March 21, 2010:  The U.S. Air Force has ordered another 6,000 JDAM (GPS satellite guided bombs) kits. These convert 500 (227 kg), 1,000 (455 kg) and 2,000 (910 kg) pound unguided bombs into highly accurate guided "smart bombs". This brings the number of JDAM kits ordered to 210,000. The new order will be delivered within three years. The original JDAMs cost $24,000 (adjusted for inflation), while current models (after many upgrades and improvements) cost 50 percent more. Some JDAM are also fitted with laser guidance capability. JDAM turned out to be a revolutionary weapon, and an unexpected one at that.

JDAM were developed in the 1990s, shortly after the GPS network went live. These weapons entered service in time for the 1999 Kosovo campaign, and have been so successful, that their use has actually sharply reduced the number of bombs dropped, and the number of sorties required by bombers. The air force generals are still trying to figure out where this is all going.

After the invasion of Iraq, the U.S. Air Force ordered a sharp increase in JDAM production, aiming for 5,000 JDAM a month. They ended up needing far less. In 2005, about 30,000 JDAM were ordered. That fell to 11,605 in 2006 and 10,661 in 2007. In 2008, only 5,000 were ordered. Most of those ordered in the past few years are being put into the war reserve. Only a few thousand a year are actually being used, and this includes those expended during training. The war reserve contains over 100,000 kits, to be used in some unspecified, but big, future conflict.

The appearance, and impact, of JDAM has been sudden. While guided bombs first appeared towards the end of World War II, they did not really become a factor until highly accurate laser guided bombs were developed in the 1960s. A decade later, TV guided bombs came into service. But these guided bombs were expensive, costing over $100,000 per bomb. Even as late as the 1991 Gulf war, only 16 percent of the 250,000 bombs dropped were guided. But analysis of the battlefield later revealed that the guided bombs had done 75 percent of the actual damage. But the guided bombs were still too expensive, and lasers were blocked by many weather conditions (rain, mist, sand storms). Something new was needed to replace dumb bombs completely. The solution was GPS guided bombs.

In 1991, the GPS system was just coming into service. There were already plans for something like JDAM, but no one was sure that it would work. Once the engineers got onto it, it was discovered that JDAM not only worked, but cost less than half as much to build ($18,000 per bomb) as the air force expected ($40,000 a bomb, or about $53,000 adjusted for inflation).

So in 1996, production of JDAM began. During their first use, in Kosovo, 98 percent of the 652 JDAMs used, hit their targets. In 2001, JDAM proved the ideal weapon for supporting the few hundred Special Forces and CIA personnel the U.S. had on the ground in Afghanistan. The JDAM was more accurate, and effective, than anticipated. By January, 2002, the U.S. had dropped about half their inventory, of 10,000 JDAMs, in Afghanistan.

In 2003, 6,500 JDAM were used in the three week 2003 Iraq invasion. Since 1999, American aircraft have used less than 25,000. New versions have added more capabilities. The latest versions are even more accurate, putting half the bombs within ten meters of the aiming point. A new 250 pound version (the SDB) entered service last year. Another new version, with wings, is on the way, which will enable a bomber to drop the bomb up to 100 kilometers from the target. JDAMs are pretty rugged. F-22s have dropped half ton JDAMs, from 50,000 feet (16,100 meters), while moving at over 1,500 kilometers an hour.

In the last decade, the appearance of so many precision weapons has changed tactics on the ground. This proliferation of precision has also changed the way smart bombs are designed. With the ability to put a weapon within a meter of the aiming point (using laser guidance) or 5-10 meters (using GPS), smaller is now better, especially in urban areas where there are a lot of civilians about. But even without civilians around, smaller, more precise bombs and missiles are preferred, as that allows friendly troops to get closer to the target, and rush in right after the explosion, to finish the job. Troops have changed the way they fight because of this. There is more movement in urban warfare because of all this precision firepower, and fewer friendly fire casualties from bombs and artillery.

The army also has 155mm GPS guided 155mm shells (Excalibur). Each hundred pound shell has about 20 (9 kg) pounds of explosives. This makes for a bigger bang than Hellfire or Tow, but much less than smart bombs. There's also a 227mm MLRS GPS rocket. But this carries over 150 (70 kg) pounds of explosives. About half the bang of a 500 pound JDAM. The GPS guided 155mm shell and MLRS rocket each cost over $50,000 each. The big advantage of these GPS artillery munitions is that they are available to the troops 24/7, and the need for fewer rounds per mission means there are fewer problems with running out, or low, on supplies.

Price is not really a factor when it comes to these weapons. The whole point of smart (much more accurate) munitions is to reduce the number of explosions, and to only blow up what needs to be destroyed. The proliferation of rockets, smart bombs and missiles, from those with a pound (450 grams) of explosives (LAW) to 500 pound bombs (with 280 pounds), gives troops a lot of flexibility on the battlefield. This makes American troops much more lethal, and greatly reduces friendly, and civilian, casualties.

The enemy had a hard time adapting to smart weapons. In Afghanistan and Iraq, the enemy largely gave up trying to fight American troops head on. Ambush, roadside bombs and boobytraps became the preferred methods of attacking U.S. troops. This is a major concession by the enemy, and has been a major factor in the success of American forces since JDAM became available. You cannot win if you cannot eventually confront and defeat the enemy ground troops.

As long as the U.S. maintains air superiority, as it has since 1944, enemy forces will not benefit from the new precision bombs. They will still be able to use precision ground launched missiles and artillery shells, but that will be small consolation when your forces are being pounded by thousands of JDAMs.