How Will New Ballistic Missile Defense Systems Perform in Combat?

Joseph Cirincione
Senior Associate
Henry L. Stimson Center

Presentation to the AFCEA and U.S. Naval Institute Western Conference and Exposition
"Military and Naval Operations in the Information Age"

San Diego, 15 January 1998

Based on current schedules and all available evidence it is reasonable to assume that when the new, high-altitude, ballistic missile defense systems are used in combat they will fall far short of predicted effectiveness. It is unlikely that the systems will completely fail, but the evidence indicates that they will perform significantly below either tested or predicted kill rates. Military commanders, therefore, would be wise not to base troop deployments or enemy engagement strategies on unrealistic expectations of the protection these defenses will offer. Officials should consider reallocating the excessive funds devoted to overlapping and duplicative new systems and planning more realistic development schedules for missile defense efforts.

The evidence available includes:

  • the performance of the Patriot missile system in the Gulf War
  • the performance of high-altitude missile defense systems in tests to-date
  • current test plans for proposed systems prior to production and deployment

The Patriot Experience

In the United States, confusion over the Patriot’s performance in the Gulf War still fuels overly optimistic estimates of the effectiveness of new, proposed defensive systems. During the war, many believed that the Patriot had achieved a near-perfect intercept rate, as was reported initially from the battlefield and Washington. Claims were revised downwards from 96 percent in testimony to Congress after the war, to 80 percent, 70 percent, and--after a Congressional investigation in 1992--to 52 percent, though the Army report notes that destruction of only 25 percent of the Scud warheads is supported by evidence with high confidence levels.(1)

Independent evaluations are more pessimistic, concluding that the Patriot hit few if any Scuds during the war. These include assessments conducted by the Israeli Defense Force, the Congressional Research Service, the General Accounting Office, the Massachusetts Institute of Technology and staff of the Government Operation Committee.

The General Accounting Office review of the evidence in support of the Army claims revealed that, using the Army’s own methodology and evidence, a strong case can be made that Patriots hit only 9 percent of the Scud warheads engaged, and there are serious questions about these few hits. (2) The speed of the Scuds, the limitations of the Patriot missile system, and the confusion and targeting difficulties caused by the break-up of the Scud missile as it re-entered the atmosphere seem to have contributed to the high failure rate.

The Patriot missile, equipped with a new multi-mode seeker, failed in two out of three intercept tests conducted after the war. The Army declared it "operationally unacceptable." The new replacement interceptor missile, the ERINT, will not be fully tested and initially deployed until 1999. Until then, US forces cannot reliably intercept even the short-range Scuds encountered in the Gulf War.

Whatever the kill ratio attributed to Patriot, the few unclassified hard figures released by the Army should serve as a sobering reminder of how combat conditions can wreck havoc even on systems that perform well on the test ranges, as the Patriot did.

A total of 158 Patriot missiles were fired at fewer than 47 Scuds during the war:

  • 86 Patriots were launched at real Scud targets in Saudi Arabia and Israel, but
  • 30 per cent of the Patriots were launched as Scud debris mistaken for targets, and
  • 15 per cent of the Patriots were launched against false targets caused by radar backlobe and sidelobe interference (including one launched by accident in Turkey.)

The fragmentation and EMC problems were known at the time (the Scud fragmentation had been observed during the Iran-Iraq war) but were not included in deployment and operational planning for the Patriot nor were they included in any tests of the system.

The Historic Test Record

All the proposed new missile defense systems employ hit-to-kill interceptors. That is, unlike the Patriot interceptors, which used a proximity fuze and an explosive warhead to scatter pellet-size fragment in the path of the intended target, the new interceptors will attempt to hit the target head-on using the kinetic energy of the encounter to destroy the target.

