National Missile Defense and Early Warning Radars: Background and Issues

National Missile Defense and Early Warning Radars: Background and Issues

Order Code RL30654
CRS Report for Congress
Received through the CRS Web
National Missile Defense and Early Warning
Radars: Background and Issues
August 25, 2000
(name redacted)
Congressional Fellow
Foreign Affairs, Defense, and Trade Division
Congressional Research Service ˜ The Library of Congress

National Missile Defense and Early Warning Radars:
Background and Issues
Summary
The Clinton Administration is scheduled to decide by Fall 2000 whether the
United States should begin deploying a National Missile Defense (NMD) system. This
system could achieve initial operational capability by 2005 and would be designed to
protect the United States from a limited attack by intercontinental ballistic missiles
(ICBMs). As currently envisioned, the NMD system would operate as an integrated
system that would rely on a variety of sensors to detect and track incoming missiles.
One key program element is to upgrade the existing Early Warning Radars (EWR) so
that they can detect and track the incoming missiles sooner. These upgrades include
both hardware and software modifications to the existing radars. The earlier detection
and tracking allows a "shoot-look-shoot" strategy, i.e., sequential launching of
multiple interceptors at each incoming missile to increase the probability of intercept.
This report provides background information and technical details of these planned
upgrades as well as their cost and schedule.
NMD remains one of the most controversial national security issues. An in-depth
analysis of the NMD program and the debate on it can be found in CRS Issue Brief
IB10034. Although the EWR have not yet generated much discussion, their upgrades
may also become controversial. Members of Congress could focus on the cost and
technical capability of the upgrades, on the legality of these upgrades under the 1972
Anti-Ballistic Missile (ABM) Treaty, or on the international implications of the radars
that are located outside the United States. This report will address the issues
associated with the planned radar upgrades and the related options for Congress.
The early warning radars planned for the NMD system include the three PAVE
PAWS radars at Cape Cod, Massachusetts; Clear, Alaska; and Beale, California; and
the two Ballistic Missile Early Warning System (BMEWS) radars at Thule, Greenland
(Denmark) and Fylingdales, U.K.. The current mission of these five radars is to
provide the North American Aerospace Defense Command (NORAD) with early
warning and assessment of incoming ICBMs and SLBMs. The upgraded radars will
be designed to support the new NMD requirements without impacting their current
NORAD mission.
The Administration argues that upgrading current radars provides effective, low-
cost sensors for the NMD mission by reusing about 80% of the equipment at the
existing radar sites. Due to the radar operating frequency, the upgraded radars could
only provide accurate tracking information for a few warheads accompanied by simple
decoys. Thus, the Administration argues that these radar upgrades are for limited
defense against limited attacks, not total defense against more advanced ICBM
attacks.

Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Early Warning Radars Upgrades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Current Radars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Planned Upgrades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Schedules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
NMD Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
UEWR Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Issues for Congress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Cost and Technical Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
ABM Treaty Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
International Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Options for Congress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Appendix: List of Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
List of Figures
Figure 1. UEWR as an NMD System Element . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Figure 2. The Five Radar Sites and Installation/Modification Dates . . . . . . . . . . 4
Figure 3. The PAVE PAWS Radar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 4. The BMEWS Radar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 5. NMD Program Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 6. UEWR Program Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
List of Tables
Table 1. The Characteristics and Measurement Capabilities of Current and Upgraded
Radars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Table 2. Cost Estimates for the UEWR Portion of the NMD Program . . . . . . . 9
Table 3. Funding Profile for the UEWR Program . . . . . . . . . . . . . . . . . . . . . . . 10

