The Tomahawk cruise missiles that were launched Saturday against Libya are unmanned, single-use, programmable jet-engine missiles used only by the U.S. and British navies.
They fly very close to the ground, steering around natural and man-made obstacles to hit a target that is programmed into them before launch. Newer versions can be reprogrammed in flight but in this case that was not done, at least not yet.
They are different from other unmanned aerial vehicles in that they can only be used once - they are fired, they fly to the target and blow up. End of missile. A Predator and some other unmanned aerial vehicles can carry missiles, hit a target, then continue flying.
Tomahawk missiles normally carry a 1,000-pound conventional warhead. They can also carry 166 combined-effects bomblets, or mini bombs that spread out over a larger area. They can also carry nuclear warheads.
Tomahawks, developed in the 1970s, were first launched operationally by the United States during Operation Desert Storm in 1991. They are about 18 feet long with a wing span of nearly 9 feet, and they can fly at about 550 mph. Regarding Saturday's strikes against Libya, Vice Adm. William E. Gortney, director of the Joint Staff, said the missiles were in flight for about an hour, so they were likely fired several hundred miles from their targets.