Navy Aegis Ballistic Missile Defense (BMD)
May 18, 2022
Program: Background and Issues for Congress
Ronald O'Rourke
The Aegis ballistic missile defense (BMD) program, which is carried out by the Missile Defense
Specialist in Naval Affairs
Agency (MDA) and the Navy, gives Navy Aegis cruisers and destroyers a capability for

conducting BMD operations. BMD-capable Aegis ships operate in European waters to defend
Europe from potential ballistic missile attacks from countries such as Iran, and in in the Western

Pacific and the Persian Gulf to provide regional defense against potential ballistic missile attacks
from countries such as North Korea and Iran. The number of BMD-capable Aegis ships has been growing over time. MDA’s
FY2023 budget submission states that “by the end of FY 2023 there will be 50 total BMDS [BMD Systems] capable [Aegis]
ships requiring maintenance support.”
The Aegis BMD program is funded mostly through MDA’s budget. The Navy’s budget provides additional funding for
BMD-related efforts. MDA’s proposed FY2023 budget requests a total of $1,659.1 million (i.e., about $1.7 billion) in
procurement and research and development funding for Aegis BMD efforts, including funding for two Aegis Ashore sites in
Poland and Romania. MDA’s budget also includes operations and maintenance (O&M) and military construction (MilCon)
funding for the Aegis BMD program.
Issues for Congress regarding the Aegis BMD program include the following:
 whether to approve, reject, or modify MDA’s annual procurement and research and development funding
requests for the program;
 the adequacy of MDA’s cost estimating and its reporting of costs;
 what role the Aegis BMD program should play in defending the U.S. homeland against attack from
ICBMs;
 required versus available numbers of BMD-capable Aegis ships;
 the burden that BMD operations may be placing on the Navy’s fleet of Aegis ships, and whether there are
alternative ways to perform BMD missions now performed by U.S. Navy Aegis ships, such as establishing
additional Aegis Ashore sites;
 allied burden sharing—how allied contributions to regional BMD capabilities and operations compare to
U.S. naval contributions to overseas regional BMD capabilities and operations;
 the role of the Aegis BMD program in a new missile defense system architecture for Guam;
 whether to convert the Aegis test facility in Hawaii into an operational land-based Aegis BMD site;
 the potential for ship-based lasers to contribute in coming years to Navy terminal-phase BMD operations
and the impact this might eventually have on required numbers of ship-based BMD interceptor missiles;
and
 technical risk and test and evaluation issues in the Aegis BMD program.

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Navy Aegis Ballistic Missile Defense (BMD) Program

Introduction
This report provides background information and issues for Congress on the Aegis ballistic
missile defense (BMD) program, a program carried out by the Missile Defense Agency (MDA)
and the Navy that gives Navy Aegis cruisers and destroyers a capability for conducting BMD
operations. The issue for Congress is whether to approve, reject, or modify Department of
Defense (DOD) acquisition strategies and proposed funding levels for the Aegis BMD program.
Congress’s decisions on the Aegis BMD program could significantly affect U.S. BMD
capabilities and funding requirements, and the BMD-related industrial base.
Background
Aegis Ships
All but three of the Navy’s cruisers and destroyers are called Aegis ships because they are
equipped with the Aegis ship combat system—an integrated collection of sensors, computers,
software, displays, weapon launchers, and weapons named for the mythological shield that
defended Zeus. (The exceptions are the Navy’s three Zumwalt [DDG-1000] class destroyers,
which are discussed below.) The Aegis system was originally developed in the 1970s for
defending ships against aircraft, anti-ship cruise missiles (ASCMs), surface threats, and
subsurface threats. The system was first deployed by the Navy in 1983, and it has been updated
many times since. The Navy’s Aegis ships include Ticonderoga (CG-47) class cruisers and
Arleigh Burke (DDG-51) class destroyers.
