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CIAO DATE: 5/99
Missile Defense Failures Offer Lessons
March 30, 1999
Monday’s failure of the Army’s Theater High Altitude Air Defense system (THAAD) to intercept a Scud-type target should provide us with a reminder of the inherent limitations of missile defense systems.
Based on current schedules and all available evidence it is reasonable to assume that if high-altitude, ballistic missile defense systems are used in combat they will fall far short of predicted effectiveness. It is unlikely that these 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, enemy engagement strategies, or defense of the territorial United States on unrealistic expectations of the protection these defenses will offer. Similarly, national security officials should realize that any feasible national missile defense system would, at best, offer only partial protection and cannot fundamentally change the deterrent calculus.
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. After a congressional investigation, the Army revised its claims down from 96 percent to 52 percent, though noting that their data gave them high confidence in the destruction of only 25 percent of the Scud warheads.
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 Operations Committee.
The General Accounting Office review concluded that the strongest evidence supported a claim that Patriots hit only 9 percent of the 45 Scud warheads engaged. 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 contributed to the high failure rate.
The Historic Test Record
With the latest THAAD failure, the track record for tests of high-altitude interceptors should indicate caution in projections of future capabilities. Of 16 high-altitude intercept attempts since 1982, only 2 have hit, for a 12 per cent success rate. No tests have been successful since 1992. It is unlikely that all future intercepts will fail, but 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.
Prospects for Current Systems
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, and scored a success its first system test in March 1999. The Navy Area-Wide 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, thought these are significantly behind the Patriot is development time tables
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 sub-munitions 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 with ranges from 1000 to 3,500 kilometers. Few nations hostile to the United States currently have such missiles, but this is the threat represented by systems 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, THAAD and the Navy Theater-Wide system, have been disappointing. While both systems are technically feasible, THAAD has failed in all six of its test intercept attempts, and the Navy has gone zero for four.
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 plans for fiscal years 1999 through 2003. The Navy plans to use surplus Terrier missiles as targets for the Theater-Wide tests.
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. The NMD schedule is much shorter than most other major system acquisition programs, allowing only a limited amount of flight test data before the Deployment Readiness Review decision set for June 2000. By that time, there will have been 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.
By comparison, the only other U.S.-based ballistic missile defense system, the Safeguard ABM system, had an acquisition schedule twice as long. It had 111 flight tests, compared to only four tests planned before the June deployment decision. The General Accounting Office notes that the one system-level test will not be comprehensive because it will not include all system elements, and will not assess the NMD system’s capabilities against realistic threats. Similarly, the Pentagon’s Director of Operational Test and Evaluation is sharply critical of the test plans in his annual report to Congress, concluding it is “highly unlikely” that there will be enough realistic testing to support a deployment decision by June 2000. He notes, in particular that the planned targets do not represent the likely threats, do not include several likely counter-measures, will test against only one warhead at a time, “are not representative of the full sensor requirements spectrum (e.g., discrimination requirements),” and do not have flight paths that can duplicate the 7-km re-entry speeds of actual warheads.
Even if a NMD system worked as planned, a system of 100 ground-based interceptors with space-based sensor satellites will be very limited. 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”
Despite the prowess of American technology and the passionate politics surround this issue, there are no quick, cheap or easy solutions in missile defense. Military commanders and defense planners should proceed with low expectations for 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 $30 billion planned for missile defense efforts over the next seven years and the savings allocated to more pressing defense needs
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