National Missile Defense and Early Warning
Radars : Background and Issues
Introduction
Background
The Clinton Administration is scheduled to decide by Fall 2000 whether the
United States should begin deploying a National Missile Defense (NMD) system. The
system under consideration would likely include 100 land-based interceptor missiles
currently planned for a site in Alaska. According to the Administration, this system
could achieve initial operational capability by 2005 and would be designed to protect
the United States from a limited attack by intercontinental ballistic missiles (ICBMs).
The system is intended to protect the United States from emerging threats from
nations such as North Korea, which, according to intelligence reports, is seeking to
develop an ICBM capability. The current plan also envisions the possible deployment
of more extensive systems around the end of the decade for protection against more
advanced ICBM threats.
At the present time, the prospective NMD system architecture would operate as
an integrated system that would rely on a variety of sensors to detect and track
incoming missiles. This concept is shown in Figure 1. Space based sensors, Defense
Support Program (DSP) satellites at first and eventually the Space-Based Infrared
System (SBIRS) High, would detect the launch, alert the Ballistic Missile
Command/Control Center (BMC3) of a potential ballistic missile attack, and then cue
an Upgraded Early Warning Radar (UEWR) to the incoming missile. When the
incoming missile comes within range, the UEWR would begin tracking the target
missile to determine if it is a threat. Upon threat confirmation, the command center
would direct the launch of a ground-based interceptor and cue the X-Band radar. The
X-band radar would then provide tracking data to the interceptor through in-flight
targeting updates (IFTU). This tracking data would be used by the interceptor to
maneuver close enough to the target so that the interceptor’s sensor could
discriminate the warhead from possible decoys. The interceptor’s sensors would
provide the final course corrections so the interceptor could destroy the target.1
Launching multiple interceptors at each incoming missile, a "shoot-look-shoot"
strategy, is designed to increase the probability of a successful intercept. Because the
UEWR could provide earlier detection, track, and classification, these upgrades
would enable the multiple shot strategy. This report will provide background
information and technical details of the planned upgrades to the existing Early
1 National Missile Defense Program, BMDO Fact Sheet JN-00-05, January 2000.

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Warning Radars (EWR). These upgrades include both hardware and software
modifications to the existing radars. In addition, new displays would be added to
existing interior equipment. There would be no changes to the radar operating
frequency, the maximum power output, or the exterior of the existing equipment.2
Figure 1. UEWR as an NMD System Element
Issues
NMD remains one of the most controversial national security issues. Details of
this program and the debate on it can be found in CRS Issue Brief IB10034. Although
the UEWRs have not yet generated much discussion, their upgrades may also become
controversial. Members of Congress could focus on the cost and technical capability
of the upgrades, on the legality of these upgrades under the 1972 Anti-Ballistic
Missile (ABM) Treaty, or on the international aspects of the UEWRs that are located
outside the United States. This report will also address these issues associated with
the planned radar upgrades.
2 Early Warning System, BMDO Fact Sheet JN-00-13, February 2000.

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Early Warning Radars Upgrades
Current Radars
The early warning radars planned for the NMD system include the three PAVE
PAWS radars at Cape Cod, Massachusetts; Clear, Alaska; and Beale, California ; and
the two Ballistic Missile Early Warning System (BMEWS) radars at Thule, Greenland
(Denmark) and Fylingdales, U.K. These locations are shown in Figure 2. All five
radars are solid-state phased arrays. The two BMEWS radars were originally
mechanically scanned dish radars but were modified in the late 1980s to phased arrays
to improve their reliability.3 A phased array radar has no moving parts. The Clear
radar was originally a mechanically scanned BMEWS system but is currently being
replaced with a PAVE PAWS system for increased reliability.4 The PAVE PAWS
equipment came from a non-operational site at Eldorado, Texas. The PAVE PAWS
and the BMEWS radars perform similar tasks: long-range, early detection of ballistic
missiles. Originally, the BMEWS were for longer range ICBM detection while the
PAVE PAWS were for shorter range Sea Launched Ballistic Missile (SLBM)
detection. However, the 1980 BMEWS reliability modifications used PAVE PAWS
type transmit/receive (T/R) modules and antenna elements so that now both radars
have similar performance.5 The BMEWS radar still has slightly longer range due to
its larger size and therefore more T/R modules and antenna elements in each array
face.
The current mission of these five radars is to provide the North American
Aerospace Defense Command (NORAD) and the U.S. Space Command
(USSPACECOM) with early warning and assessment of incoming ICBMs and
SLBMs. In addition, these radars track space debris for USSPACECOM.
3 Matthew Bunn, “ABM Treaty and National Security,” Arms Control Associates, 1990,
pp.100-101.
4 “Clear Air Station breaks ground on new radar,” Air Force News Service, April 21, 1998.
5 Stanley Kandebo, “NMD Systems integrates new and used components,” Aviation Week and
Space Technology, 3 March 1997, pp. 47-51.