Ticonderoga (CG-47) Class Aegis Cruisers
A total of 27 CG-47s (CGs 47 through 73) were procured for the Navy between FY1978 and
FY1988; the ships entered service between 1983 and 1994. The first five ships in the class (CGs
47 through 51), which were built to an earlier technical standard in certain respects, were judged
by the Navy to be too expensive to modernize and were removed from service in 2004-2005,
leaving 22 ships in operation (CGs 52 through 73). The Navy’s FY2023 budget submission
proposes retiring five of the 22 ships in FY2023, 12 more in FY2024-FY2027, and the remaining
five in years after FY2027.
Arleigh Burke (DDG-51) Class Aegis Destroyers
The Navy began procuring DDG-51s in FY1985, and a total of 89 have been procured through
FY2022. The first DDG-51 entered service in 1991, and a total of 70 have been delivered as of
February 2022. Under the Navy’s FY2023 budget submission, the first DDG-51 is to be retired in
FY2027.
The DDG-51 design has been updated multiple times over the years. The first 28 DDG-51s are
known as Flight I/II DDG-51s. The next 34, known as Flight IIA DDG-51s, incorporate some
significant design changes, including the addition of a helicopter hangar. The version currently
being procured, called the Flight III DDG-51 design, incorporates a new radar, called the SPY 6
radar (and prior to that, the Air and Missile Defense Radar, or AMDR), that is more capable than
the SPY-1 radar installed on CG-47s and earlier DDG-51s.
No DDG-51s were procured in FY2006-FY2009. The Navy during this period instead procured
the three above-mentioned Zumwalt (DDG-1000) class destroyers. The DDG-1000 design does
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not use the Aegis system and does not include a capability for conducting BMD operations. Navy
plans do not call for modifying the three DDG-1000s to make them BMD-capable.1
Aegis Ships in Allied Navies
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, South Korea,
Australia, Spain, and Norway.2 Japan’s Aegis-equipped ships are BMD-capable. The Aegis-
equipped ships operated by South Korea, Australia, Spain, and Norway are currently not BMD-
capable.
Aegis BMD System3
Aegis ships are given a capability for conducting BMD operations by incorporating changes to
the Aegis system’s computers and software, and by arming the ships with BMD interceptor
missiles. Older Aegis ships can be modified to become BMD-capable ships, and DDG-51s
procured in FY2010 and subsequent years have been built from the start with a BMD capability.
Versions and Capabilities of Aegis BMD System
Overview
The Aegis BMD system exists in multiple variants whose ascending numerical designations
indicate ascending levels of capability. As part of MDA’s FY2022 budget submission, the
designations of Aegis BMD system variants were changed and consolidated to 4.X, 5.X, and 6.X,
with the X indicating multiple subvariants. (The 4.X variant, for example, includes the 4.1 and
4.2 subvariants.)4
BMD system variants correlate with certain versions (i.e., baselines, or BLs) of the overall Aegis
system, which have their own numbering system. The more recent BMD variants, in addition to
being able to address more challenging BMD scenarios, give BMD-equipped ships a capability to
simultaneously perform both BMD operations against ballistic missiles and anti-air warfare
(AAW) operations (aka air-defense operations) against aircraft and anti-ship cruise missiles.
Figure 1 provides a 2019 Government Accountability Office (GAO) summary of the capabilities
of the more recent BMD variants and their correlation to Aegis system baselines as of 2019.
Because Figure 1 was prepared in 2019, it uses the older designations for Aegis BMD system
variants, rather than the new designations that were introduced as part of the MDA’s FY2022
budget submission.
The Aegis BMD system was originally designed primarily to intercept theater-range ballistic
missiles, meaning short-, medium-, and intermediate-range ballistic missiles (SRBMs, MRBMs,
and IRBMs, respectively). In addition to its capability for intercepting theater-range ballistic

1 For more on the DDG-51 and DDG-1000 programs, see CRS Report RL32109, Navy DDG-51 and DDG-1000
Destroyer Programs: Background and Issues for Congress, by Ronald O'Rourke.
2 The Norwegian ships 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.
3 Unless stated otherwise, information in this section is taken from MDA briefings on the Aegis BMD program given to
CRS and CBO analysts on the MDA’s FY2023 and prior-year budget submissions.
