By Wade Boese
The Pentagon destroyed a mock strategic warhead in space October 14 with a ground-launched missile defense interceptor for the fourth consecutive time. Nearly identical to prior intercept trials, the latest test’s only new wrinkle was the addition of a ship-based radar operating in a shadow mode, meaning it observed but did not aid the intercept.
Delayed almost two months while program officials replaced rocket motors on the interceptor’s two-stage booster, the October test improved the ground-based midcourse missile defense system’s record to five hits in seven tries. A booster problem caused one of the system’s two misses, in July 2000.
Following the pattern of earlier tests, the Pentagon launched a target missile from Vandenberg Air Force Base in California over the Pacific Ocean and, roughly 20 minutes later, an interceptor from Kwajalein Atoll in the Marshall Islands. Approximately six minutes after being launched, the interceptor’s exoatmospheric kill vehicle (EKV), which uses its own onboard sensors and data from a Kwajalein-based radar to seek out the target, collided with the mock warhead, obliterating it more than 225 kilometers above the Earth.
Preprogrammed with information on the target’s characteristics, the EKV selected the right target from among three decoys, believed to be one large and two small balloons, as used in the system’s March 15 test. A couple months after that test, the Missile Defense Agency (MDA) decided to classify certain information on its future tests, including decoy details.
Lieutenant General Ronald Kadish, who heads MDA, explained in June that keeping decoy information secret was intended to prevent potential adversaries from learning how to counter a U.S. missile defense system. Democratic lawmakers, however, have objected to the new secrecy, arguing that the move lessens outside scrutiny of the missile defense program and helps insulate MDA from charges of employing simple decoys that do not resemble the mock warhead. That practice makes it easier for the EKV to discriminate between the target and decoys.
Although the Pentagon hailed the October test as the first strategic missile defense test to involve a U.S. ship, the USS John Paul Jones, the naval vessel played no active role in the intercept. The 1972 Anti-Ballistic Missile (ABM) Treaty, from which the United States withdrew in June, ruled out using sea-based systems or components to track or shoot down strategic missiles.
Having abrogated the ABM Treaty, the Bush administration is now exploring whether a sea-based missile defense system under development to protect against theater ballistic missiles, which was permitted by the 1972 accord, has any utility against long-range ballistic missiles. Past Pentagon reports concluded that the Aegis AN/SPY-1 radar used on the John Paul Jones and similar ships would not be able to support an expanded mission due to its limited detection and tracking ranges.
An MDA spokesperson said October 22 that a complete test analysis has not yet been completed, but that preliminary evidence suggests the ship’s radar performed “quite well.” The ship was stationed approximately 500 kilometers from Vandenberg Air Force Base and tasked with gathering information on the target in its boost and midcourse phases of flight.
MDA plans call for deploying at least one ship to track targets in all future tests of the ground-based midcourse missile defense system. According to the MDA spokesperson, the ship will be limited to an observing role for the next test, which may occur before the end of the year.
The upcoming test, formally referred to as IFT-10, is the last in which MDA expects to use a surrogate two-stage booster to carry the EKV into space. A new three-stage booster, which will accelerate much faster than the surrogate booster and put more stress on the EKV, is expected to be integrated into intercept testing after MDA selects a model from two competing versions, one by Lockheed Martin and the other by Orbital Sciences Corporation. The two companies are scheduled to flight-test their boosters next summer or fall, meaning that after IFT-10 there will not be a strategic missile defense intercept test until late next year.
Development of the three-stage booster has been significantly delayed. Initially, the Pentagon planned to flight-test the booster three times between February and July 2000 and then integrate it into intercept tests in the first few months of 2001. But the booster’s first flight test did not occur until August 2001, and a second one failed shortly after launch in December 2001.
Boeing, the primary contractor for the U.S. ground-based midcourse missile defense program, was developing the three-stage booster itself, but earlier this year it awarded Orbital Sciences a contract to develop an alternative booster and let Lockheed Martin take over work on the Boeing version.