The U.S. Department of Defense recently certified APKWS II (Advanced Precision Kill Weapons System) 70mm laser guided rockets for use on fixed wing warplanes like the A-10, AV-8, and F-16. The APKWS II had to prove it 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.
For three years now the U.S. Marine Corps has been using APKWS II for its helicopter gunships and SOCOM has used it 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 back in 2010, 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. The marines armed their AH-1W helicopter gunships with the guided 70mm rockets. Since then marine AH-1Ws have fired over a 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 other 70mm 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.
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 about six kilometers. 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 smaller Griffin is an alternative to the Hellfire II because it weighs only 16 kg (35 pounds) with a 5.9 kg (13 pound) warhead. Griffin has pop-out wings, allowing it to glide, and thus has a longer range (15 kilometers) than Hellfire. UAVs can carry more of the smaller missiles, typically two of them in place of one Hellfire.
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.