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Figure 2. The Five Radar Sites and Installation/Modification Dates
160°
180°
160°
40°
N o r t h P a c i f i c O c e a n
140°
50°
140°
B e r i n g S e a
S e a o f
Beale AFB
O k h o t s k
1976-1979
Clear AS
60°
1997-2001
C h u k c h i
S e a
Wrangel
120°
Island
70°
120°
B e a u f o r t
New
S e a
Siberian
Banks
A r c t i c
Islands
Island
L a p t e v
O c e a n
80°
S e a
Victoria
Island
Queen
100°
100°
Elizabeth
Severnaya
Zemlya
Islands
North
H u d s o n
Pole
Ellesmere Island
B a y
K a t a
S e a
80°
80°
Baffin
Thule AB
Franz
Josef
Land
Island
B a f f i n
B a y 1983-1987
Novaya
Zemlya
80°
Cape Cod AS
1976-1979
B a r e n t s S e a
D a v i s S t r a i t
G r e e n l a n d
S e a
70°
60°
60°
D e n m a r k S t r a i t
N o r w e g i a n
L a b r a d o r
S e a
S e a
60°
N o r t h
A t la n t i c
O c e a n
RAF Fylingdales
50°
1988-1992
40°
40°
B l a c k S e a
40°
20°
0°
20°
Adapted by CRS from Magellan Geographix.

CRS-5
The BMEWS at Thule and all three PAVE PAWS radars have two array faces.
Each array face provides 120 degrees of azimuth coverage and from 3 to 85 degrees
elevation coverage in search and track modes. The BMEWS at Fylingdales has three
array faces and provides 360 degrees of azimuth coverage.6 All the radars operate
at the ultra high frequency (UHF) band. Figure 3 shows the PAVE PAWS radar and
Figure 4 shows the BMEWS radar.
Figure 3. The PAVE PAWS Radar
l UHF (420-450 MHZ)
l Number of T/Rs/Face: 1,792
Elements./Face: 2,677
l Number manufactured: 4
l Diameter: 72 Ft
l Built by Raytheon
Figure 4. The BMEWS Radar
l UHF (420-450 MHZ)
l Number. T/Rs/Face: 2,560
Elements/Face: 3,584
l Number manufactured: 2
l Diameter: 84 FT
l Built by Raytheon
6 “Phased Array: Advances and Future Trends,” paper presented by Dr. Eli Brookner at the
International Radar Conference, Washington, D.C., May 2000.

