by Tom Clancy
The other munitions program the Air Force has pinned its hopes to is the Joint Direct Attack Munition System, or JDAM. Trust me when I say this, JDAM is the program that must work if the Air Force is to be a viable force into the 21st century. There is that much riding on it. The JDAM family of munitions is designed to replace the old Paveway II-series weapons, which are starting to show their age. Like JSOW, the JDAM program began as a pair of Navy/Marine and Air Force programs that were combined into a single joint requirement. Currently, the program is being competed for by two contractor teams consisting of McDonnell Douglas and Rockwell International on one side with Lockheed Martin and Trimble Navigation on the other. Rockwell and Trimble are on the teams to supply GPS/inertial guidance system expertise, since that, as in JSOW, will be the primary guidance system for the JDAM family of munitions. Selection of a final winner is expected in 1996, with the weapons entering service in the late 1990s.
The idea is to produce a weapons family with the accuracy of the early LGBs, utilizing only a GPS/strapdown inertial-guidance system to find the target. This is the critical requirement. For the first time, aircraft without a laser-designator or data-link pod will be able to deliver precision weapons onto known targets. And it will do so without exposing the launching aircraft to direct fire by enemy defenses. Thus, stealth aircraft like the F-117A, F-22A, and B-2A will be able to use JDAM without generating telltale data link or laser designator emissions which might be detected by an enemy.
The basic features of the baseline JDAM family of weapons (called Phase I) include the following:• 32.8 foot/10 meter three-dimensional accuracy at the point of impact.
• A common guidance kit for every version of the weapon, independent of the warhead used.
• Interfaces with the most popular bomb warheads (Mk 83, Mk 84, and BLU-109/B).
• In-flight targeting and delivery, independent of weather and/or lighting conditions.
• Good standoff range (more than 8.5nm./15.5km. downrange and 2 nm./3.7 km. cross-range) and the ability to target more than one target /weapon at a time.
While this may sound like quite a lot to ask of a munition which has yet to even undergo its first engineering drop tests, the principles behind the JDAM system are both sound and mature. GPS/inertial guidance systems proved their worth during Desert Storm, and are more than capable of doing the job with JDAM. And as we have mentioned earlier, JDAM may not even be the first GPS-aided bombs, if Northrop and Rockwell have their way.
As currently planned, there will be five separate versions of the Phase I JDAM family. They include:
Each JDAM kit will be composed of an aerodynamic nose cap which is bolted onto the nose fitting of the bomb warhead, and a guidance section/fin group which is bolted onto the rear. Contained in the fin group at the rear of the bomb will probably be a small GPS/receiver antenna system to pull in the signals from the satellites and feed navigational updates to the inertial guidance /steering system. Other than that, all mounting, fusing, and arming hardware will be identical to other PGMs.
A mockup of the Lockheed Martin entry in the Joint Direct Attack Munition (JDAM) competition. Built around a conventional bomb warhead, it is guided by an onboard GPS satellite receiver to its target. McDonnell Douglas is the other JDAM competititor. John D. Gresham
As for their employment, all the pilot of an attacking aircraft will require is a known target location (preferably one with coordinates correlated with GPS accuracy), and a weapons delivery system capable of plotting a ballistic course to the target. While an onboard GPS receiver would be of great help, it is not necessary to the delivery of the JDAM munition. Once the bomb has been fed the target position and is launched, it will do its best, within the limits of the energy imparted by the launch aircraft, to head for the three-dimensional position of the target. Once there, it acts like any other bomb and explodes—in short, a very simple, yet very elegant solution to getting PGMs on target. Early tests of JDAM hardware on test benches are already showing accuracies in the 3.3-to-9.8 foot / 1-to-3 meter range, without any other added guidance systems. This is the future of PGMs, where the attacking aircraft only has to know the position of a target to kill it.
