Order Code RL33745
Sea-Based Ballistic Missile Defense —
Background and Issues for Congress
Updated December 11, 2006
Ronald O’Rourke
Specialist in National Defense
Foreign Affairs, Defense, and Trade Division

Sea-Based Ballistic Missile Defense — Background
and Issues for Congress
Summary
In developing a global ballistic missile defense (BMD) system, the Department
of Defense (DOD) currently is modifying 18 Navy cruisers and destroyers for BMD
operations, and has placed a large BMD radar — the Sea-Based X-Band Radar
(SBX) — on a modified floating oil platform. The eventual role for sea-based
systems in the worldwide U.S. BMD architecture has not been determined. The issue
for Congress for this report is: What should be the role of sea-based systems in U.S.
ballistic missile defense?
Compared to other BMD systems, sea-based BMD systems offer potential
strengths and limitations. Potential strengths include the ability to conduct BMD
operations from advantageous locations at sea that are inaccessible to ground-based
systems, the ability to operate in forward locations in international waters without
permission from foreign governments, and the ability to readily move to new
maritime locations as needed. Potential limitations of sea-based BMD systems
include possible conflicts with performing other ship missions, higher costs relative
to ground-based systems, and vulnerability to attack when operating in forward
locations.
The Aegis BMD system in its current (i.e., Block 2004) configuration is
intended to track ballistic missiles of all ranges, including intercontinental ballistic
missiles (ICBMs), and to intercept shorter-ranged ballistic missiles. The current
configuration is not intended to intercept ICBMs. Current DOD plans call for
modifying 3 Aegis cruisers and 15 Aegis destroyers with the Aegis BMD capability
by the end of 2009. Future versions of the system are to include a faster interceptor
designed to intercept certain ICBMs. The Aegis BMD system has achieved seven
successful exo-atmospheric intercepts in nine test flights. Japan is acquiring the
Aegis BMD system; some other allied navies have expressed an interest in adding
BMD capabilities.
For FY2007, the Administration requested $1,031.9 million in research and
development funding for the Aegis BMD program; Congress appropriated $1,127.4
million — a $95.5-million increase over the requested amount.
The SBX has experienced technical issues that have delayed its movement from
Hawaii, where it currently is located, to its intended homeport of Adak, Alaska.
Potential issues for Congress regarding sea-based BMD systems include the role
of sea-based BMD systems in the eventual U.S. BMD architecture, whether to initiate
a program to fully replace the canceled Navy Area Defense (NAD) program for sea-
based terminal-defense operations, pacing and funding for Aegis BMD radar and
missile upgrades, and whether the Aegis BMD development approach offers potential
lessons for the ground-based midcourse development program. This report will be
updated as events warrant.

Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Rationale for Sea-Based BMD Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Potential Strengths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Potential Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Arms Control Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Aegis BMD Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Program Origin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Intended Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Aegis Ships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Modification Schedule and Initial Deployments . . . . . . . . . . . . . . . . . . 7
Development, Testing, and Certification . . . . . . . . . . . . . . . . . . . . . . . . 8
Program Funding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Potential Allied Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Sea-Based X-Band Radar (SBX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Technical Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Potential Other Uses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Potential Issues for Congress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Sea-Based Systems in Eventual BMD Architecture . . . . . . . . . . . . . . . . . . 11
Replacement for Navy Area Defense (NAD) Program . . . . . . . . . . . . . . . . 12
Aegis Radar Upgrades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
SM-3 Block II/IIA Missile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Kinetic Energy Interceptor (KEI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
CG(X) Cruiser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Development and Testing of Aegis BMD System . . . . . . . . . . . . . . . . . . . . 17
Potential Allied Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Legislative Activity for FY2007 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
FY2007 Defense Authorization Act (H.R. 5122/P.L. 109-364) . . . . . . . . . 19
House . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Senate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Conference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
FY2007 Defense Appropriations Act (H.R. 5631/P.L. 109-289) . . . . . . . . 23
House . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Senate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Conference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
List of Tables
Table 1. Aegis BMD Installation Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 2. ALI and Aegis BMD Flight Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Table 3. Aegis BMD Program Funding, FY1995-FY2011 . . . . . . . . . . . . . . . . . . 7

Sea-Based Ballistic Missile Defense —
Background and Issues for Congress
Introduction
In developing a global ballistic missile defense (BMD) system, the Department
of Defense (DOD) currently is modifying 18 Navy cruisers and destroyers for BMD
operations, and has placed a large BMD radar — the Sea-Based X-Band Radar
(SBX) — on a modified floating oil platform. The eventual role for sea-based
systems in the world-wide U.S. BMD architecture has not been determined. The
issue for Congress for this report is: What should be the role of sea-based systems in
U.S. ballistic missile defense? Decisions that Congress reaches on this issue could
affect U.S. BMD capabilities and funding requirements; the size, capabilities, and
operational patterns of the Navy and the other services; and the shipbuilding
industrial base.
The next section of this report provides background information on DOD’s sea-
based BMD systems. The section that follows presents potential issues for Congress
relating to these systems. The final section summarizes recent legislative activity on
the topic.
Background
Rationale for Sea-Based BMD Systems
Why do DOD plans for BMD include sea-based systems? What are the potential
strengths and limitations of sea-based BMD systems?

DOD’s overall BMD plan includes ground-based, sea-based, airborne, and
space-based systems, each of which have potential strengths and limitations. DOD
believes that a combination of these systems will provide a more capable BMD
architecture.
Potential Strengths. Potential strengths of sea-based BMD systems
compared to other BMD systems include the following:
! Advantageous locations at sea. Sea-based systems can conduct
BMD operations from locations at sea that are potentially
advantageous for BMD operations but inaccessible to ground-based
BMD systems.

CRS-2
! Base access and freedom of action. Sea-based systems can be
operated in forward (i.e., overseas) locations in international waters
without need for negotiating base access from other governments,
and without restrictions from foreign governments on how they
might be used.
! Visibility. Sea-based systems can operate over the horizon from
observers ashore, making them potentially less visible and less
provocative.
! Mobility. Navy ships with BMD systems can readily move
themselves to respond to changing demands for BMD capabilities or
to evade detection and targeting by enemy forces, and can do so
without placing demands on U.S. airlift assets.
Regarding the first of these potential strengths, there are at least four ways that
a location at sea can be advantageous for U.S. BMD operations:
! The location might lie along a ballistic missile’s potential flight path,
which can facilitate tracking and intercepting the attacking missile.
! The location might permit a sea-based radar to view a ballistic
missile from a different angle than other U.S. BMD sensors, which
might permit the U.S. BMD system to track the attacking missile
more effectively.
! If a potential adversary’s ballistic missile launchers are relatively
close to its coast, then a U.S. Navy ship equipped with BMD
interceptors that is operating relatively close to that coast could
attempt to defend a large down-range territory against potential
attack by ballistic missiles fired from those launchers.1 One to four
Navy ships operating in the Sea of Japan, for example, could attempt
to defend most or all of Japan against theater-range ballistic missiles
(TBMs)2 fired from North Korea.
1 The ship’s potential ability to do this is broadly analogous to how a hand casts a shadow
in a candle-lit room. The closer that the hand (i.e., the Navy ship) is moved to the candle
(the ballistic missile launcher), the larger becomes the hand’s shadow on the far wall (the
down-range area that the ship can help defend against ballistic missile attack). In BMD
parlance, the area in shadow is referred to as the defended footprint.
2 TBMs include, in ascending order of range, short-range ballistic missiles (SRBMs), which
generally fly up to about 600 kilometers (about 324 nautical miles), medium-range ballistic
missiles (MRBMs), which generally fly up to about 1,300 kilometers (about 702 nm), and
intermediate-range ballistic missiles (IRBMs), which generally fly up to about 5,500
kilometers (about 2,970 nm). Intercontinental ballistic missiles (ICBMS) are longer-ranged
missiles that can fly 10,000 kilometers (about 5,400 nm) or more. Although ICBMs can be
used to attack targets within their own military theater, they are not referred to as TBMs.

CRS-3
! If a Navy ship were equipped with very fast interceptors (i.e.,
interceptors faster than those the Navy is currently deploying), and
if that ship were deployed to an overseas location relatively close to
enemy ballistic missile launchers, the ship might be able to attempt
to intercept ballistic missiles fired from those launchers during the
missiles’ boost phase of flight — the initial phase, during which the
ballistic missiles’ rocket engines are burning. A ballistic missile in
the boost phase of flight is a relatively large, hot-burning target that
might be easier to intercept (in part because the missile is flying
relatively slowly and is readily seen by radar), and the debris from
a missile intercepted during its boost phase might be more likely to
not fall on or near the intended target of the attacking missile.
Potential Limitations. Potential limitations of sea-based BMD systems
compared to other BMD systems include the following:
! Conflicts with other ship missions. Using multimission Navy
cruisers and destroyers for BMD operations might reduce their
ability to perform other missions, such as air-defense operations
against aircraft and anti-ship cruise missiles (ASCMs), land-attack
operations, and anti-submarine warfare operations, for four reasons:
— Conducting BMD operations might require a ship to
operate in a location that is unsuitable for performing one or
more other missions.
— Conducting BMD operations may reduce a ship’s ability
to conduct air-defense operations against aircraft and cruise
missiles due to limits on ship radar abilities.
— BMD interceptors occupy ship weapon-launch tubes that
might otherwise be used for air-defense, land-attack, or anti-
submarine weapons.
— Launching a BMD interceptor from a submarine might
give away the submarine’s location, which might make it more
difficult for the submarine to perform missions that require
stealthy operations (and potentially make the submarine more
vulnerable to attack).
! Costs relative to ground-based systems. A sea-based system
might be more expensive to procure than an equivalent ground-
based system due to the potential need to engineer the sea-based
system to resist the corrosive marine environment, resist
electromagnetic interference from other powerful shipboard systems
and meet shipboard safety requirements, or fit into a limited space
aboard ship. A BMD system on a ship or floating platform that is
dedicated to BMD operations might be more expensive to operate
and support than an equivalent ground-based system due to the
maintenance costs associated with operating the ship or platform in
the marine environment and the need for a crew of some size to
operate the ship or platform.

