The development of submarine-launched ballistic missile (SLBM) systems was a critical aspect of the Cold War arms race between the United States and the Soviet Union. These systems, deployed on nuclear-powered submarines (SSBNs), were at the forefront of technological competition between the two superpowers, driving advancements in both military and civilian technologies, including space exploration. The rivalry shaped the design, automation, and operational tactics of these systems, reflecting the distinct economic, scientific, political, ideological, and cultural characteristics of each nation.
Technologically, the Soviet Union relied on liquid-fuel missiles, prioritizing high automation in submarine operations and maximizing submarine performance. The nation achieved significant innovations, occasionally gaining advantages in specific technical areas. SLBM systems were the most effective means of strategic nuclear deterrence, forming a cornerstone of their respective nuclear triads, alongside land-based missiles and strategic bombers, except during the early Cold War period.
Origins
The concept of submarine-launched ballistic missiles (SLBM) is related to the German V-2 rocket program during World War II. In 1944, Klaus Riedel, a member of the Peenemünde research team, proposed launching V-2 rockets from the North Sea against the United Kingdom, using submarines to tow launch containers. These containers, approximately long, in diameter, and with a displacement of 500 tons, housed a single V-2 missile, crew quarters, a control center, and fuel and ballast tanks. A single submarine could tow up to three containers. Plans also included towing containers across the Atlantic to target New York City. The crew would travel aboard the submarine, transfer to the container for fueling, and launch the missile. The project, developed at the AG Vulcan Stettin shipyard in Szczecin, reached 65–70% completion for three containers by the war's end, with a prototype tested near Peenemünde.
After the war, the Soviet Union established the Rabe Institute in Bleicherode, near Nordhausen, where captured German scientists, including Helmut Gröttrup, continued their work under Soviet supervision. In October 1946, the NKVD arrested approximately 5,000 German specialists, relocating them to the Soviet Union to advance Soviet ballistic missile development. As a result, the German V-2 designers made a significant contribution to the Soviet ballistic missile programs.
First-generation systems Starting in October 1945, the United Kingdom, the United States, and the Soviet Union began a series of tests on captured or assembled V-2 missiles. The Soviet Union was aware of the German concept of underwater missile launchers, but showed little interest in this idea at the time, placing greater hopes in sea-launched cruise missiles for long-range strikes. The ballistic missile program was overseen by government structures, especially the NKVD and the Artillery Directorate of the Red Army.
In 1949, the Soviet Union developed a preliminary design for a missile submarine under the designation , intended to strike land targets. The design was developed by CKB-18 (later the Rubin Design Bureau). The submarine was projected to have a surface displacement of nearly 5,400 tons and to carry 12 R-1 missiles (Soviet versions of the V-2) and cruise missiles. However, the program encountered numerous issues that the designers could not overcome, including, among others, problems with stabilizing the missile prior to launch. In the early phase of developing sea-to-land missile systems, the Soviet Union regarded this kind of weapon solely as a tactical asset without strategic significance.
Soviet development of SLBM systems began with a government decree on 26 January 1954, appointing Sergei Korolev, head of OKB-1 NII-88, to lead the D-1 missile system program. Between 1953 and 1954, Korolev proposed a naval variant of the liquid-fueled R-11 missile, designated R-11FM, with modified fuel components and navigation systems to accept launch data from submarines. Test launches of the R-11FM were carried out between 1954 and 1955 at the 4th Missile Test Range in Kapustin Yar. After three launches from a stationary platform, one launch was conducted from a moving platform to simulate motion. OKB-1 developed a launch procedure involving the missile being raised from a surfaced submarine container before ignition from above the container. Although the Soviet Navy insisted on the ability to launch the missile from a submerged submarine, Korolev opposed the idea, arguing that a surface launch would take less time. Apart from the missile itself, the program faced numerous challenges, including determining the submarine's exact position, accurately aiming at targets, ensuring safe communication, and other related issues. However, all of these were eventually resolved, and by the end of 1956 a full set of construction documents had been completed.
The world's first submarine equipped with ballistic missiles was the Soviet modified Project 611 submarine (NATO code: Zulu) – . On this submarine, two vertical R-11FM missile launchers were installed in an enlarged sail, which required sacrificing part of the electric battery compartments beneath the sail as well as several officers' quarters, who were relocated to the torpedo storage area. The first-ever launch of a ballistic missile from a submarine took place on 16 September 1955. Fired from the surfaced B-67 in the White Sea, the R-11FM missile struck the test range on Novaya Zemlya. That same year, work began on a modified version of Project 611, designated AW611.
