Test Drive

Will a planned defense shield defeat real missiles?

Join Our Community of Science Lovers!

Perhaps as early as this month, President George W. Bush is expected to declare that a handful of prototype missiles in California and Alaska are ready to protect the U.S. from long-range missile attacks. The Pentagon calls the system a "test bed," one that still needs more sophisticated radar, interceptors and space-based lasers to realize Ronald Reagan's dream of a "Star Wars" antimissile program. The Defense Department, however, maintains that it can defeat North Korea's small arsenal of long-range missiles--a claim that may be hard to swallow given the limited number of tests done so far.

The ground-based midcourse defense system, as it is called, will start off with no more than 10 "hit-to-kill" interceptors designed to collide directly with incoming missiles in space. To date, the program has intercepted target missiles in five of eight heavily scripted tests.

But critics say those trials prove little. The Union of Concerned Scientists, in a report released earlier this year, concluded that the initial system ¿will be ineffective against a real attack¿ and also slammed the administration for ¿irresponsible exaggerations¿ about its abilities. In June opponents in Congress tried unsuccessfully to postpone deployment on grounds that the system should be tested further. During a Senate debate, Senator Barbara Boxer of California likened the plan to the Wizard of Oz, who ¿was scary, but when you pull back the curtain, it was just some little guy,¿ she said.


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


The Pentagon's Missile Defense Agency (MDA) has long held that live tests, which are costly, difficult to plan, and limited by range and safety concerns, are not the only means of proving the system's efficacy. According to the Pentagon, sophisticated modeling, simulations and exercises can offset the paucity of real intercepts. In April, Air Force Lt. Gen. Ronald Kadish, then head of the MDA, told Congress: ¿We use models and simulations, and not flight tests, as the primary verification tools.¿

But the Center for Defense Information's Philip Coyle, the Pentagon's top tester during the Clinton administration, argues that such technology ¿simply doesn't capture the basic physics and the variables in a missile defense engagement.¿ His successor under Bush, Thomas Christie, told Congress in March that such virtual assessment is ¿not a good substitute for integrated system testing.¿ And the Pentagon's Defense Science Board, a high-level advisory group, concluded in a May report that the MDA's current models and simulations are ¿legacy¿ items that are ¿not well designed to fit together.¿ As a result, Coyle says, the military will be ¿operating blind¿ once the program is up and running. The science board also stated that the MDA models of the system's ability to discriminate between actual targets and decoys are ¿oversimplified.¿

Richard Matlock, named the MDA's first director of modeling and simulation after the science board report was released, says current models ¿do a very good job at predicting the performance of system components.¿ But the report did confirm the need to enhance those models as missile defense evolves, he remarks. According to the MDA, an aggressive evaluation program will occur over the next few years as the test bed is upgraded. ¿We will constantly improve our capabilities through operationally realistic testing,¿ an MDA spokesman comments. ¿We can't operationally test the system until we put it into place.¿

That will happen shortly before voters decide between Bush and presidential candidate Senator John Kerry of Massachusetts, who says missile defense research is important but believes the Bush approach has not been sufficiently tested. The Pentagon asserts that the timing of the deployment is a coincidence, but opponents are skeptical. ¿I believe that's a big part of the push for deployment this year,¿ Coyle says.


Daniel G. Dupont edits InsideDefense.com, an online news service. He wrote about the threat of high-altitude nuclear explosions in the June issue.

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American

Subscribe