CRS-4
! Ship quantities for forward deployments. Maintaining a standing
presence of a Navy BMD ship in a location where other Navy
missions do not require such a deployment, and where there is no
nearby U.S. home port, can require a total commitment of several
Navy ships, due to the mathematics of maintaining Navy ship
forward deployments.3
! Vulnerability to attack. A sea-based BMD system operating in a
forward location might be more vulnerable to enemy attack than a
ground-based system, particularly a ground-based system located in
a less-forward location. Defending a sea-based system against
potential attack could require the presence of additional Navy ships
or other forces.
! Rough waters. Very rough waters might inhibit a crew’s ability to
operate a ship’s systems, including its BMD systems, potentially
creating occasional gaps in BMD coverage.
Arms Control Considerations
Do arms control treaties limit sea-based BMD systems?
No arms control treaty currently in force limits sea-based BMD systems. 4
Aegis BMD Program5
What is the Aegis BMD program?
Program Origin. The Aegis Ballistic Missile Defense (Aegis BMD) program
is DOD’s primary sea-based BMD program. The program was created by the Missile
3 For more on the mathematics of Navy ship forward deployments, see CRS Report
RS21338, Navy Ship Deployments: New Approaches — Background and Issues for
Congress
, by Ronald O’Rourke.
4 The U.S.-Soviet Anti-Ballistic Missile (ABM) Treaty, which was in force from 1972 until
the United States withdrew from the treaty in 2002, prohibited sea-based defenses against
strategic (i.e., long-range) ballistic missiles. Article V of the treaty states in part: “Each
Party undertakes not to develop, test, or deploy ABM systems or components which are
sea-based, air-based, space-based, or mobile land-based. ” Article II defines an ABM
system as “a system to counter strategic ballistic missiles or their elements in flight
trajectory....” For more on the ABM Treaty, see CRS Report RL30033, Arms Control and
Nonproliferation Activities: A Catalog of Recent Events
, by Amy F. Woolf, coordinator, et
al. The United States withdrew from the ABM Treaty in 2002, according to the treaty's
procedures for doing so. For a discussion, see CRS Report RS21088, Withdrawal from the
ABM Treaty: Legal Considerations
, by David M. Ackerman.
5 Unless otherwise stated, information in this section is taken from an April 2006 Missile
Defense Agency (MDA) briefing on the Aegis BMD program — “Aegis Ballistic Missile
Defense, Aegis BMD Update and Plans, Briefing to the Future Naval Plans & Requirements
Conference,” Scott Perry, Aegis BMD [Program Office], April 26, 2006, 22 pp.

CRS-5
Defense Agency (MDA) in 2002. Earlier names for the program include the Sea-
Based Midcourse program, the Navy Theater Wide Defense program, and the Sea-
Based Upper Tier program. The program is the successor to earlier sea-based BMD
development efforts dating back to the early 1990s.6
The Aegis BMD program office is an MDA directorate that reports directly to
the director of MDA. MDA provides direction, funding, and guidance to the Aegis
BMD program office and is the acquisition executive for the program. To execute
the program, the Aegis BMD program office was established as a Naval Sea Systems
Command (NAVSEA) field activity. NAVSEA provides administrative support
(e.g., contracting, comptroller, and security) to the Aegis BMD program office.
Intended Capabilities. The Aegis BMD system in its current configuration
(called the Block 2004 configuration; see discussion below) is designed to:
! detect and track ballistic missiles of any range, including ICBMs,
and
! intercept short-, and medium-range ballistic missiles (SRBMs and
MRBMs above the atmosphere (i.e., exo-atmospherically) during
their midcourse phase of flight.
When tracking ICBMs, Aegis BMD ships are to act as sensor platforms
providing fire-control-quality tracking data to the overall U.S. BMD architecture.
The Aegis BMD system in its current configuration is not designed to:
! intercept intercontinental ballistic missiles (ICBMs) or
! intercept ballistic missiles inside the atmosphere, during either their
initial boost phase of flight or their final (terminal) phase of flight.
In contrast to the current configuration of the Aegis BMD system, the ground-
based midcourse BMD program, with interceptors based in Alaska and California,
is designed to intercept ICBMs in the midcourse phase of flight. Discussions
comparing the current configuration of the Aegis BMD system and the ground-based
6 The Aegis BMD program is the successor to the Aegis LEAP Intercept (ALI) Flight
Demonstration Project (FDP), which in turn was preceded by the Terrier Lightweight
Exo-Atmospheric Projectile (LEAP) Project, an effort that began in the early 1990s. Terrier
is an older Navy SAM replaced in fleet use by the Standard Missile. Although succeeded
by the Standard Missile in fleet use, the Navy continued to use the Terrier missile for
development and testing.
As mentioned in an earlier footnote (see section on arms control considerations), the ABM
Treaty, which was in force until 2002, prohibited sea-based defenses against strategic (i.e.,
long-range) ballistic missiles. Navy BMD development activities that took place prior to
2002 were permissible under the ABM treaty because they were not aimed at developing
technologies for countering long-range ballistic missiles.

CRS-6
midcourse program have not always noted this basic difference in the kinds of
ballistic missiles they are intended to intercept.
Aegis Ships. The Aegis BMD system builds on the capabilities of the Navy’s
Aegis ship combat system, which was originally developed for defending ships
against airborne, surface, and subsurface threats.7 The Aegis system was first
deployed by the Navy in 1983 and has been updated several times since. The part of
the Aegis combat system for countering airborne threats is the called the Aegis
Weapon System. Key components of the Aegis Weapon System relevant to this
discussion include the following:
! the SPY-1 radar — a powerful, phased-array, multifunction radar
that is designed to detect and track multiple targets in flight, and to
provide midcourse guidance to interceptor missiles;
! a suite of computers running the Aegis fire control and battle-
management computer program; and
! the Standard Missile (SM), the Navy’s longer-ranged surface-to-air
missile (SAM), so called because it was first developed many years
ago as a common, or standard, replacement for a variety of older
Navy SAMs.8
The version of the Standard Missile currently used for air-defense operations is
called the SM-2 Block IV, meaning the fourth upgrade to the second major version
of the Standard Missile. The Navy is developing a new version of the Standard
Missile for future air-defense operations called the SM-6 Extended Range Active
Missile (SM-6 ERAM).
U.S. Navy ships equipped with the Aegis system include Ticonderoga (CG-47)
class cruisers and Arleigh Burke (DDG-51) class destroyers. A total of 27 CG-47s
were procured for the Navy between FY1978 and FY1988; the ships entered service
between 1983 and 1994. The first five, which were built to an earlier technical
standard, were judged by the Navy to be too expensive to modernize and were
removed from service in 2004-2005. The Navy currently plans to keep the remaining
22 ships in service to age 35.
A total of 62 DDG-51s were procured for the Navy between FY1985 and
FY2005; the first entered service in 1991 and the 62nd is scheduled to enter service
in late 2010 or early 2011. The Navy currently plans to keep them in service to age
35.
7 The Aegis system is named after the mythological shield carried by Zeus.
8 For more on the Aegis system and its principal components as originally deployed, see
CRS Report 84-180 F, The Aegis Anti-Air Warfare System: Its Principal Components, Its
Installation on the CG-47 and DDG-51 Class Ships, and its Effectiveness
, by Ronald
O’Rourke. (October 24, 1984) This report is out of print and is available directly from the
author.

CRS-7
Between 2010/2011, when the 62nd DDG-51 enters service, and 2021, when the
first of the 22 remaining CG-47s reaches age 35, the Navy plans to maintain a force
of 84 Aegis ships — 22 cruisers and 62 destroyers.
Sales of the Aegis system to allied countries began in the late 1980s. Allied
countries that now operate, are building, or are planning to build Aegis-equipped
ships include Japan (the first foreign buyer, with 4 destroyers in service and 2 more
under construction), South Korea (3 destroyers under construction or planned),
Australia (3 destroyers planned), Spain (4 frigates in service and 1 or 2 more
planned), and Norway (1 frigate in service and 4 more under construction or
planned).9 The Norwegian frigates are somewhat smaller than the other Aegis ships,
and consequently carry a reduced-size version of the Aegis system that includes a
smaller, less-powerful version of the SPY-1 radar.
Modification Schedule and Initial Deployments.
Modifications to
Aegis Ships for BMD Operations. Modifying an Aegis ship for BMD
operations involves making two principal changes:
! changing the Aegis computer program to permit the SPY-1 radar to
detect and track high-flying ballistic missiles; and
! arming the ship with a BMD version of the Standard Missile called
the SM-3 Block 1A.
A ship with the first modification is referred to as having a long-range search
and track (LRS&T) capability. A ship with both modifications is referred to as an
engage-capable ship. Modifying each ship reportedly takes about six weeks and costs
about $10.5 million.10
The SM-3 Block IA is equipped with a kinetic (i.e., non-explosive) warhead
designed to destroy a ballistic missile’s warhead by colliding with it outside the
atmosphere, during the enemy missile’s midcourse phase of flight. It is intended to
intercept SRBMs and MRBMs. An improved version, the Block IB, is to offer some
capability for intercepting intermediate-range ballistic missiles (IRBMs). The Block
IA and IB do not fly fast enough to offer a substantial capability for intercepting
ICBMs.11
A faster-flying version of the SM-3, called the Block II/IIA, is now being
developed (see discussion below). The Block II/IIA version is intended to give Aegis
BMD ships a capability for intercepting certain ICBMs.
9 Source: Jane’s Fighting Ships 2006-2007. Numbers of ships are planned eventual totals.
10 Jack Dorsey, “Navy On Front Line Of Missile Defense,” Norfolk Virginian-Pilot, Oct. 21,
2006.
11 Longer-range ballistic missiles generally fly faster than shorter-range ballistic missiles.
Consequently, intercepting a longer-range missile generally requires a faster-flying
interceptor than is required for intercepting a shorter-range ballistic missile. The SM-3
Block IA and 1B fly fast enough to intercept TBMs, but not fast enough to provide an
effective capability for intercepting ICBMs.

CRS-8
Modification Schedule. Current DOD plans call for modifying 18 U.S.
Aegis ships — 3 cruisers and 15 destroyers — with the Aegis BMD capability.
Table 1 shows the planned installation schedule as of October 2006. Under this
schedule, some of the 18 ships will be modified in two steps, with the LRS&T
capability being added first, and the SM-3 missile being added at a later point. Thus,
in Table 1, some ships shown as LRS&T ships in earlier years migrate to the engage-
capable category in later years. As can be seen in the table, the schedule calls for the
Navy to have 10 LRS&T ships plus 6 engage-capable ships by the end of calender
2006 — with all 16 ships reportedly to be based in the Pacific Fleet, at least for the
time being, according to one report12 — and 18 engage-capable ships by the end of
calendar 2009.
Table 1. Aegis BMD Installation Schedule
(as of October 4, 2006)
Cumulative total by end of calendar year
2004
2005
2006
2007
2008
2009
LRS&T ships
CG-47s
1
0
0
0
0
0
DDG-51s
5
9
10
8
1
0
Subtotal
6
9
10
8
1
0
Engage-capable ships
CG-47s
0
2a
3
3
3
3
DDG-51s
0
0
3
6
14
15
Subtotal
0
2a
6
9
17
18
Total LRS&T Engage-capable ships
6
11
16
17
18
18
Source: U.S. Navy data provided to CRS by Navy Office of Legislative Affairs, October
11, 2006.
a. Emergency (i.e., preliminary) engage capability.
Initial Deployments. LRS&T Aegis destroyers began operating in September
2004. Engage-capable Aegis cruisers began operating in September 2005.13
Development, Testing, and Certification. B l o c k D e v e l o p m e n t
Strategy. Consistent with the approach used for other parts of DOD’s BMD
acquisition effort, the Aegis BMD system is being developed and deployed in a series
of increasingly capable versions, or blocks, that are named after their approximate
anticipated years of deployment:
12 Jack Dorsey, “Navy On Front Line Of Missile Defense,” Norfolk Virginian-Pilot, Oct. 21,
2006.
13 The engage-capable cruisers conducted their first operations with an emergency (i.e.,
preliminary) version of the engagement capability.

