Growing demand from nervous allies confronting ominous moves by Russia, China, North Korea and Iran have led to increased production of the American AGM-158 JASSM (Joint Air-to-Surface Standoff Missiles). The latest production order in mid-2017 was for 360 more of the most expensive version; AGM-158B JASSM ER (extended range of 900 kilometers). These will cost $1.15 million each and be delivered by mid-2020. Since it entered production in 2009 over 3,000 JASSM have been ordered, including 910 of JASSM ER. Basically JASSM delivers a GPS guided bomb long distances (beyond the range of enemy air defenses) and does it relatively inexpensively.
Development of JASSM began in 1995 and in the late 1990s the air force and navy planned to buy over 5,000 of them. But before mass production was to begin in 2004 there was growing opposition in the military and in Congress. JASSM were ten times more 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. Then came 2001 and now there were other priorities. 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. The technical difficulties almost led to JASSM being cancelled but that appeared to motivate the developers to get the system working and production began in 2009. Then Russia and China became more of a threat and orders from allies in East Europe and East Asia increased.
JASSM was designed to handle the most modern Russian surface to air missiles, which are also 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. So there is a need for a missile like JASSM, at least one that works. With Russian air defense systems now operating in Syria and Iran JASSM may be needed there before elsewhere in Europe or Asia. JASSM was designed for use on F-16s, F-15Es, F-18s and all three American heavy bombers. Customers for the F-35 now want it for that aircraft as well. There are currently four foreign users with more showing interest.
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 three meters (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.) This capability is apparently what attracted the South Koreans, who now have F-15K aircraft that can carry JASSM. It also caught the attention of Poland when Russian began making threatening noises.
JASSM is the third family of GPS guided smart bombs to be developed and is the most expensive. The original JDAM GPS 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 over half a million dollars (the 400 kilometer version) to over a million dollars (the 900 kilometer 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. All these are basically GPS guided smart bombs.
JASSM missiles are 1,045 kg (2,300 pound) weapons that are basically 455 kg (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 original reason for buying these was to have something to deal with air defenses of a nation like China.