The Department of Defense announced on July 5 that an intercept test earlier that day of the Ground-Based Midcourse Defense (GMD) missile defense system, which protects U.S. territory against long-range missiles, failed to result in a successful intercept.[1] The GMD version that was tested is the system that is already in the field; thus, this was an operational test, not a developmental test.

Unless the failure was due to a problem not related to the interceptor system—such as a failure of the test target missile—this is a serious setback for the GMD system. Further, the last successful test of the GMD system was in 2008, and the system has now achieved eight intercepts out of 14 attempts. Accordingly, the Missile Defense Agency (MDA) should maintain another option for defending U.S. territory against long-range missiles.

The Sea-Based Option for Defending the U.S.

Earlier this year, the House of Representatives included a provision in its version of the National Defense Authorization Act for fiscal year 2014 to move forward with fielding a long-range missile defense site along the East Coast. This could consist of GMD interceptors, but it could also include a modified version of sea-based Aegis missile defense system.

Currently, the Aegis system has been tested against only short-range and intermediate-range target missiles. However, retired Navy Vice Admiral J. D. Williams explains how even the current version of the Aegis standard missile interceptor, which is already deployed with surfaced ships in the fleet, could be modified to give it the capability to intercept long-range missiles in the late midcourse stage of flight.[2] This would require fielding forward-deployed radar or space-based tracking sensors and modernizing the command-and-control system.

The test record of the Aegis system is quite admirable. According to the MDA, the system is now 25 out of 31 in intercept tests since 2002, the last successful test being in May of this year.[3]

Preserving the GMD Program

This is not to say that the MDA should abandon the GMD system. At the moment, the GMD system, with interceptors fielded in Alaska and California, is the only fielded missile defense system that has demonstrated the basic ability to destroy long-range missile warheads headed toward the U.S. This was the position taken by four senior members of the House and Senate Armed Services Committees in a July 12 letter to Secretary of Defense Chuck Hagel in the aftermath of the unsuccessful test.[4]

The U.S. government cannot afford to leave the American people completely vulnerable to this threat. Secretary Hagel recognized this when he announced in March a plan to restore the full complement of GMD interceptors in Alaska and California to 44, the number proposed by President George W. Bush.[5] President Obama reduced to the number to 30 in 2009. The same can be said regarding the proposal of the House of Representatives to locate interceptors along the East Coast.

The problems with the GMD stem from a weakness with the basic technology. Both the GMD system and Aegis system use the same basic approach: to destroy the attacking missile or missile warhead with a direct hit and by the force of collision. The difference is that the Navy has pursued a more disciplined and effective development and testing regime with Aegis. GMD system program managers should be able to put their system back on track by replicating Aegis’s more disciplined regime.

GMD: Mend It—Don’t End It

Clearly, the U.S. needs a more robust missile defense capability for the protection of its own people and territory against long-range missiles. Despite the GMD’s recent failures, it is worth the investment to pursue both the Aegis system and the GMD system in parallel while improving both.

—Baker Spring is F. M. Kirby Research Fellow in National Security Policy in the Douglas and Sarah Allison Center for Foreign Policy Studies, a division of the Kathryn and Shelby Cullom Davis Institute for International Studies, at The Heritage Foundation.