The track record for test of hit-to-kill interceptors should indicate caution in projections of future capabilities. There have only been 20 intercept attempts conducted by the Department of Defense since 1982. Of these, only 6, or about 30 per cent, actually hit their targets. Worse, only two of the successful intercepts were against higher-altitude targets similar to those the new missile defense systems are intended to counter. Of 14 high-altitude intercept attempts only 2 hit, for a 14 per cent success rate. The low number of past tests and the weak success rate warrant deep skepticism for much success in the near future with the proposed systems.

The Current Test Record and Plans

Lower-Tier Systems

The most promising new system, the improved Patriot system, or PAC 3, is designed to intercept Scud-type missiles of the type now deployed by potential Third World adversaries. These 300- to 1000-kilometer-range missiles will represent a challenge, but one which the PAC-3 should be capable of intercepting. The new ERINT missile for the system successfully intercepted two targets (although at relatively short ranges) in a shoot-off with the Patriot multi-mode missile in 1993, but its has since undergone some design changes and has not had an intercept test since then. The PAC-3 had two flight test at White Sands in December 1997 (no intercepts were attempted). Five intercept attempt are scheduled during fiscal year 1998. The Navy Area-Wide (Lower Tier) system (an upgrade to the AEGIS radar system and Standard missile) and the multi-national MEADS program are also aimed at these lower-range threats. No tests of these systems are scheduled in fiscal year 1998.

Without realistic tests it is impossible to predict performance, but these lower-tier systems appear to hold out the best possibility of successfully intercepting the existing Third World missile threats armed with single warheads. (Missiles armed with submunitions released after the boost phase would defeat any known kinetic energy missile defense system.) They rely on previously developed radar and hardware systems and, because they intercept their targets within the atmosphere after any decoys deployed would have been stripped away, they do not encounter the difficult discrimination problems facing higher, outside the atmosphere interceptors. Countermeasures remain one of the major unsolved technical barriers to effective missile defense despite decades of effort.

Higher-Tier Systems

Potentially more threatening than Scuds are medium-range missiles that travel from 1000 to 3,500 kilometers. No nation hostile to the United States currently has such missiles, but this is the threat represented by systems reportedly under development in North Korea and Iran. Both the Administration and Congress favor developing systems to intercept these missiles, with Congress trying to force a faster development and deployment schedule. To-date, tests of the most promising candidates, the Army’s Theater High-Altitude Area Defense system (THAAD) and the Navy Theater-Wide (Upper Tier) system, have been disappointing. While both systems are technically feasible, THAAD has failed in all four of its test intercept attempts, and the Navy has gone zero for two.

These were tests against specially designed targets, with known trajectories and characteristics, well within the expected performance range of the systems. The THAAD tests were against Storm and Hera targets, which have a maximum range of about 750 and 1,100 kilometers, respectively. A suitable long-range target of 2,000 kilometers or more, does not yet exist, nor is funding currently in BMDO plans for fiscal years 1999 through 2003, according to General Accounting Office reports. The Navy plans to use surplus Terrier missiles as targets for the Theater-Wide tests.

THAAD is scheduled for three intercept attempts in the second, third and fourth quarters of fiscal year 1998, while the Navy Theater-Wide system will undergo two flight tests in the second and fourth quarter of the year. Despite the lack of success in the two programs or in previous intercept attempts over the past two decades, the last approved THAAD acquisition plan calls for significant production of deployment hardware almost 2 years before beginning independent operational testing to assess the system’s effectiveness. The current contracts for the THAAD system allow the award of a production contract after one successful intercept. The DOD Director of Operational Test and Evaluation has urged this condition be revised.

Similarly, the General Accounting Office is concerned that the number of test flights planned as the basis for entering the engineering and manufacturing development phase was reduced from 20 to 9 flights partly to stay on schedule. GAO recommended in December 1997 that the Secretary of Defense:

    direct BMDO to delay low-rate initial production of the THAAD system until after the Director, Operational Test and Evaluation, has certified, based on sufficient independent testing in an operational environment, that the system can meet its key performance requirements.(3)

National Missile Defense System

There have not yet been any intercept tests of the proposed National Missile Defense system (NMD) and few are scheduled before a deployment decision is to be made. Noting that the NMD schedule is shorter than most other major system acquisition programs, the General Accounting Office recently warned of the high risks inherent in the program:

    Because of the compressed development schedule, only a limited amount of flight test data will be available for the system deployment decision in fiscal year 2000. By that time, BMDO will have conducted only one system-level flight test, and that test may not include all system elements or involve stressing conditions such as targets that employ sophisticated countermeasure or multiple warheads. As a result, not all technical issues, such as discrimination, will be resolved by the time of the deployment review. Also the current schedule will permit only a single test of the integrated ground-based interceptor before production of the interceptor’s booster element must begin. If subsequent tests reveal problems, costly redesign or modification of already produced hardware may be required. (4)

By comparison, the only other U.S.-based ballistic missile defense system, the Safeguard, had an acquisition schedule twice as long as planned for the NMD program. Safeguard also had 111 flight tests, compared to only three intercept tests and one system-level flight test before a fiscal year 2000 deployment decision. The GAO notes that even this system-level test will not be comprehensive because it will not include all system elements, and:

    . . . the single integrated system test . . . will not assess the NMD system’s capabilities against stressing threats such as those that use sophisticated countermeasures or multiple warheads. The test is to be conducted against a single target with only simple countermeasures such as decoys. No test against multiple warheads is planned.

Even if everything in a NMD system worked as planned, a system of 100 ground-based interceptors with space-based sensor satellites might be able to intercept only a few warheads. Deputy Secretary of Defense John White reported to Congress in June 1996:

    If the number of threats increases or the complexity of the threats increases then this basic system is likely to provide poor protection of the U.S. This poor protection is due partly to a lack of sufficient discrimination capability against complex threats, which will cause the interceptor inventory to be depleted by shooting at warhead decoys, allowing some real warheads to penetrate the defense…The system is not designed to protect against an unauthorized launch which might contain a large number of warheads (e.g., a full load of warheads from a Russian SSBN).

Similarly, the National Defense Panel report, "Transforming Defense: National Security in the 21st Century," recommended a go-slow approach to national missile defense. NDP Chairman Philip Odeen said in a December interview:

    We think the technology just is not ready. To deploy a system now you are likely to have a not-very-effective system. And the threats have not developed. We think you have enough time, if you are smart about it, to deploy in time to protect yourself as these threats emerge. And the longer you wait, the better technology you are going to get. I think the hedging kind of concept the administration is following is the one we support.(5)


There are no plans to test either the THAAD, the Navy Theater-Wide or the NMD system against a realistic threats such as multiple warhead missiles that deploy warheads with decoys or jammers or that take minor twists and turns as they reenter the Earth’s atmosphere to evade defense. This should give military commanders and defense planners low confidence in the ability of these systems, if deployed, to provide their troops, the nation or US allies any appreciable degree of protection against longer-range ballistic missile threats. Defense planner should consider whether more realistic schedules and elimination of duplicative programs could reduce the approximately $20 billion planned for missile defense efforts over the next five years and the savings allocated to more pressing defense needs.

Joseph Cirincione is a Senior Associate at the Henry L. Stimson Center in Washington, D.C. He served for nine years as a national security specialist on the professional staff of the House Armed Services Committee and the Government Operations Committee. His research on missile defenses is on-line at

1. The Army evaluations were prepared by a small team of nine officials from the Patriot Program Office and related Army offices. The resulting reports remain the only official government assessment ever conducted on the Patriot's performance. Return to text.

2. "Operation Desert Storm: Data Does Not Exist to Conclusively Say How Well Patriot Performed," September 1992, General Accounting Office, NSIAD 92-340. Return to text.

3. "Ballistic Missile Defense: Improvements Needed in THAAD Acquisition Planning," General Accounting Office, NSIAD-97-188.Return to text.

4. "National Missile Defense: Schedule and Technical Risks Represent Significant Development Challenges," December 1997, General Accounting Office, NSIAD-98-28. Return to text.

5. "Inside Missile Defense," December 3, 1997.Return to text.