CRS-9
! The current Block 2004 version includes the SM-3 Block IA missile
and a version of the Aegis computer program called Aegis BMD 3.6,
which allows the ship to perform BMD operations and other warfare
operations (such as air defense) at the same time. (The previous 3.0
version of the computer program did not permit this.)14 The Block
2004 version is intended to counter SRBMs and MRBMs.
! The Block 2006/2008 version is to include various improvements,
including the Block IB version of the SM-3 and the Aegis BMD
signal processor (Aegis BSP) — a radar signal and data processor
that improves the SPY-1’s ballistic missile target-discrimination
performance. The improvements are intended to, among other
things, give the system a limited ability to intercept IRBMs.
! The Block 2010/2012/2014 version is to include further
improvements, including the Block II version of the SM-3 around
2013, and the Block IIA version in 2015. The improvements are
intended to, among other things, give the system some ability to
counter ICBMs. This version will also incorporate changes intended
to make the system suitable for broader international ship
participation.
Flight Tests. From January 2002 through December 2006, the Aegis BMD
system has achieved seven successful exo-atmospheric intercepts in nine flight tests.
The ninth flight test, on December 7, 2006, was not successful, and was the first
unsuccessful flight test since June 2003.
Another CRS report, based on historical flight test data provided by MDA to
CRS in June 2005, summarizes early sea-based BMD tests as follows:
The Navy developed its own indigenous LEAP program, which flight tested
from 1992-1995. Three non-intercept flight tests achieved all primary and
secondary objectives. Of the five planned intercept tests, only the second was
considered a successful intercept, however. Failures were due to various
hardware, software, and launch problems. Even so, the Navy determined that it
achieved about 82% of its primary objectives (18 of 22) and all of its secondary
objectives in these tests.15
Regarding the Aegis BMD program’s development approach, the Aegis BMD
program office states:
We have an expression in the Navy and the Aegis BMD program, “test a little,
learn a lot.” Test more and more and more.... More importantly, the Navy has
chosen to work with the Test and Evaluation community to get the most
14 For further discussion of the multimission capability of the 3.6 program see Christopher
P. Cavas, “U.S. Warships To Get Missile Defense Upgrades,” Defense News, Oct. 9, 2006:
4.
15 CRS Report RL33240, Kinetic Energy Kill for Ballistic Missile Defense: A Status
Overview
, by Steven A. Hildreth.

CRS-10
operationally relevant scenarios we can. The [engage-capable Aegis cruiser]
USS Lake Erie, on our last few shots, was on a simulated patrol mission. It had
a window of vulnerability — read hours — that they could launch. That was all
the pre-alert they had, with the exception that the captain was notified of that
launch time for safety. Only the ships’ crews man the consoles; there are no
technicians there from outside to help the crew. The forward deployed [BMD-
equipped Aegis] ships are operating with this capability.16
MDA similarly states that:
The test program for Aegis BMD has focused on the philosophy of “test a
little, learn a lot” since its inception in the early 1990’s with the TERRIER
Lightweight Exo-Atmospheric Projectile (LEAP) Project. TERRIER LEAP
included four flight tests between 1992 and 1995, and was successful in
demonstrating that LEAP technology could be integrated into a sea-based tactical
missile for exoatmospheric ballistic missile defense.
The lessons learned from TERRIER LEAP evolved into the Aegis LEAP
Intercept (ALI) Flight Demonstration Project (FDP), the goal of which was to
utilize the Aegis Weapons System and Standard Missile 3 (SM-3) to hit a
ballistic missile in the exoatmosphere. The ALI test objectives were achieved
with two successful descent phase intercepts of a ballistic missile during Flight
Mission 2 (FM-2) and FM-3 in January 2002 and June 2002 respectively firing
an SM-3 from the [Aegis cruiser] USS LAKE ERIE.
The transition of ALI to an Aegis BMD capability commenced with FM-4
in November of 2002 with USS LAKE ERIE, executing the first successful
ascent phase intercept of a short range ballistic missile (SRBM) by the Aegis
BMD element.17
Table 2 below summarizes seven ALI and Aegis BMD flight tests (called FTM-
2 through FTM-8, with the FTM standing for “flight test mission18) conducted
between January 2002 and November 2005. As shown in the table, 6 of the 7 tests
resulted in successful intercepts.
16 A. Brad Hicks, Aegis Ballistic Missile Defense (BMD) System. Washington, George C.
Marshall Institute, 2005(?). (Washington Roundtable on Science & Public Policy,
December 19, 2005) p. 13.
17 “Aegis Ballistic Missile Defense,” MDA fact sheet, January 30, 2004.
18 In some presentations, the flight tests are referred to as FM-2, etc., without the “T.”

CRS-11
Table 2. ALI and Aegis BMD Flight Tests
Test name
FTM-2
FTM-3
FTM-4
FTM-5
FTM-6
FTM-7
FTM-8
Date
1/22/02
6/13/02
11/21/02
6/18/03
12/11/03
2/24/05
11/17/05
Target
300km
300km
160km
160km
160km
160km
227km
apogee
Target range
500km
500km
600km
600km
600km
600km
925km
Aegis
ALI
ALI
ALI
ALI
ALI
BMD
BMD
computer
1.2
1.2
2.0
2.0
2.2.2
3.0
3.0
program
SM-3
Block 0
Block 0
Block 0
Block 0
Block 0
Block 1
Block 1
version
Engagement
Uncued
Uncued
Uncued
Cued*
Cued*
Uncued
Uncued
sequence
Intercept
430km
430km
250km
250km
482km
250km
462km
down range
Intercept
240km
240km
200km
150km
248km
150km
150km
cross range
Crew
Yes
Yes
Yes
Yes
No
No
No
disclosure
Ship’s
Steady
Steady
Steady
Steady
Maneuv-
Maneuv-
Maneuv-
heading
ering
ering
ering
Target flight
Descent
Descent
Ascent
Ascent
Descent
Descent
Descent
phase
Lethal
No
No
Aimpoint
Yes
Yes
Yes
Yes
aimpont
shift
Kinetic
Yes
Yes
Yes
No
Yes
Yes
Yes
warhead
intercept

Source: “Aegis Ballistic Missile Defense, Aegis BMD Update and Plans,” Briefing to the Future
Naval Plans & Requirements Conference, Scott Perry, Aegis BMD [Program], April 26, 2006, slide
11.
* Aegis ship to Aegis ship and external sensor to Aegis ship.
On June 22, 2006, an eighth Aegis BMD flight test called FTM-10 resulted in
a seventh successful exo-atmospheric intercept in eight attempts. This was the first
test to use the Aegis 3.6 computer program.19
MDA states that the ninth test, called FTM-11, conducted on December 7, 2006,
was not completed due to an incorrect system setting aboard the Aegis-class
cruiser USS Lake Erie prior to the launch of two interceptor missiles from the
ship. The incorrect configuration prevented the fire control system aboard the
19 For additional information on this test, see Missile Defense Agency, “Missile Defense
Test Results in Successful ‘Hit To Kill’ Intercept,”June 22, 2006 (06-NEWS-0018); the
Johns Hopkins University Applied Physics Laboratory press release, “Ballistic Missile
Defense Flight Test a Success,” June 23, 2006, the Lockheed Martin press release, “Aegis
Ballistic Missile Defense Weapon System Guides Missiles to Seventh Successful Target
Intercept,” June 22, 2006; Zachary M. Peterson, “Navy And Missile Defense Agency
Intercept Separating Target,” Inside the Navy, June 26, 2006; and “Take Two: Missile
Defense Test A Success,” NavyTimes.com, June 23, 2006.

ship from launching the first of the two interceptor missiles. Since a primary test
objective was a near-simultaneous launch of two missiles against two different
targets, the second interceptor missile was intentionally not launched.
The planned test was to involve the launch of a Standard Missile 3 against
a ballistic missile target and a Standard Missile 2 against a surrogate aircraft
target. The ballistic missile target was launched from the Pacific Missile Range
Facility, Kauai, Hawaii and the aircraft target was launched from a Navy aircraft.
The USS Lake Erie (CG 70), USS Hopper (DDG 70) and the Royal Netherlands
Navy frigate TROMP were all successful in detecting and tracking their
respective targets. Both targets fell into the ocean as planned.
After a thorough review, the Missile Defense Agency and the U.S. Navy
will determine a new test date.20
A news article about the test stated:
“You can say it’s seven of nine, rather than eight of nine,” Missile Defense
Agency spokesman Chris Taylor said of the second failure in tests of the system
by the agency and the Navy....
The drill was planned to demonstrate the Navy’s ability to knock down two
incoming missiles at once from the same ship.
“In a real world situation it is possible, maybe even probable, that in
addition to engaging a ballistic missile threat that was launched, you may be
engaging a surface action,” said Joe Rappisi before the test. He is director for the
Aegis Ballistic Missile Defense system at Lockheed Martin, the primary
contractor for the program.
The test would have marked the first time a ship has shot down one target
in space and another target in the air at the same time.
The test presented a greater challenge to the ship’s crew and the ballistic
missile defense system than previous tests, Rappisi said. The multiple target
scenario is also closer to what sailors might actually face in battle.
The U.S. Pacific Fleet has been gradually installing missile surveillance and
tracking technology on many of its destroyers and cruisers amid concerns about
North Korea’s long-range missile program.
It is also installing interceptor missiles on many of its ships, even as the
technology to track and shoot down incoming missiles is being developed and
perfected.
The Royal Netherlands Navy joined the tracking and monitoring off Kauai
to see how its equipment works. The Dutch presence marked the first time a
European ally has sent one of its vessels to participate in a U.S. ballistic missile
defense test.21
20 Untitled Missile Defense Agency “For Your Information” statement dated December 7,
2006 (06-FYI-0090).
21 David Briscoe, “Test Interceptor Missile Fails To Launch,” NavyTimes.com, December
(continued...)

CRS-2
Another news article stated:
An e-mail issued by the Missile Defense Advocacy Alliance, a lobbying
organization based in Alexandria, VA, said the test has been delayed until spring
due to “operational factors.”...
Philip Coyle, a former head of the Pentagon’s testing directorate, gives the
Navy credit for “discipline and successes so far” in its sea-based ballistic missile
defense testing program. Coyle is now a senior adviser at the Center for Defense
Information.
“The U.S. Navy has an enviable track record of successful flight intercept
tests, and is making the most of its current, limited Aegis missile defense
capabilities in these tests,” Coyle told [Inside the Navy] Dec. 7.
“Difficulties such as those that delayed the latest flight intercept attempt
illustrate the complexity of the system, and how everything must be carefully
orchestrated to achieve success,” Coyle added. “Nevertheless, this particular
setback won’t take the Navy long to correct.”22
Certification. On September 11, 2006, the Navy and MDA certified the
version of the Aegis BMD system using the Aegis BMD 3.6 computer program for
tactical deployment.23
SM-3 Block II/IIA Missile. Under a memorandum of agreement signed in
1999, the United States and Japan have cooperated in researching technologies for
the Block II/IIA version of the SM-3. The cooperative research has focused on risk
reduction for four parts of the missile: the sensor, an advanced kinetic warhead, the
second-stage propulsion, and a lightweight nose cone.
In contrast to the Block IA/1B version of the SM-3, which has a 21-inch-
diameter booster stage but is 13.5 inches in diameter along the remainder of its
length, the Block II/IIA version would have a 21-inch diameter along its entire
length. The increase in diameter to a uniform 21 inches is to give the missile a
burnout velocity (a maximum velocity, reached at the time the propulsion stack burns
out) that is 45% to 60% greater than that of the Block IA/IB version.24 The Block IIA
21 (...continued)
8, 2006.
22 Zachary M. Peterson, “Sea-Based Missile Defense Test Fails Due To ‘Incorrect
Configuration,’” Inside the Navy, December 11, 2006.
23 See Missile Defense Agency, “Aegis Ballistic Missile Defense Weapon System Gains
Fleet Certification,” September 1, 2006 (06-FYI-0082); and Lockheed Martin, “Aegis
Ballistic Missile Defense Weapon System Gains Fleet Certification,” September 11, 2006.
24 The 13.5-inch version has a reported burnout velocity of 3.0 to 3.5 kilometers per second
(kps). See, for example, J. D. Marshall, The Future Of Aegis Ballistic Missile Defense,
point paper dated October 15, 2004, available at [http://www.marshall.org/
pdf/materials/259.pdf]; “STANDARD Missile-3 Destroyers a Ballistic Missile Target in
Test of Sea-based Missile Defense System,” Raytheon news release circa January 26, 2002,
(continued...)

