'Recognition of the effectiveness of submarine-launched cruise missile in the land-attack role has led to heightened interest in these systems among naval forces around the world. The projection of power ashore has long been a function of naval surface forces, through bombardment by artillery, the landing of ground forces, and latterly by the use of carrier air power and cruise missiles to prosecute inland targets. The use of the submarine as a cruise-missile launch platform developed after the Second World War with the US Navy (USN) experimenting with the JB-2 'Loon' copy of the German V-1 flying bomb, and then developing the nuclear-armed Regulus series of missiles in the 1950s. These were large missiles stored in hangars requiring assembly prior to a surface launch, which left the submarine exposed. A significant reduction in the density of computing electronics and in the size of the INS and nuclear warheads as well as the development of small fuel-efficient jet engines, allowed the USN at the end of 1972 to specify a long-range cruise missile that was small enough in terms of weight and dimensions to be discharged from a submarine torpedo tube.'