The U.S. Air Force successfully tested the long range (900 kilometers) version of its JASSM cruise missile, called JASSM ER. The test missile flew over 500 kilometers, then hit the intended target (several shipping containers). JASSM is the third family of GPS guided smart bombs to be developed. The original JDAM bomb kit (added to 500, 1,000 and 2,000 pound bombs), cost $26,000 each. The longer range JSOW (JDAM with wings and more powerful guidance system), cost $460,000 each. The even longer range JASSM cost $500,000 (the 400 kilometers version) to $930,000 (JASSM ER) each. Then there is the SDB (Small Diameter Bomb), a 250 pound JDAM that can also punch through concrete bunkers and other structures. These cost $75,000 each.
The AGM-158 JASSM missiles are 2,300 pound weapons that are basically 1,000 pound JDAMS (GPS guided bombs) with a motor added. JASSM was designed to go after enemy air defense systems, or targets deep in heavily defended (against air attack) enemy territory. The air force and navy planed to buy over 5,000 JASSM, but there has been some opposition in the military and in Congress. The missiles are ten times as expensive than a JADM bomb of the same weight. But the aviators make the argument that many aircraft and pilots would be lost if the air defenses of a nation like, perhaps China, were attacked without using JASSM.
The U.S. Air Force ordered the AGM-158 JASSM into full production in early 2004. But only a few have been produced, because of test failures. Air force purchasing plans have been cut way back because of reliability problems, and this has delayed shipment of the missiles to combat units until 2008.
JASSM is stealthy and uses GPS and terminal (infrared) guidance to zero in on heavily defended targets (like air defense sites.) The terminal guidance enables the missile to land within ten feet of the aiming point. If there were a war with North Korea, for example, JASSM would be essential to taking out enemy air defenses, or any other targets that have to be hit early in a war (before air defenses can be shut down.) JASSM was designed to handle the most modern Russian surface to air missiles, which are being sold to China. North Korea has older stuff, and can't afford the newer Russian SAMs. But even these older air defenses can be dangerous, and are best addressed with long range missiles.
Reliability and cost problems caused Congress to cut back on money for JASSM. There's also been no opportunity to use JASSM in the war on terror. So, at the moment, it looks like fewer than a thousand will be bought.