WASHINGTON — The defense policy bill signed into law by U.S. President Barack Obama Jan. 7 is generally supportive of the nation’s missile defense programs, but it will prevent the Pentagon from spending money in 2011 on a European missile shield until certain requirements are met, including firm agreements by European countries to host the necessary assets.

Numerous congressional hearings were held over the past year to analyze the overhauled plan to deploy a European missile defense system that was announced by the Obama administration in September 2009. The 2011 Defense Authorization Act supports the White House’s vision for the shield, calling it an “appropriate response to the existing ballistic missile threat from Iran to the European territory of [NATO] countries, and to potential future ballistic missile capabilities of Iran.”

The United States in 2006 first announced plans to field a system to protect European allies and deployed forces from ballistic missile attacks. The original plan would have placed 10 fixed-site interceptor missiles in Poland and a radar site in the Czech Republic. The Obama administration’s revamped plan, called Phased Adaptive Approach, calls for the deployment of interceptor-equipped Aegis ships to European waters and a radar system in southern Europe in 2011. Land-based derivatives of the Standard Missile-3 interceptor, which today is fired exclusively from ships at sea, would be deployed in Romania and Poland starting in 2015 and 2018, respectively.

Administration officials say the Phased Adaptive Approach will field an initial capability sooner than the previous plan, but detractors note that it will not be able to provide an additional layer of defense for the U.S. homeland until 2020, five years later than the previous plan.

The 2011 Defense Authorization Act bars the Pentagon from spending any money on the European missile shield in 2011 until any asset-basing agreements have been signed and ratified by the host nation and 45 days have elapsed from when the U.S. secretary of defense submits an independent analysis of alternatives for European missile defense that was prescribed by the previous year’s legislation. In addition, the Pentagon may not purchase any interceptors for European defense until the secretary of defense, advised by the director of operational test and evaluation, submits a report saying the interceptors have been demonstrated under operationally realistic conditions and have a high probability of being effective, the bill says.

The law will also require the U.S. Navy to submit by March 31 a report on any changes to its force structure requirements that would result from implementing the Phased Adaptive Approach.

The report will include an analysis of how many Aegis ships would be needed by each of the combatant commanders to meet ballistic missile defense requirements and whether the Navy will need to increase the total size of its fleet to do so.

Lawmakers also focused on the existing system that protects the U.S. homeland from ballistic missiles, the Ground-based Midcourse Defense (GMD) system. The GMD interceptors fielded in Alaska and California provide an adequate defensive capability against future long-range ballistic missile attacks from Iran, and the system will be enhanced when a U.S. radar is placed in southern Europe in 2011, the law says. Congress wants to ensure the GMD system is sustained in the long term, and the bill thus will require the Pentagon to submit an independent assessment of the system within 180 days of its enactment.

The secretary of defense would be required to select an entity outside the Defense Department to review the GMD force structure and inventory requirements; to analyze the costs and potential advantages of deploying additional interceptors; and to plan for funding continued development, testing and improvement of the system, the bill says.

Meanwhile, the law will limit Pentagon spending in 2011 on a joint missile defense project with Germany and Italy until the secretary of the defense makes a firm decision to produce the system. The Medium Extended Air Defense System (MEADS) has been in development for more than a decade and is planned to replace the U.S. Army’s aging Patriot air and missile defense system. MEADS completed its critical design review in August, but the Pentagon has yet to announce whether it will pay to produce the system.

The Pentagon will be allowed to spend no more than 25 percent of any MEADS research and development funds appropriated for 2011 until the secretary of defense submits in writing to Congress a decision to fully produce the system, the law says. No more than 50 percent of the appropriated funds could be obligated or spent until 30 days after Congress receives this |notification.

The secretary of defense’s report will contain a detailed explanation for proceeding with production of the system; a cost estimate from the Pentagon’s director of cost assessment and program evaluation; an analysis of alternatives to MEADS; a description of the planned schedule for development, production and deployment; and a description of how Germany and Italy will contribute to production and deployment.