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Planned Upgrades
The planned NMD system architecture relies on earlier radar detection, track,
and classification of targets to enable an earlier launch of its interceptors for the
shoot-look-shoot strategy. Upgrades to the existing early warning radars are
designed to improve the detection and track range by detecting objects closer to the
radar horizon, tracking them with improved accuracy, and then sending the target
position and velocity directly to the NMD command system. The upgrades are
designed to improve the radar performance in the following specific areas:7
! Acquisition - Acquire warhead sized objects at longer range
! Tracking - Provide precise track estimates to allow earlier
interceptor launch
! Object Classification - Identify and distinguish between threatening
and non-threatening objects
! Multiple Missions - Perform the new NMD missions without
degrading the current early warning and surveillance missions
! Command and Control - Provide real-time communications to the
NMD command system in addition to current communication
channels
The major hardware modifications planned for the UEWR include replacing the
existing computers, displays, and communication equipment with off-the-shelf
equipment and developing a new radar exciter receiver. The radar’s exciter receiver
provides the basic radar transmission signal and then receives and decodes the return
signal. The new exciter receiver would provide wider instantaneous bandwidth that
allows improved signal processing. This improved signal processing enables the finer
range resolution required for improved tracking and object classification.8
Fortunately, the increased instantaneous bandwidth still lies within the current
allocated UHF bandwidth so that additional frequency allocation is not required.
The radar software would be rewritten to include the improved acquisition,
tracking, and classification algorithms for small objects near the horizon. The existing
software is modular and would be rewritten in seven phases (or builds).9 The
upgraded radar would then be able to search for different types of missiles, distinguish
hostile objects such as warheads from other objects, and provide this data to the
NMD control system using an improved communications system.
The Administration argues that upgrading current radars provides effective, low-
cost sensors for the NMD mission by reusing approximately 80% of the equipment
at the existing radar sites. The radiated peak and average power, radar patterns, and
operating bandwidth of the upgraded radars remain unchanged from the current
radars. Also, there would be no increase in the number of personnel operating the
equipment.
7 Early Warning System, BMDO Fact Sheet JN-00-13, February 2000.
8 Discussions with the Raytheon Business Development Office, June 2000.
9 Discussions with the Raytheon Business Development Office, June 2000.

CRS-7
Table 1 is a summary of the characteristics and measurement capabilities of the
current and upgraded radars.10 As can be seen, the only performance change is the
improved instantaneous bandwidth provided by the new exciter receiver that allows
the finer range resolution required for improved tracking and object classification. In
view of these radar technical characteristics (the UHF operating frequency in
particular), the upgraded radars could only provide accurate tracking information for
a few warheads accompanied by simple decoys. Thus, the Administration argues that
these radar upgrades are for limited defense against limited attacks, not total defense
against large scale attacks.
Table 1. The Characteristics and Measurement Capabilities of
Current and Upgraded Radars
Current PAVE
Current BMEWS
Upgraded Early
PAWS
Warning Radars
(in Alaska, California,
(in Greenland and
and Massachusetts)
Britain)
Frequency
420-450 MHz
420-450 MHz
Unchanged
Antenna Diameter
22.1 m
25.6 m
Unchanged
Average Power
150 kW
255 kW
Unchanged
(per face)
Detection Range
5,000 km in search
5,000+ km in
Unchanged
mode
search mode
Bandwidth
100 kHz
300-600 kHz
# 30 MHz
(search mode);
(search mode);
1 MHz
5-10 MHz
(track mode)
(track mode)
Range Resolution
1,500 m
250-500 m
$ 5 m
(search mode);
(search mode);
150 m
15-30 m
(track mode)
(track mode)
Angular
0.038 radians
. 2.0°
Unchanged
Beamwidth
= 2.2°
Cross-Range
75 km
70 km
Unchanged
Resolution (for
objects at a range
of 2,000
kilometers)
10 “Countermeasures,” Union of Concerned Scientists, MIT Security Studies Program, p.
140, April 2000.

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Schedules
NMD Schedule
For perspective, the overall NMD program schedule, as outlined in Pentagon
programming documents, is shown in Figure 5.11 There are three major program
milestones, but only the Defense Acquisition Board (DAB) in fiscal year 2001 (FY01)
affects the UEWR program. The FY01 DAB approval is required for initiation of the
UEWR upgrades.
Figure 5. NMD Program Schedule
UEWR Schedule
Raytheon would perform the majority of the work for the UEWR program.
Raytheon also built the PAVE PAWS radars and performed the phased array
modifications to the BMEWS radars in the 1980s. Raytheon currently has a contract
that continues until April 2001 for the development of the hardware and software
upgrades. This development program is on schedule, having completed Phase 1
(Build 1) of the software development and also the Receiver/Exciter preliminary
design review (REX PDR) as shown in Figure 6.12
The DAB in the third Quarter of FY01 would authorize Raytheon to complete
the development and then the deployment of the radar upgrades. Figure 6 shows the
total UEWR program schedule, including the software development (7 phases or
builds), the hardware development, the testing, and the deployment. As can be seen,
the UEWR schedule in Figure 6 corresponds with the NMD schedule in Figure 5. The
majority of the UEWR program is after the UEWR critical design review (CDR) and
the NMD DAB in the third Quarter of FY01.
11 Boeing Briefing Booklet for IFT 5, p. 33, July 2000.
12 Discussions with the Raytheon Business Development Office, June 2000.

