In early 2019 the U.S. Department of Defense revealed some details of a recent and infrequently used version of the AGM-114R9 Hellfire II missile, one with a non-explosive but still very deadly warhead for hitting targets near innocent civilians. The R9X warhead was known to be deadly but no one in the general public (or the media) knew exactly how it worked except that it caused considerable damage inside a vehicle without using explosives. It was noted that the windows were not blown out in a sedan or SUV hit with a R9X. Nicknamed the Hellfire Ninja, this model employed six knife like extensions that popped out of the warhead and apparently spun when the warhead was activated. This shredded metal and anything else as it penetrated the roof of a vehicle and usually expended all its momentum inside the vehicle. It was a gruesome way to die but for nearby civilians it was good news indeed.
The first public and acknowledged use of the non-explosive Hellfire was an early 2917 attack on an Islamic terrorist leader in Syria was. Cell phone photos of the vehicle the dead man had been in made it clear the U.S. had used a Hellfire with a non-explosive warhead. That Hellfire killed the al Qaeda second-in-command while he was in a moving vehicle. Pictures of the automobile showed the large hole in the roof but no signs of an explosion. Some saw this as a new development, but it wasn’t.
There is nothing high-tech about the ninja missile either. The Israelis have frequently used Hellfire missiles with practice (non-explosive) warheads that will kill a few people travelling in an automobile and not cause additional damage. Users of Hellfire and ATGMs (anti-tank guided missiles) had long known that a practice warhead could still do a lot of damage because the practice warhead weighed the same as the explosive one, was heavy, and travelling at high speed. Troops noted the damage these practice rounds could do to a variety of targets. Thus with the U.S. and Israel became unofficial policy in some units to carry a practice TOW missile with them on some missions where it would be important to avoid casualties to nearby civilians. The Israelis later used the same technique with Hellfires.
But why go to the expense of developing the R9X? Apparently this was because the dummy warhead did not kill all the targeted people in a vehicle. A little something extra was needed and the R9X provided that. Before the use of R9X and practice missiles in combat became common the U.S. Air Force and Navy had, for years, been working on lower "bang" 500 pound bombs. The objective was to create a bomb that could be used in urban areas to destroy a single structure or just part of a larger one without injuring nearby civilians and the structures they were in. This eventually led to development of the FLM (Focused Lethality Munition) bomb. This uses a composite (carbon fiber) casing and replaces the normal 127.2 kg (280 pounds) of explosives with 93 kg of explosives surrounded by high density filler (fine tungsten powder). A regular 500 pound bomb has a blast radius (injury from blast pressure) out to 13 meters, with dangerous fragments lethal out to 40 meters. The FAM cut these distances by at least half. Meanwhile, the filler makes the bomb deadlier within the smaller blast radius. FAM, of course, was GPS or laser guided.
Before that, in 2007, the U.S. Navy began using the LCDB (Low Collateral Damage Bomb) in Iraq. This was basically a 500 pound JDAM (GPS guided smart bomb) with 89 percent of the explosives removed, and replaced with non-explosive material (so the bombs flight characteristics remain the same.) The remaining 13.6 kg (30 pounds) of explosives gave the bomb a much smaller bang, and thus less chance of nearby civilians getting hurt. The LCDB has a bang that was closer to that of a 155mm artillery shell. What's interesting about that is the U.S. Army had begun using GPS guided 155mm shells in Iraq at the same time. But these GPS shells cost twice as much as an LCDB as does the new (then) air force SBD (121 kg/265 pound Small Diameter Bomb). Thus the demand for a cheaper, variable explosive 500 pound bomb.
The concept of the VEB, FAM and LCDB goes back even further. During the 1990s, the U.S. Air Force replaced all the 189 kg (416 pounds) of explosives (with concrete) in thousand pound laser guided bombs used against Iraqi anti-aircraft guns and missiles. This was because Iraq dictator Saddam Hussein ordered his anti-aircraft weapons placed inside densely packed residential areas, in the hope that any American or British aircraft responding to fire from his anti-aircraft weapons, would also kill lots of civilians. That would make for a great photo op, as Saddam was trying to turn himself into a victim of American and British aggression. Dead civilians helped a lot. Concrete smart bombs took out the anti-aircraft weapons, but rarely hurt any nearby civilians. The LCDB was used against targets in buildings, or out in the open, who need at least a little bang, and bomb fragments, to take out the bad guys.
Variable yield nuclear explosives have been around for decades, because it is easier to limit the amount of nuclear material that will be turned into a nuclear explosion. But it has proved more difficult to do this with conventional explosives. Despite that in 2010 the U.S. Navy began working on a variable explosive bomb (VEB), based on technology demonstrated by weapons manufacturer ATK. Such a bomb could be set to a different amount of explosive force by the pilot, before dropping it. This is important for smart bombs, which can precisely hit a target. But often the targets have civilians nearby, and a smaller explosion will kill the enemy, and avoid civilian casualties.
The ATK demonstration bomb had three different settings, with the lowest creating a blast radius 40 percent less than at full power. This works by having the explosives split up in different compartments inside the bomb. For lower power, some of the explosives are ignited, using a lower power detonator that sets them to burn, like a rocket, rather than exploding. Modern explosives, like C-4, have long been used by troops as fuel, to boil water, by lighting them, rather than using an explosive detonator. Not recommended, but done anyway since before the Vietnam War and since. ATK used a bomb design that takes advantage of this. The navy spent $10 million to find that it was possible to produce a workable version of a variable explosive 223 kg (500 pound) bomb but in the meantime other, cheaper and more effective solutions turned up.
The appearance of the AGM-114R series Hellfire II missiles in 2010 led to the development of sub-variants that were less lethal and the details of these, like the R9X, were not made public. The original 114R version had a new warhead that is effective against personnel and structures, as well as armored vehicles. Many existing users of Hellfire had been asking for this type of warhead. The targets, for Middle Eastern users, were often unarmored vehicles used by gangsters, terrorists or smugglers who are spotted near populated areas. The 114R proved popular with all users and the U.S. Army converted thousands of its older AGM-114K Hellfire missiles to the new AGM-114R standard. Hellfires are the most frequently used American missiles these days. The AGM-114R (Hellfire II) missiles use either an armor-piercing or blast/fragmentation (for use against non-armored targets and bunkers) warhead. The ones fired from UAVs usually have the blast warhead. The Hellfire II weighs 48.2 kg (106 pounds), carries a 9 kg (20 pound) warhead, and has a range of 8,000 meters.
The AGM-114R is but the latest version of the Hellfire II, which first appeared in 1993 as the AGM-114K and included a lot of basic improvements in Hellfire design and capabilities. The original Hellfire entered service in 1985 as a Cold War anti-tank weapon. But when the Cold War ended in 1991, and the combat experience with Hellfire during the 1991 Kuwait campaign was noted, Hellfire found itself in more demand for other chores. This quickly led to Hellfire II, which was designed to more easily accept new features and some of the latest ones in an electronics package (a circuit board and internal sensors) that monitors and reports the status of missile components. This Captive Carry Health Monitoring package constantly tracks the status of the missile and the environment (heat, vibration, and humidity). Maintenance personnel can jack into the missile and get a report at any time, making it easier to keep missiles fit for action. Older versions of the missile required this information to be logged manually and much more effort to insure that the missile was ready for combat.
Because Hellfire is the most widely used UAV guided missile and regularly used against Islamic terrorists who regularly use civilians as human shields, work began on less lethal Hellfire warheads. Details were kept secret because in some cases the enemy knowing these special Hellfires might be used, could take precautions to make the target less vulnerable.