The U.S. Air Force, which awarded two contracts in August to mature designs for the Ground-based Strategic Deterrent (GBSD), plans to hold the program’s first major review in October, a program official said Sept. 28.

The system requirements review will ensure the prime contractors, Boeing [BA] and Northrop Grumman [NOC], fully understand the system’s requirements, said Col. Heath Collins, the Air Force’s GBSD program manager. 

A system functional review will follow about a year later and will ensure that lower-level requirements are defined, Collins told reporters after speaking at a Capitol Hill conference on the nuclear triad. A preliminary design review will occur in fiscal year 2020.

In August, Boeing and Northrop Grumman received technology maturation and risk reduction contracts valued at $349.2 million and $328.6 million, respectively, over three years.

The Air Force plans to award a single engineering and manufacturing development (EMD) contract to one of the companies in late 2020. A request for proposals for EMD will be released in 2019.

GBSD will replace the Air Force’s aging, nuclear-armed Minuteman III intercontinental ballistic missile (ICBM). Flight testing is expected to begin in the mid-2020s.