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Figure 6. UEWR Program Schedule
S
FY 98 FY 99
FY 00 FY 01 FY 02
FY 03 FY 04
FY 05
FY 06 FY 07
NMD Milestones
ATP
DRR
DAB
SFR
ERR
PDR
System IOC
UEWR Program Plan
IDR
CDR
Software Development
Build 1 - Infrastructure
Build 2 - Radar Mgmt/Track
Build 3 - Signal Processing / BMC3
Build 4 - REX / Displays
Build 5 - Spacetrack
Build 6 - Iono
FQT
Build 7 SRD Rev 3
REX PDR
REX CDR
Hardware Development
REX #1 Complete
Basic
Delivery Schedule
Delivery Schedule
Deployment
Beale
Beale
11/03
11/03
Thule
Thule
1/05
1/05
Clear
Clear
8/04
8/04
Fylingdales
Fylingdales
9/05
9/05
Cape Cod
6/05
Time Now
Cape Cod
6/05
Cost
For several years, the Clinton Administration estimated that a limited NMD
system would cost $9 to $11 billion to develop, test, and deploy. In January 1999, the
Administration included $10.6 billion in the Future Years Defense Program (FYDP)
to cover the cost of developing and deploying an initial system of 20 interceptors. In
February 2000, the Administration provided a life-cycle cost estimate of $26.6 billion
for an initial system of 100 ground-based interceptors, presumably in Alaska. Even
more recently, the Pentagon provided a life-cycle estimate of $30.2 billion for the
NMD system ($FY1991). As time passes and more detailed assessments are
completed, these numbers are likely to change.

Table 2 gives the latest estimates for both the UEWR program and the NMD
program. It includes the Administration estimate and the Congressional Budget Office
(CBO) estimate.13 As can be seen, the UEWR program is approximately 4.5% of the
total NMD program. Also, the CBO estimate for the UEWR is very close to the
Administration estimate which implies that CBO does not believe there is much cost
risk or technical risk in the UEWR portion of the NMD program.
Table 2. Cost Estimates for the UEWR Portion of the NMD Program
Administration Estimate
CBO Estimate
UEWR
$1.2 B
$1.3 B
NMD total
$30.2 B
$29.5 B
% UEWR
4.0%
4.4%
13 “Budgetary and Technical Implications of the Administration’s Plan for NMD,” CBO
paper, April 2000.

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Table 3 shows the planned funding profile for the UEWR program.14 The
funding profile is based on constrained funding in FY01. The funding requirement
then increases significantly in FY02 through FY04 to accomplish development and
procurement for initial operating capability in 2005. This increased funding would
come after the UEWR authorizing DAB in third Quarter FY01. Lesser funding levels
after 2005 would be required to sustain additional software modifications as required.
Table 3. Funding Profile for the UEWR Program
(in millions of dollars)
Priors FY01 FY02 FY03 FY04 FY05 FY06 FY07 FY08
Total
Development
154
121
131
89
64
18
2
$579M
Procurement
7
152
318
128
22
3
3
3
$636M
Total
154
128
283
407
192
40
5
3
3 $1215M
Issues for Congress
Cost and Technical Risks
As described earlier, the upgrades to the existing early warning radars would
require few technical breakthroughs and therefore are considered relatively low risk
(both technical risk and cost risk). Raytheon built the original PAVE PAWS radars
and performed the phased array modifications to the BMEWS radars in the 1980s.
They have developed similar hardware and software upgrades. Raytheon is under
contract for the initial hardware and software development. If the upgrades are
approved, follow-on UEWR contract funding would be required in April 2001 to
meet the planned schedule. The only major cost risk is a break in contract funding,
which could delay the program and therefore increase the program cost.
One technical risk area is the available time-line to accomplish both the NMD
target tracking requirements and at the same time maintain the current early warning
and assessment surveillance for other possible incoming ICBM’s. Current analysis
shows that both these tasks can be accomplished in the available time-line, but this is
an area for continual monitoring.
ABM Treaty Issues
The plans to upgrade the existing early warning radars and to integrate these into
the NMD system could raise questions about compliance with the 1972 ABM
Treaty.15 This Treaty draws a sharp distinction between ABM radars, which are
14 Discussions with Congressional Budget Office, June 2000.
15 This report recognizes the debate over whether the ABM treaty remains in force due to the
dissolution of the Soviet Union. However, because it remains the U.S. policy to abide by the

