Satellite images of US ballistic missile submarines and their bases
In the early 1970s, most of the U.S. strategic nuclear warheads were deployed on long-range bombers and intercontinental ballistic missiles. rockets silo-based, which were at the disposal of the Strategic aviation US Air Force Command. However, by that time the accuracy of ICBM warheads had improved so much that a surprise strike became possible, in which one side could try to win a global conflict by destroying the stationary missile silos whose coordinates were known.
In order to guarantee “nuclear retaliation” in any eventuality, the parties, in addition to increasing the resistance of silo launchers to the damaging effects of a nuclear explosion, rapidly developed mobile platforms.
The Soviet Union, in parallel with strategic missile submarines, built mobile ground-based and rail-based missile systems, while the United States placed its bets on missile submarines, and already in the early 1980s, the basis of the American strategic nuclear forces became SSBNs armed with intercontinental-range missiles with thermonuclear warheads of individual guidance.
In 1985, several types of American missile carriers were on combat patrol in the world's oceans. These were the first-generation George Washington and Ethan Allen-class submarines with UGM-27C Polaris A-3 SLBMs, the Lafayette-class submarines with UGM-73 Poseidon missiles, the second-generation James Madison and Benjamin Franklin-class SSBNs with UGM-73 Poseidon and UGM-96 Trident I missiles, and six new third-generation Ohio-class submarines with UGM-96 Trident I SLBMs.
It was very expensive and troublesome to operate three generations of boats. In addition, the presence of fleet SSBNs armed with different types of missiles gave trump cards to the proponents of creating mobile ground and rail missile systems, which, according to the developers, required less capital investment than submarine missile carriers. In this regard, the US Navy command in the mid-1980s decided to reduce the types of submarine strategic missile carriers and standardize their weapons. However, the Americans kept this secret, using the refusal of old boats as an argument in negotiations with the USSR.
Unlike the USSR, which held on to the last for its outdated, noisy nuclear submarines, American admirals placed their bets on the new Ohio-class submarines, which were significantly superior to other SSBNs in key parameters – stealth, diving depth, service life between overhauls, and striking power. Against the backdrop of the imminent write-off of the hopelessly outdated and worn-out first-generation missile submarines and the abandonment of the second-generation submarines in the next decade, it was concluded that Ohio-class submarines should become the backbone of the naval component of the American strategic nuclear forces in the long term. The high modernization potential and large reserve of operational life of the third-generation submarines allowed them to be used for several decades, which was later confirmed in practice.
As part of the unification, it was decided to create a new SLBM that would meet the highest requirements and be capable of becoming the basis of American strategic nuclear forces for a long time.
Initially, the characteristics of the UGM-96A Trident I SLBM were limited by the need to fit into the dimensions of the missile silos of second-generation SSBNs, previously armed with UGM-73 Poseidon C-3 missiles.
During the design of the third-generation submarine, a missile silo diameter of 2,4 m and a length of 14,8 m were adopted, and the width of the hull of the Ohio-class missile carriers made it possible to arm already built and newly built submarines with new, much heavier and longer missiles with a firing range of more than 10 km, which made it possible to conduct combat patrols in areas directly adjacent to American territorial waters, outside the zone of action of the Soviet fleet and anti-submarine aviation. This increased the combat stability of submarine missile carriers and made it possible to abandon the use of forward basing points abroad.
The UGM-96A Trident I SLBM had a longer launch range than the UGM-73 Poseidon C-3 and UGM-27C Polaris A-3, but was still inferior to the silo-based LGM-30G Minuteman III and LGM-118A Peacekeeper ICBMs. To close the gap with the ballistic missiles available to the US Air Force SAC, in the late 1970s, Lockheed began developing an SLBM weighing about 60 tons, designated UGM-133A Trident II. The goal was also to increase the throw weight, which would allow the missile to be equipped with a larger number of warheads with individual guidance and means of overcoming anti-missile defenses.
