It noted that maintaining operational credibility of France’s nuclear weapons is required given the international environment. 

The M51.3 missile is an upgraded version of the M51, a three-stage sea-land strategic ballistic missile designed to be launched from French Navy submarines.

Ballistic missiles are similar to rockets and follow elliptic trajectories after launch, often leaving the earth’s atmosphere to reach lower space, unlike cruise missiles, which typically follow straight trajectories at low altitude, powered by continuous thrust until they reach their target.