Introduction to the AGM-158 JASSM

The AGM-158 Joint Air-to-Surface Standoff Missile (JASSM) is a family of air-launched cruise missiles developed and produced by Lockheed Martin. Designed as a stealthy, long-range weapon, the JASSM allows aircraft to engage high-value, well-defended targets from standoff distances, well outside the reach of enemy air defenses. The missile family has evolved into several variants, each tailored for specific mission requirements, including the baseline AGM-158A, the extended-range AGM-158B JASSM-ER, and the anti-ship AGM-158C LRASM.

AGM-158A JASSM (Baseline Model)

The AGM-158A is the foundational missile of the JASSM family. It is a stealthy, air-launched cruise missile designed for standoff precision strikes.

The missile’s physical design is highly aerodynamic, resembling a small aircraft with pop-out wings and tail surfaces that deploy after launch. It has a launch weight of approximately 1 metric ton (1,000 kg), a length of 4.3 meters, and a body width of 0.5 meters. The JASSM-A carries a 450 kg armor-piercing warhead capable of destroying hardened targets.

As a standoff weapon, the AGM-158A has an operational range of around 370 kilometers. Its guidance system ensures a high degree of precision, with a Circular Error Probable (CEP) of just 3 meters. During its mid-course flight, the missile navigates using an Inertial Navigation System (INS) augmented with GPS updates. For the final attack phase, it employs an Imaging Infrared (IIR) seeker to identify and home in on the target. The inclusion of datalinks allows for in-flight communication.

The estimated unit cost for the baseline JASSM is approximately $700,000, with a production rate noted at around 500 missiles per year.

AGM-158B JASSM-ER (Extended Range)

The AGM-158B JASSM-ER is a major evolution of the original missile, designed to significantly increase its operational reach. The extended range is achieved primarily by incorporating a more efficient engine and increasing the internal fuel volume. While it maintains the same 4.3-meter length as the baseline model, its weight increases to 1.2 metric tons and its width to 0.6 meters to accommodate these changes.

The most critical enhancement is its performance. The JASSM-ER can strike targets at distances greater than 930 kilometers, more than doubling the standoff range of the AGM-158A while maintaining the same 3-meter CEP. JASSM-ER maintains a high degree of hardware and software commonality with the original, streamlining logistics and aircraft integration.

JASSM-ER has a higher estimated unit cost of $1.6 million per missile.

AGM-158C LRASM (Long Range Anti-Ship Missile)

The AGM-158C Long Range Anti-Ship Missile (LRASM) is a anti-ship variant of the JASSM-ER.

The LRASM is capable of autonomous targeting. LRASM can automatically acquire and engage targets without prior intelligence or auxillary services like GPS. It is believed to be able to target a particular ship among a group of ships and coordinate with sibling LRASMs to form a swarm.

LRASM has an additional multi-mode passive radio frequency (RF) homing system. It maintains the 930 km range and 3 m CEP of JASSM-ER

Beyond the main missile variants, several related programs and concepts have been developed to enhance or expand the capabilities of the JASSM family.

  • JASSM-D: This designation refers to a future planned development within the AGM-158 missile program, representing the next step in its evolution.

  • Rapid Dragon: This is a novel deployment concept rather than a missile variant. The Rapid Dragon system uses palletized launchers that can be airdropped from conventional cargo aircraft, such as the C-130 or C-17. This approach can rapidly convert transport planes into standoff missile carriers, providing a surge capability for mass missile strikes.

  • CHAMP: The Counter-electronics High-Power Microwave Advanced Missile Project (CHAMP) is a non-kinetic payload that can be integrated into the JASSM airframe. Instead of a conventional explosive warhead, CHAMP is designed to emit a powerful burst of microwave energy to disable or destroy targeted electronic systems, providing a unique non-lethal or low-collateral damage attack option.