Pentagon: Missile defense test successful

A vapor trail from the missile test as seen from Northridge, California, on Friday.

WASHINGTON (CNN) --The Pentagon's Missile Defense Agency said its sixth test of its missile defense system Friday was a success, meaning it intercepted an intercontinental ballistic missile in space about 30 minutes after it was launched.

The Ground-based Midcourse Defense system was formerly known as the National Missile Defense system. Pentagon officials called Friday night's test a "major step" in the U.S. Missile Defense Agency's test program.

They said this test was similar to a December 3 test, which resulted in a successful missile intercept. But in this case, the latest ballistic missile carried three decoy balloons designed to confuse the "exoatmospheric kill vehicle," the device that seeks out the ballistic missile. In the December test, only one decoy was deployed.

Pentagon officials said the performance of all systems involved -- including ground and space-based radars, sensors and the interceptor itself -- will be examined in the coming days.

Step by step

The first phase of Friday night's test was the launch of a modified Minuteman intercontinental ballistic missile from Vandenberg Air Force Base in California at 9:11 p.m. EST. About 20 minutes later and 4,800 miles away, an interceptor was launched at 9:32 p.m. from Kwajalein Atoll in the Republic of the Marshall Islands.

The kill vehicle separated from its rocket booster more than 1,400 miles from the target warhead.

After separation, the interceptor used its on-board infrared and visual sensors, augmented with the X-Band radar data provided by Battle Management, Command Control and Communications (BMC3) via the In-flight Interceptor Communications System, to locate and track the target.

Sensors aboard the interceptor also successfully selected the target instead of the decoys. Only system-generated data was used for the intercept after the EKV separated from its booster rocket.

A C-band transponder aboard the target warhead did not provide any tracking or targeting information to the interceptor after the interceptor was launched. The intercept took place about 10 minutes after the interceptor is launched, more than 140 miles above the central Pacific Ocean.

It will take about a week for experts to analyze the data and decide whether all test objectives were met.

Previous test results

The first intercept test of the GMD system research and development program, on October 3, 1999, resulted in the successful intercept of a ballistic missile target.

The second test, on January 19, 2000, missed an intercept because of a clogged cooling pipe on the "kill vehicle," but officials said the launch did provide a good test of the integrated system of elements.

The third test, on July 8, 2000, missed an intercept because of unsuccessful separation of the "kill vehicle" from the booster rocket.

Both the fourth test, on July 14, 2001, and the December test successfully intercepted ballistic missile targets.