4 The 4.X variant is the new designation for the variants previously designated 3.6.X, 4.0.X, 4.1, and 4.2. The 5.X
variant is the new designation for the variants previously designated 5.0CU (with the CU standing for Capability
Upgrade) and 5.1. The 6.X variant is the new designation for the variant previously designated 6.0.
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missiles, detection and tracking data collected by the Aegis BMD system’s radar might be passed
to other U.S. BMD systems that are designed to intercept intercontinental ballistic missiles
(ICBMs), which might support intercepts of ICBMs that are conducted by those other U.S. BMD
systems.
Figure 1. GAO Summary of Capabilities of Aegis BMD System Variants

Source: Government Accountability Office, Missile Defense[:] Delivery Delays Provide Opportunity for Increased
Testing to Better Understand Capability, GAO-19-387, June 2019, Table 5 on p. 31.
April 2021 Press Report About Upcoming Test Against Mock Hypersonic Weapon
An April 14, 2021, press report stated
The Missile Defense Agency, together with the U.S. Navy, plan to test an SM-6 missile
against an “advanced maneuvering threat,” a term that has been used in relation to
unpowered hypersonic boost-glide vehicles, later this year. The Pentagon says that
unspecified versions of the SM-6 have already demonstrated some degree of capability
against these types of weapons, examples of which Russia and China have already begun
putting to service. A new variant of the SM-6, the Block IB, is already under development
and will itself be able to reach hypersonic speeds.
Barbara McQuiston, a senior U.S. official currently performing the duties of the Under
Secretary of Defense for Research and Engineering, including mention of the scheduled
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SM-6 test in her testimony before the Senate Appropriations Committee’s Subcommittee
on Defense yesterday….
“MDA [the Missile Defense Agency], in cooperation with the U.S. Navy, demonstrated
early capability against maneuvering threats during flight-testing of the Standard Missile
(SM)-6 Sea-Based Terminal (SBT) defense, and it will further demonstrate this capability
against an advanced maneuvering threat-representative target later this year,” according to
McQuiston’s written testimony. “We will continue to advance our SBT capability to
address the regional hypersonic threat and will test that capability in the FY 2024
timeframe.”…
This is not the first time the Pentagon has publicly discussed using a variant of the SM-6
for hypersonic defense. In March 2020, Mike Griffin, then the Under Secretary of Defense
for Research and Engineering, first revealed that this missile was among those being
considered for this role and that there were plans to test one of them against an actual
hypersonic boost-glide vehicle sometime in the 2023 Fiscal Year. It’s not clear whether the
test Griffin was referring to is the one now scheduled for this year or the one that MDA
now plans to carry out in the 2024 Fiscal Year.5
Aegis BMD Interceptor Missiles
The BMD interceptor missiles used by Aegis ships are the Standard6 Missile-3 (SM-3) and the
SM-6.
SM-3 Midcourse Interceptor
The SM-3 is designed to intercept ballistic missiles above the atmosphere (i.e., exo-atmospheric
intercept), in the midcourse phase of an enemy ballistic missile’s flight. It is equipped with a “hit-
to-kill” warhead, called a kinetic vehicle, that is designed to destroy a ballistic missile’s warhead
by colliding with it. The current versions of the SM-3 missile include the SM-3 Block IA, the
SM-3 Block IB, and the SM-3 Block IIA.7
Compared to the Block IA version, the Block IB version has an improved (two-color) target
seeker, an advanced signal processor, and an improved divert/attitude control system for adjusting
its course. Compared to the Block IA and 1B versions, which have a 21-inch-diameter booster
stage at the bottom but are 13.5 inches in diameter along the remainder of their lengths, the Block
IIA version has a 21-inch diameter along its entire length. The increase in diameter to a uniform
21 inches provides more room for rocket fuel, permitting the Block IIA version to have a burnout
velocity (a maximum velocity, reached at the time the propulsion stack burns out) that is greater
than that of the Block IA and IB versions, as well as a larger-diameter kinetic warhead. The
United States and Japan cooperated in developing certain technologies for the Block IIA version,
with Japan funding a significant share of the effort.8

5 Joseph Trevithick, “Navy SM-6 Missile Will Attempt To Swat Down A Mock Hypersonic Weapon,” The Drive, April
14, 2021.
