May 1, 2012:  In response to recent Iranian sabre rattling, the United States has moved two carrier task forces and one SSGN (nuclear powered cruise missile submarine) to the Persian Gulf. While this puts about 80 carrier based combat aircraft in area, it also brings over 400 Tomahawk cruise missiles. Used in large quantities these weapons have proved devastating. For example, on March 19th, 2011, the initial NATO attack on Libya involved over a hundred Tomahawks, most of them fired from a single SSGN.

The U.S. has four Ohio class ballistic missile submarines (SSBN) that were converted to SSGNs. These boats entered service over the last six years, and Libya was the first time one of them fired its missiles in combat. Each of these Ohio class SSGNs carries 154 Tomahawk cruise missiles and provides space for 66 commandos (usually SEALs) and their equipment. The Tomahawks used in this kind of surprise attack are very effective at destroying air defenses and other weapons that tend to be sent into hiding once a war begins. The latest Tomahawk can be redirected while in flight and UAVs and spy satellites can provide real-time observation of key targets to make this work.

The current Tomahawk, the Block 4, costs about $1.8 million each, weighs 1.4 tons, has a range of 1,500 kilometers, and carries a half ton warhead. It moves to its target at a speed of 880 kilometers an hour. The Tomahawk was introduced 29 years ago, and over 6,000 have been manufactured. The U.S. Navy has fired nearly 2,000 in combat and training.

The Block 4s are also getting upgraded so that they can hit moving targets. This is mainly intended to turn the Tomahawk into an anti-ship missile, although it can also hit moving land targets. The Tomahawk has been a primary land attack weapon for surface ships and submarines since the 1990s. The Block 3 entered service in 1994, but the Block 4 was a big upgrade, adding GPS and the ability to go after a different target while the missile was in flight.

The cruise missile, when it showed up in the 1980s, was one of the first UAVs, it just wasn't reusable. UAVs that carry bombs and missiles, and can be reused are going to provide competition for cruise missiles. That said, cruise missiles travel low and slow and can be shot down. That will always give them an edge against more expensive reusable UAVs.