Although the APKWS II (Advanced Precision Kill Weapons System) 70mm laser guided rocket was certified for use on fixed wing American warplanes like the A-10, AV-8, and F-16 in 2013 it was only in early 2016 that U.S. Marine Corps AV-8 (Harrier) vertical takeoff jets were equipped to use APKWS. The 2013 certification was all about confirming that APKWS II (an improved AKPWS which entered service in 2012) could be successfully launched from fast moving aircraft and still be able to continue in flight to the ground target its laser sensor was attracted to (because of laser light being bounced off it). Britain demonstrated how effective such small missiles can be when used by “fast movers” (jets). Normally, smaller missiles like this are designed for helicopters, but Britain took the American Hellfire and came up with a version (Brimstone) that worked on jets. It was a big success in Libya in 2011, and earlier in Afghanistan.
The marines have been using APKWS on their AH-1Z helicopter gunships since 2010 as has SOCOM (Special Operations Command) on its slow moving AC-130 gunships. The marines were so pleased with it that they bought APKWS II kits to convert some of their 100,000 70mm unguided rockets to laser guided ones. All this began when the marines bought fifty APKWS II missiles for testing and that proved successful. There followed the first sale for 70mm guided rockets after more than a decade of trying to get anyone to buy more than a few evaluation missiles or upgrade kits. Marine AH-1s have fired several hundred APKWS II in Afghanistan and none of them missed. That led to modifications for use on fast movers and the recent successful tests.
After more than a decade of development effort, by several different companies, there are now several guided versions of the 70mm air-to-ground rocket. Developing a guided 70mm rocket took so long because the manufacturers underestimated the technical difficulties of getting the laser seeker and flight control mechanisms into that small a package, at a weight and price the customer could afford. The price of the new 70mm missile is about $30,000 each. This is typical for these weapons and about a third less than a smart bomb and less than a third of what a Hellfire missile costs.
The guided 70mm rocket is used against targets that don't require a larger (49 kg/108 pound), and more expensive (over $100,000), Hellfire missile but still needs some targeting precision. In tests the APKWS hit within a meter (a few feet) of the aiming point, about what Hellfire and similar missiles are capable of. The 70mm missile makes an excellent weapon for UAVs, especially since you can carry more of them. The launcher for carrying these missiles is designed to replace the one for Hellfire but can carry four missiles instead of one. APKWS can also be used from a modified Hydra launcher (that carries seven missiles) which was long used for the unguided 70mm rockets.
All these 70mm guided rockets are basically 13.6 kg (30 pound) 70mm rockets, with a laser seeker, a 2.7 kg (six pound) warhead, and a range of five kilometers from helicopters or 11 kilometers from fixed wing aircraft. Laser designators on a helicopter, aircraft, or with troops on the ground, are pointed at the target and the laser seeker in the front of the 70mm missile homes in on the reflected laser light.
The 2.75 inch (70mm) rockets were developed during World War II, as an air-to-air weapon for use against heavy bomber formations. The Germans had developed a similar and very successful weapon (the R4M). Before long it was noted that neither the Japanese nor the Germans had any heavy bombers, so the U.S. 70mm rocket was switched to air-to-ground use. Actually, the 70mm rocket was retained for air-to-air use into the 1950s, but it was never successful in that role. The 70mm rocket became very popular in the 1960s, when it was discovered that the weapon worked very well when launched from multiple (7 or 19 tube) launchers mounted on helicopters. The 108-138m cm (42-55 inch) long rockets could be fired singly or in salvoes and gave helicopter pilots some airborne artillery for supporting troops on the ground. There are many variations in terms of warheads and rocket motors. Some versions can go over ten kilometers.
For a long time orders for 70mm guided missiles were not forthcoming because the Hellfire was doing the job and there just wasn't a big demand for a smaller missile. Several smaller missiles have been developed, and one of them, the Griffin, is being used over Pakistan and Afghanistan on American UAVs. The marines, and now the navy and air force, believe that a mini-Hellfire, in the form of their APKWS II, has a role on the battlefield and plan to keep using it in combat. The APKWS is a lot cheaper than Hellfire or Griffin and for some situations is seen as a better choice.