There Are Limits on Sea-Based NMD

By Commander John M. Pollin, U.S. Navy
  • Obviate the need for forward, land-based radars
  • Allow for earlier engagements of missiles, and consequently a higher kill probability
  • Reduce the strategic consequences of single system failure
  • Provide operational flexibility in response to strategic requirements, for example, in moving at-sea forces to defend against particular threats, or defending against "depressed trajectory" launches
  • Offer an alternative to multiple land-based sites

Unfortunately, in their enthusiasm to present the capability of Aegis ships in the most favorable light, some authors have allowed misrepresentations about future naval capabilities to be digested by the media and the public at large. There is, for example, an implication that this powerful defense may be ready for the nation shortly, or be of little added expense to the taxpayer. On the other hand, opponents argue against using warships in strategic missile defense, saying that such single-mission tasking would rob the Navy of many of its numerous and critical roles within the framework of sea control. Fortunately for the nation, the truth lies somewhere "twixt the wind and the water," as the saying goes. A comprehensive discussion of the limits of sea-based NMD should not dissuade naval enthusiasts. Rather, it should arm them appropriately, and ensure that future discussions of the naval role in missile defense will be fact based—which in the long run will prove profitable.

We should begin by reminding ourselves that the seabased national missile defense concept is based on the evolution and amplification of the Navy Theater Wide (NTW) ballistic missile defense program. Navy Theater Wide defends a very large battlespace: it offers the largest defended footprint of theater-level systems, allows engagements at very high altitude (in fact, exclusively exoatmospheric intercepts), and is capable of engaging ballistic missiles in the ascent phase. These NTW capabilities:

  • Mitigate the "ground effects" caused by the detonation of chemical and biological weapons
  • Extend the engagement envelope to a theater-wide level, and significantly enlarge the defended area footprint
  • Allow overland engagements, thus potentially pulling strategic regions of the world, such as Israel and Japan (see Figure 1), into a naval missile envelope
  • Offer reengagement opportunities

The argument then can be made that by improving the interceptor missile, the kill vehicle atop the interceptor, the battle management/command, control, and communications (BM/C3) suite, and radar—and the associated fire control signals to and from the interceptor—and by placing Aegis cruisers and destroyers strategically along an anticipated ballistic missile flight path, the existing Aegis fleet can deliver to the nation a sea-based NMD.

Yet, the course to achieve this capability is not quite as simple, quick, or cheap as some would have us think. Limits on sea-based NMD include:

  • Programmatics
  • Operational limitations
  • Cost
  • Anti-Ballistic Missile (ABM) Treaty implications

Programmatics . The programmatic requirements associated with Navy Theater Wide are vast and complicated. Engaging an intercontinental ballistic missile (ICBM) successfully will require the ability to launch an interceptor missile with enough initial velocity to rise into the exoatmosphere and stop the extremely fast, opposing ICBM. The current NTW program will use an SM-3, but this interceptor would have only limited defensive capabilities against threats to the national territory. It probably would not produce a successful intercept of a sophisticated ICBM, although it would be acceptable versus a medium-range or short-range (and therefore theater-level) threat. What will be needed for sea-based NMD is an interceptor of higher initial velocity—and that interceptor has not yet been identified.

The interceptor kill vehicle will require a very sensitive infrared sensor, a refined divert and attitude control system, a heavy and hardened kill vehicle, and the ability to communicate with a modified Aegis combat system. To date, the kill vehicle has been neither developed nor funded. Full evolution from the Navy Theater Wide Block II SM-3 to a sea-based NMD missile for strategic defense will be a large engineering challenge.

The AN/SPY-I radar—which was never intended for ballistic missile tracking—may need to be upgraded to allow it to conduct high-power target detection, discrimination, and engagement in the exoatmosphere. ICBMs are being designed today to dislodge decoys as the warhead travels in the exoatmosphere. Inability by the radar to distinguish valid targets from decoys may doom any potential engagement of these types of missiles. Fortunately, Congress is aware of many of the technical requirements associated with challenging radar operations, and the Fiscal Year 99 Authorization Bill includes $50 million for pursuing SPY-1 upgrades. Obviously, the Navy must exploit modeling and simulation techniques in addition to conducting live hardware and software testing and experimentation, but this represents a solid beginning for the naval ballistic missile defense efforts in general. The key will be for Congress and the administration to fund radar and associated weapon control system modifications on a consistent basis throughout future years to help build a coherent acquisition strategy.

