Bad weather Wednesday forced the military to scrub the first full flight test of its national missile defense system (search) in nearly two years.

"It is just heavy cloud cover," Rick Lehner, a spokesman for the Missile Defense Agency (search), said of conditions Wednesday evening off the Alaskan coast.

The launch was being put on hold for 24 to 48 hours.

The $85 million test comes as the military is in final preparations to activate missile defenses designed to protect against an intercontinental ballistic missile attack from North Korea (search) or elsewhere in eastern Asia.

During the test, a target missile will be launched from Kodiak Island, Alaska, and an interceptor missile will fire from Kwajalein Island in the central Pacific Ocean.

Because the launches will test several new aspects of the missile defense system, Lehner said the interceptor actually shooting down the target is not a primary goal of the mission.

The test is the first in which the interceptor uses the same booster rocket that the operational system uses, Lehner said.

Two previous tests scheduled for this year were delayed due to technical problems. In earlier testing, which critics derided as highly scripted, the interceptors went five-for-eight when launched with the goal of hitting target missiles.