US Air Force seeks sources for Stand-in Assault Weapon appropriate with F-47, B-21
The U.S. Air Force is seeking additional industry sources capable of producing a Stand-in Attack Weapon or equivalent system compatible with the future F-47 fighter and B-21 Raider stealth bomber, according to a sources sought notice posted Wednesday on SAM.gov.
The notice, issued by the Air Force Life Cycle Management Center’s weapons office at Eglin Air Force Base, Florida, is not a solicitation but a market research tool to identify firms capable of producing a system with “similar or improved capabilities” to the SiAW. Responses are due March 19.
The SiAW is a supersonic air-to-ground missile designed to rapidly strike mobile targets, including integrated air defense systems, ballistic missile launchers, GPS jammers and antisatellite systems in contested environments.
The Air Force awarded Northrop Grumman a $705 million contract to develop and test the SiAW in September 2023, following an initial phase that also included Lockheed Martin and L3Harris. Northrop Grumman delivered the first SiAW test missile to the Air Force in November 2024, and completed a successful F-16 separation test in December 2025.
The sources sought notice lists platform compatibility requirements that include the F-35, F-16, F-47 and B-21. This marks the first time the F-47, Boeing’s Next-Generation Air Dominance fighter, has appeared by name in a public Air Force acquisition document tied to a specific weapon system. The F-35 is the initial platform for the SiAW, and the Air Force has previously indicated the B-21 bomber may also carry the weapon.
The SiAW program is currently executing a Middle Tier Acquisition Rapid Prototyping phase. The notice calls for a 48-month period of performance from contract award, with a first production lot delivery targeted for 2030. Fiscal 2026 budget documents show prototype development is slated to continue through the first quarter of fiscal 2027.
Required capabilities outlined in the notice include extended standoff range, an advanced antiradiation seeker capable of targeting frequency-agile and low-probability-of-intercept radar systems, precision GPS/INS navigation with antijamming capabilities, robust electronic counter-countermeasures and the ability to reattack. The Air Force is seeking production capacity of up to 600 all-up-rounds per year with a 15-year service life requirement.
The outreach comes as Operation Epic Fury against Iran has heightened concerns about munitions stockpiles and industrial base capacity, according to a Center for Strategic and International Studies report published Thursday.
The notice does not explain why the Air Force is seeking alternate sources for a SiAW equivalent, or whether identifying additional vendors could affect the Northrop Grumman program.