A Pentagon office charged with evaluating proposed U.S. weapons systems reported to Congress in February that missile defense systems scheduled to be fielded in 2004 have not yet been proven to work.
As part of its annual assessment of weapons programs that are under development, the Pentagon’s office of Operational Test and Evaluation reviewed the status of the Missile Defense Agency’s ground-based midcourse defense system, sea-based system, Airborne Laser (ABL), and Theater High Altitude Area Defense (THAAD).
Thomas Christie, director of the operational test and evaluation office, wrote that the ground-based defense, which is designed to destroy warheads launched atop long-range ballistic missiles traveling through outer space, “has yet to demonstrate significant operational capability.”
Last December, President George W. Bush ordered that the initial fielding of this system begin in 2004 to “add to America’s security and serve as a starting point for improved and expanded [missile defense] capabilities later.” Bush also called for the deployment, by the end of 2005, of up to 20 missile interceptors based on ships to shoot down short- and medium-range ballistic missiles. (See ACT, January/February 2003.)
Christie identified three “major” testing limitations of the ground-based system. He pointed out that past testing has relied on a transmitter on the target for tracking purposes, has involved “unrealistic engagement[s] at relatively low altitudes,” and has been conducted with a rocket booster that accelerates more slowly than the one to be used in a final system.
Earlier Pentagon plans called for incorporating a more powerful booster in intercept testing in the first few months of 2001, but that is now scheduled to take place at the end of this year at the earliest. The new booster must still be selected from two competing versions this summer.
An independent review of the ground-based system released in November 1999 expressed concern that the system’s exoatmospheric kill vehicle (EKV)—a sensitive, light-weight device that is carried into space by the booster to seek out and collide with an incoming warhead—might not be able to withstand the shock loads of a more powerful booster. The review, conducted by the so-called Welch Panel, noted that the estimated shock loads of a new booster would be more than 10 times as great as those caused by the booster used in intercept testing.
In the eight intercept attempts to date, five of which resulted in the target’s destruction, the booster and EKV are launched toward the general area where, using data from the target’s transmitter, an intercept is projected to take place. The Missile Defense Agency (MDA), which oversees research and development of all missile defense programs, defends this practice by contending that there is no radar available in the testing area to perform the necessary tracking and that the EKV, after separating from its booster, does not receive any data from the transmitter.
MDA is seeking to develop a mobile, sea-based radar by late 2005. If MDA succeeds, the radar would presumably obviate use of the transmitter.
Test intercepts have all occurred approximately 220-240 kilometers above the Earth’s surface with the target and EKV coming together at a combined velocity of roughly 26,000 kilometers per hour. The similarity of all the tests reflects test-range constraints and prohibitions against creating space debris.
Christie noted that the testing limitations he cited “are not the result of [MDA’s] conscious decisions to minimize the test program, but result from an effort to gain early insight into system design at a reasonable pace and cost.”
In addition to addressing the testing limitations he had noted, Christie called on MDA to employ more realistic targets and countermeasures. He noted that balloon decoys used in past testing “were not intended to be representative of actual countermeasures, but to increase the number of objects to be tracked, without over-stressing the ground sensor or kill vehicle discrimination capabilities.”
Christie further recommended that MDA reduce the amount of information that the EKV is given about the target before the test. In testing to date, the EKV is provided details on the target and decoys so it can distinguish between them. Future tests “should reflect the operator’s imperfect knowledge of the characteristics of the threat,” Christie stated.
Status of Other MDA Programs
MDA’s sea-based system succeeded in all three of its intercept tests in 2002, but Christie observed that the “flight test engagement geometries, scenarios, and timelines were non-stressing.”
To make sea-based testing more challenging, Christie underscored the need to use a target that has a warhead which separates from its booster, a step MDA plans to take. The past three tests have involved a target that stays in one piece, making it easier to track and hit.
Although sea-based testing has been conducted from the actual ships tabbed for missile defense missions in the future, the report cautioned that the system could only be deployed “in an emergency with limited expectation of success.”
The ABL and THAAD programs, both of which are designed to counter short- and medium-range ballistic missiles, are even further behind in development.
ABL is to be tested for the first time against a ballistic missile target at the end of 2004, while THAAD’s next intercept test is set for the last months of 2005. THAAD tallied two hits and six failures in intercept testing between 1995 and 1999 before being put under redesign.
Neither ABL nor THAAD is advanced enough to be deployed even in an emergency. Christie noted that there is “no ABL emergency capability apart from some passive detection capabilities” and THAAD “has no operational capability because there is no deployable hardware.”