6 The Standard Missile is so named because it was originally developed, decades ago, as a surface-to-air (i.e., air
defense) missile to serve as the common (i.e., standard) successor to the Navy’s then-existing collection of Talos,
Terrier, and Tartar air defense missiles, which were sometimes referred to collectively as the 3-T missiles.
7 MDA and Navy plans at one point called for the SM-3 Block IIA to be succeeded by a still-more-capable interceptor
called the SM-3 Block IIB. The effort to develop that missile, however, was ended years ago, and MDA at the time was
reportedly not pursuing any follow-on capabilities to the SM-3 Block IIA. (See, for example, Justin Doubleday,
“Missile Defense Agency Not Pursuing Follow-On to SM-3 Block IIA Interceptor,” Inside the Navy, October 24,
2016.)
8 The cooperative research effort was carried out under a U.S.-Japan memorandum of agreement signed in 1999. The
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A March 31, 2020, press report stated
Raytheon and the Missile Defense Agency are exploring options to extend the range of the
Standard Missile-3 Block IB—pushing the ballistic missile interceptor to dramatically
expand a defended area by allowing the weapon to communicate with off-board radars—a
move that would require enhancing one of the Aegis ballistic missile defense system’s
newest features: Engage-on-Remote….
MDA Director Vice Adm. Jon Hill told Congress earlier this month that the new Engage-
on-Remote capability provides “a seven-fold increase in missile defense coverage when
compared to an autonomous Aegis platform.”9
SM-6 Terminal Interceptor
The SM-2 Block IV was MDA’s and the Navy’s initial sea-based terminal-phase BMD
interceptor. It was designed to intercept ballistic missiles inside the atmosphere (i.e., endo-
atmospheric intercept), during the terminal phase of an enemy ballistic missile’s flight. It was
equipped with a blast fragmentation warhead. A limited number of these missiles were produced
years ago.10 The SM-2 Block IV has now been replaced by the SM-6.
The SM-6 is MDA’s and the Navy’s more capable next-generation sea-based terminal-phase (i.e.,
endo-atmospheric) BMD interceptor. It is based on the SM-6 air defense missile (the Navy’s
successor to the SM-2 air defense missile). The SM-6 is a dual-capability missile that can be used
for either air defense (i.e., countering aircraft and ASCMs) or ballistic missile defense. A July 23,
2018, press report states the following:
The Defense Department has launched a prototype project that aims to dramatically
increase the speed and range of the Navy’s Standard Missile-6 by adding a larger rocket
motor to the ship-launched weapon, a move that aims to improve both the offensive and
defensive reach of the Raytheon-built system.
On Jan. 17 [2018], the Navy approved plans to develop a Dual Thrust Rocket Motor with
a 21-inch diameter for the SM-6, which is currently fielded with a 13.5-inch propulsion
package. The new rocket motor would sit atop the current 21-inch booster, producing a
new variant of the missile: the SM-6 Block IB.11
Numbers of BMD-Capable Aegis Ships
The number of BMD-capable Aegis ships has been growing over time. MDA’s FY2023 budget
submission states that “by the end of FY 2023 there will be 50 total BMDS [BMD Systems]
capable [Aegis] ships requiring maintenance support.”12

effort 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.
9 Jason Sherman, “After MDA Demonstrates 7x Increase in Defended Area, Raytheon Pitching EOR for Older SM-3s,”
Inside Defense, March 31, 2020.
10 The inventory of SM-2 Block IVs was created by modifying SM-2s that were originally built to intercept aircraft and
ASCMs. A total of 75 SM-2 Block IVs were modified, and at least 3 were used in BMD flight tests through February
2012.
