When the U.S. military wanted to take out Moammar Gadhafi's air defense systems, it unleashed a barrage of 122 Tomahawk cruise missiles. But these munitions aren't like most others in the American arsenal.

Smart, maneuverable, able to see its surroundings and shift to new targets in mid-flight, the newest Tomahawks are closer to the unmanned planes flying over Afghanistan than to the weapons they fire. In some ways, the Tomahawk is the drone's suicidal cousin: a robotic aircraft, packed with explosives, that has no intention of ever coming home.

When officers get ready to shoot off a Tomahawk, "they are basically planning a flight for a little airplane," one Navy official tells Danger Room. "It's got stubby little wings – but is is an unmanned aerial vehicle."

The next-gen Tomahawks – known as "Block IVs" – start their flights out just like other missiles, launched from ships or subs. But after 12 seconds of flight, things change. The Tomahawk starts to fly horizontally, skimming above the ocean at a height of less than 50 feet to avoid enemy radar.

GPS waypoints keep the missile on track, until it makes landfall. Then, a Tercom (Terrain Contour Matching) system kicks in. too. Using a radar altimeter, the Tomahawk Tercom checks its height. Then it matches that altitude against a database of satellite and overhead imagery, to make sure the missile is headed in the right direction and at the right height.

Once the Tomahawk's target is in sight, the missile can dart in for the attack. A Digital Scene-Mapping Area Correlator ("dee-smack" in military jargon) matches a stored picture of the target to the missile's last sight, to make sure the two match.

Or, the missile can wait a while. The Tomahawk's controller can give it a new route, telling the Tomahawk to circle around in the air, lingering until an enemy pops up its head. Then comes the strike.

Last May, the Tomahawk demonstrated a new move, as Sam LaGrone from Jane's Defence Weekly reported at the time. The Los Angeles-class submarine USS Cheyenne fired off a Block IV at a target in the Mojave Desert.

Meanwhile, a team from Naval Special Warfare Group 3 shot a second set of co-ordinates to the Tomahawk's controllers in Japan, nearly 5,000 miles away. They reprogrammed the missile via satellite, and sent the Tomahawk crashing into a new target. (In an earlier test (.pdf), special operations forces were able to use the pictures taken from a handheld Raven drone to direct its bigger, more destructive relative to its end.)

Cruise missiles have been around in one form or another since World War II, and Tomahawks have been schwacking American enemies since the days of Desert Storm. Some earlier models had nuclear warheads. Others (still in service) employ cluster-bombs, much to the chagrin of human rights groups, who hate how the minimunitions can linger on a battlefield long after a war is over.

From the outside, the Block IVs look much like their predecessors: a little over 20 feet long, and about 3,300 pounds. Like the older models, they're still expensive, too – at about $1.1 million a pop, the initial assault on Libya chewed through $134 million in missile costs alone. They can fly for about two hours or 1,000 miles, whichever comes first.

But that could radically change, if an experimental Air Force program pans out. The X-51a aircraft is designed to test technologies for a next-gen cruise missile – one that would fly at six times the speed of sound.

Which means tomorrow's cruise missiles could be like suicidal, smart, and more than eight times faster than today's Tomahawks.

Photo: Navy

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