The U.S. Missile Defense Agency released Jan. 19 a draft solicitation for the Ground-based Midcourse Defense (GMD) Development and Sustainment contract expected to be worth around $600 million a year. No date was given for the final request for proposals.

Boeing Defense, Space & Security of St. Louis has been the prime contractor on the nation’s primary strategic missile shield since 1998, responsible for system development and operations as well as sustainment of missile defense installations in Alaska and California.

Lockheed Martin, Northrop Grumman and Raytheon all have said they intend to challenge Boeing for the new contract, which the Pentagon expects to award in early 2011.

The Missile Defense Agency is holding an industry day Feb. 5 in Huntsville, Ala., to discuss the procurement with interested bidders.