This brief is adapted from a longer article by Joseph Cirincione in Inside Missile Defense, September 6, 2000.

Sea-based national missile defense systems have become the most discussed and least understood of all proposed missile defense projects. Proponents assert that Aegis destroyers and cruisers can quickly and inexpensively provide a highly effective defense.


In fact, sea-based national defense systems face major technological uncertainties, cannot be deployed for at least a decade and could prove prohibitively expensive.


The Closer You Look, the Farther Away It Gets


As technical problems mount with the Clinton administration’s plans for ground-based missile defense interceptors, there is new interest in this old idea.


There has never been a shortage of missile defense proposals, but each, upon closer examination, proved fatally flawed. The original Strategic Defense Initiative program went through space-based X-ray lasers, chemical lasers and particle-beam weapons, ground-based free-electron lasers, ground-based interceptors, space-based kinetic-kill vehicles, and a smaller KKV dubbed "Brilliant Pebbles," among others.


All were generously funded. None worked. In short, space- and sea-based systems proposed in the waning days of the previous administration were hardly the ready-to-go weapons that advocates now fondly remember.


One if by Land


This is why the Administration chose the land-based option for deployment. It was not the ideal system, just the most technically feasible. It promised a relatively quick deployment compared to the decade needed for sea-based options and decades for any space-based plan.


Land-based, midcourse intercept systems are clearly not the most desirable missile defenses. Since the early 1960s, experts have recognized that land-based systems can be overwhelmed by barrage attacks, defeated by decoys and other countermeasures, and blinded by attacks on vulnerable radar systems. Serious students of missile defense have long recognized that it is far preferable to attack missiles in their ascent, or boost-phase, when they are slow, fat and hot, than in the midcourse, when the warhead is fast, small, and cold.

The problem has been basing. Boost-phase intercepts can only be effected from ranges close to the missile’s launch site. Despite tens of billions of dollars spent during the Bush and Reagan administrations, it proved impossible to package these capabilities into satellites. Ships offer an appealing, but ultimately illusory, compromise.


Two if by Sea


The Navy has two proposed systems. The Navy Theater Wide, the larger system, would field a new Standard Missile 3 with a kinetic, hit-to-kill warhead designed to attempt intercepts outside the atmosphere in the midcourse of an intermediate-range ballistic missile’s flight. A Ballistic Missile Defense Organization (BMDO) report in 1998 warned against congressional efforts to accelerate deployment of the system through increased funds and mandated requirements, arguing that even on the planned schedule, "the ability of the KW [kinetic warhead] to ‘kill’ its target, remains a complex challenge."


BMDO then estimated deployment could begin in 2005. Since then, funds have steadily increased and schedules have steadily slipped. The Navy now believes it can field a system in 2010.


Even so, this weapon remains high-risk. The General Accounting Office (GAO) points out in a May report that there is "significant technical and schedule risks in the program." Initial operational testing would not begin until 2010, even though all of the required 80 missiles would be produced and delivered then. Such high concurrency essentially guarantees that the system will have cost overruns, schedule delays, and deploy substandard system elements. Worse, by siphoning off defense dollars and ship assets for a system that, at best, will deliver only marginal military benefits, the pursuit of national missile defense schemes at sea could cause real harm to our national defense.


Kill Vehicle, Jr.


This "buy before fly" approach might be justified if the system was a minor modification to the Aegis as some claim. But it is not as simple as adding a room to an existing house. It is more like replacing your oil burner with a nuclear reactor.


Among the technical risks are:


1. Discrimination. Since 1982, even in highly controlled tests, only four of 15 interceptors have successfully hit their targets outside the atmosphere. The GAO notes that it remains uncertain if upgrades to the AN/SPY-1 radar on Aegis ships can give it the capability to detect a warhead at all.

2. Lethality. The Standard missile will use a Lightweight Exo-Atmospheric Projectile (LEAP) that is smaller than the warhead on the ground-based interceptor. BMDO officials are concerned that it might not be able to "see" the target through the debris cloud created by its own divert and attitude control system, and, if it does, whether it has enough force to destroy the target.


In addition, the system would need a completely different missile and kill vehicle if it were to attempt boost-phase intercept. A new BMDO study outlines concepts for developing three new missiles, each larger and faster than the current missile, building to a missile with a velocity of 6.5 kilometer per second.

This still may not be powerful enough and fast enough to attempt boost-phase intercepts, which is why some analysts have argued for development of a special barge or cargo ship that could carry the type of large missile necessary. In any event, these remain just concepts, years away from design, testing and deployment.

3. There is also the very serious issue of vulnerability. Sea-based missile defense systems are almost certain to come under attack by any foe contemplating a nuclear attack on the United States. Any nation capable of deploying nuclear-armed missiles would be capable of launching attacks against the Aegis ships by aircraft, cruise missiles, short-range ballistic missile, as well as mines and clandestine attack. Destruction of the ship would not be necessary, just a serious enough attack to divert the ship’s assets from missile defense to self-defense.

4. Finally, the operational requirements for sea-based, boost-phase missile defense would be formidable, perhaps overwhelming. There is approximately a 180-second window between the time a launch is detected and an interceptor must be launched in order to have any chance of intercepting a missile in boost-phase. This may require that sailors stay on high-alert, 24-hours a day, seven days a week. It is unclear whether this extremely rapid reaction mode could be sustained even for weeks during a crisis.

Lt. Gen. John Costello, the commander of the Army Space and Missile Defense Command, recently warned that the sea-based option couldn’t be realistically deployed until the end of this decade and space-based defenses couldn’t be considered until the end of the next decade. A Navy boost-phase system, he said would require "a major reworking" of the Aegis system and 12 million lines of computer code that drives the system, as well as significant structural changes in the ships themselves.


He argues, for example, that the vertical launch system aboard the ships is not big enough or sturdy enough to withstand the stresses from launching the types of high-energy interceptors needed for boost-phase intercept.


"When you boil all this down," Costello says, "what you end up with is this: the only NMD options that can be deployed in the near term – by 2005, and frankly that date is even a little in question – is the land-based option. No other option, no matter how much money is thrown at it, is possible before the end of the next decade."


It is also worth remembering the words of former BMDO Director Air Force General Lester Lyles. In directly rebutting the claims of the Heritage Foundation that effective sea-based missile defenses could be rapidly deployed, he told the Senate last year, "When someone advertises a system as ‘quick, cheap or easy,’ it seldom is."