Boeing and Northrop have submitted a final proposal for the US Missile Defense Agency (mda) ground-based midcourse defence (GMD) development and sustainment contract.

The contract involves development, manufacturing, testing, training, operations and sustainment support for the GMD element of the ballistic missile defence system.

Boeing has supported the MDA as the prime contractor for the GMD programme since 2001.

Boeing and Northrop are competing for the contract against a Lockheed Martin-led GMD team that also includes Raytheon, ATK Aerospace Systems and Harris Corporation among others.

GMD uses radars, command-and-control facilities, communications terminals and a 20,000-mile fibre-optic communications network to defend the US against long-range ballistic missile threats.