The U.S. Navy has anchored more securely its so-called Phased Adaptive Approach to European ballistic missile defense (BMD) thanks to this week’s international agreement to base Aegis-equipped ships at Rota, Spain, about 60 mi. northwest of Gibraltar.

The agreement between the U.S. and Spain comes about five months after the U.S. deployed the Ticonderoga-class guided-missile cruiser USS Monterery as the first U.S. Navy ship with the enhanced Aegis system in the Mediterranean as part of Phased Adaptive Approach.

Shortly after the ship deployed, Monterery Capt. Jim Kilby told Aviation Week in an exclusive interview that the updated Aegis system was working as it should and the system would prompt naval officers to think tactics and procedures for BMD and other missions.

And the Rota basing should play to U.S. strengths as the Navy figures out how to best deploy and employ the Aegis ships. “Basing at Rota will enable the Navy to better support U.S. objectives in North Africa and the Middle East,” says Loren Thompson, defense analyst for the Lexington Institute. “Aegis warships are now the centerpiece of U.S. theater missile defense plans, and may become an important part of the architecture with intercontinental ballistic missiles, too.”

In a statement about the basing agreement, U.S. Defense Secretary Leon Panetta said, “With four Aegis ships at Rota, the alliance is significantly boosting combined naval capabilities in the Mediterranean, and enhancing our ability to ensure the security of this vital region.”

Panetta also emphasized the importance of the BMD mission in the region.

“These ships will also support NATO’s critical efforts to build effective missile defense,” he said. “Alongside important agreements that were recently concluded with Romania, Poland, and Turkey, Spain’s decision represents a critical step in implementing the European Phased Adaptive Approach. The United States is fully committed to building a missile defense capability for the full coverage and protection of all our NATO European populations, their territory and their forces against the growing threat posed by ballistic missiles.”

Another major facet of the Phased Adaptive Approach is the Aegis Ashore system. The Missile Defense Agency last week awarded a $115.5 million sole source, cost-plus-award-fee/cost-plus-fixed-fee modification to Lockheed Martin for system adaptation efforts, site planning, transportation planning and technology initiatives. The total contract is now worth about $176.7 million.

The U.S. Navy has put such a high priority on the Aegis system and related BMD roles that the service recently restarted the DDG-51 Arleigh Burke-class destroyer production line to build more ships to support enhanced Aegis shields components. The service is planning an even more efficient system for BMD and ship defense — the Air and Missile Radar (AMDR) that is slated for redesigned Flight III Arleigh Burkes.

To make room for the additional Arleigh Burkes, the Navy cut the planned fleet size for new DDG-1000 Zumwalt-class destroyers from seven down to three.

The U.S. Government Accountability Office is now investigating that DDG-51 restart decision, with a report due in January.