AGM-158 JASSM

America's premier low-observable air-launched standoff cruise missile, delivered in short-, extended- and extreme-range variants, and the weapon that consumed the largest inventory share in the 2026 Iran campaign.

Overview

The AGM-158 Joint Air-to-Surface Standoff Missile (JASSM) is a family of subsonic, stealthy cruise missiles produced by Lockheed Martin. Designed to penetrate advanced integrated air-defence systems, the missile uses a low-radar-cross-section airframe, GPS/INS mid-course guidance, and an imaging infrared (IIR) terminal seeker with automatic target recognition. The baseline AGM-158A entered service in 2003; the extended-range AGM-158B JASSM-ER stretches that envelope to roughly 925–1,000 km, and the in-development AGM-158D (JASSM-XR) targets ranges beyond 1,600 km. JASSM became the principal long-range standoff weapon of the 2026 US–Israel war on Iran, where more than 1,000 missiles were fired in the first month alone, triggering a massive recapitalisation drive.

Development

The programme originated from the U.S. Air Force’s need to replace the AGM-86 ALCM and the cancelled TSSAM. Lockheed Martin won the engineering-and-manufacturing-development contract in 1998 and the missile first flew in 1999. Development was turbulent: the programme suffered a Nunn-McCurdy unit-cost breach in 2002 and a series of test failures forced a major restructure before AGM-158A achieved initial operational capability in 2003. From 2006 the Air Force funded an extended-range variant that added a larger fuel tank and the Williams F107 turbofan; the resulting AGM-158B JASSM-ER attained IOC in 2015. The most recent iteration, AGM-158D, is in low-rate initial production and pushes range into the extreme-standoff class. Throughout, the missile has been assembled at Lockheed Martin’s Camden, Arkansas, facility, with propulsion by Williams International, guidance computers from BAE Systems, and the IIR seeker from DRS Technologies. Significant production milestones are documented by Designation-Systems.Net, while the surge in procurement following the Iran campaign is detailed by Breaking Defense.

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