Paris Air Show

Paris 2011: Missiles merge roles for mission flexibility

 - June 20, 2011, 1:30 AM

Missile developers in the U.S. are working on new weapons that combine the effects and capabilities of several previous munitions into single weapons, with the aim of significantly reducing the number of types held in the inventory and dramatically increasing the in-flight flexibility of aircraft and helicopters compared with current armament options.

The drive toward greater flexibility is already well under way. The dual-mode bomb such as the Enhanced Paveway, which combines GPS/INS guidance and infrared or laser terminal guidance, is already an accepted asset in combat operations. Companies have also been examining ways of using existing weapons in more roles. Raytheon, for instance, has highlighted the capability of the AGM-88 HARM anti-radar weapon to be used against coordinate-based non-emitting targets, and has demonstrated the use of the AIM-9X infrared-guided air-to-air missile as a weapon against moving surface targets.

More flexibility is also accompanied by a need for increasingly low collateral damage effect (CDE). Low CDE has been made possible by the increasing precision with which weapons can be delivered, not only against fixed targets but those on the move as well. If a weapon has a high probability of hitting a target, rather than detonating close to it, then the warhead can be much smaller to achieve the desired effect with much-reduced blast.

Multi-role Air-to-ground Weapons

Smaller and smarter are the watchwords for air-to-surface weapon development. This was the rationale behind the GBU-53 Small Diameter Bomb II program, for which Raytheon was selected last August. At 250 pounds, the SDB-II is half the size of the current principal U.S. precision-guided munition–the GBU-12 laser-guided bomb–and it features a tri-mode seeker that offers semi-active laser (SAL), uncooled imaging infrared (IIR) and millimeter-wave radar (MMW) guidance options.

That seeker has been adapted for Raytheon/Boeing’s proposal for the Joint Air-to-Ground Missile, arguably the most important air-to-surface weapon development program currently under way. JAGM arose from the earlier Joint Common Missile project and is aimed at replacing the AGM-114 Hellfire, AGM-65 Maverick and BGM-71 TOW missiles for the U.S. Army, Navy and Marine Corps. In April, request for proposals for engineering, manufacture and development were issued to the Raytheon/Boeing team and to Lockheed Martin.

No weapon program illustrates the drive for multi-role versatility better than the JAGM.

The Hellfire, for example, comes in a wide range of variants with SAL or MMW guidance and several warhead options. The JAGM will replace all of them with a single weapon. The tri-mode seeker is one answer, but also, new warheads are being developed that combine the effects of shaped charge and two-phase blast frag into a single unit. Perhaps the greatest challenge is adapting the missile to both the low-speed world of the attack helicopter and the high-speed environment of fast jets with a single motor design, not forgetting the need for insensitive munition (IM) technology to allow safe shipboard operation.

A weapon such as the JAGM greatly smoothes the logistics chain by replacing a wide array of weapon variants with a single missile, but the greatest advantage comes in the air. A multi-purpose effects warhead, three guidance options and other choices such as fuzing and trajectory allow aircrew to match the missile’s mode to the nature of the target and its environment while in flight, rather than having to make most of their choices before they take off.

Unmanned and Non-traditional Challenges

Traditionally, air-to-ground weapons have been launched from fast jets or attack helicopters, but in recent years that has been challenged by the rise of UAVs and the growing appearance of non-traditional aircraft types such as utility transports and trainers in the irregular warfare role. Initially, existing weapons such as the Hellfire and Paveway have been adapted to these new vehicles, but developers are working on new weapons that are better suited to these platforms.

Given the payload restrictions of many UAVs and light aircraft, “smaller” is a major concern here, as is low CDE. This has led to the development of precision-guided weapons such as Northrop Grumman’s Viper Strike, Raytheon’s Griffin and STM, and Moog FTS’s Talon/Mini-Talon series. Cost is an issue, answered to a large degree by the development of common guidance packages that can be applied to various weapon systems in a modular fashion.

Air Dominance

In the air-to-air world, the U.S. relies on the AIM-120 AMRAAM and AIM-9X to answer its current needs, while AGM-88 handles the ground radar threat. In the short term, they are being developed with improved performance to maintain their edge in air combat and to exploit advances in radar/sensor technology. However, projects are now under way to look at replacements.

Next Generation Missile (NGM) is the most important of them. Formerly known as Joint Dual-Role Air Dominance Missile (JDRADM), the NGM is being developed as the replacement for both the AIM-120 and AGM-88, again showing the drive for multi-role flexibility by replacing a long-range air-to-air missile and an anti-radar weapon with a single type that can tackle air threats, ground radars and cruise missiles. A key driver behind the NGM program is to develop multi-role weapons that can be carried internally by stealthy fighters. Development contracts were awarded late last year to both Boeing and Raytheon under the Triple Target Terminator (T3) program, with an eye on fielding a missile around 2025.

Already, the U.S. Air Force is talking about an AIM-9X replacement in the form of the Small Advanced Capabilities Missile. This would take on the short-range air threat duties of the AIM-9X, but may also offer other capabilities such as air-to-surface attack and anti-missile defense. Beyond these programs lies the promising technology of high-energy lasers, which are being eyed for fielding on fighters to undertake some of the roles currently undertaken by missiles at much-reduced cost.