M20 submarine ballistic missile

The practical development of a nuclear submarine project in France began in 1958, when the first nuclear submarine was laid at the state shipyard in Cherbourg. However, a year later, due to difficulties encountered in building a nuclear reactor for the main power plant, the construction of the submarine was temporarily suspended. A significant amount of additional research work was required. Eventually, the design of the first nuclear submarine was taken out of construction. Later, the hull was used for the new but already experimental diesel-electric submarine "Le Gymnote", designed to test the systems of future SSBNs, as well as for flight testing of ballistic missiles. It was equipped with four mine launchers, which were converted to test new SLBMs. The first setbacks caused some hesitation in the minds of the French military about the way forward in building a strategic nuclear force. The final decision to develop a sea-based missile and nuclear weapon system was taken only in 1963. The development of the maritime nuclear missile force was carried out jointly by the CEA Commissariat for Atomic Energy, the DEN's Missile Directorate and the DCN's Coelacanthe Naval Construction Directorate. The French Ocean Strategic Forces FOST was officially formed in 1967.

By the time the official decision to create a SLBM was made, French missile builders had already accumulated some experience in building small solid-fuel missiles that were being tested at the Hammagir test site in Algeria (the site was code-named "Gems"). It was decided to maximize the integration of the French SLBM and MRBM programmes. In order to create the first French strategic missiles, the French National Ballistic and Aerodynamic Research Laboratory was established under the auspices of the state organization sEREB (Organization for Research and Development of Ballistic Missiles). The efforts of the leading French aerospace companies of that time, first of all "Aerospace", "Norde Aviación" and "Zude Aviación", were combined. The combat unit was designed and manufactured by the CEA, the civil commissariat for nuclear energy. Successes in the field of rocket engineering, achieved by French scientists and designers in the second half of the 60's, allowed to create a prototype of the first own SLBM, designated M112 and tested at Hammagir and Ile du Levant (complexes Nemo and Brigitte, respectively) by 1966. In 1967, testing of this missile began with the "Le Gymnote" submarine. This success was a strong incentive to maximize the construction of French SSBNs: the second Five-Year National Armed Forces Development Plan (1966-1970) provided funding for the construction of three missile carriers. However, the plans were soon noticeably expanded - in 1967, the Ministry of Defense officially announced its decision to build a fourth nuclear missile boat, and in 1971 (when the first SSBNs were added to the fleet) a fifth. The five SSBNs planned to be built within ten years were to be equipped with more advanced missiles as they became operational.

The first national SSBN - "Le Redoutable" was introduced into the fleet in 1971, and in 1972 entered the ocean for combat patrols. The second submarine in the "Le Terrible" class was handed over to the Navy in 1973 and at the same time entered the first combat patrol. The first French SLBM was the M1 SLBM, which entered service in 1971. This missile was a two-stage solid propellant rocket with sequential connection of stages and a monoblock nuclear HC MR-41 with a power of 0.5Mt. The range of missiles, according to published data, was 2600 km at the KVO 3.2 km.

However, the third SSBN - "Le Foudroyant", which joined the fleet in 1974, was equipped with more advanced M2 SLBMs, adopted for service in 1974. The new missile differed from the M1 by a modified second marching stage and improved inertial control system, which allowed to increase the range up to 3000 km while reducing the CVO to 2km. According to some data, two SSBNs equipped with M1 were also adapted for the new SLBM.

However, the qualitative increase in the attack power of French SSBNs occurred with the adoption of the M20 SLBMs in 1976. When designing the new SLBM, the designers were tasked with improving all characteristics - range and accuracy, as well as RF power. It was planned to equip the missile and the missile defense system - this decision was largely motivated by the significant successes achieved by the U.S. and the Soviet Union in the creation of missile defense (ABM). The economic situation in France in the late 60's - early 70's was difficult, so in addition to the above tasks, the designers were tasked with the maximum unification of the new SLBM both with the M2 missile already in service, and with the emerging promising S3 MRBM. The new missile was to receive the TN-60 thermonuclear HF with the power of 1.2 Mt.

The first serial TN-60 HF was handed over to the military in January 1976. However, this HC was not in service for long - in 1977, the first serial improved TN-61 HC was released, which differed from its predecessor by reduced weight and increased resistance to fossil fuels. The M20 SLBM entered service first of all with two new SSBNs - "L'Indomptable" (in service since 1976, first combat patrol in 1977) and "Le Tonnant" (in service since 1980, first combat patrol in 1980). The previously operational submarines were upgraded to a new missile system in 1977-1979. Thus, by 1981, the French Maritime Strategic Nuclear Forces had five identical SSBNs equipped with the M20 system. However, despite the sharp increase in the capabilities of French SSBNs, they were still much inferior to modern American and Soviet SSBNs.

The next stage of French SSBNs development began in 1985 with the entry into service of the sixth SSBNs and the adoption of a new M4 family of SSBNs. The process of modernization of previously released submarines and equipping them with new missiles began immediately. All modified submarines went into service between 1987 and 1993. It was decided not to rearm the first submarine in the class - Le Redoutable - in the new geopolitical conditions (the end of the Cold War, etc.), and by the end of 1991 it was withdrawn from the fleet, and the missile system M20 - the last French complex with SLBMs of the first generation - was at the same time withdrawn from service.