defense advisor to the Federal Aviation Administration in Washington, D.C. Previous assignments have included Minuteman III ICBM launch officer, weapons controller in ground-based mobile radar systems, mission crew on E-3 AWACS and E-8 Joint STARS aircraft, and military historian. This is his first article for Air Force Magazine.

In More Depth
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