Missile m1/m2

The M1 is an intermediate-range ballistic missile developed by France to equip its first nuclear ballistic missile submarines. With a range of 2,450 kilometers, it is equipped with a single 500 kiloton TNT equivalent nuclear warhead. Deployed from 1971 on Le Redoutable class submarines, it was quickly replaced by the M2 in 1974 due to its limited range.

The M1, with a mass of 18 tonnes and a diameter of 1.5 meters, is powered by two solid propellant stages. This choice of fuel is motivated by its storage stability, crucial on board submarines over long periods of time. The manufacture of the missile involves several manufacturers, notably SNECMA, SEPR and Sud-Aviation. Missile tests, both static and dynamic, are taking place at several sites in France, notably in Saint-Médard-en-Jalles and Hammaguir.

Launching a ballistic missile from a diving submarine presents major technical challenges. The missile must be ejected from the tube precisely despite the submarine's movements and changing surface conditions. To overcome these challenges, tests are carried out on a small scale, then on a full scale, notably using the experimental submarine Gymnote. After successful tests, the M1 became operational in 1972, two years behind the initial schedule.

Since 1964, France has had a nuclear weapon of 50 kilotons equivalent to TNT, transported by Mirage IV aircraft. To equip the missiles of the Le Redoutable class submarines, a more powerful warhead of 500 kilotons is developed, while retaining the dimensions of the Mirage IV weapons. Studies began in 1963, with the idea of using a more compact thermonuclear bomb, but ultimately a variant of the A bomb was chosen. The MR41 nuclear warhead was tested in 1968, with some technical problems to resolve, particularly linked to the use of tritium.

The development of this weapon was delayed until 1971 due to high security constraints imposed by the French Navy. An operational version was successfully tested in June 1971, and the first missiles were loaded onto the Redoutable in 1972. This nuclear warhead was quickly replaced by the MR60, using a thermonuclear bomb, deployed from 1977.

The M1 missile, initially fitted to the first Redoutable, is composed of two solid propellant stages and stored in an elastic internal tube inside the submarine. It is launched at shallow depth with a compressed air flushing system. However, its limited range of 2,450 kilometers makes it ineffective in hitting strategic targets such as Moscow. It is replaced by the M2, M20 and M4 missiles with improved ranges.