Weather delays missile defense test for 2nd night

WASHINGTON (CNN) -- Inclement weather forced the government to postpone the fifth test of its ground-based missile interceptor on Sunday night, a day after bad weather forced the Pentagon to scrub its originally scheduled test.

The new test is scheduled to begin Monday between 9 p.m. and 1 a.m. ET, the Pentagon said. The mission will only proceed if weather conditions improve and "meet range safety requirements."

The statement said the Ballistic Missile Defense Organization will conduct the test in support of the Ground-based Midcourse Defense program, formerly known as the National Missile Defense system.

Two previous attempts to intercept an in-flight missile have failed and two have been successful.

The so-called "hit to kill" test will not involve any explosives on the "kill vehicle." Instead, the kinetic energy from one rocket hitting another will be counted on to destroy the target.

The test target will be launched from Vandenberg Air Force Base, home to the Air Force's 30th Space Wing, heading about 4,800 miles from the central Californian coast into the central Pacific Ocean.

EXTRA INFORMATION How missile defense works

Defense officials hope a ground-based interceptor missile, launched from the Reagan Missile Defense Test Site on Kwajalein Island in the Marshall Islands, will hit the test target about 144 miles above the Earth.

The test will simulate a long-range intercontinental ballistic missile in midcourse -- in effect, "two small objects going ... close to 15,000 mph and trying to collide with one another," said Air Force Lt. Gen. Ronald Kadish, head of the missile defense program.

In a Friday news conference, Kadish insisted a test failure should not be interpreted as a failure of the entire program.

"We are learning about the system," he said. "We will make corrections as a result of any anomalies, and we continue to test to build our confidence and learn more until such time as we feel confident to do operational testing against more realistic targets and realistic scenarios."

The target area is "measured in centimeters, not meters or feet," he said. "So that's the challenge that we have tomorrow and it's the same one that we have been using since we started these integrated flight test attempts."

Some critics have questioned the Defense Department's classification of two previous tests as successful, citing "unrealistic condition."

If Sunday night's test proceeds as planned, the next test is expected to take place in February.