Currently deployed on the United States Air Force B-1 Lancer, B-2 Spirit and B-52 Stratofortress bombers and F-15E Strike Eagle, F-16 multi-role fighters, the AGM-158 Joint Air-to- Surface Standoff Missile (JASSM) is a 14 foot long, 2,250 lb autonomous, stealthy, long range standoff missile designed to destroy high value, well defended fixed or relocatable targets, from ranges of over 200 nautical miles. The missile is also in service with the armed forces of Australia, Finland and Poland. Powered by the Teledyne CAE J402-CA-100 turbojet, the autonomous navigation based on inertial and Global Positioning System (GPS) programmes, the missile follows a pre-planned low-level terrain following route to the target area. Once in predesignated location, the missile uses its Imaging Infra-Red (IIR) seeker of medium wavelength sensor using a 256 x 256 Focal Plane Array (FPA) and on-board, real-time Automatic Target Correlating (ATC) algorithms to precisely locate and strike the desired target aim point. The missile can also engage enemy jammers. Lockheed Martin’s ATC algorithms use an insensitive, redundant approach and realtime processors to provide a robust system that significantly reduces the missile’s Circular Error Probability (CEP) impact any time of the day or night. This gives the missile ability to hit a precise spot, such as a specific point in a hardened bunker, cave entry or ventilation shaft, using a target model built months earlier. To make the missile more immune to GPS deception and jamming, JASSM Block 1A missiles are equipped with Selective Availability/Anti- Spoofing Module (SAASM) technology, which itself is an enhanced, digital antijam GPS receiver. This capability gives JASSM the ability to successfully complete its mission even in intense jamming environments. JASSM is equipped with a WDU-42/B (J-1000) 1000 lb dual-mode blast-fragmentation penetration warhead with 240lb of AFX-757 for maximum effect against hard targets. A unique feature of the current model of JASSM is its capability to send back a sequence of pre-strike images of the target, just before impact, the process providing partial Battle Damage Assessment (BDA) capability.
Further improvements of AGM-158B JASSM-ER will include an improved engine and larger fuel capacity, with an improved two-way datalink which will provide flexible re-targeting of the missile, including tracked, moving maritime targets. The ER version maintains the same outer mould lines of the stealthy airframe, which makes JASSM extremely difficult for air defence systems to engage. It also retains the dual-mode penetration and blast fragmentation warhead of the baseline JASSM missile. This capability will transform JASSM into a network-enabled system, providing inflight re-routing, retargeting, or aim-point refinements and blue-force tracking, to eliminate fratricide risks. The introduction of JASSM-ER will also provide limited loitering capability or further range extension beyond 500 nautical miles. Loitering will enable planners to more flexibly integrate JASSM with other means of attacks, such as decoys and defence suppression weapons etc. Flight testing for JASSM-ER began in May 2006 with tests at White Sands missile testing range in New Mexico and entered USAF service in April 2014 with B-1B squadrons. During one flight test, the missile was released from a B-1B aircraft and flew a preplanned course to collect data, to fine-tune navigation algorithms, and then destroyed the designated target. The B-1B can carry a full load of 24 JASSM-ERs, the B-2 has 16 JASSM-ERs and the B-52 is able to carry 20 JASSM-ERs, eight internally and 12 on external pylons. The USAF plans a total procurement of 4900 JASSMs, both the 200 nautical miles basic weapon and 500 nautical miles JASSM-ERs.
During May 2015, the head of the Air Force Research Laboratory nominated the JASSM-ER as the optimal air vehicle to carry the Counter-electronics High Power Microwave Advanced Missile Project (CHAMP) payload designed to destroy hostile electronic equipment with bursts of high-power microwave energy, non-kinetically neutralising them. AGM- 158C is the long range Anti-Ship Missile (AShM) variant.
Sayan Majumdar