When designing the Trident-2 SLBM, new technical solutions were successfully combined with existing, well-proven developments. This made it possible to create a highly sophisticated missile with high service, operational and combat characteristics, which continues to remain relevant even after 35 years have passed since its adoption into service.
Compared to Trident 1, the new SLBM has become much larger and heavier. The length has increased from 10,3 to 13,53 m, the diameter – from 1,8 to 2,3 m. The weight has increased by about 70% – to 59,08 tons. Throw-in weight is 2800 kg. The launch range with a minimum combat load (three Mk.5 warheads) is more than 11 km. With a maximum load (eight Mk.000 warheads) – 5 km.
The UGM-133A Trident II (D5) missile is capable of carrying up to 8 Mk.5 independently targetable warheads equipped with W88 thermonuclear warheads with a yield of 475 kt or up to 14 Mk.4 warheads with W76 warheads with a yield of 100 kt. The CEP for Mk.5 warheads is 130 m. If a satellite navigation system is used in the guidance process, more than half of the warheads fall within a circle with a diameter of 90 m, which makes it possible to destroy “hardened” (in American terminology) targets, such as silo launchers and underground command posts, with a high probability. When firing at ICBM silos, the so-called “two by one” method is provided for - in this case, two warheads from different missiles are guided to one target. According to American data, the probability of destroying a “hardened” target with Mk.5 warheads is at least 0,95. In total, the US Navy received approximately 400 warheads with W88 warheads, but most of the Trident II missiles carried Mk.2 warheads, which were previously used on the UGM-4A Trident I SLBM. In this version, the probability of destroying the silo using the "two by one" method is estimated to be no higher than 96, which is due to the lower power of the charge.
As with other American SLBMs, the Trident 2 is launched using a "dry" launch method - from a missile silo, without filling it with water. The missiles can be launched at intervals of 15-20 seconds from a depth of no more than 30 m, at a submarine speed of about 5 knots and sea state up to 6 points. Theoretically, all the missiles on board the Ohio-class SSBN can be launched in one salvo, but in reality such firings have never been carried out.
Lockheed Martin delivered 1989 missiles to the US Navy and 2007 missiles to the Royal Navy between 425 and 58. The Trident 2 missile is the backbone of the US naval component of the strategic nuclear forces and will remain so for the next decade.
From 2007 to 2012, a comprehensive modernization program was implemented. In particular, previously built rockets were equipped with new control and astrocorrection equipment, built using high-speed radiation-resistant microprocessors. In addition, solid fuel was replaced.
Lockheed Martin has been awarded a $559 million contract to upgrade existing missiles to the Trident II D5LE standard, which will extend their service life until the Ohio-class strategic nuclear submarines are decommissioned. The upgraded Trident II missiles are already loaded into the missile silos of SSBNs on combat patrol. The upgraded missiles are expected to gradually replace all older SLBMs on American and British boats.
Test infrastructure for UGM-133A Trident II missiles
The first launch of the Trident 2 rocket was made from the Eastern Missile Range at Cape Canaveral in 1987.
Google Earth Satellite Image: Cape Canaveral Missile Range East
The missile range is primarily known for its space research programs, but prior to the UGM-133A Trident II SLBM, other submarine-launched ballistic missiles, intermediate-range ballistic missiles, and silo-based intercontinental ballistic missiles were also tested here.
The Trident 2 SLBM tests were carried out from the LC25C and LC25D launch complexes.
Google Earth satellite image of the launch pad from which the Trident 2 SLBM test launches were carried out
Before being accepted into service, 19 launches were made from a land-based test site. In the spring of 1989, the new SLBM was launched from the USS Tennessee (SSBN-734). This ninth Ohio-class submarine, delivered to the US Navy in December 1988, was originally built for the Trident II missile. In 2, the UGM-1990A Trident II SLBM (also designated Trident D133) officially entered service.
Construction and modernization of Ohio-class SSBNs
The first boat USS Ohio (SSGN-726) entered service in late 1981. The newest American strategic submarine USS Louisiana (SSBN 743) entered service in September 1997.
