Lockheed Martin AGM-158 JASSM
AGM-158C LRASM

The JASSM (Joint Air-to-Surface Standoff Missile) program was initated in 1995 following the cancellation of the AGM-137 TSSAM (Tri-Service Standoff Attack Missile) because of high cost. Development goal was a low-observable long-range precision guided stand-off missile for significantly lower cost than the TSSAM. In June 1996, program-definition and risk-reduction contracts were awarded to Lockheed Martin and McDonnell Douglas (now Boeing). At the same time, the missile designations AGM-158A and AGM-159A were allocated to the two competing JASSM designs. In April 1998, Lockheed Martin won the development contract for the EMD (Engineering and Manufacturing Development) phase of JASSM.

Photo: Lockheed Martin

AGM-158A

The AGM-158A is a stealthy cruise missile powered by a Teledyne CAE J402 turbojet. It uses flip-out wings with control surfaces and a single vertical tail for flight control. It is guided by a jamming-resistant GPS-aided inertial navigation system, and uses an IIR (Imaging Infrared) seeker for autonomous pattern-based target selection and terminal homing. The missile is armed with a 450 kg (1000 lb) WDU-42/B insensitive munitions penetrating warhead, and accuracy is quoted as around 2.4 m (8 ft) CEP. The AGM-158A is also equipped with a data link to transmit status and location information until impact to assist bomb damage assessment. The DATM-158A is a fully inert version for ground handling training.

Photos: Lockheed Martin
AGM-158A

Powered flight tests of the AGM-158A began in November 1999, and developmental testing of the missile began in January 2001. Low rate initial production of the JASSM was approved in December 2001, and in mid-2002, the AGM-158 officially entered the OT&E (Operational Testing & Evaluation) phase. Two warhead-related test failures in late 2002 have delayed the program for at least three months, but JASSM successfully completed the DT (Development Test) phase in April 2003. However, the first two OT (Operational Test) flight tests in May 2003 failed, because of engine and launcher problems. The AGM-158A was finally certified as ready for operational use in October 2003, and could be employed operationally by the B-52. JASSM will eventually be integrated with all current U.S. strike aircraft, including the F-15E, F-16, F/A-18, F-35, B-1B, B-2 and B-52.

Photo: Greg Goebel

AGM-158A

In May 2004 the Air Force approved full-rate production of the AGM-158A. Although the U.S. Navy was a partner in the JASSM program, it has been more reluctant than the USAF to field the AGM-158, preferring the AGM-84H/K SLAM-ER for many missions instead. Procurement of the Navy's originally planned 450 JASSMs was first postponed to 2007, but was finally cancelled altogether in 2005.

The first major enhanced version of JASSM was the AGM-158B JASSM-ER (Extended Range). It has a new Williams F107-WR-105 turbofan engine for a significantly increased range of up to 1000 km (600 miles). The AGM-158B first flew in 2006, entered USAF service in 2014, and is the current production variant of JASSM. The AGM-158B-2 upgrade features a new electronic fuze, a new GPS receiver, an upgraded Missile Control Unit, and enhanced software. The further improved AGM-158B-3 has a jamming-resistant "M-Code" GPS receiver.

Image: Lockheed Martin

AGM-158B

There is some confusion about the upcoming AGM-158D version. It was originally linked to a development called JASSM-XR (Extreme Range), which is planned to be a missile with a longer fuselage for a range of up to 1600 km (1000 miles). However, recent USAF documents say that the AGM-158D is another JASSM-ER variant, which is equipped with a Weapon Data Link (WDL) for post-launch in-flight mission and targeting updates.

At the time of this writing, the AGM-158A, -158B and -158B-2 variants are in service, while the -158B-3 and -158D are still in developemt. Several thousand JASSM missiles have been delivered so far, and the total USAF requirement is for at least 7000 AGM-158s.

LRASM (Long Range Anti-Ship Missile)

Around 2009, DARPA (Defense Advanced Research Projects Agency) began the LRASM (Long Range Anti-Ship Missile) program to develop an air-launched anti-ship cruise missile based on the AGM-158B JASSM-ER, to replace the aging AGM-84 Harpoon in the anti-ship role. Flight tests began in 2013, and in 2016, LRASM was designated as AGM-158C. The missile upgrades the baseline AGM-158B with a new data link, a passive RF seeker, and software logic to autonomously detect and destroy hostile ships. The AGM-158C reached Initial Operational Capability with the USAF's B-1B in 2018 and the Navy's F/A-18E/F in 2019. Integration with the F-35B/C and P-8A is on-going. Non-tactical LRASM variants are the ATM-158C instrumented training version and the DATM-158C ground handling trainer.

Image: Lockheed Martin

AGM-158C

Specifications

Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!

Data for AGM-158A/B:

Main Sources

[1] Hajime Ozu: "Missile 2000 - Reference Guide to World Missile Systems", Shinkigensha, 2000
[2] Lockheed Martin Missiles & Fire Control Website
[3] Robert Wall: "Rocky Road", article in Aviaton Week & Space Technology, 19 May 2003
[4] Department of Defense: FY 2026 Budget Estimates, Missile Procurement, Air Force
[5] Various sources referenced in Wikipedia: AGM-158 JASSM and AGM-158C LRASM

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Last Updated: 14 December 2025