AIR-TO-GROUND MISSILES
Ever since young David used a stone projected by a sling to slay the giant warrior Goliath from a safe distance, warriors have dreamed of weapons that allow them to attack from a distance that makes counterattack impossible. Standoff. This has been the idea behind almost every weapon innovation—from the catapult, to the cannon, to the Intercontinental Ballistic Missile (ICBM). During the 1940s and 1950s, a generation of designers and engineers worked to create long-range weapons. For Nazi Germany, there was the Fi-103 flying bomb, known better as Vergeltungwaffe-1, or V-1. Called the “Doodlebug” or “Buzz Bomb” by its victims, it was the first practical example of what we now call a cruise missile. Later, in the 1950s, standoff cruise missiles were produced to extend the reach of nuclear bombers and maritime strike aircraft.
None of these early standoff weapons had any real precision; the mission was simple delivery of a large warhead to the general target area. True stand-off precision weapons had to wait for the development of electronic seeker technology in the 1960s. Earlier, we saw how the first precision seekers were developed for guided bombs like the Paveway-series LGBs, and the GBU-15, so that they could destroy point targets like bridges and bunkers. A precision-guided missile combines seeker technology with a propulsion system to extend its range.
As we head towards the 21st century, the USAF has a growing array of standoff air-to-ground missiles (known by their AGM designator) for use against heavily defended targets. These weapons are highly specialized for the targets they are designed to destroy. They also tend to be expensive, with typical unit prices in the six-figure range. However, when compared to the cost of a lost aircraft ($20 million and up) and the human and political costs of lost or imprisoned aircrews, these weapons can be very cheap indeed.
AGM-65 Maverick
We’ll start our look at what pilots like to call “gopher zappers” with the oldest air-to-ground missile in the USAF inventory, the AGM-65 Maverick. Maverick draws its roots from two different programs, the early electro-optical guided bomb projects and the Martin AGM-12 Bullpup (originally designated the ASM-N-7 Bullpup A by its first user, the U.S. Navy). Bullpup was an attempt to extend the range of the basic High Velocity Artillery Rocket (HVAR) used by U.S. aircraft since World War II. Bullpup provided a large warhead (250 lb./113.6 kg.), a rocket motor, and a guidance package to keep the whole thing on course. From a safe distance (8.8 nm./16.1 km.) one Bullpup could kill targets that previously required many aircraft with lots of bombs or unguided rockets. Guidance was provided by a command line-of-sight system, which sent the missile flying down a radio “pencil beam.” All the operator had to do was keep the nose of his aircraft on the target, and the missile would fly down the beam and impact the target. When it came into service in 1959, it was a wonder to its operators, who saw it as something of a “silver bullet.” The problem was that the AGM-12’s guidance system compelled the combat aircrew to fly straight and level toward the target during the missile’s entire time of flight.
In 1965, the Air Force began a program to develop a successor to the Bullpup. After a three-year competition between Hughes Missile Systems and Rockwell, Hughes won the contract in 1968. The development of the new missile proceeded smoothly, and it came into service in 1972 as the AGM-65A Maverick. Aircrews who saw the new weapon thought it looked like the big brother of the AIM-4/GAR-8 Falcon air-to-air missile, which was no surprise, since Hughes had also designed and built the Falcon. The Maverick shows its Hughes family roots, having the same general configuration as the Navy’s much larger AIM-54 Phoenix air-to-air missile. Externally, the Maverick has changed very little in the last two decades that it has been in service. The airframe is 12in./30.5cm. in diameter and 98in./ 248.9 cm. long. Wingspan of the cruciform guidance and stabilization fins is 28.3 in
./71.9 cm. These dimensions make it the smallest, most compact AGM in the USAF inventory, one of the major reasons for its popularity.