The boats were assembled at General Dynamics Electric Boat Corporation's Groton, Connecticut, shipyard from 13-foot-long sections shipped from the company's Quonset Point, Rhode Island, plant.
Google Earth satellite image of General Dynamics Electric Boat Corporation shipyards in Groton
At the design stage, the service life of the Ohio-class submarines was calculated at 20 years with one reactor recharge. However, a large margin of safety and significant modernization potential allowed for a significant extension of the operational life. In the second half of the 1990s, a phased modernization began, carried out during two-year major repairs combined with the replacement of nuclear fuel.
After examining the submarines placed for major repairs, specialists came to the conclusion that the SSBNs in service can be used for approximately 45 years. At the same time, the nuclear fuel must be replaced every 20 years.
The lead submarine, USS Ohio (SSGN-726), which currently carries cruise missiles, is scheduled to be decommissioned in 2026. Of the submarines armed with ballistic missiles, the first in line to be decommissioned in 2027 is USS Henry M. Jackson (SSBN-730) (formerly Rhode Island).
Operation and deployment locations of the Ohio-class SSBNs
Currently, nuclear deterrence missions are assigned to 16 Ohio-class SSBNs. Another four nuclear submarines, previously armed with Trident-1 missiles, have been converted into carriers of UGM-109 Tomahawk cruise missiles and combat swimmer delivery vehicles.
Of the fourteen SSBNs in service, two are undergoing scheduled major repairs. According to publicly available information, the US Navy has 240 submarine-launched ballistic missiles, each of which can carry 4 warheads. Combat duty in the world's oceans can be carried out simultaneously by 8-9 submarines with 160-180 missiles on board, carrying 640-720 warheads.
The US says that the missiles on board the patrol boats do not have flight missions loaded into them, and that target designation is issued after receiving an order to use them. Combat control signals are received via radio, including ultra-long-wave communications, and are transmitted from Boeing E-6B Mercury aircraft (more details here).
Strategic Command, headquartered at Offutt Air Force Base, Nebraska, operates two very long wave radio stations located on the Pacific and Atlantic coasts.
Google Earth satellite image of the US Navy's Coast Guard Very Long Wave Radio Station at Cutler
The US Navy radio station at Cutler, Maine, operates on 24 kHz and has a power of 1,8 megawatts.
The US Navy's Jim Creek Radio Station, located near Oso, Washington, transmits on 24,8 kHz with a power of 1,2 megawatts.
Google Earth satellite image of the US Navy's Jim Creek Very Long Wave Radio Transmitter Center and Antennas
When the international situation is calm and there is no high probability of a global crisis developing, American missile submarines conduct combat patrols off their shores, under the close protection of their ships and aircraft in areas for which precise hydrological maps exist. Thanks to this, the navigation systems of the submarines in a submerged position receive all the necessary data from the onboard hydroacoustic complex to correct the error in tracking their coordinates. However, approximately 25-30% of the time, American SSBNs spend in remote areas of the world's oceans. In the past, American boats were on duty in the Indian Ocean, the Mediterranean Sea and the North Atlantic.
According to statistics, Ohio-class submarines perform an average of 3-4 combat missions per year. Each American strategic nuclear submarine in service spends more than 200 days on combat patrol each year.
The permanent home of American SSBNs on the West Coast is the Bangor Naval Base, and on the East Coast is the Kings Bay Naval Base. Both American bases are located in areas with a mild climate, which significantly facilitates service and reduces the cost of operating the boats.
Ohio-class SSBN permanent basing locations in the United States
There are currently eight Ohio-class SSBNs based at Bangor, Washington, in the Pacific Ocean.
Google Earth satellite image shows US submarines moored at Bangor Naval Base
The Bangor Pacific Naval Base has a highly developed infrastructure necessary for the long-term operation and maintenance of nuclear submarines.
Google Earth satellite image of Ohio-class SSBN in dry dock at Bangor Naval Base, with some missile silo covers open
The presence of a dry dock and high-capacity cranes at the naval base allows for routine maintenance and prompt repairs of Ohio-class SSBNs.
