Ballistic missile submarine

A ballistic missile submarine is a submarine equipped to launch ballistic missiles at sea, almost always from underwater. They share the engineering challenges of all submarines, but have some unique to their operational role. In general, ballistic missile submarines, all modern versions of which have the naval vessel designation code SSBN (Ship Submersible Ballistic Nuclear), are larger, slower, and quieter than attack submarines.

Ballistic missile submarines are national-level strategic assets; their most important advantage is that they are nearly undetectable, and thus nearly invulnerable. To be undetectable, their designers take extreme care to make them as quiet as possible.

Another major challenge is communicating with submerged submarines. Most radio waves do not penetrate water well, except in the Very Low Frequency or Extremely Low Frequency bands, which require extremely long antennas. Shore stations transmitting on these frequencies are immense, so a survivable approach includes putting them in special-purpose aircraft, such as the E-6 TACAMO.

Yet another challenge is inherent to ballistic missiles, which fly a trajectory calculated to take them from one known point to another known point. Since the submarine is moving, it must have extremely accurate navigation systems to make the point of launch comparably well known as for a land-based intercontinental ballistic missile.

U.S.

The United States deployed the first operational ballistic missile submarines, of the George Washington-class armed with UGM-27 Polaris missiles. The program was directed by VADM "Red" Raborn.

U.K.

There has been considerable cooperation between the U.S. and U.K. programs. Both use U.S. missiles, although the nuclear weapons on the U.K. boats are British designed- and built. The United Kingdom currently operates four ballisitic missile submarines, all of which are of the Vanguard-class.