The UAE (United Arab Emirates) has ordered 218 of the latest version of the U.S. Sidewinder air-to-air missile, the AIM-9X-2. This one can lock-on-after-launch. That is, the missile can be fired, and then directed to a target via a datalink. The X-2 version also makes improvements in the warhead fuze and other components. Nearly 4,000 X model Sidewinders have been built since it entered service in 2003. Block II entered service three years ago. The UAE will pay over half a million dollars for each missile.
The AIM-9 is a heat seeking missile, and the heat sensors have become much more sensitive since the first AIM-9 entered service half a century ago. The current versions of the missile work by detecting a heat source at the point where the pilot is looking. This is done using the JHMCS (Joint Helmet Mounted Cueing Systems), which allows a pilot to see, displayed on his visor, critical flight and navigation information. Sort of like a see-through computer monitor or HUD (Head Up Display). Most importantly, the pilot can turn his head towards a target, get an enemy aircraft, or ground target, into the crosshairs displayed on the visor, and fire a missile that will promptly go after target the pilot was looking at. For Sidewinder, the pilot has to be looking at something giving off enough heat to catch the attention of the missile's heat sensor. With the X-2 Sidewinder, the pilot can launch the missile before he has located the target via the JHMCS, saving a critical few seconds.
The JHMCS is already used with some air-to-ground missiles, although it was revealed that no special air-to-ground software was needed for Sidewinders fired at ground targets. Instead, the air-to-air software was modified. This is important, because one of the reasons for this mod was to give the F-15C, which carries no air-to-ground weapons (it's strictly an air-to-air fighter) some air-to-ground capability. In addition, fighter-bombers (like the F-18, F-16, F-22 and F-35) will now be able to use their air-to-air weapons, in a pinch, once all their actual air-to-ground weapons are gone.
Although over half a century old, the Sidewinder has been the most effective air-to-air missile ever produced. The first Sidewinder (AIM-9B) was 3 meters (9.3 feet) long, weighed 71 kg (156 pounds) and had a max range of five kilometers. The most current model, the AIM-9X, is the same size, and weighs 87 kg (191 pounds) and has a max range of over 20 kilometers. All models have a warhead weighing about 10 kg (22 pounds) The AIM-9X can go after the target from all angles, while the AIM-9B could only be used from directly behind the target. The AIM-9X is about seven times more likely to bring down the target than the AIM-9B. The 9X entered service in 2000, but the older 9M is nearly as accurate, although more expensive to upgrade. Current Sidewinders cost several hundred thousand dollars each.