CRS-3
version would also include an improved kinetic warhead.25 MDA states that the
Block II/IIA version could “engage many [ballistic missile] targets that would
outpace, fly over, or be beyond the engagement range” of earlier versions of the SM-
3, and that
the net result, when coupled with enhanced discrimination capability, is more
types and ranges of engageable [ballistic missile] targets; with greater probability
of kill, and a large increase in defended “footprint” or geography predicted....
The SM-3 Blk II/IIA missile with it[s] full 21-inch propulsion stack provides the
necessary fly out acceleration to engage IRBM and certain ICBM threats.26
MDA stated in 2005 that “The Block II/IIA development plan is undergoing
refinement. MDA plans to proceed with the development of the SM-3 Blk II/IIA
missile variant if an agreeable cost share with Japan can be reached.... [The currently
envisaged development plan] may have to be tempered by budget realities for the
agency.”27
In March 2005, the estimated total development cost for the Block II/Block IIA
missile was reportedly $1.4 billion.28 In September 2005, it was reported that this
estimate had more than doubled, to about $3 billion.29 MDA estimates that the Block
II version of the missile could enter service around 2013, and the Block IIA version
in 2015.
Cancellation of NAD Program. As a complement to the Aegis BMD
system’s capability for intercepting TBMs outside the atmosphere, during their
midcourse phase of flight, there was at one time an additional program to develop a
sea-based capability for intercepting TBMs in the final, or descent, phase of flight,
after the missiles reentered the atmosphere, so as provide local-area defense of U.S.
ships as well as friendly forces, ports, airfields, and other critical assets ashore. The
24 (...continued)
a va i l a b l e o n t h e In t e r n e t a t [ h t t p : / / w w w . p r newswi r e.com/ c gi -b i n /
micro_stories.pl?ACCT=683194&TICK=RTN4&STORY=/www/story/01-26-2002/0001
655926&EDATE=Jan+26,+2002]; and Hans Mark, “A White Paper on the Defense Against
Ballistic Missiles,” The Bridge, summer 2001, pp. 17-26, available on the Internet at
[ h t t p : / / w w w . n a e . e d u / n a e / b r i d g e c o m . n s f / w e b l i n k s /
NAEW-63BM86/$FILE/BrSum01.pdf?OpenElement]. See also the section on “Sea-Based
Midcourse” in CRS Report RL31111, Missile Defense: The Current Debate, coordinated
by Steven A. Hildreth.
25 Source for information on SM-3: Missile Defense Agency, “Aegis Ballistic Missile
Defense SM-3 Block IIA (21-Inch) Missile Plan (U), August 2005,” a 9-page point paper
provided by MDA to CRS, August 24, 2005.
26 “Aegis Ballistic Missile Defense SM-3 Block IIA (21-Inch) Missile Plan (U), August
2005,” op. cit, pp. 3-4.
27 Ibid., p. 3.
28 Aarti Shah, “U.S. Navy Working With Japanese On Billion-Dollar Missile Upgrade,”
Inside the Navy, Mar. 14, 2005.
29 “Cost Of Joint Japan-U.S. Interceptor System Triples,” Yomiuri Shimbun (Japan),
September 25, 2005.

CRS-4
program was called the Navy Area Defense (NAD) program or Navy Area TBMD
(Theater BMD) program, and before that, the Sea-Based Terminal or Navy Lower
Tier program.
The NAD system was to have been deployed on Navy Aegis ships. The
program involved modifying the SM-2 Block IV air-defense missile. The missile,
as modified, was called the Block IVA version. The system was designed to
intercept descending missiles endo-atmospherically (i.e., within the atmosphere) and
destroy them with the Block IVA missile’s blast-fragmentation warhead.
In December 2001, DOD announced that it had canceled the NAD program. In
announcing its decision, DOD cited poor performance, significant cost overruns, and
substantial development delays. DOD stated that the program’s unit acquisition and
unit procurement costs had risen 57% and 65%, respectively.30
Following cancellation of the NAD program, DOD officials stated that the
requirement for a sea-based terminal BMD system remained intact. This led some
observers to believe that a replacement for the NAD program might be initiated. In
May 2002, however, DOD announced that instead of starting a replacement program,
MDA had instead decided on a two-part strategy to (1) modify the SM-3 missile to
intercept ballistic missiles at somewhat lower altitudes, and (2) modify the Navy’s
inventory of about 100 SM-2 Block IV air defense missiles to cover some of the
remaining portion of the sea-based terminal defense requirement. The modified
Block IV missile uses a blast-fragmentation warhead similar in concept to that used
in the Israeli Arrow BMD interceptor. DOD officials said the two modified missiles
could together provide much (but not all) of the capability that was to have been
30 Acquisition cost is the sum of procurement cost plus research, development, test and
evaluation (RDT&E) cost. In announcing the cancellation, DOD cited the Nunn-McCurdy
provision, a defense acquisition law enacted in 1981. Under the provision as it existed in
2001, a major defense acquisition program experienced what is called a Nunn-McCurdy unit
cost breach when its projected unit cost increased by at least 15%. If the increase reached
25%, the Secretary of Defense, to permit the program to continue, must certify that the
program is essential to national security, that there are no alternatives to the program that
would provide equal or greater military capability at less cost, that new estimates of the
program's unit acquisition cost or unit procurement cost appear reasonable, and that the
management structure for the program is adequate to control the program's unit acquisition
or unit procurement cost.
Edward C. "Pete" Aldridge, the Under Secretary of Defense for Acquisition, Technology
and Logistics — the Pentagon's chief acquisition executive — concluded, after examining
the NAD program, that he could not recommend to Secretary of Defense Donald Rumsfeld
that he make such a certification. Rumsfeld accepted Aldridge's recommendation and
declined to issue the certification, triggering the program's cancellation. This was the first
defense acquisition program that DOD officials could recall having been canceled as a result
of a decision to not certify under a Nunn-McCurdy unit cost breach. (“Navy Area Missile
Defense Program Cancelled,” Department of Defense News Release No. 637-01, December
14, 2001; James Dao, “Navy Missile Defense Plan Is Canceled By the Pentagon,” New York
Times
, December 16, 2001; Gopal Ratnam, “Raytheon Chief Asks DOD To Revive Navy
Program,” Defense News, January 14-20, 2002: 10.)

CRS-5
provided by the Block IVA missile. One aim of the modification strategy, DOD
officials suggested, was to avoid the added costs to the BMD program of starting a
replacement sea-based terminal defense program.31
MDA states that:
There is currently no sea-based terminal ballistic missile defense capability.
The Navy Area [Defense] Theater Ballistic Missile Defense (TBMD) Program,
had been under development, but was terminated in December 2001. In ballistic
missile defense, the modified Aegis Weapon System, with a modified SM-2
Block IV missile provides a near term, limited emergency capability against a
very specific segment of the ballistic missile threat. The Navy and MDA
consider it vital to develop a more robust capability for terminal ballistic missile
defense of the joint sea base and friendly force embarkation points ashore.32
A modified Block SM-2 IV missile successfully intercepted a target ballistic
missile inside the atmosphere, during the terminal phase of flight, in a test conducted
on May 24, 2006.33
DOD Inspector General Report. A March 2006 DOD Inspector General
Report on system engineering for DOD’s overall missile effort stated:
Although the Aegis BMD element manager (the element manager) followed
many of the systems engineering processes described in the Defense Acquisition
Guidebook, she had not completed several systems engineering documents and
processes that are important to transition the Aegis BMD Element (the element)
capabilities for Block [20]04 to the Navy.34
Government Accountability Office (GAO) Report. A March 2006
Government Accountability Office (GAO) report assessing the status of selected
major weapon programs stated of the Aegis BMD program:
31 Zachary M. Peterson, “Navy To Field Terminal Pahse, Sea-Based Missile Defense
Capability,” Inside the Navy, June 5, 2006; Gopal Ratnam, “U.S. Studies New Solution To
Naval Missile Defense,” Defense News, May 13-19, 2002: 4; Randy Woods, “DOD Scraps
Navy Area Requirements, Will Expand Midcourse System,” Inside the Navy, May 6, 2002.
32 Missile Defense Agency, “First at-Sea Demonstration of Sea-Based Terminal Capability
Successfully Completed,” May 24, 2006 (06-FYI-0079).
33 See Missile Defense Agency, “First at-Sea Demonstration of Sea-Based Terminal
Capability Successfully Completed,” May 24, 2006 (06-FYI-0079); Gregg K. Kakesako,
“Missile Defense System Makes History,” Honolulu Star-Bulletin, May 25, 2006; Audrey
McAvoy, “Ship Shoots Down Test Missile For The First Time,” NavyTimes.com, May 25,
2006; “Navy, MDA Announce First Terminal Sea-Based Intercept,” Aerospace Daily &
Defense Report
, May 26, 2006; Zachary M. Peterson, “Navy Conducts First Sea-Based
Terminal Phase Missile Defense Test,” Inside the Navy, May 29, 2006; and Jeremy Singer,
“Sea-Based Terminal May Boost U.S. Missile Defense Capability,” Space News
(www.space.com)
, June 12, 2006.
34 Department of Defense, Office of Inspector General, Acquisition: System Engineering
Planning for the Ballistic Missile Defense System (D-2006-060)
, March 2, 2006 (redacted
version), p. 9. The report elaborates on the situation in detail on pages 9-16.