CRS-11
radars “constructed and deployed for an ABM role, or of a type tested in an ABM
mode”16 and early warning radars, which simply provide warning of strategic ballistic
missile attack. The Treaty states that ABM radars or ABM radar complexes must be
located within the ABM system deployment area, which must have a radius of no
more than 150 kilometers.17 It also states that the parties are not to give radars, other
than ABM radars, capabilities to counter strategic offensive ballistic missiles, and not
to test radars, other than ABM radars, in an ABM mode.18 Essentially, this means
that non-ABM radars, i.e., those located outside the 150km radius of the permitted
ABM site, cannot provide tracking and intercept information to the battle-
management network for the ABM system and they cannot be tested in conjunction
with the other components of the ABM system. But this is precisely what the United
States intends to do with the upgraded early warning radars. This issue will have to
be resolved at some point if the ABM Treaty remains in force.
A second Treaty issue that might come up as the United States upgrades the
radars in Greenland and Great Britain is the Treaty’s provision that future early
warning radars must be deployed on the periphery of the nation’s territory and must
be oriented outwards.19 Because the radars at Thule and Fylingdales were in place
prior to the signing of the ABM Treaty, they were grand-fathered into the Treaty and
are not considered to be a Treaty violation. When the United States modified the
radars in the late 1980s, the Soviet Union objected on the grounds that the
modifications and new construction altered the facilities enough to create “new”
radars, that, according to the treaty, could not be located anywhere except on the
periphery of the United States. However, because the modifications were intended
to improve the reliability and operations of the radars, and did not alter their
capabilities, the United States argued that the radars remained consistent with the
terms of the ABM Treaty. The two nations addressed and resolved this issue in the
Standing Consultative Commission (SCC), a body established by the ABM Treaty to
address compliance issues. The United States could take a similar position this time,
and argue that even though the upgrades alter the capabilities of the radars (arguably
prohibited by the Treaty), the facilities remain where they were prior to the signing
of the ABM Treaty, and, therefore remain consistent with the Treaty. Russia is likely
to question whether the upgrades are enough to create “future” early warning radars,
and the two nations could, again, address this issue in the SCC.
A third ABM Treaty issue raised by the plans to upgrade the early warning
radars comes from the Treaty’s provision stating that “each party undertakes not to
Treaty (neither the Executive Branch nor the Senate have determined otherwise), this report
examines the planned radar upgrades in the context of the Treaty.
16 Treaty between the United States of America and the Union of Soviet Socialist Republics
on the Limitation of Anti-Ballistic Missile Systems (ABM Treaty). Article II, para 1(c).
Reprinted in United States Arms Control and Disarmament Agency. Arms Control and
Disarmament Agreements; Texts and Histories of the Negotiations. Washington D.C. 1990.
p. 157.
17 ABM Treaty, Article III.
18 ABM Treaty, Article VI.
19 ABM Treaty, Article VI.

