South Korea, along with many other countries, has developed a guided version of the 70mm unguided rocket. The South Korean one is called LOGIR and is being put into service to help deal with possible naval operations by North Korea. LOGIR was developed in cooperation with the U.S. Navy. This is not the U.S. Navy's only experience with weapons like this. Last year, the navy bought fifty APKWS II (Advanced Precision Kill Weapons System) 70mm missiles, to test on Marine Corps AV-8 (Harrier) vertical takeoff aircraft, and U.S. Air Force A-10 (Warthog) ground attack aircraft. The AV-8 has previously used unguided 70mm rockets, but the A-10 has not. These tests were successful, but the South Koreans wanted something a little different. To that end, LOGIR does not use laser guidance (requiring the target have a laser constantly pointed at it), but an imaging system where the user merely points a vidcam type sensor at the target, and the LOGIR missile uses that image to keep heading for the intended target. This enables one LOGIR armed aircraft to engage many small naval targets at once. The U.S. Navy also seeks to use LOGIR against similar attacks from Iranians or Chinese forces. LOGIR is expected to enter service in three years and the U.S. Navy wants to buy 30,000.
For the last two decades, there have been over dozen development efforts, by several different companies, for 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. For example, the price of the new DAGR 70mm missile is about $20,000 each (about a third less than a smart bomb, and much less than a Hellfire missile). The developer of the competing APKWS, BAE, believed it was close to perfecting APKWS, but Congress ran out of patience and money for it two years ago. The marines took over APKWS development, completed it and got the navy to try it out.
The guided 70mm rocker is to be used against targets that don't require a larger (49 kg/107 pound), and more expensive (over $100,000) Hellfire missile, but still need some targeting precision. In tests, the APKWS hit within a few feet of the aiming point, and the DAGR and APKWS are just as accurate. The 70mm missile makes an excellent weapon for UAVs, especially since you can carry four of them in place of one Hellfire.
Aside from LOGIR, the most recent 70mm missile to arrive on the scene is from Lockheed-Martin, which recently completed twelve out of twelve successful tests of their DAGR 70mm guided rocket. DAGR was declared ready for service in 2008, but the U.S. Department of Defense didn't respond with any orders. LOGIR would have also languished if it had not been pointed out that the North Koreans would likely use a lot of small naval craft for an attack on, say, several small islands off the west coast of Korea, near the maritime border between north and south Korea.
Guided rockets like DAGR would appear to be an ideal weapon, as it also uses the Hellfire fire control system. APKWS and DAGR are both basically a 13.6 kg/30 pound 70mm rocket, with a laser seeker, a 2.7 kg/six pound warhead and a range of about six kilometers. Laser designators on a helicopter, or with troops on the ground, are pointed at the target, and the laser seeker in the front of the DAGR homes 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 55mm R4M), but 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 107-140 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 10 kilometers.
Apparently the orders for 70mm guided missiles have not been forthcoming because the Hellfire is doing the job and there just isn't a big demand for a smaller missile. But the marines believe that a mini-Hellfire, in the form of their APKWS II, has a role on the battlefield. Testing the weapon on the A-10 is an effort to get the air force convinced as well. The marines are also testing APKWS II on their helicopter gunships, in an effort to get the army interested. Actually, the army is already interested, and if the marines can succeed in getting the Department of Defense to allow them to order it for combat use, the army will probably follow. But LOGIR is most effective at sea, and is a bit more expensive than laser guided rockets.