There also may be sensor and BM/C3 applications to the combat system that would eliminate the need for SPY-1 in the detect-to-engage sequence for ballistic missiles. Broad shipboard BM/C3 upgrades may be needed to allow rapid and accurate assimilation of long-range satellite information, intelligence reports, and data and targeting updates. This will alter the current Aegis combat system configuration, specifically in the Aegis display, command and decision, and weapons control system computers. Much will depend on the future of external systems that can be networked and linked to the Aegis combat system. Again, experimentation and modeling should be exploited to determine the optimum battle management suite for the ships.

Satellite information—first to provide cueing but perhaps later also to provide fire-control data to the ship's combat system and interceptors—must be fielded to support full sea-based firepower. Satellite support to the entire sea-based NMD architecture seems nonnegotiable, and this unique interoperability requirement may prove to be a frustrating limiting factor. If, for example, the satellite system is not developed along the same timeline, or to the same capability as the shipboard weapon component, the envisioned defensive architecture as a whole might be compromised. Ultimately, Navy leaders will have to determine what the combat system suite and associated missile will look like for sea-based NMD.

Finally, a sea-based NMD architecture would derive from the Navy Theater Wide Block II, which would be an upgrade to the currently funded NTW Block I. The earliest that Block I would be fielded is 2007. Any follow on Block II system would be fielded later—discussions today suggest 2010 as a possible date. An evolved seabased NMD, then, is not a near-term alternative.

Operational limitations . It has been only within the past few years of battle group operations that the Navy has begun to address ballistic missile defense. (The first battle-group level ballistic missile defense exercise occurred during the 1994 Kitty Hawk [CV-63] battle group deployment—and that was simply to establish track management and reporting connectivity among the Vincennes [CG-49], Cowpens [CG-63], and Kitty Hawk and to develop lessons learned.) We recently have begun to incorporate ballistic missile defense concepts into our operational taskings, but even then, we address only theater-level operations. We have not, as a warfare community, explored the implications of future strategic-level sea-based defense. And our operational taskings in general remain more than moderately foreign to our sister services. The Navy will need a forum in which to conduct NMD scenarios within a context of battle group operations. Using the lessons learned from these and continued scenarios, the surface community can begin to develop a body of proven tactics that, ultimately, will provide the framework of any national level strategic sea-based NMD doctrine.

Sea-based NMD will require us to be more fully integrated with the other services, in particular the Air Force, and in no small way, with other nations. In combined-arms ballistic missile defense, Israel and Japan almost assuredly will be both future users of and contributors to any potential sea-based missile defenses; we also may find ourselves integrating South Korea and some of the more advanced NATO countries into data link and track reporting functions. These contributions by our allies may help our ships to extend the engagement timelines or to expand our reengagement envelopes against ballistic missiles, perhaps even ICBMs. The Navy will have to build on existing combined-arms operations to exploit fully what our allies may be able to offer. Today, however, we are considerably limited in combined-arms doctrine in general and combined-arms ballistic missile defensive doctrine in particular. Future efforts at joint and combined ballistic missile defense argue firmly for an aggressive program to develop doctrine before the weapon systems arrive. The Navy should be able to demonstrate to our civilian leaders that we have considered the procedures that will lay the keel for any eventual national-level missile defense strategy should they decide that a sea-based NMD is worthwhile.

Finally, the number of Aegis warships that would have to be patrolling on station to serve as a dedicated strategic defense still is being determined. Numbers between four and nine have been offered recently, but these figures are based on modeling and simulations, and are subject to debate. Yet the idea behind the number requirements is simple. The ship positioning to optimize organic sensor coverage and engagement envelopes will have to be generally along the line of trajectory of an ICBM to reduce the crossing aspect or angle to the minimum and to allow for maximum reengagement opportunities. For example, to protect the U.S. West Coast, given the current Asian threat, would require a number of warships operating in the Northern Pacific, an area that we transit en route to Japan but rarely patrol. (Figure 2 offers a general view of relative ship positioning. A May 1998 Report to Congress on sea-based NMD contains classified diagrams suggesting a number of strategic positions where the Navy might maintain dedicated NMD-tasked ships.)

Having been driven to the littorals by the demise of the Soviet Union and its blue-water navy, the increasing requirement for naval forces in "edge of war" scenarios with coastal nations, and the doctrine outlined in ". . . From the Sea" and "Forward . . . from the Sea," the surface forces now may find themselves back in open waters. The need to maintain ships in specific regions for sustained periods may result in a profound revision of deployment schedules, cause planners to rethink our current battle group configurations, alter normal patrol regions, and dilute the massive firepower available in LAMPS III/SQQ89(V)/Tomahawk-capable ships. At minimum, battle group staffs still must deal with:

  • Tactical- and operational-level antisubmarine warfare
  • Broad area antisurface operations
  • Area air defense command requirements
  • Strike planning
  • Evolving requirements, such as psychological operations or special force integration

These requirements may be harder to fulfill if multimission ships cannot be counted on to participate in the traditional battle group. Evidence does suggest, however, that when off-board sensor support is available to the NMD patrolling ships, the need to restrict their patrol areas can be reduced substantially.