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transfer to other states, and not to deploy outside its national territory, ABM systems
or their components limited by this Treaty.”20 If the radars at Thule and Fyingdales
are upgraded and integrated into the U.S. NMD system, then the United States will
have deployed ABM systems or components outside of its national territory.
The Clinton Administration has recognized that its plans to upgrade the early
warning radars so that they can be integrated into the NMD system would be
inconsistent with the current terms of the ABM Treaty. It has raised this issue in its
discussions with Russia on possible modifications to the treaty. In the Protocol that
the Administration presented to the Russians in January 2000, the United States
reportedly proposed that the United States and Russia be “permitted to enable
strategic ballistic missile attack warning radars in existence on December 1, 1999 to
perform ABM radar functions to support the limited territorial missile defense
system”21 In other words, the United States realizes that it would need to alter the
treaty’s ban on giving non-ABM radars ABM roles, and its ban on deploying these
components outside its national territory to accommodate the upgrades to the early
warning radars.
Russia has, thus far, refused to discuss specific proposals for modifications to the
ABM Treaty, either to permit the United States to deploy an NMD system in Alaska
or to include its early warning radars in the architecture for that NMD system. If
Russia does not agree to these modifications, then the United States would violate the
ABM Treaty if it completed the upgrades to the early warning radars and tested these
radars in conjunction with tests of other components of the NMD system.22 Because
other elements of the U.S. NMD program could lead to conflicts with the ABM
Treaty at an earlier date than the upgrades to the early warning radars, it is possible
that the United States and Russia would have resolved their differences, or that the
United States would have decided to withdraw from the treaty, prior to the date on
which the radar upgrades violated the treaty. On the other hand, it is possible that
Russia might eventually agree to permit the deployment of a limited NMD site in
Alaska without agreeing to alter the Treaty’s ban on the use of early warning radars
in an ABM mode. In that case, the United States would have to decide whether to
proceed with the upgrades and violate the treaty, or to cancel the upgrades and accept
a less capable NMD system.
International Issues
The upgrades planned for the early warning radars at Fylingdales and Thule not
only raise ABM Treaty compliance issues but may also cause some friction between
the United States and its allies in Europe. Many European nations have questioned
20 ABM Treaty Article IX.
21 This document was obtained by the Bulletin of the Atomic Scientists from sources in
Moscow. The text of the Protocol, along with U.S. analysis and talking points for the
discussions were published in the Bulletin of the Atomic Scientists and posted on the
magazine’s internet site. See {http://www.bullatomsci.org}
22 It is not clear that the upgrades, alone, would violate the Treaty if the United States
continued to use these radars only in an early warning role.

CRS-13
the U.S. plans, arguing that, by undermining the ABM Treaty, the NMD system could
undermine the whole U.S.-Russian strategic relationship. Some U.S. allies have also
questioned the U.S. assessment of the threat posed by nations seeking to acquire
ballistic missiles, and have suggested that diplomacy or arms control, rather than
missile defenses, could mitigate this threat.
The United States would seek to reach agreement with the governments of
Denmark and Great Britain before it modified the early warning radars on their
territories and included the radars in the U.S. NMD system.23 Some officials in both
nations have voiced opposition to the U.S. NMD system. In early August, the House
of Commons Foreign Affairs Committee issued a report that outlined British concerns
with the U.S. plans. The report stated that the United States ''cannot necessarily
assume unqualified cooperation'' from Great Britain. The report specifically noted
that the committee was concerned about the negative effect that NMD deployment
might have on arms control efforts.24 Officials in Denmark have expressed similar
concerns. They issued a statement in February stating “the government continues to
desire that the use of the Thule radar does not contravene international agreements
in force.”25 The challenge in both countries, with regard to the radar upgrades, will
be to balance domestic concerns with their U.S. partnership.
The United States continues to press this issue with Great Britain and Denmark.
In testimony before the Senate Armed Services Committee in late July, 2000,
Secretary of Defense Cohen stated that the United States would need the support of
its allies to successfully deploy an NMD.26 If the U.S. cannot upgrade and integrate
the radars at Thule and Fylingdales into the NMD system, the United States might
have to accept a system with reduced capabilities until other alternative early warning
systems can be developed.
Options for Congress
At present, cost and technical challenges for the radar upgrades appear less
controversial than ABM Treaty issues and international issues. The latter two issues
could spark more detailed and complex public discussion on the planned radar
upgrades.
Congress has not directly addressed the radar upgrades and their implications.
Supporters of the ABM Treaty may eventually seek alternatives. Some may seek to
suspend the program or eliminate funding for the upgrades until the United States and
Russia resolve the issues related to the ABM Treaty. Alternatively, funding for the
23 “U.S., Denmark discuss Missile Defense”, Washington Post, August 23, 2000, p. 19.
24 Tom Buerkle. U.K. Panel Questions U.S. Missile Shield Plans. Commons Committee's
'Warning Shot' Puts British Aid in Doubt. International Herald Tribune. August 3, 2000,
p. 1.
25 Gopal Ratnam and Amy Svitak. Pentagon Eyes Naval Deployment Of NMD Radar.
Defense News, August 21, 2000. p. 1.
26 Hearing before the Senate Armed Services Committee, July 25, 2000.

