May 3,2008: Australia has joined the United States, Sweden and Canada as users of the Excalibur GPS guided 155mm artillery shell. Australia has ordered 250 of the Excalibur shells, and 28 electronic fire control devices for its M198 towed 155mm howitzers (which do not, like all self-propelled, and most towed, artillery, have this fire control gear build in.)

American and Canadian troops have begun using the Excalibur shell in Afghanistan earlier this year. A year ago, American troops began using Excalibur in Iraq. This was just timely, because Islamic warriors tend to use civilians as human shields, and that means you have to be precise when you go after the bad guys with artillery. A typical situation has enemy gunmen holding out in one building of a walled compound or village. In nearby buildings, there are women and children. While killing the enemy is good, killing the civilians can be a very bad thing. Smart bombs should be able to fix this, except that sometimes one of the smaller smart bombs, the 500 pounder, has too much bang (280 pounds of explosives).

A 155mm artillery shell should do the trick (only 20 pounds of explosives each), but at long range (20 kilometers or more), some of these shells will hit the civilians. That's because at that range, an unguided 155mm shell can land up to 100 meters from where you aimed it. This is where Excalibur comes in handy. The GPS guided Excalibur shell falls within a ten meter circle (the middle of that circle being the "aim point") no matter what the range. After a year of use in Iraq, the troops find Excalibur invaluable for hitting just what you want to hit, and with a minimal amount of bang.

For most nations, the drawback is cost. A "dumb" 155mm shell costs under a thousand dollars, while one Excalibur costs up to $150,000. But when you take into account the civilian lives saved (and good will retained), it's a different story. Moreover, friendly troops can be closer to the target when Excalibur is used, meaning your infantry can get into the shelled target quicker, before any surviving enemy can get ready to shoot back.

The Excalibur shell is worth it in other ways. Ten 155mm shells (of any type, with their propellant and packaging) weigh about a ton. Ammo supply has always been a major problem with artillery, and Excalibur is the solution. With Excalibur, fewer 155mm shells have to be shipped thousands of miles, and looked after until they are used.

Excalibur was developed in the United States, in cooperation with Swedish engineers, The Excalibur was originally supposed to cost under $50,000 each, and with more being produced, the per-shell price will fall. Currently, 150 Excaliburs are being produced each month. Developing electronics and control systems that fit inside a 155mm diameter shell, and survive being fired out of a cannon, proved more difficult than expected. That's why a GPS guided smart bomb only costs about $30,000, while the first hundred or so Excaliburs cost a lot more.

Developing smart artillery shells is risky. The U.S. Navy recently cancelled a project to develop a similar 127mm shell, and is now looking into adopting the Excalibur technology for a GPS guided 127mm shell that works. Smart shells are a nice idea, but getting from here to there is a risky process.