December Missile Defense Tests Yield One Success, One Failure

Wade Boese

The Pentagon conducted two missile defense tests in December, including a successful intercept attempt by the ground-based midcourse system and a failed test of the system’s prototype booster, which ended abruptly when the rocket went off course and had to be destroyed roughly 30 seconds after launch. Both tests were repeats of successful tests this past summer.

Following two test postponements caused by poor weather at the target launch site of Vandenberg Air Force Base, California, the Pentagon successfully hit a target warhead December 3 with an exoatmospheric kill vehicle (EKV) carried into space by a booster fired from the Kwajalein Atoll in the Marshall Islands. The EKV and target collided at a combined speed of approximately 26,000 kilometers per hour about 240 kilometers above the Pacific Ocean.

The intercept was the second in a row for the ground-based midcourse system and the third hit in five total attempts since October 1999. Accompanied by a large balloon decoy, the mock warhead flew the same trajectory as in the previous four intercept tests.

Lieutenant General Ronald Kadish, who oversees U.S. missile defense programs as head of the Ballistic Missile Defense Organization (BMDO), told reporters November 30 that the test was structured to mimic previous ones so that the Pentagon could build confidence in the system and work out any problems before moving to harder tests.

Kadish acknowledged that the test involved some “artificialities” that BMDO intends to eliminate eventually in later testing. For example, as a substitute for radars required for an operational system, the mock warhead is equipped with both a C-band transponder and a global positioning system (GPS) beacon, which provide information on where the target is.

This information is used as “truth data” to verify that the missile defense system’s tracking of the warhead is correct and to formulate the initial weapons task plan, which is used to guide the interceptor to a general area where the intercept is projected to take place and where the EKV separates from its booster. Once the EKV separates, it is not supposed to use data from the transponder or GPS beacon but is supposed to rely on information provided by a prototype radar based at Kwajalein and then, in the final seconds before intercept, use its own infrared sensors to collide with the target. A post-test Pentagon press release stated “only system-generated data was used for the intercept after the EKV separated from its booster rocket.”

The booster used in the test, however, is only a surrogate for the actual booster that is to be part of an operational system. Although initial BMDO plans called for including the actual booster with the EKV in this latest intercept test, booster development is far behind schedule.

On December 13, the booster that will eventually be used in the midcourse system flew in its second flight test, which testers aborted shortly after launch when the booster flew off course and had to be destroyed for safety reasons. The test failure came only hours after President George W. Bush announced the United States would withdraw from the Anti-Ballistic Missile Treaty because it hinders U.S. missile defense testing. (See DOD Mulls Missile Defense Test Site; Plan Could Violate ABM Treaty.)

In its first flight test on August 31, which was originally scheduled for February 2000, the booster stayed on course despite a problem with its vehicle roll control, which helps stabilize the missile in flight. A BMDO spokesman stated December 17 that it is unknown why the booster strayed in the latest test.

During his November 30 briefing, Kadish projected the actual booster would not be used in an intercept attempt for at least another five to eight intercept tries. This estimate may be further delayed because of the December 13 failure.

The next booster flight test is currently not scheduled. Boeing, which is the lead contractor for the ground-based midcourse missile defense system, is slated to pick a second company in January to develop an alternative booster in case the current one is scrapped.

Until the actual booster is completed, BMDO will continue intercept attempts using a surrogate booster, which accelerates much slower than the one planned for a final system.

The next intercept attempt is tentatively set for February or March. Kadish ventured it may be made more challenging than previous tests by employing additional or more realistic decoys, although that remains undecided.