The U.S. Navy says it will begin deploying a cruise missile derivative of the stealthy AGM-154 Joint Stand-Off Weapon glide bomb, or JSOW, no later than the end of 2023, as an option for its F/A-18E/F Super Hornets and F-35C Joint Strike Fighters. The weapons will give these jets a significant additional extended-range strike capability, which is important given the increasingly advanced nature of integrated air defenses among potential opponents, especially Russia and China. On Feb. 7, 2019, Naval Air Systems Command (NAVAIR) announced its intention to issue a sole-source contract to Raytheon for work related to the new weapon, known as the JSOW-Extended Range, or JSOW-ER, on the U.S. government’s main contracting website, FedBizOpps. The Massachusetts-headquartered defense contractor developed the unpowered JSOW and you can read about it and the cruise missile derivative in depth in a previous feature from The War Zone. The notice also said that the JSOW-ER would be compatible with the U.S. Air Force’s F-35A Joint Strike Fighter, but it is not clear if that service actually intends to purchase the missiles.

“The Requirements for the JSOW-ER includes: extending the range of the existing JSOW [AGM-154]C-1 variant while maintaining targeting and performance capabilities, carriage on F-18 and internal carriage on F-35A/C while minimizing any changes to existing aircraft integration and limitations, hardware and software modifications to optimize midcourse and endgame performance for the powered variant of the JSOW, and deployment to the fleet no later than FY23,” the announcement explains. The Navy has been actively working with Raytheon on the development of the JSOW-ER since June 2017. In April 2018, the service announced it was moving the program to a more advanced phase.

Lockheed Martin An F-35C with its weapons bays open to show a pair of AGM-154C-1 JSOWs during a test.

That same month, Raytheon declared that the unpowered AGM-154C-1, or JSOW-C, was fully compatible with the F-35C’s internal weapons bays. “This is absolutely a critical opportunity for the Navy because now this is their top-line, medium-range precision strike weapon that is capable now of being integrated internally on JSF,” Mark Borup, a member of Raytheon's Medium-Range Strike and Attack Air Warfare Systems Division, said in an interview with Military.com at the time. But the JSOW-ER concept actually dates back more than a decade. Raytheon had pitched the idea of a powered version with the Williams International WJ24-8 turbojet to the United Kingdom as part of the Conventionally Armed Standoff Missile (CASOM) program. This weapon lost out to European consortium MBDA’s Storm Shadow cruise missile. In 2009, Raytheon flight tested a second iteration of the JSOW-ER using the Hamilton Sundstrand TJ-50 turbojet. The company also uses this engine to power its ADM-160 Miniature Air-Launched Decoy (MALD) system, which you can read about in more detail here. The design can also reportedly hit targets out to distances of nearly 265 miles, nearly four times the maximum range of the unpowered JSOW-C when released from a high altitude.

Raytheon The rear end of a JSOW-ER.

That added range is important given that potential opponents are only fielding surface-to-air missiles, as well as associated radars and other sensors, with ever-increasing range and precision. In turn, adding extra stand-off range to air-launched weapons will only become more vital to reduce the vulnerability to launching aircraft as time goes on. Combined with the Navy’s stealth F-35C, in particular, the JSOW-ER will also give the Navy an additional means of targeting those defenses directly. The Joint Strike Fighters could then cut a path open for non-stealth platforms to follow through for subsequent strikes. The stealthy features of the JSOW-ER itself only help reduce its own vulnerability to enemy defenses. This combat doctrine would only be more potent with the help of electronic warfare support from EA-18G Growlers. It is not clear if the latest JSOW-ER design still uses Hamilton Sundstrand TJ-50, as well as the flush-mounted intake that helps keep the weapon stealthy, from the 2009 design. It would make good sense that Raytheon would have continued to refine this version, though, which reportedly has the same basic dimensions as the unpowered AGM-154C-1. This would make it relatively easy to integrate into the F-35C’s internal weapons bays. The JSOW-ER will otherwise retain many of the features of the existing JSOW-C, including its guidance package, according to NAVAIR’s notice. The latest Block III AGM-154C-1s added an imaging infrared seeker to the weapons existing GPS-assisted inertial navigation system (INS) targeting system. This additional feature allows it to spot and home in on targets in the terminal stage of flight and, as a result, engage moving vehicles, like ships.

USN A Block III AGM-154C-1 about to hit a floating test target.