In 1959, the first R-11FM missiles achieved operational readiness, making the Soviet Union the first country armed with submarine-launched ballistic missiles. During regular patrols, these missiles were not equipped with their designated RDS-4 nuclear warheads (yield: 10 kilotons), which were stored on land and could be installed on the missiles in case of an imminent threat.
Meanwhile, in 1955, Sergei Korolev decided to transfer work on submarine ballistic missiles from OKB-1 to a special design bureau, SKB-385, headed by Viktor Makeyev. This allowed Korolev to focus on longer-range strategic missiles and space programs. After the transfer, SKB-385 began developing the D-2 missile system, consisting of the new R-13 missile and a new series of submarines under Project 629 (NATO: Golf class). The R-13 missile, with a range of , was powered by a liquid-fuel engine and, like the R-11, was launched from the surface. The submarines designed for this missile used the same diesel-electric propulsion system as their contemporary Project 641 boats (NATO code: Foxtrot). Built at CKB-16 under the direction of Isanin, the Project 629 submarines had a surface displacement of 2,850 tons and could carry three R-13 missiles.
The launch tubes for these missiles extended through the entire height of the inner hull, reaching up into the submarine's sail. Launches took place from the surface, after the missiles were raised above the sail. The first five submarines of this type carried R-11FM missiles, while later ones were equipped with R-13s. During the construction of the first vessels, CKB-16 began developing a system with a small reactor designed to supply energy for battery charging on Project 629 submarines, eliminating the need for diesel engines for this purpose. However, this program was discontinued. The lead ship of Project 629 was (later designated ), which was built at Severodvinsk and delivered to the navy in 1959. Over the following three years, shipyards in Severodvinsk and Komsomolsk-on-Amur built 22 submarines of this class. Sections for two additional units built at the latter yard were transferred to China, where one was assembled in Dalian and designated as Type 035. The second unit was never completed.
On 20 October 1961, the world's first test of a submarine-launched ballistic missile armed with a thermonuclear warhead was conducted. A Project 629 submarine launched an R-13 missile equipped with a 1-megaton warhead, which detonated at the "Rainbow" military training area on Novaya Zemlya. As a result of this test, nuclear-armed R-13 missiles were approved for use on submarines. In 1955, experimental work began on launching ballistic missiles from submerged submarines. After overcoming numerous difficulties, the first test involving the launch of a missile mock-up from a submerged vessel was carried out in 1957. The mock-up was launched from the submerged Project 613D4 (NATO: Whiskey) submarine . The vessel was modified at the Black Sea Shipyard in Mykolaiv on the Black Sea, with two launch towers protruding above the hull and sail installed amidships. The missile mock-ups featured a solid-fuel booster stage and a second liquid-fuel stage.
At Severodvinsk, the previously used test submarine B-67 of Project W611 (Zulu) was also modified under the designation PW611. The first underwater launch from B-67 took place in August 1959 but ended in failure. On 10 September 1960, the S4-7 missile (a modified R-11FM) was successfully launched from a submerged submarine. Shortly before the completion of the first Project 629 (NATO: Golf) submarine, SKB-385 began work in 1958 on a new liquid-fueled missile, the R-21 (NATO: SS-N-5 Serb), with a range of , twice that of the R-13. The R-21 could be launched from depths of while the submarine was moving at speeds of up to .
The first submerged launch of an R-21 missile took place in 1961 from the submarine S-229. The vessel had been fitted with two individual launch tubes housed in towers protruding above the hull. A year later, two such launch towers were installed on , the final Project 629 (Golf) submarine built at Severodvinsk – this version was redesigned as Project 629B. Completed in 1961, K-142 carried out its first submerged missile launch on 24 February 1962.
By 1972, 13 additional submarines from Projects 629 (Golf) and 658 (NATO: Hotel) were modified to carry three R-21 missiles capable of being launched from underwater. These submarines became, respectively, Projects 629A (Golf II) and 658M. The modified 629A vessels were repurposed as non-strategic missile platforms. In 1976, six of them were transferred from the Northern Fleet to the Baltic Fleet to serve as sea-based platforms for tactical ballistic missiles; the remaining seven served with the Pacific Fleet. These submarines remained in service for nearly three decades – until 1989, when the last units were decommissioned. The Golf-class submarines were considered relatively successful, although one of them, (a converted Project 629A/Golf II), sank during a patrol in the North Pacific on 25 February 1968, with the loss of all 98 crew members.