CRS-6
According to program officials, the Block 2004 increment of SM-3 missiles
being fielded during 2004-2005 has mature technologies and a stable design.
However, the program deferred full functionality of the missile's Solid Divert and
Altitude Control System, which maneuvers the missile's kinetic warhead to its
target, to a future upgrade. Program officials noted that even with reduced
capability, the first increment of missiles provide a credible defense against a
large population of the threat. All drawings for the first increment of missiles
have been released to manufacturing. The program is not collecting statistical
data on its production process but is using other means to gauge production
readiness....
Technology Maturity
Program officials estimate that all three technologies critical to the SM-3
missile are mature. These technologies — the missile's third stage rocket motor
and the kinetic warhead's infrared seeker and Solid Divert and Attitude Control
System (SDACS) — have been tested in flight. While the first two technologies
were fully demonstrated in flight tests, the SDACS, which steers the kinetic
warhead, was only partially demonstrated. The SDACS operation in “pulse
mode,” which increases the missile's divert capability, failed during a June 2003
flight test. According to program officials, the test failure was likely caused by
a defective subcomponent within the SDACS, a problem that should be corrected
through specific design modifications. To implement these corrective actions, the
program is deferring full functionality of the missile's SDACS technology to the
next upgrade of the hit-to-kill missile. Program officials note that only partial
functionality of the SDACS is required for Block 2004, which has been
successfully demonstrated in flight tests.
Design Stability
Program officials reported that the design for the first 11 SM-3 missiles
being produced during Block 2004 is stable with 100 percent of its drawings
released to manufacturing. The program plans to implement design changes in
subsequent blocks (delivered during 2006-2007) to resolve the SDACS failure
witnessed in the June 2003 flight test.
Production Maturity
We did not assess the production maturity of the SM-3 missiles being
procured for Block 2004. Program officials stated that given the low quantity of
missiles being produced, statistical process control data on the production
process would have no significance. The Aegis BMD program is using other
means to assess progress in production and manufacturing, such as integrated
product team reviews, risk reviews, Engineering Manufacturing Readiness
Levels, and missile metrics.
Other Program Issues
The Aegis BMD element builds upon the existing capabilities of
Aegis-equipped Navy cruisers and destroyers. Planned hardware and software
upgrades to these ships will enable them to carry out the ballistic missile defense
mission. In particular, the program is working to upgrade Aegis destroyers for
surveillance and tracking of intercontinental ballistic missiles. Because this
function is new to the element, the program has faced a tight schedule to develop

CRS-7
and test this added functionality during the Block 2004 time frame. Although the
program aims to upgrade ten destroyers as part of its Block 2004 increment, this
new functionality has been exercised in a limited number of flight tests and has
never been validated in an end-to-end flight test with the GMD system, for which
it is providing long range surveillance and tracking.35
Program Funding.
How much funding has the Aegis BMD program received in previous years? How
much does the Administration plan to request for the program in future years?

For FY2007, the Administration requested $1,031.9 million in research and
development funding for the Aegis BMD program; Congress appropriated about
$1,127.4 million — a $95.5-million increase over the requested amount.
Table 3 shows actual or programmed funding for the Aegis BMD program from
FY1995 through FY2011.
Table 3. Aegis BMD Program Funding, FY1995-FY2011
(in millions of dollars, rounded to the nearest tenth; figures for
FY2008-FY2011 as shown in FY2007-FY2011 FYDP)
FY95
75.0
FY96
200.4
FY97
304.2
FY98
410.0
FY99
338.4
FY00
380.0
FY01
462.7
FY02
476.0
FY03
464.0
FY04
726.2
FY05
1,159.8
FY06
939.1
FY07
1,127.4
FY08*
951.6*
FY09*
980.5*
FY10*
973.2*
FY11*
799.2*
Source: DOD Information Paper provided to CRS by Navy Office of Legislative Affairs,
November 14, 2006.
35 Government Accountability Office, Defense Acquisitions: Assessments of Selected Major
Weapon Programs
, GAO-06-391, March 2006, pp. 25-26.

CRS-8
* Figures for FY2008-FY2011 are those shown in FY2007-FY2011 Future Years Defense
Plan (FYDP).
Potential Allied Programs.
Japan. Japan’s interest in BMD, and in
cooperating with the United States on the issue, was heightened in August 1998,
when North Korea test-fired a Taepo Dong-1ballistic missile that flew over Japan
before falling into the Pacific.36 In addition to cooperating with the United States on
development of technologies for the SM-3 Block II/IIA missile, current plans call for
Japan to modify four of its Aegis destroyers with the Block 2004 version of the Aegis
BMD system between FY2007 and early FY2011, at a pace of about one ship per
year. Under this plan, Japan would have an opportunity in FY2011 and subsequent
years to upgrade the ships’ BMD capability to a later Block standard, and to install
the Aegis BMD capability on its two remaining Aegis destroyers. A Japanese Aegis
ship participated as a tracking platform in FTM-10, the June 22, 2006, flight test of
the Aegis BMD system. This was the first time that an allied military unit
participated in a U.S. Aegis BMD intercept test.37
Other Countries. Other countries that DOD views as potential naval BMD
operators include South Korea, Australia, the UK, Germany, the Netherlands, Spain,
and Italy. As mentioned earlier, South Korea, Australia, and Spain either operate, are
building, or are planning to build Aegis ships. The other countries operate destroyers
and frigates with different combat systems that may have potential for contributing
to BMD operations.
The United States has conducted high-level discussions with Korea about
equipping Korea’s Aegis destroyers with a BMD capability. The United States
signed a memorandum of understanding (MOU) on BMD with the UK in 2003, and
another with Australia in 2004. A U.S.-UK study on a potential BMD capability for
the UK’s planned Type 45 destroyers was initiated in 2006. The United States has
provided pricing data to the Netherlands, and is conducting initial discussions with
the Dutch to assess the potential for installing a BMD capability on certain Dutch
ships. An October 2006 press report states that the Dutch government has decided
to upgrade one of its frigates with BMD capability, and that the ship will participate
as a tracking platform in a U.S. test of the Aegis BMD system in late 2006. Germany
has a liaison officer working with the Aegis BMD office to understand BMD-related
issues.38
36 For a discussion, see CRS Report RL31337, Japan-U.S. Cooperation on Ballistic Missile
Defense: Issues and Prospects
, by Richard P. Cronin. This archived report was last updated
on March 19, 2002. See also CRS Report RL33436, Japan-U.S. Relations: Issues for
Congress
, by Emma Chanlett-Avery, Mark E. Manyin, and William H. Cooper.
37 Missile Defense Agency, “Missile Defense Test Results in Successful ‘Hit To Kill’
Intercept,” June 22, 2006 (06-NEWS-0018).
38 Primary source for this paragraph: Missile Defense Agency, Frequently Asked Questions,
available online at [http://www.mda.mil/mdalink/html/faq.html]. The October 2006 press
report about the Dutch frigate is: Jack Dorsey, “Navy On Front Line Of Missile Defense,”
Norfolk Virginian-Pilot, Oct. 21, 2006.

CRS-9
Sea-Based X-Band Radar (SBX)
What is the Sea-Based X-Band Radar (SBX)?
General. The Sea-Based X-Band Radar (SBX) is DOD’s other principal sea-
based BMD element. It is a midcourse fire-control radar designed to support long-
range BMD systems. Its principal functions are to detect and establish precise
tracking information on ballistic missiles, discriminate missile warheads from decoys
and debris, provide data for updating ground-based interceptors in flight, and assess
the results of intercept attempts. SBX is intended to support more operationally
realistic testing of the ground-based midcourse system and enhance overall BMD
system operational capability.
SBX is a large, powerful, phased-array radar operating in the X band, a part of
the radio frequency spectrum that is suitable for tracking missile warheads with high
accuracy. The radar is mounted on a modified, self-propelled, semi-submersible oil
platform that can transit at a speed of 8 knots and is designed to be stable in high
winds and rough seas.39
SBX was completed in 2005 for the Missile Defense Test Bed. The semi-
submersible platform was designed by a Norwegian firm and built in Russia. It was
purchased for the SBX program, and modified and integrated with the SBX radar in
Texas.40 SBX underwent sea trials and high-power radiation testing in the Gulf of
Mexico in 2005. It was then moved by a heavy transport vessel to Hawaii, arriving
there in January 2006. From there, it is to transit to Adak, Alaska, in the Aleutian
Islands, where it is to be homeported and put into operation.
Technical Issues. Technical issues relating to the SBX platform have
delayed the SBX’s planned departure for Alaska. A November 2006 press report
stated that:
the vessel carrying the radar has sprung leaks and blown out electrical circuits.
Such mundane problems have kept this vital part of the nation's defense
against missile attacks stuck in the wrong harbor. If all had gone according to
39 The platform is 238 feet wide and 398 feet long. It measures 282 from its submerged keel
to the top of the radar dome. The SBX has a total displacement of almost 50,000 tons —
about one-half the full load displacement of a Navy aircraft carrier. SBX is operated by a
crew of about 75.
40 The platform was designed by Moss Maritime, a Norwegian firm, and built for Moss in
2001-2002 by Vyborg shipbuilding, which is located in Vyborg, Russia (a city north of St.
Petersburg, on the Gulf of Finland, that is near the Finnish border). Vyborg Shipbuilding’s
products include semi-submersible oil platforms. Moss sold the platform to Boeing. Boeing
and a subcontractor, Vertex RSI (a part of General Dynamics), modified the platform at the
Keppel AMFELS shipyard in Brownsville, TX. The platform was then moved to Kiewit
Offshore Services of Corpus Christi, TX, where the radar was added by a combined team
of Boeing, Raytheon, Vertex RSI, and Kiewit. (“MDA Completes Integration of X-Band
Radar On Sea-Going Platform,” Defense Daily, Apr. 5, 2005; and “Sea-Based X-band
Radar,” GlobalSecurity.org.)

CRS-10
plan, the $950 million radar rig, known as SBX, would be operating now off the
Aleutian Islands in Alaska and ready to defend against threats from North Korea.
Instead, after a three-year odyssey from Norway to Texas and around South
America, the 28-story-high converted oil platform is in Hawaii, 2,000 miles and
months away from its final destination....
By late 2005, it looked as if SBX might come close to meeting its [end-of-
2005] target for arriving in Alaska. After trials in the Gulf of Mexico, it was
hauled 15,000 miles around South America — the rig is too big for the Panama
Canal — and it arrived in Hawaii in January of this year [2006]. The trip to
Alaska seemed around the corner, but in March, alarms went off in SBX's engine
room. A leaky valve caused water to flood into SBX's pontoon. The rig had to
return to Pearl Harbor for repairs to the flaw, which an independent panel later
called a ‘major casualty.’
Then in June [2006], an electrical fault tripped circuit breakers, forcing
SBX back into port for two more weeks of repairs. Such problems are typical
during the initial ‘shakedown’ phase of a new class of ship, says Tom Alexiou,
Boeing's SBX program manager. Most important, adds Paul Smith, a Boeing
radar manager, there haven't been major issues in the ‘far more complex’ task of
integrating the radar with other ship systems....
Col. John Fellows, the Pentagon's manager for SBX, says staying near
Hawaii makes it easier to iron out kinks and join the tests, although officials are
eager for the radar's permanent deployment. ‘We're pressured on both sides,’ he
says.
In any case, further issues must be sorted out before the trip to Alaska. The
independent panel hired by the Pentagon concluded in June that while SBX ‘is
an inherently rugged and suitable platform,’ the vessel needs 47 modifications
before it goes into service. Among them: a better plan for operating in harsh
winters and steps to ensure the rig is protected against being rammed by boats.
Senior program officials call the modifications minor and say they have agreed
to almost all of them.
The panel also noted that maintaining morale poses a challenge. SBX’s
crew is composed mostly of defense-industry employees and merchant mariners
hired by Boeing subcontractors. Only a handful of shipmates are servicemen.
Civilian mariners rotate only every 56 days, much longer than work cycles for
comparable oil-industry jobs. Leisure consists of a gym, a basketball hoop on the
deck and movies under the stars, though plasma TVs and more DVDs are on the
way.
Funding for SBX’s mooring in the Aleutians, previously cut in another
headache for project managers, has been restored, but construction won't be
finished until next August, says Col. Fellows. The latest projection for the trip
to Alaska is sometime next year [2007].41
41 Jonathan Karp, “A Radar Unit’s Journey Reflects Hopes, Snafus In Missile Defense,”
Wall Street Journal, Nov. 28, 2006: 1. See also Kirsten Scharnberg, “Radar Staying Longer
Than Planned,” Chicago Tribune, Sept. 3, 2006. The article was also published in the
Honolulu Advertiser.

