Boeing and Northrop Grumman have submitted their final proposal for future work on the Ground-based Midcourse Defense (GMD) element of the United States' ballistic missile defense system.

Following proposal submission, the companies released the following statement:

"Our final proposal for the GMD development and sustainment contract represents the best our companies have to offer for the future of the ballistic missile defense program.

"We are confident that our offer maintains mission readiness and demonstrates flexibility for this next phase of the program's lifecycle.

"The final proposal is the culmination of a process that brought together a broad industry group - selected for extensive heritage GMD expertise - to deliver the best value and lowest risk to the customer.

For the past two years, we have worked to prepare an expansive proposal building on our experience as GMD's industry leader and outlining innovative solutions and a cost-effective approach to program management and execution.

"We stand ready to execute immediately upon contract award with the world-class team that designed, developed and currently supports this national security capability.

"As GMD remains the nation's only defense against long-range ballistic missile threats, Boeing and Northrop Grumman are proud of our partnership with the Missile Defense Agency and remain committed to ensuring GMD is ready, reliable and affordable."