Northrop Grumman’s Stand-in Attack Weapon aims to penetrate anti-access/area denial zones

Airpower

By Alex Hollings

August 4, 2025

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Northrop Grumman’s new Stand-in Attack Weapon, or SiAW, could be the air-to-ground missile to rule them all.

In essence, the SiAW is envisioned as a means to engage just about any stationary or moving target on the ground or even at sea. To achieve that it will leverage multi-mode guidance.

The new SiAW missile is being built upon the basic structure of the Navy-led Advanced Anti-Radiation Guided Missile-Extended Range (AARGM-ER) program. (The will AARGM-ER program will develop a long-range radar hunting missile to be deployed by carrier-based F-35Cs.)

The SiAW will carry a different warhead and fuse than the AARGM-ER, but appears to boast the same GPS-assisted inertial navigation system and millimeter-wave radar seeker alongside its anti-radiation, or radar-hunting seeker. That means these missiles can close with pre-programmed targets, even in GPS-denied environments, or identify targets within a set area to engage.

In the AARGM-ER, this capability allows the missile to continue chasing after enemy radar arrays – even after they power down – by first identifying the array and then using its inertial and GPS navigation to close with its last broadcast location. The millimeter wave radar seeker can even allow the missile to close with moving targets within the target area if the air defense array is on the move. If target information changes while the missile is already in flight, a two-way data link allows the launching aircraft (or other nearby assets) to provide the weapon with new target coordinates on the spot.

When combined with the advanced sensor suite of the F-35 or the B-21, the SiAW will offer a single weapon that can address a wide variety of surface threats. Its overall range – and that of the AARGM-ER – remain undisclosed, but previous claims have suggested that it will offer an increase in range from 20% to even 50% over the AGM-88E it is set to replace. This would give the SiAW – and its AARGM-ER – sibling a range of somewhere between 96 and 120 miles with a roughly 60-pound high explosive warhead.

In November 2024, the Air Force performed a successful drop test of an inert SiAW from an F-16C.

Feature Image: A 40th Flight Test Squadron F-16 Fighting Falcon flies with a Stand-in Attack Weapon on its rail Nov. 7 at Eglin Air Force Base, Florida. The mission marked the first time the weapon was successfully released from an aircraft. (U.S. Air Force photo by Staff Sgt. Blake Wiles)