CRS-11
The independent assessment referred to in the above-quoted article was
completed in June 2006. The report concluded that SBX:
is an inherently rugged and suitable platform for the intended mission[,]
however, the [assessment] panel found that at the current time:

1. Crew Readiness and Materiel Readiness issues indicate that SBX-1
needs additional underway shakedown time and inport time to address crew and
material issues in the Hawaiian area, and
2. Operational Considerations identifies issues for which operational
commanders and developing commands need a full understanding of associated
implications, and which require resolution prior to departure from Hawaii and
operations at the Adak winter MODLOC [modified location] in the Bering Sea.42
According to a November 2006 press report, the top U.S. military officer in
Alaska believes the SBX will arrive in Adak in January 2007.43
Potential Other Uses. A March 2006 press report states:
Boeing missile defense officials refuse to answer questions about whether
they are developing techniques to produce high-energy weapon effects from the
SBX sea-based radar. However, since large distributed-array devices [like the
SBX] can be focused to deliver large spikes of energy, powerful enough to
disable electronic equipment, the potential is known to exist and is being fielded
on a range of U.S., British and Australian aircraft.44
Potential Issues for Congress
Sea-Based Systems in Eventual BMD Architecture
What should be the role of sea-based systems in the eventual national BMD
architecture?

A key potential issue for Congress concerns the role of sea-based systems in the
eventual U.S. BMD architecture. The eventual architecture is to be defined by U.S.
Strategic Command (USSTRATCOM) — the U.S. military command responsible for
42 SBX-1 Operational Suitability and Viability Assessment, An Independent Assessment.
Arlington (VA), SYColeman, 2006, pp. i-ii. (Final Report, June 2, 2006, Submitted to:
Director, Mission Readiness Task Force, Missile Defense Agency, Submitted by:
Independent Assessment Team, Prepared by: SYColeman, A Wholly Owned Subsidiary of
L-3 Communications). The report is available online at [http://www.pogo.org/m/dp/
dp-SBXOVA-06022006.pdf]
43 Associated Press, “Floating Missile Detector May Reach Alaska in January,”
ArmyTimes.com, Nov. 16, 2006.
44 “Radar Weapons,” Aerospace Daily & Defense Report, Mar. 20, 2006.

CRS-12
“synchronized DoD effects to combat adversary weapons of mass destruction
worldwide,” including integrated missile defense45 — in consultation with MDA.
Under the evolutionary acquisition approach adopted for the overall U.S. BMD
program, it likely will be a number of years before USSTRATCOM and MDA define
the eventual BMD architecture.46 Until then, the absence of an objective architecture
might complicate the task of assessing whether the types and numbers of sea-based
BMD systems being acquired are correct. If the role of sea-based systems in the
eventual U.S. BMD architecture turns out to be greater than what DOD has assumed
deciding to equip 18 Aegis ships with BMD capabilities, then additional funding
might be needed to expand the scope of the program to include more than 18 ships.
The issue could also affect the required total number of Navy cruisers and
destroyers. As discussed in another CRS report,47 the Navy faces a long-term
challenge in being able to maintain its planned force of 88 cruisers and destroyers.
If the role of sea-based systems in the eventual U.S. BMD architecture turns out to
be greater than what the Navy has assumed in calculating its 88-ship cruiser-
destroyer requirement, then the requirement might need to be increased to something
more than 88 ships, which could exacerbate the potential long-term shortfall in
cruisers and destroyers. Potential oversight questions for Congress include the
following:
! In the absence of a defined U.S. BMD architecture, what was the
basis for deciding that 18 Aegis ships should be equipped for BMD
operations? What is the likelihood that 18 BMD-equipped Aegis
ships will turn out to be too many or not enough?
! What kinds of BMD operations were factored into the Navy
requirement for maintaining a force of at least 88 cruisers and
destroyers? If BMD operations by Navy ships turn out to be more
significant than what the Navy assumed in calculating the 88-ship
figure, will the figure need to be increased, and if so, by how much?
Replacement for Navy Area Defense (NAD) Program
Should a new program be initiated to fully replace the canceled Navy Area Defense
(NAD) program?

45 For more on USSTRATCOM, see CRS Report RL33408, Nuclear Command and Control:
Current Programs and Issues
, by Robert D. Critchlow. See also USSTRATCOM’s website
at [http://www.stratcom.mil/], from which the quoted passage is taken.
46 For more on evolutionary acquisition in general, see CRS Report RS21195, Evolutionary
Acquisition and Spiral Development in DOD Programs: Policy Issues for Congress
, by
Gary J. Pagliano and Ronald O’Rourke. As ballistic missile threats change over time, it is
possible that the U.S. BMD architecture may never be fully defined.
47 CRS Report RL32109, Navy DDG-1000 (DD(X)) and CG(X) Ship Acquisition Programs:
Oversight Issues and Options for Congress
, by Ronald O’Rourke.

CRS-13
As discussed in the background section, DOD in 2002 decided against initiating
a new program to fully replace the canceled NAD program, opting instead for a
two-part strategy to (1) modify the SM-3 missile to intercept ballistic missiles at
lower altitude, and (2) modify the SM-2 Block IV air defense missile to cover some
of the remaining portion of the sea-based terminal defense requirement. As discussed
earlier, this effort is aimed at replacing most (but not all) of the capability that was
to have been provided by the NAD system.
The potential issue for Congress is whether to continue with this two-part
strategy or pursue a new strategy, such as initiating a new program to fully replace
the capability that was to have been provided by the NAD system. Reported options
for a new NAD-replacement program include a system using a modified version of
the Army’s Patriot Advanced Capability-3 (PAC-3) interceptor or a system using a
modified version of the SM-6 Extended Range Active Missile (SM-6 ERAM) air
defense missile being developed by the Navy.48
In October 2002, it was reported that senior Navy officials
continue to speak of the need for a sea-based terminal BMD capability “sooner
rather than later” and have proposed a path to get there. “The cancellation of the
Navy Area missile defence programme left a huge hole in our developing basket
of missile-defence capabilities,” said Adm. [Michael] Mullen. “Cancelling the
programme didn’t eliminate the warfighting requirement.”
“The nation, not just the navy, needs a sea-based area missile defence
capability, not to protect our ships as much as to protect our forces ashore,
airports and seaports of debarkation” and critical overseas infrastructure
including protection of friends and allies.49
The above-quoted Admiral Mullen became the Chief of Naval Operations
(CNO) on July 22, 2005.
In July 2004 it was reported that:
The Navy’s senior leadership is rebuilding the case for a sea-based terminal
missile defense requirement that would protect U.S. forces flowing through
foreign ports and Navy ships from short-range missiles, according to Vice Adm.
John Nathman, the Navy’s top requirements advocate.
The new requirement, Nathman said, would fill the gap left when the
Pentagon terminated the Navy Area missile defense program in December 2001.
... However, he emphasized the Navy is not looking to reinstate the old [NAD]
system. “That’s exactly what we are not talking about,” he said March 24....
48 See, for example, Jason Ma and Christopher J. Castelli, “Adaptation Of PAC-3 For Sea-
Based Terminal Missile Defense Examined,” Inside the Navy, July 19, 2004; Malina Brown,
“Navy Rebuilding Case For Terminal Missile Defense Requirement,” Inside the Navy, Apr.
19, 2004.
49 Michael Sirak, “Sea-Based Ballistic Missile Defence: The ‘Standard’ Response,” Jane’s
Defence Weekly
, Oct. 30, 2002.

CRS-14
The need to bring back a terminal missile defense program was made clear
after reviewing the “analytic case” for the requirement, he said. Though
Nathman could only talk in general terms about the analysis, due to its classified
nature, he said its primary focus was “pacing the threat” issues. Such issues
involve threats that are not a concern today, but could be in the future, he said.
Part of the purpose of the study was to look at the potential time line for those
threats and the regions where they could emerge.50
Supporters of staying with the current two-part strategy could argue that it
replaces enough of the planned NAD capability to provide Navy ships with a
sufficient degree of terminal defense capability. They could also argue that initiating
a full NAD-replacement program could increase development risks, delay the
fielding of a useful terminal defense capability, or require reducing funding for other
BMD programs or other DOD priorities, increasing operational risks in other areas.
Supporters of initiating a new replacement program could note that the Navy
and MDA state that they “consider it vital to develop a more robust capability for
terminal ballistic missile defense of the joint sea base and friendly force embarkation
points ashore.” Supporters of a new replacement program could argue that a full
capability for intercepting missiles in the terminal phase could prove useful, if not
critical, for intercepting missiles — such as SRBMs or ballistic missiles fired along
depressed trajectories — that do not fly high enough to exit the atmosphere and
consequently cannot be intercepted by the SM-3. They could also argue a full NAD
replacement program would provide a more robust ability to counter potential
Chinese TBMs equipped with maneuverable reentry vehicles (MaRVs) capable of
hitting moving ships at sea.51
Aegis Radar Upgrades
Are current plans for upgrading the BMD capabilities of the SPY-1 radars on Navy
Aegis ships appropriate for meeting requirements for sea-based BMD?

As discussed in the background section, current plans for upgrading the radar
capabilities of the Navy’s Aegis cruisers and destroyers include the Aegis BSP,
which forms part of the planned Block 06 version of the Navy’s Aegis BMD
capability. One potential issue for Congress is whether current plans for developing
and installing the Aegis BSP are adequate and sufficiently funded for meeting
requirements for sea-based BMD. A second potential issue is whether there are other
50 Malina Brown, “Navy Rebuilding Case For Terminal Missile Defense Requirement,”
Inside the Navy, Apr. 19, 2004.
51 As discussed in another CRS report, China may now be developing TBMs equipped with
maneuverable reentry vehicles (MaRVs). Observers have expressed strong concern about
this potential development, because such missiles, in combination with a broad-area
maritime surveillance and targeting system, would permit China to attack moving U.S. Navy
ships at sea. The U.S. Navy has not previously faced a threat from highly accurate ballistic
missiles capable of hitting moving ships at sea. Due to their ability to change course,
MaRVs would be more difficult to intercept than non-maneuvering ballistic missile reentry
vehicles. See CRS Report RL33153, China Naval Modernization: Implications for U.S.
Navy Capabilities — Background and Issues for Congress
, by Ronald O’Rourke.

CRS-15
opportunities for improving the radar capabilities of the Navy’s Aegis cruisers and
destroyers that are not currently being pursued or are funded at limited levels, and if
so, whether funding for these efforts should be increased, so as to better meet
requirements for sea-based BMD.
SM-3 Block II/IIA Missile
If feasible, should the effort to develop the Block II/Block IIA version of the Standard
Missile 3 (SM-3) interceptor missile be accelerated?

Another potential question is whether, if feasible, the effort to develop the Block
II/Block IIA missile should be accelerated, and if so, whether this should be done
even if this requires the United States to assume a greater share of the combined
U.S.-Japan development cost. Views on this issue could be affected by estimates of
when other countries might deploy ballistic missiles of various kinds.
Kinetic Energy Interceptor (KEI)
If the Kinetic Energy Interceptor (KEI) is developed for land-based BMD
operations, should it also be based at sea? If so, what kind of sea-based platform
should be used?