CRS-14
program could remain in the budget, but the next Administration might be required
to report on progress in the negotiations, on possible alternatives if the negotiations
fail, or on U.S. intentions to withdraw from the ABM Treaty if the negotiations fail
before it permits the new President to spend additional funds on the radar upgrades.
Others may argue that Treaty issues should not affect plans to upgrade the radars,
either because they believe the United States should withdraw from the ABM Treaty
or because they believe that the ABM Treaty lapsed after the demise of the Soviet
Union.

If the governments in Great Britain and Denmark remain skeptical about U.S.
plans for NMD and continue to question the implications of the upgrades to the radars
on their territories, the issues raised by the radar upgrade effort could receive more
attention in Congress and could generate discussion in the next Administration on
altering the plans for both the radar upgrades and the NMD program. However, the
United States could operate the limited NMD system without the radars at Thule and
Fylingdales. Many analysts believe that the three UEWRs in the United States would
provide adequate coverage for missile attacks from East Asia, although these three
radars would not be sufficient to track and identify possible missile attacks from the
Middle East. Another option for the end of the decade would be a space-based
infrared-radar system (SBIRS-low), which would provide a spaced based early
warning, track, and identify capability. While some analysts may believe the United
States should delay its NMD program until the U.S. receives approval from Great
Britain and Denmark to upgrade the early warning radars on their territories, others
may argue that the United States should proceed regardless, and seek alternative
technologies to enhance the capabilities of the system if required.27
27 According to some experts, the Pentagon is exploring the possibility of basing a version of
the land-based NMD radar at sea as an early warning radar if Great Britain does not permit
upgrades to the early warning radar at Fylingdales. See Gopal Ratnam and Amy Svitak.
Pentagon Eyes Naval Deployment Of NMD Radar. Defense News, August 21, 2000. p. 1.

CRS-15
Appendix: List of Acronyms
ABM
Anti-Ballistic Missile
BMC3
Ballistic Missile Command/Control Center
BMDO
Ballistic Missile Defense Organization
BMEWS
Ballistic Missile Early Warning System
CBO
Congressional Budget Office
CDR
Critical Design Review
CRS
Congressional Research Service
DAB
Defense Acquisition Board
DSP
Defense Support Program
EWR
Early Warning Radar
FY
Fiscal Year
FYDP
Future Years Defense Program
ICBM
Intercontinental Ballistic Missiles
IFTU
In-flight Targeting Update
NMD
National Missile Defense
NORAD
North American Aerospace Defense Command
PAVE PAWS
Air Force Nomenclature for Phased Array Radars
PDR
Preliminary Design Review
REX
Receiver Exciter
SBIRS
Space-Based Infrared System
SCC
Standing Consultative Commission
SLBM
Sea Launched Ballistic Missile
T/R
Transmit/Receive Modules
UEWR
Upgraded Early Warning Radar
UHF
Ultra High Frequency
USSPACECOM
United States Space Command

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