DATE=1/14/2000 TYPE=BACKGROUNDER TITLE=MISSILE DEFENSE TEST NUMBER=5-45252 BYLINE=JIM RANDLE DATELINE=PENTAGON CONTENT= VOICED AT: /// Eds: Test set for some time after 9pm EST Tuesday /// INTRO: U-S efforts to build a nation-wide defense against ballistic missiles face a key test next Tuesday. Engineers hope their defensive missile can track and destroy another missile high above the Pacific Ocean. Supporters say the program is a vital defense against missiles launched from rogue countries such as North Korea. Critics say U-S domestic politics make it likely the system will be approved regardless of the test results. V-O-A's Jim Randle reports from the Pentagon. TEXT: A senior defense official says Tuesday's effort will begin when an intercontinental ballistic missile thunders into space from a launch pad in California. About 20 minutes later, a second missile will be launched from an island in the mid-Pacific, to find the first missile and crash into it at more than 20- thousand kilometers per hour. The proposed U-S National Missile Defense, (or N-M- D),.uses satellites to spot the fast-moving, searing heat of a missile launch, and new kinds of ground- based radar to track the weapon through space. Pentagon experts say N-M-D uses a swift, three-stage rocket to hurl a small robot spacecraft on a suicidal collision course with the target. The spacecraft is called a "kill vehicle" and it is about a meter and a half tall, and weighs about the same as a small man. A brand new, powerful computer is supposed to take all of the sensor information, and repeatedly calculate ever more accurate predictions of the course, speed, and altitude of the target. This information is designed to allow defenders to get the kill vehicle reasonably close to the target. Once in space, the kill vehicle uses heat sensors, telescopes and a computer to track the target, and small rocket thrusters to maneuver on a collision course. Testing the new radar systems, the "battle management" computer - and hitting the target -- are major goals of Tuesday's 100-million dollar exercise. The new test comes as critics say Pentagon officials exaggerated the success of a previous test last October. In that case, the navigation system broke down, and critics say the weapon relied on "luck" to strike its target. A senior defense official denies that, and says the point of tests is not to hit every target, but to find and fix flaws in the staggeringly complex system. Pentagon spokesman Ken Bacon says the tests are also supposed to give the president enough information to decide if the government will spend the many billions of dollars needed to develop and build the system. /// Bacon Act /// This is a very high priority program. We are working very hard in this building to give the president the information he needs from the technical side to make a decision. /// End Act /// That decision is expected next June. If approved, the system would consist of one hundred missile interceptors and take about five years to build. /// Begin Opt /// The National Missile Defense is designed to cover all 50 U-S states. A smaller scale system - called Theater Missile Defense - could put a defensive umbrella over a small country. But the T-M-D program has been troubled by a string of embarrassing test failures, and is not yet ready to deploy. The Patriot Missile system has been used in battle (the Gulf war of 1991) against crude Iraqi Scud missiles with limited success. Defense experts say the Patriot system has since been upgraded, and may be able to defend a city or an airfield against short-range missile attack. /// End Opt /// Defense expert John Pike of the Federation of American Scientists says the president faces political as well as technical questions. /// Pike Act /// Even if this test fails though, there is so much political support in the Congress and growing support in the administration for deploying a missile defense, that I think even if this next test fails, that we are probably going to see President Clinton commit to deploy this system and they will hope to work out the bugs a few years down the road. /// End Act /// Many Republican members of Congress and candidates for president strongly support missile defenses, saying it is irresponsible not to build defenses against a threat that could kill millions of Americans if it is technically possible to do so. But critics say the task of hitting an incoming ballistic missile is so difficult that such defenses will not work, or can easily be fooled by decoys (fake warheads) launched with real warheads. Russian officials are sharply critical of the U-S plan, saying the missile defenses violate the 1972 Anti Ballistic Missile treaty that puts sharp limits on such systems. They say the system would cost billions of dollars and make Americans less safe by undermining the nuclear deterrence that has kept the peace over decades. (Signed). NEB/JR/JP 14-Jan-2000 17:16 PM EDT (14-Jan-2000 2216 UTC) NNNN Source: Voice of America .