A cutaway of the Hughes AGM-65G Maverick Air-to-Ground Missile. Jack Ryan Enterprises, Ltd., by Laura Alpher
It’s what’s inside that counts, and that is what differentiates the various versions of the AGM-65. The -A model Maverick, which first entered combat service during the Christmas bombing of North Vietnam in 1972, is an E/O guided weapon, much like the GBU-8 or GBU-15. Its main characteristics were a 5° field-of-view (FOV) DSU-27/B seeker, with a huge 125 lb./56.8 kg. shaped charge warhead (that’s really big for one of these!) that could cut through virtually any armor or bunker in existence. Weighing in at 463 lb./ 210 kg., it was powered by a Thiokol SR 109-TC-1/TX-481 two-stage (boost and sustainer) solid propellant rocket motor, giving it a maximum range of roughly 13.2 nm./24.1 km. To fire it, the operator (the backseater of an F-4D Phantom II fighter) selected a missile and powered it up. Once the missile was “warm” with the onboard gyros running, the operator would view the picture from the missile’s onboard black-and-white TV seeker and select a target with a set of crosshairs. Like other early E/O weapons, the -A model Maverick tracked its targets by looking for zones of contrast between light and dark areas. For example, a tank or bunker might appear as a dark shape on a lighter background, and this was what the TV seeker of the early Maverick was designed to track. Once the operator had the target in the crosshairs, he would press a switch to lock on the target, and the seeker would begin to track the target, regardless of the motion of the launching aircraft or the target. After confirming lock-on, all the operator had to do was to press the firing button to send the missile on its way, and the firing aircraft was free to maneuver or evade. All models of Maverick are very accurate. If the missile functions properly, it should place the warhead well within 5 feet/1.5 meters of the aimpoint, which makes it a deadly anti-tank weapon.
Early combat Maverick shots went extremely well, helped by favorable environmental conditions. About sixty were fired in North Vietnam in December 1972 (fairly cool, clear air), and hundreds more by the Israelis in the October 1973 Yom Kippur War (good contrast background, along with dry, clear air). Both situations favored the TV seeker of the -A model Maverick. But in the hazy, muggy summer weather of Central Europe, its effective range was often reduced; an E/O TV tracker had a hard time seeing the camouflaged tanks of the Warsaw Pact in Central Europe. Combined with the different lighting conditions and heavy air pollution, this limited the effectiveness of the AGM-65A. From a pilot’s point of view, these conditions forced the user to get much closer to the target than is desirable. This problem was partially solved by reducing the FOV on the next version, the AGM-65B, to only 2.5°, which allowed for twice the magnification of the target scene by the missile optics. Also, for AGM-65s produced in FY-1981 and later, the rocket motor was replaced with an improved reduced smoke model. Nevertheless, the TV-series Mavericks remained difficult to use, especially in conditions of haze or ground cover, particularly by single-seat aircraft like the A-10 (the Warthog) and the F-16.
New versions of the Maverick were already on the way by the late 1970s. One idea was to make it into a laser-guided weapon like an LGB. A developmental version with a laser seeker, designated AGM-65C, was built by Rockwell. But the Air Force did not choose to put it into production (the USMC did, as the AGM-65E). This version also introduced a 300 lb./136.4 kg. blast fragmentation warhead with excellent penetration against everything from warships and bunkers to armored vehicles.
What everyone did want—including the Navy and a variety of foreign air forces—was a missile with a seeker that was immune to the problems of a visible-light TV tracking system. The answer was something entirely new—an Imaging Infrared (IIR) seeker. Like the Sidewinder missile, it would see the infrared (IR) energy given off by an engine or the body heat of a human being. However, instead of using a single detector element like the Sidewinder’s seeker, the new Hughes seeker would use multiple elements clustered into a matrix called an imaging array. This array is similar to the photo-electronic pickups used in a home video camcorder. This made the seeker head, designated WGU-10/B, essentially a “poor man’s” FLIR. Hughes designed the WGU-10/B to be a “common” seeker, which eventually was used on the IIR versions of the GBU-15, AGM-130, and the AGM-84E Standoff, Land Attack Missile (SLAM).
The IIR seeker integrated into a Maverick airframe proved to be a winner. The seeker was sensitive enough to see through smoke, haze, and fog to find its targets. Initially, the Air Force simply installed the new seeker onto the existing AGM-65B airframe with its 125 lb./56.8 kg. shaped charge warhead. Weighing in at 485 lb./220 kg., the AGM-65D, as it was designated, first arrived in service in 1983 and was very popular, especially in the A-10 community. They even found it could be used as a sensor during Desert Storm, when they would power up one missile on the rack and use its IIR seeker head video to help them navigate on night missions! The Navy and Marine Corps were also quick to see the advantages of the IIR seeker; and as soon as the production of the laser-guided -E model was completed in 1985, Hughes began production of the Navy variant, the AGM-65F. This model utilized the large 300 lb./136 kg. blast fragmentation/penetrator warhead of the AGM-65E and was designed to provide U.S. Navy and Marine Corps aircraft with a serious punch against heavy land targets or ships like patrol craft and amphibious vessels. It too was a great success during Desert Storm. IIR Mavericks can be distinguished from their earlier TV E/O brethren by their drab green or gray paint (versus white for the TV Mavericks); and they have either a milky silver or translucent amber colored optical seeker window (the TV seeker uses a clear optical window).
