Mixed Results in U.S. TMD Tests

Wade Boese

In July tests of two U.S. theater missile defense (TMD) systems, the Pentagon tallied two successes and suffered one failure. The Army's Patriot Advanced Capability-3 (PAC-3) missile struck low-altitude drone targets in two separate intercept tests, while the Navy Theater Wide (NTW) system experienced a booster failure during a flight test.

The United States, in addition to developing a national missile defense (NMD) to defend against strategic ballistic missiles, is pursuing several programs to counter non-strategic ballistic and cruise missiles. These TMD systems are aimed at protecting U.S. military forces in the field and at sea, as well as U.S. allies, from regional missile attacks.

On July 22 and 28, the PAC-3 system tracked and destroyed low-altitude drone targets acting as surrogates for cruise missiles. The tests marked the fourth and fifth consecutive intercepts by the Patriot system, which is a "hit-to-kill" system requiring a collision with the target to destroy it. The first successful intercept, which was not a test objective, occurred March 15, 1999, with two successful tests following on September 16, 1999, and February 5, 2000.

Originally designed as an air defense missile, the Patriot system evolved into a missile defense system after being pressed into service during the 1991 Persian Gulf War to help defend against Iraqi Scud missiles. The Patriot's record against the Scud is disputed but is now recognized as being significantly less successful than initially touted. The latest version of the Patriot is intended to intercept short- to medium-range ballistic missiles, cruise missiles, and aircraft within the atmosphere.

Eleven more PAC-3 missiles will be tested against "various classes of targets," according to the Pentagon, with the next test tentatively scheduled for September 21. Pentagon plans call for completing the flight tests by next fall.

Navy Theater Wide

In its second flight test, which was conducted July 14, the NTW system's SM-3 missile failed to achieve separation between its second- and third-stage boosters. The test was the first involving the third-stage booster, which will carry a kinetic warhead designed for exoatmospheric collisions with missile warheads. The failed test did not involve a target.

NTW's first flight test was designed to test the first two stages of the system's booster. That test took place September 24, 1999, and was successful, according to the Pentagon.

NTW is a ship-launched system building upon the Aegis combat system, which employs a high-powered radar capable of conducting simultaneous multiple missile tracking and guidance operations. Intended to counter medium- and long-range theater ballistic missiles, the NTW system, when completed, will also provide a capability to "effect ascent phase intercepts" if deployed near a missile launch site, according to the Ballistic Missile Defense Organization. A Navy spokesman said ascent phase describes the time from rocket motor burnout to apogee, but does not include the boost phase.

Many congressional critics of the Clinton administration's proposed limited NMD view a sea-based option for boost-phase intercepts as integral to a more robust national missile defense. Secretary of Defense William Cohen and other Pentagon officials contend that a boost-phase capability will not be ready for at least 10 years. The Navy Theater Wide system falls within the guidelines for permitted missile defenses set forth in a 1997 protocol to the ABM Treaty that differentiates permitted theater missile defenses from prohibited strategic missile defenses.

Navy officials are still trying to determine what went wrong in the July 14 test and hope to complete their investigation by early September. The Navy spokesman said it is unclear whether the next test, not yet scheduled, will try to repeat the last test's objective or proceed as planned to the next testing objective. Pentagon plans originally scheduled the first intercept attempt to occur after the next test.