Atlantic Base Kings Bay, Georgia, is home to six more strategic submarines.
Google Earth satellite image of Naval Air Station Kings Bay
The infrastructure of each naval base is designed to service 10 SSBNs.
Google Earth satellite image of Ohio-class SSBN at Kings Bay Naval Base
During combat patrols, American nuclear submarines visit the Guam and Pearl Harbor naval bases to replenish supplies, perform minor repairs, and give their crews a short rest.
Google Earth satellite image of Ohio-class SSBN and supply vessel at Naval Base Guam
The Guam naval base has rotational supply vessels that load supplies onto American nuclear submarines and, if necessary, replenish ammunition.
While Guam is only capable of replenishing supplies and carrying out minor repairs, Pearl Harbor Naval Base, located in Hawaii, provides full-fledged long-term basing and servicing for ships of all classes.
Google Earth satellite image: US submarines and warships at Pearl Harbor naval base
A full-fledged arsenal with hangars for maintaining missile combat readiness, as well as underground fortified storage facilities for mine-torpedo and missile weapons with adjacent piers, were built at Pearl Harbor.
Google Earth satellite image: American nuclear submarine moored to a pier located next to mine-torpedo and missile storage facilities
Nuclear arsenals of the American Ohio-class SSBNs
Under the START-3 treaty, the number of silos loaded with SLBMs on American SSBNs is limited to 20, and the total salvo of missiles from one submarine must not exceed 80 thermonuclear warheads.
Currently, the American UGM-133A Trident II SLBMs carry 4 Mk.5 warheads with W88 and Mk.4A warheads with W76-1 warheads, which have undergone a life extension program. In 2021, production of modernized W88 ALT 370 warheads began, the service life of which should be at least 20 years. Since 2019, some Trident 2 missiles have been equipped with warheads of improved accuracy with W76-2 warheads with a yield of 5-6 kt (only plutonium charges without a thermonuclear stage). It is stated that these high-precision warheads of lower power, capable of deepening into the ground, are intended to some extent to compensate for the US lag in tactical nuclear weaponsSuch warheads are quite suitable for “surgical” strikes on intercontinental ballistic missile silos, chemical and bacteriological weapons storage facilities, and for destroying underground command posts.
The boats returning from combat patrol to the base are moored to a specially designated pier with heavy-duty cranes, where the SLBMs are unloaded from the missile silos over the course of several days. The missiles are then sent for diagnostics and maintenance.
Google Earth satellite image of the SLBM loading and unloading pier at Naval Base Bangor
Thus, American submarine “strategists”, unlike Russian SSBNs, do not carry out combat duty at their berths in their permanent bases.
At the Kings Bay naval base, special covered structures have been built into which boats enter to unload and load ammunition.
Google Earth satellite image of the facilities for unloading and loading SLBMs into SSBN missile silos at Kings Bay Naval Base
Buildings have been erected near the berths with loading equipment, where the technical condition of the Trident-2 missiles is monitored and prepared for further operation.
Google Earth satellite image of the berthing facilities and missile maintenance buildings at Bangor Naval Base
The naval bases where US SSBNs are based have arsenals and hardened storage facilities for servicing, repairing and housing the missiles.
Google Earth satellite image of nuclear storage facility at Bangor Naval Base
At the Bangor naval base, the nuclear storage facilities were recently reconstructed, with the area cleared of vegetation.
Google Earth satellite image of mothballed nuclear storage facility at Bangor Naval Base
Close to the perimeter of this facility there are mothballed underground storage facilities built in the 1960s.
Google Earth satellite image of nuclear storage facility at Kings Bay naval base
The storage facility at Naval Base Kings Bay is divided into two isolated areas. The "hot" area, a highly secure area with 42 hardened bunkers, is located in the southern part.
Publications from this series
US Air Force Nuclear Forces in Satellite Images: Silo-Based Ballistic Missiles
US Air Force Nuclear Forces in Satellite Images: Long-Range Bomber Aviation
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