Another potential issue for Congress concerns the Kinetic Energy Interceptor
(KEI) — a new ballistic missile interceptor that, if developed, could be used as a
ground-based interceptor and perhaps subsequently as a sea-based interceptor.
Compared to the SM-3, the KEI would be much larger (perhaps 40 inches in diameter
and 36 feet in length) and would have a much higher burnout velocity. Because of
its much higher burnout velocity, it might be possible to use a KEI based on a
forward-deployed ship to attempt to intercept ballistic missiles during the boost and
early ascent phases of their flights. Development funding for the KEI has been
reduced by Congress in recent budgets, slowing the missile’s development schedule.
DOD, however, plans to increase the budget for KEI significantly over the next
several years. Under current plans, the missile could become available for Navy use
in 2014-2015.52
The issue is whether the KEI, if developed, should be based at sea, and if so,
what kind of sea-based platform should be used. Basing the KEI on a ship would
require the ship to have missile-launch tubes that are bigger than those currently
installed on Navy cruisers, destroyers, and attack submarines. Potential sea-based
platforms for the KEI include, but are not necessarily limited to, the following:
! ballistic missile submarines (which have launch tubes large enough
to accommodate the KEI);
52 Government Accountability Office, Defense Acquisitions[:] Assessments of Selected
Major Weapon Programs
, GAO-05-301, March 2005, pp. 89-90. See also Thomas Duffy,
“Northrop, MDA Working On KEI Changes Spurred By $800 Million Cut,” Inside Missile
Defense
, Mar. 30, 2005: p. 1.

CRS-16
! surface combatants equipped with newly developed missile-launch
tubes large enough for the KEI; and
! a non-combat DOD ship (perhaps based on a commercial hull) or
floating platform.
Supporters of deploying the KEI at sea could argue that it would be more
capable than the SM-3 Block II/IIA for intercepting ICBMs and that it could enable
navy ships to attempt to intercept certain missiles during the boost phase of flight.
Skeptics could argue that in light of other planned BMD capabilities, the need for
basing the KEI at sea is not clear.
Among supporters of basing the KEI at sea, supporters of basing it on ballistic
missile submarines could argue that submarines can operate close to enemy coasts,
in positions suitable for attempting to intercept missiles during their boost phase of
flight, while remaining undetected and less vulnerable to attack than surface
platforms. Skeptics of basing the KEI on ballistic missile submarines could argue
that communication links to submarines are not sufficiently fast to support boost-
phase intercept operations, and that launching the KEI could give away the
submarine’s location, making it potentially vulnerable to attack.
Supporters of basing the KEI on surface combatants equipped with missile-
launch tubes large enough for the KEI could argue that surface ships have faster
communication links than submarines and more capability to defend themselves than
non-combat ships or floating platforms. Skeptics could argue that surface
combatants might not be able to get close enough to enemy coasts to permit boost-
phase intercepts, and that the defensive capabilities of a surface combatant are
excessive to what would be needed for a KEI platform operating in the middle of the
ocean, far from potential threats, for the purpose of using the KEI for midcourse
intercepts.
Supporters of a non-combat ship or floating platform could argue that a non-
combat ship or floating platform would be suitable for basing the KEI in mid-ocean
locations, far from potential threats, for the purpose of using the KEI for midcourse
intercepts. Skeptics could argue that using such a platform could not be used close
to an enemy coast, for the purpose of attempting a boost-phase intercept, unless it
were protected by other forces.
According to one report, MDA has been studying possibilities for basing the
KEI at sea and was to have selected a preferred sea-based platform in May 2006.53
53 Marc Selinger, “MDA To Pick Platform For Sea-Based KEI in May,” Aerospace Daily
& Defense Report
,” Aug. 19, 2005: 2.

CRS-17
CG(X) Cruiser
Should procurement of the planned CG(X) cruiser be accelerated?
As a replacement for its 22 remaining Aegis cruisers, the Navy plans to procure
18 or 19 new CG(X) cruisers. The radar capabilities of the CG(X) are to be greater
than that of the Navy’s Aegis ships, and the CG(X) has been justified primarily in
connection with future air defense and BMD operations. Under Navy plans, the first
CG(X) is to be procured in FY2011, and the final ship in FY2023. The Navy had
earlier planned to begin CG(X) procurement in FY2018, but accelerated the planned
start of procurement to FY2011 as part of its FY2006 budget submission. If procured
as planned, the first CG(X) might enter service in 2017, and the final ship might enter
service in 2029. It is possible that limitations on Navy budgets combined with
desires to fund other Navy programs may limit CG(X) procurement to no more than
one ship per year, which would delay the completion of an 18- or 19-ship CG(X)
program by several years.54
If improvements to Aegis radar capabilities are not sufficient to achieve the
desired level of sea-based radar capability for BMD operations, CG(X) radar
capabilities could become important to achieving this desired capability. If so, then
a potential additional issue is whether the planned CG(X) procurement profile would
be sufficient to achieve this desired capability in a timely manner. CG(X) radar
technologies could be introduced into the fleet more quickly by accelerating planned
procurement of CG(X)s or by designing a less expensive ship that preserves CG(X)
radar capabilities while reducing other capabilities less critical to BMD operations,
and then procuring this ship more rapidly than the CG(X) could afford to be
procured. The option of a reduced-cost ship that preserves CG(X) radar capabilities
while reducing other capabilities is discussed in more detail in another CRS report.55
Development and Testing of Aegis BMD System
Are there lessons from development and testing of the Aegis BMD system that can
be applied to programs for developing and testing land-based systems?

With seven successful intercepts in eight flight tests, the Aegis BMD program
has achieved a higher rate of successful intercepts than has the ground-based
midcourse system. At least some part of the Aegis BMD program’s higher success
rate may be due to two factors:
! The configuration of the Aegis BMD system that has been tested to
date is intended to shoot down shorter-range ballistic missiles. In
general, shorter-range missiles fly at lower speeds than longer-ranged
missiles, and interceptors intended to shoot down shorter-ranged
54 For more on the CG(X) program, see CRS Report RL32109, Navy DDG-1000 (DD(X))
and CG(X) Ship Acquisition Programs: Oversight Issues and Options for Congress
, by
Ronald O’Rourke.
55 See the “Options For Congress” section of CRS Report RL32109, op. cit.

CRS-18
ballistic missiles don’t need to be as fast as interceptors intended to
shoot down longer-ranged ballistic missiles. Consequently, the
closing speeds56 involved in intercepts of shorter-ranged ballistic
missiles are generally lower than those for intercepts of longer-ranged
ballistic missiles. Intercepts involving lower closing speeds can be
less difficult to attempt than intercepts involving higher closing
speeds. In BMD tests over more than 20 years, tests of shorter-range
kinetic-energy BMD systems has generally been more successful than
tests of longer-range BMD systems.57
! The Aegis BMD system is being developed as an extension of the
existing Aegis air defense system, and can thus benefit from the
proven radar, software, and interceptor technology of that system,
whereas the ground-based midcourse system is being developed
essentially as a relatively new weapon system.
The potential question is whether these two factors account completely for the
difference in success rates for testing of the Aegis BMD program and the ground-
based midcourse program. If they do not, then one potential issue is whether there
is something about the approach adopted for developing and testing the Aegis BMD
capability, compared to that of the ground-based midcourse program that accounts
for part of the difference.
As mentioned earlier, the Aegis BMD program says it has focused since its
inception on the philosophy of “test a little, learn a lot.” It can also be noted that the
Navy has a long history of air-defense missile development programs, and has
established a record of technical discipline, rigorousness, and excellence in areas
such as nuclear propulsion and submarine-launched ballistic missiles. Potential
questions for Congress include the following:
! How do the Aegis BMD and ground-based midcourse programs
compare in terms of their approaches for system development and
testing?
! Are there features of the Aegis BMD program’s approach that, if
applied to the ground-based midcourse program or other U.S. BMD
programs, could improve the development and test efforts for these
programs?
56 Closing speed is the relative speed at which the missile warhead and the interceptor
kinetic kill vehicle approach one another.
57 For a discussion, see CRS Report RL33240, Kinetic Energy Kill for Ballistic Missile
Defense: A Status Overview
, by Steven A. Hildreth.

CRS-19
Potential Allied Programs
Should current efforts to explore the potential for establishing BMD capabilities in
allied navies be reduced, accelerated, or maintained at current levels?

A final potential issue for Congress concerns the potential for establishing BMD
capabilities in allied navies. Should these efforts be reduced, accelerated, or
maintained at current levels? Potential oversight questions for Congress include the
following:
! What are the potential military and political advantages and
disadvantages of establishing BMD capabilities in allied navies?
! To what degree, if any, would these capabilities be integrated into
the overall U.S. BMD architecture? How, in terms of technology,
command and control, doctrine, and training, would such an
integration be accomplished? If these capabilities are not integrated
into the U.S. architecture, what kind of coordination mechanisms
might be needed to maximize the collective utility of U.S. and allied
sea-based BMD capabilities or to ensure that they do not work at
cross-purposes?
! How might the establishment of BMD capabilities in allied navies
affect U.S. requirements for sea-based BMD systems? To what
degree, if any, could allied BMD ships perform BMD operations
now envisaged for U.S. Aegis ships?
! What are the potential implications for regional security of missile
proliferation and proliferation of BMD systems?
Legislative Activity for FY2007
For FY2007, the Administration requested $1,031.9 million in research and
development funding for the Aegis BMD program; Congress appropriated about
$1,127.4 million — a $95.5-million increase over the requested amount.
FY2007 Defense Authorization Act (H.R. 5122/P.L. 109-364)
House. The House Armed Services Committee, in its report (H.Rept. 109-452
of May 5, 2006) on H.R. 5122, stated the following with regard to the FY2007
request for research and development funding for the Aegis BMD program:
The budget request contained $1.0 billion in PE [program element] 63892C
for Aegis ballistic missile defense (BMD).
The committee is encouraged by the Aegis BMD program performance and
overall cost/schedule performance. The committee understands that budget

CRS-20
constraints have reduced planned SM-3 interceptor procurement, thereby
delaying SM-3 interceptor deployment to Aegis BMD platforms.
The committee recommends $1.1 billion in PE 63892C for Aegis BMD, an
increase of $40.0 million, to include: $10.0 million for continued S-band
advanced radar algorithm work for missile defense applications, $10.0 million
for Aegis open architecture program acceleration, and $20.0 million to increase
the SM-3 production rate from two per month to four per month. (Page 242)
The report also stated:
The budget request contained $473.1 million in PE 63890C for ballistic
missile defense systems (BMDS) core.
The committee is concerned with the results of a March 2006 Department
of Defense Inspector General report finding weaknesses in the Missile Defense
Agency’s systems engineering plans and processes. The committee is
particularly concerned with the report’s finding that the Aegis missile defense
system, an element of the BMDS that has achieved success in actual intercept
tests and that is being fielded and deployed now, lacks an approved systems
engineering plan. The committee directs the Secretary of Defense to submit a
report to the congressional defense committees by February 1, 2007, stating the
specific deficiencies in the Aegis systems engineering plan and the required
corrective action.
The committee recommends $483.1 million in PE 63890C, an increase of
$10.0 million for additional support for the Aegis missile defense system
information assurance and systems engineering integration efforts. (Page 243)
The report also stated:
The budget request contained $75.3 million for AEGIS support equipment,
but included no funds for modernizing AEGIS land-based test sites.
The committee understands that the AEGIS land-based test sites are
essential to the operational effectiveness of the AEGIS weapons system,
including the development of an integrated missile defense system capable of
providing a layered defense against ballistic and cruise missiles. The committee
is aware that in order to maintain the highest possible level of effectiveness, the
land-based test sites require state-of-the-art upgrades to peripheral emulators and
switching systems used to collect and analyze combat system performance data.
Modernization of the emulators and switches will ensure timely testing,
certification and delivery of updated AEGIS baselines to the fleet.
The committee recommends $80.3 million for AEGIS Support Equipment,
an increase of $5.0 million to be used for modernizing AEGIS land-based test
sites. (Page 82)
Senate. Section 232 of S. 2766, the Senate-passed version of the FY2007
defense authorization bill, stated:

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SEC. 232. POLICY OF THE UNITED STATES ON PRIORITIES IN THE
DEVELOPMENT, TESTING, AND FIELDING OF MISSILE DEFENSE
CAPABILITIES.
(a) FINDINGS- Congress makes the following findings:
(1) In response to the threat posed by ballistic missiles, President George
W. Bush in December 2002 directed the Secretary of Defense to proceed with the
fielding of an initial set of missile defense capabilities in 2004 and 2005.
(2) According to assessments by the intelligence community of the United
States, North Korea tested in 2005 a new solid propellant short-range ballistic
missile and is likely developing intermediate-range and intercontinental ballistic
missile capabilities that could someday reach as far as the United States with a
nuclear payload.
(3) According to assessments by the intelligence community of the United
States, Iran continued in 2005 to test its medium range ballistic missile, and the
danger that Iran will acquire a nuclear weapon and integrate it with a ballistic
missile Iran already possesses is a reason for immediate concern.
(b) POLICY- It is the policy of the United States that the Department of
Defense accord a priority within the missile defense program to the development,
testing, fielding, and improvement of effective near-term missile defense
capabilities, including the ground-based midcourse defense system, the Aegis
ballistic missile defense system, the Patriot PAC-3 system, the Terminal High
Altitude Area Defense system, and the sensors necessary to support such
systems.
The Senate Armed Services Committee, in its report (S.Rept. 109-254 of May
9, 2006) on S. 2766, stated:
The budget request included $1.0 billion in PE 63892C, for the sea-based
Aegis Ballistic Missile Defense (BMD) system. The Aegis BMD is intended to
provide protection against short- and medium-range ballistic missiles. The
committee recommends an increase of $100.0 million in PE 63892C to restore
the delivery of SM-3 interceptors to 120 by the end of fiscal year 2011, and to
increase the overall effectiveness of the Aegis BMD system capability against
longer-range threats. Of the increased amount, the committee directs $70.0
million be applied toward procuring 24 additional SM-3 block 1B missiles over
fiscal years 2008 to 2011, and $30.0 million be used to accelerate SM-3 and
Aegis weapon system integration to take full advantage of missile and weapons
systems capabilities, including the BMD signal processor and two-color seeker.
MDA is expected to budget for the completion of these tasks over fiscal years
2008 to 2011. (Page 126)
Conference. Section 223 of the conference report (H.Rept. 109-702 of
September 29, 2006) on H.R. 5122 (P.L. 109-364 of October 17, 2006) stated:
SEC. 223. POLICY OF THE UNITED STATES ON PRIORITIES IN THE
DEVELOPMENT, TESTING, AND FIELDING OF MISSILE DEFENSE
CAPABILITIES.
(a) FINDINGS.—Congress makes the following findings:
(1) In response to the threat posed by ballistic missiles, President George
W. Bush in December 2002 directed the Secretary of Defense to proceed with the
fielding of an initial set of missile defense capabilities in 2004 and 2005.

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(2) According to assessments by the intelligence community of the United
States, North Korea tested in 2005 a new solid propellant short-range ballistic
missile, conducted a launch of a Taepodong-2 ballistic missile/space launch
vehicle in 2006, and is likely developing intermediate-range and intercontinental
ballistic missile capabilities that could someday reach as far as the United States
with a nuclear payload.
(3) According to assessments by the intelligence community of the United
States, Iran continued in 2005 to test its medium-range ballistic missile, and the
danger that Iran will acquire a nuclear weapon and integrate it with a ballistic
missile Iran already possesses is a reason for immediate concern.
(b) POLICY.—It is the policy of the United States that the Department of
Defense accord a priority within the missile defense program to the development,
testing, fielding, and improvement of effective near-term missile defense
capabilities, including the ground-based midcourse defense system, the Aegis
ballistic missile defense system, the Patriot PAC-3 system, the Terminal High
Altitude Area Defense system, and the sensors necessary to support such
systems.
The report discusses this provision on pages 639-640. With regard to the
FY2007 funding request for the Aegis BMD program, the report stated:
The budget request included $1.0 billion in PE 63892C for the sea-based
Aegis Ballistic Missile Defense system.
The House bill would authorize an increase of $40.0 million in PE 63892C.
The Senate amendment would authorize an increase of $100.0 million in
PE 63892C.
The conferees agree to authorize $1.1 billion in PE 63892C, an increase of
$100.0 million. The increase is directed as follows: $10.0 million for continued
S-band advanced radar algorithm work; $20.0 million for Aegis BMD signal
processor, 2-color seeker development, and acceleration of the open architecture
program; and $70.0 million to support the procurement of 24 additional SM-3
block 1B missiles over fiscal years 2008 to 2011. MDA is expected to budget
for the completion of these tasks over fiscal years 2008 to 2011.
The conferees are aware that the MDA and the Department of the Navy are
exploring the feasibility of modifying 100 SM-2 Block IV missiles to obtain a
near-term sea-based terminal ballistic missile defense capability starting in fiscal
year 2007 with conversion of all missiles completed by the end of fiscal year
2009. According to briefings by the MDA and Department of the Navy, such a
capability could afford protection for ships and other critical assets against
short-range ballistic missiles in the Scud A/B class. This proposed development
would cost approximately $130.0 million over fiscal years 2007 to 2009, with the
Navy share estimated at approximately $20.0 million in fiscal year 2007. The
conferees, while supportive of efforts to provide near-term missile defense
capability, require further information before authorizing this development effort
to proceed. Therefore, the conferees encourage the Department of Defense to
submit to Congress a reprogramming request in fiscal year 2007 to pursue a
sea-based terminal missile defense capability, should such a step be consistent
with Department requirements and resource constraints. If submitted, the
reprogramming request should be accompanied by documentation that: (1)
explains the need for such a capability; (2) indicates Department of the Navy

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endorsement of this program; and (3) includes a Navy-MDA cost-share
agreement through completion of the effort. (Page 629)
FY2007 Defense Appropriations Act (H.R. 5631/P.L. 109-289)
House. The House Appropriations Committee, in its report (H.Rept. 109-504
of June 16, 2006), recommended a $25-million increase to the amount requested for
research and development funding for the Aegis BMD program, of which $20 million
is for “Aegis BMD Spiral Processor and Migration of Aegis BMD into OA [open
architecture]” and $5 million is for “Asymmetric Missile Defense” (page 285). The
report stated:
The Committee commends the Missile Defense Agency (MDA) for
showing progress and promise for continued success in its Aegis Ballistic Missile
Defense System. The Committee strongly urges that MDA refrain from
transferring funds out of the Aegis program to other missile defense programs
during the year of execution and in the Future Years Defense Program (FYDP)
and expects MDA shall fully fund and execute the Aegis program as Congress
intends. (Page 290)
The report also recommended a $4-million increase to the $75.3 million
requested in FY2007 for Aegis support equipment (page 144).
Senate. The Senate Appropriations Committee, in its report (S.Rept. 109-292
of July 25, 2006) on H.R. 5631, recommended a $108.2-million increase to the
amount requested for research and development funding for the Aegis BMD
program, of which $20 million is for “Aegis BMD Signal Processor and Migration
of Aegis BMD into OA [open architecture],” $80 million is for Aegis SM-3
development and procurement, and $8.2 million is for upgrades to the Pacific Missile
Range Facility (PMRF) in Hawaii (page 213). The report stated:
The Committee recognizes MDA’s concern over expanding and evolving
threats. However, the Committee is concerned that MDA is investing too much
funding in future systems and technology in advance of adequate testing and
fielding of currently available technology. Therefore, the Committee’s budget
recommendations reflect a continuing emphasis on improving, testing and
fielding the current missile defense components, in particular: Ground Based
Midcourse Defense, AEGIS Ballistic Missile Defense, Theater High Altitude
Area Defense and Airborne Laser.
The Committee commends MDA for successful testing of both the Theater
High-Altitude Area Defense and AEGIS systems over the fiscal year 2006
period. In addition, the Committee was encouraged by MDA’s ability to quickly
transition between development and test to provide immediate operational
capability during the recent North Korean missile launches. The Committee
understands that periods of immediate operational need will continue to arise in
parallel with the development efforts; and therefore supports MDA’s efforts to
expand concurrent test and operations. To address these issues, the Committee
provides an increase of $225,000,000 for additional test infrastructure
enhancements, operational support, and interceptors. (Pages 216-217)

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Conference. The conference report (H.Rept. 109-676 of September 25, 2006)
on H.R. 5631 (P.L. 109-289 of September 29, 2006) recommended a total of
$1,127.4 million in research and development funding for the Aegis BMD program
— a $95.5-million increase over the requested amount, of which of which $20
million is for “Aegis BMD Signal Processor and Migration of Aegis BMD into OA
[open architecture],” $4 million is for “Asymmetric Missile Defense,” $65 million
is for “Aegis Improvements,” and $6.56 million is for upgrades to the Pacific Missile
Range Facility (PMRF) in Hawaii (page 337). The report stated:
The conferees have provided $65,000,000 for AEGIS Improvements. Of
that amount $15,000,000 is available for the Sea-Based Terminal Capability, and
$50,000,000 is available for development and procurement of SM-3 Interceptors.
The conferees are aware that there is an additional requirement of
$20,000,000 in fiscal year 2007 for Sea-Based Terminal Defense, and direct the
Missile Defense Agency to submit a prior approval reprogramming to fully fund
this requirement. (Page 343)
The report also stated:
The conferees remain concerned that the Missile Defense Agency is
moving funds between various elements and programs and/or moving contract
scope across elements and programs in order to avoid reductions made by the
congressional defense committees. This practice is unacceptable and MDA is
directed to use prior approval reprogramming procedures specified in the report
accompanying the House version of the fiscal year 2007 Department of Defense
Appropriations bill (H.R. 109-504) for any movement of funds or contract scope
beyond the $10,000,000 threshold in research, development, test and evaluation.
The MDA shall follow the limitation that prior approval reprogramming is set at
either the specified dollar threshold or 20% of the line, whichever is less. The
conferees agree that: Ballistic Missile Defense AEGIS, PE 0603892C; Ballistic
Missile Defense Terminal Defense Segment, PE 0603881C; Ballistic Missile
Defense Midcourse Defense Segment, PE 0603882C; and Multiple Kill Vehicle,
PE 0603894C are designated as congressional special interest items subject to
prior approval reprogramming procedures. (Page 342)
The report also recommended a $1.8-million increase to the $75.3 million
requested in FY2007 for Aegis support equipment for Aegis computer center
upgrades (page 190).
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