11 Jason Sherman, “Navy Looking to Increase Range, Speed of SM-6 with Larger Rocket Motor,” Inside the Navy, July
23, 2018.
12 Missile Defense Agency, Fiscal Year 2023 Budget Estimates, Missile Defense Agency, April 2022, p. 11. (This is the
FY2023 budget justification book for MDA’s portion of the Operation and Maintenance, Defense-Wide appropriation
account.)
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BMD-Capable Aegis Destroyers Forward-Homeported in Spain
On October 5, 2011, the United States, Spain, and NATO jointly announced that four BMD-
capable U.S. Navy Aegis destroyers were to be forward-homeported (i.e., based) at the naval base
at Rota, Spain.13 The initial set of four ships was transferred to Rota in FY2014 and FY2015.14
They were reportedly scheduled to return to the United States and replaced at Rota by a new set
of four BMD-capable U.S. Navy Aegis destroyers in 2020-2022.15
Navy officials have said that the four Rota-based ships can provide a level of level of presence in
the Mediterranean for performing BMD patrols and other missions equivalent to what could be
provided by about 10 BMD-capable Aegis ships that are homeported on the U.S. east coast. The
Rota homeporting arrangement thus effectively releases about six U.S. Navy BMD-capable Aegis
ships for performing BMD patrols or other missions elsewhere. In February and March 2020,
DOD officials testified that DOD is considering forward-homeporting an additional two BMD-
capable Aegis destroyers at Rota, which would make for a total of six destroyers at the site.16
Navy officials testified in 2020 that they support the idea.17
Aegis Ashore Sites
Two Navy-Operated Sites in Romania and Poland
The land-based version of the Aegis BMD system is called Aegis Ashore. There are two Aegis
Ashore sites in Europe—one in Romania, and one in Poland. The sites are intended to help
defend Europe against ballistic missile threats from countries such as Iran. Each Aegis Ashore site
includes a structure housing an Aegis system that is similar to the deckhouse on an Aegis ship,
and 24 SM-3 missiles launched from a relocatable Vertical Launch System (VLS) based on the
VLS that is installed in Navy Aegis ships.18
The plan to establish the two Aegis Ashore sites in Romania and Poland was announced in 2009,
as part of a plan for providing regional BMD defense in Europe called the European Phased

13 “Announcement on missile defence cooperation by NATO Secretary General Anders Fogh Rasmussen, the Prime
Minister of Spain, Jose Luis Rodriguez Zapatero and US Defense Secretary Leon Panetta,” October 5, 2011, accessed
May 18, 2022, at http://www.nato.int/cps/en/SID-107ADE55-FF83A6B8/natolive/opinions_78838.htm. See also
“SECDEF Announces Stationing of Aegis Ships at Rota, Spain,” accessed May 18, 2022, at https://web.archive.org/
web/20120117065346/http:/www.navy.mil/search/display.asp?story_id=63109.
Rota is on the southwestern Atlantic coast of Spain, a few miles northwest of Cadiz, and about 65 miles northwest of
the Strait of Gibraltar leading into the Mediterranean. U.S. Navy ships have been homeported at Rota at various points
in the past, most recently (prior to the current arrangement) in 1979. (Source: Sam Fellman, “U.S. To Base Anti-
Missile Ships in Spain,” Defense News, October 10, 2011: 76.)
14 The four ships were the destroyers Ross (DDG-71) and Donald Cook (DDG-75), which moved to Rota in FY2014,
and the destroyers Carney (DDG-64) and Porter (DDG-78), which moved to Rota in FY2015.
15 See, for example, Mallory Shelbourne, “USS Arleigh Burke Arrives in Spain, USS Donald Cook Will Head to
Mayport,” USNI News, April 12, 2021.
16 See, for example, Paul McCleary, “EUCOM Calls For Two More Ships For Spanish Port,” Breaking Defense,
February 25, 2020; David B. Larter, “Push to Base Six US Navy Destroyers in Spain Could Be Gaining Steam,”
Defense News, March 3, 2020.