Cost . Over the past few years, some members of the Navy, as well as some policy analysts, have gone on record stating that the United States could have a workable seabased national missile defense in three to five years for about $3 to $4 billion. This is an alluring figure, indeed. It is, however, starkly at odds with the report to Congress generated by the Ballistic Missile Defense Organization (BMDO), which asserts that a more reasonable total cost for accelerating the Navy Theater Wide system to make it available by fiscal year 2006-2008 for a strategic application would be approximately $16 billion:

The post FY97 [research, development, test, and evaluation] procurement and military construction for the land-based NMD capability . . . is estimated to cost between $13B to $14B. Alternatively, a stand-alone seabased architecture that could protect all 50 states is estimated to cost $16B to $19B (a rough order of magnitude estimate that includes the cost of 3-6 Aegis DDG-51 ships and a $700M estimate for [an upgradable missile] which is not currently budgeted). ("The Utility of a Sea-based National Missile Defense," Report to Congress, May 1998, p. 3)

Given that Navy Theater Wide Block II still is a conceptual program, with as yet undefined milestones, and has not had its Defense Acquisition Board review, the Navy would be wise to consider the larger, rather than the smaller, dollar amount as operative.

ABM Treaty . Article V[1]—"Each party undertakes not to develop, test, or deploy ABM systems or components which are sea based, air based, or mobile land based"—simply dismisses the use of warships for other than theater-level ballistic missile defense. NTW, as currently envisioned, is treaty compliant, but expanding on its potential to serve strategic purposes, unless portions of the treaty were renegotiated or amended, likely would put the United States in violation. So the enthusiasm for a sea-based NMD might be dampened by the reality of current restrictions explicit in the ABM Treaty. In addition, the treaty might not limit just the United States: the potential future use of Japanese Aegis destroyers in a strategic role (certainly not beyond the limits of imagination in the years ahead) could very well be interpreted as noncompliant and therefore disagreeable to our treaty partners (currently understood by the Clinton administration as Russia, Ukraine, Belarus, and Kazakhstan).

Also restrictive to the Navy at this point are the so-called New York demarcation agreements. Rarely discussed and sometimes misunderstood, these protocols restrict the initial velocity of an interceptor (called the burn-out velocity or vbo) to below 3 km/sec. High-speed interceptors (high speed meaning having an initial vbo above 3) fired at an intercontinental ballistic missile would be considered a treaty violation. Thus, at some point, developing a sea-based NMD architecture might require the United States to confront our treaty partners over portions of the demarcation agreements, too.

Toward a Considered Decision

On 15 September 1998, at a seminar on ballistic missile defense attended by academicians, members of the Japanese Maritime Self-Defense Force, Israeli Defense Force, and Turkish Army, and House National Security Committee Research and Development Subcommittee Chairman Curt Weldon (R-PA), then-Speaker of the House Newt Gingrich (R-GA) articulated his vision for future ballistic missile defense. Admitting that he was not a technician, but rather a citizen who views the world as an "integrated market," he conjured a future in which:

  • Spaced-based sensors provide the fire-control information to assist interceptors in flight
  • Navy warships establish the front line of missile defense
  • Strong joint service and combined operations exploit the best technologies from within the U.S. defense establishment as well as those of the international community
  • U.S. cities no longer are completely vulnerable to ICBM attack

Our tradition of navalism, forward deployment, and power projection, and the impressive legacy of success that the Aegis combat system has given our surface fleet may propel the Navy into the forefront of ballistic missile defense. Certainly the current Navy Area and Navy Theater Wide ballistic missile defense programs enjoy strong and enthusiastic bipartisan support in Congress. The former Speaker of the House may well have articulated, in layman's terms, the strategic defenses in which naval officers of the next generation will participate. His vision and the general support of Congress for the Navy's two existing programs should be welcomed by the Navy. However, the third potential system, a sea-based national missile defense evolved from Navy Theater Wide Block II, has limitations that would have to be addressed by the Navy's leadership. Given careful articulation of reasonable and responsible goals for any future strategic defense from the sea, national leaders will be able to make a considered decision on whether sea-based NMD is, in fact, workable, worth the cost, and consistent with our overall naval strategy.

Commander Pollin is a congressional liaison at the Ballistic Missile Defense Organization. He served in the Aegis cruisers Leyte Gulf (CG-55) and Vincennes (CG-49) and as Officer in Charge of the Aegis Training Unit at Moorestown, New Jersey.



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