The Stand-in Attack Weapon (SiAW) is a tactical air-to-surface missile under development for the United States Air Force (USAF) by Northrop Grumman.
In May 2022, the USAF awarded contracts to L3Harris Technologies, Lockheed Martin and Northrop Grumman to begin the first phase of development for the Stand-in Attack Weapon (SiAW).[1][2]
On 28 September 2023, the USAF awarded a US$705m contract to Northrop Grumman to develop and test the SiAW. The SiAW is intended to attack relocatable targets including theater ballistic missile launchers, cruise and anti-ship missile launchers, GPS jamming platforms and anti-satellite systems. It will have a shorter range than standoff weapons, being fired by an aircraft after penetrating enemy airspace. The SiAW will fit inside the F-35 Lightning II's internal weapon bays. The design leverages work on the United States Navy's AGM-88G Advanced Anti-Radiation Guided Missile - Extended Range (AARGM-ER). The USAF plans to have an operational weapon by 2026.[3][4]
In November 2024, Northrop Grumman delivered the first SiAW to the USAF for flight testing.[5][6]