The U.S. military is exploring other options for expanding the coverage of its missile defense system if negotiations on locating a third ground-based interceptor site in Poland are not continued under President-elect Barack Obama.

"We are in discussions with the MDA [Missile Defense Agency] on alternatives if the discussions in Europe do not continue," says Air Force Gen. Victor Renuart Jr., head of both the North American Aerospace Defense Command and the U.S. Northern Command.

Alternatives could involve two-stage and three-stage interceptors, he told a National Defense Industrial Association luncheon in Washington today. Interceptors now based in Alaska and California are three-stage; those planned for Europe would be two-stage.

Russia opposes the so-called Third Site interceptor plan in Eastern Europe, and Russian leaders have threatened to base short-range ballistic missiles just across the Russian border. Bush administration and Pentagon officials argue the European site is needed to meet the threat from Iran, which Renuart speculates could have a "crude" intercontinental ballistic missile by 2012 to 2015.

Renuart, meanwhile, says he is pushing for tests of the Ground-based Midcourse Defense (GMD) system to become "more complex and more operationally focused". The last three tests involved operational crews, and increased the number of sensors used "to make the system as real as we can make it."

Earlier this year, during preparation for the FTG-05 intercept conducted on Dec. 5, the possibility of a North Korean missile test prompted the GMD system to "adjust the schedule, sensor package and software installation to get it more operational and away from a test," he says. It went back to a test when the Korean launch did not occur.

Western and South Korean commentaries have noted the possibility of a North Korean test this year as Six-Party talks faltered amid disagreements over de-nuclear verification issues in the North.

Although a test, FTG-05 involved both operational commands, Norad and NorthCom, and "operationally sound execution," says Renuart. The test was designed to show the system's ability to discriminate the warhead from a decoy. Although the decoy did not deploy as planned, the kill-vehicle sensors did discriminate the target from "junk", he says.

Meanwhile, Renuart says the operational commands are pushing for a policy decision on homeland cruise missile defense. "We need to grow the missile-defense umbrella to include cruise missiles," he says. "But we need a national decision first so we can determine the extent to commit investment dollars."

Investment decisions on new sensors are also required. The Distant Early Warning Line radars in northern Canada "is beginning to time out and structurally degrade," he says. A service life extension will keep them going to 2016, "when we need to be well down the road to a solution," which could include space-based or over-the-horizon radar, he says.