The latest IIR Maverick variant, the AGM-65G, is still being produced for the U.S. Air Force. Weighing in at 670 lb./304.5 kg., this version takes advantage of everything that has been learned about building Mavericks to date. The AGM-65G’s features include the WGU-10/B IIR seeker head, the 300 lb./136.4 kg. warhead, more reliable and accurate pneumatic control surface actuators, a digital autopilot, and the TX-633 reduced smoke rocket motor. Additionally, the -G model Maverick has a ship track “aimpoint biasing” mode, which allows the operator to pick an exact spot on a target where the missile will hit. This allows a pilot to designate the missile to hit at the water-line of a target vessel, greatly increasing the chance of critical flooding. When tied to a FLIR-based targeting system like LANTIRN, the AGM-65G is a weapon of deadly capability. (The unit price is $50,000 per missile in FY- 1991 dollars.)
So, how do you fire a Maverick? Suppose that you are flying in the backseat of an F-15E Strike Eagle equipped with LANTIRN pods and carrying four AGM-65G IIR Mavericks. You are told to attack a column of enemy armor, stopping them for other aircraft following you to finish them off. You ingress (pilot talk for “approach”) the target area and locate the armored column along a road. Using the LANTIRN hand controller, you target the lead vehicle in the column and automatically “hand-off” to the seeker the first missile. Then you repeat this setup for the last vehicle in the column (effectively trapping the vehicles in the middle of the column). Closing in for the attack run, you verify that both missiles are tracking their assigned targets, set the MASTER ARM switch to ON, wait for the missiles to come into range (up to 14 nm./25.6 km. at higher launch altitudes), and launch the missiles as fast as your finger can cycle on the firing button. The missiles should now be on their way to their targets. When each missile impacts, the AN/ AAQ-14 will record the result (to provide BDA footage of the event). Before you say this sounds like an advertisement for Hughes and Raytheon (the primary and secondary source contractors respectively), be aware that over 90% of the Mavericks fired during the Gulf War successfully hit their targets, and most of these were TV E/O and early IIR versions of the missile.
Today, the Maverick missile program is going strong, with fairly bright prospects for the future, given the current defense budget climate worldwide. A number of other nations have continuin
g Maverick procurement programs of their own, with orders continuing to come in. As for new Maverick developments, there are several ideas being kicked around the engineering shops of Hughes’s Tucson, Arizona, plant. Under evaluation is a variant with a new seeker that uses an active millimeter wave (MMW) radar to determine the exact shape of a target in virtually any weather conditions. Millimeter wave guidance uses radar waves small enough (less than a centimeter/0.4 inch) to resolve fine details on a target. The Maverick MMW seeker is only 9.45 in./24 cm. in diameter, so it fits neatly within the current dimensions of the AGM-65. Another option under consideration is to replace the rocket motor used on all previous versions of the Maverick with a turbojet power plant. Called the Longhorn project, it could triple the range of the AGM-65 without increasing the weight or significantly reducing the explosive payload. Neither modification is currently planned for production. Nevertheless, with over thirty thousand Mavericks built to date, the weapon has to be considered a success, with a long career still ahead of it.
AGM-88 HARM
On May 1st, 1960, over the farmlands of central Russia, a small air battle took place that forever changed the nature of air warfare. Almost 13 miles/21 kilometers in the sky, PVO-Strany was desperately trying to shoot down one of their most hated enemies, a CIA Lockheed U-2 spy plane. It was a costly battle. Several of their own fighters were lost to “friendly fire,” and the American intruder almost escaped. What won the day for them was the first success of a new tactical weapon, the surface-to-air missile (SAM). When Francis Gary Powers’s U-2 was shot down by the proximity detonation of an S-75 Dvina/SA-2 SAM (NATO code-named Guideline), it set off a scramble to counter this new and lethal weapons technology.