17 See, for example, David B. Larter, “The US Navy’s Top Officer Declares Support for Basing 6 Destroyers in Spain,”
Defense News, March 5, 2020. See also John Vandiver, “Rota to Gain Two US Destroyers by Middle of the Decade,
EUCOM Chief Says,” Stars and Stripes, April 15, 2021.
18 For additional discussion of the Aegis Ashore sites, see Edward Lundquist, “Aegis Ashore Adapts Sea-Based Missile
Defense System to Protect Europe,” National Defense, September 2016.
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Adaptive Approach (EPAA). The Aegis Ashore site in Romania achieved operational certification
in May 2016.19 The site in Poland began construction in May 201620 and was initially scheduled
to be completed in 2018. Its completion, however, has been delayed to the end of 2022 by
construction contractor performance issues.21 An April 2021 GAO report on deliveries and testing
of U.S. missile defense systems in FY2020 stated the following:
According to MDA officials, the Aegis Ashore site in Poland continues to experience
delays owing to poor performance by the main construction contractor. Based on MDA’s
latest estimate of completion no earlier than fiscal year 2022, the site will be between three
and four years late. According to MDA, in February 2020, the Army Corps of Engineers
(which manages construction at the site) notified the main contractor that earnings from all
future invoices would be retained, and released only upon the completion of certain key
activities. MDA stated that the contractor did not meet these benchmarks and as a result
had not been paid since February 2020.
MDA currently attributes $79 million in cost increases to these delays.22
Navy Interest in Divesting Aegis Ashore Sites It Operates
On January 11, 2021, the Chief of Naval Operations (CNO), Admiral Michael Gilday, released a
guidance document for the Navy entitled CNO NavPlan (with NavPlan being short for navigation
plan) that states
To remain ahead of our competitors, we will divest ourselves of legacy capabilities that no
longer bring sufficient lethality to the fight. This includes divestment of experimental
Littoral Combat Ship hulls, legacy Cruisers, and older Dock Landing Ships. It also includes
divesting non-core Navy missions like Aegis-ashore. Transferring shore-based Ballistic
Missile Defense sites to ground forces enables Sailors to focus on their core missions at
sea and frees up resources to increase our lethality.23
A January 12, 2021, press report states
The chief of naval operation’s new call to focus on sea control and power projection could
lead the service to shed other non-core missions the Navy conducts today, such as manning
Aegis Ashore missile defense sites.
The biggest problem is, no one else has agreed to take over that mission yet….
… no one else operates Aegis systems today, and no one has yet agreed to take over Aegis
Ashore, Rear Adm. Paul Schlise, the director of surface warfare on the CNO’s staff
(OPNAV N96), said today during a panel presentation at the Surface Navy Association’s
annual symposium.

19 See, for example, Amy Forsythe, “U.S. Navy Aegis Ashore Base in Romania Hosts NATO Country Ambassadors,”
Defense Visual Information Distribution Service (DVIDS), November 19, 2019; “Aegis Ashore,” Missile Defense
Advocacy Alliance, accessed May 18, 2022, at https://missiledefenseadvocacy.org/defense-systems/aegis-ashore/; US
Naval Forces Europe-Africa, “Aegis Ashore Missile Defense System (AAMDS)-Romania Operationally Certified,”
Defense-Aerospace.com, May 12, 2016.
20 See, for example, “Aegis Ashore,” Missile Defense Advocacy Alliance, accessed May 18, 2022, at
https://missiledefenseadvocacy.org/defense-systems/aegis-ashore/.
21 See, for example, Rich Abott, “Aegis Ashore Poland Set To Be Operational By End Of 2022,” Defense Daily,
November 22, 2021; Jen Judson, “Construction of Aegis Ashore in Poland Nearing Completion,” Defense News, March
9, 2022.
22 Government Accountability Office, Missile Defense[:] Fiscal Year 2020 Delivery and Testing Progressed, but
Annual Goals Unmet, GAO 21-314, April 2021, p. 24.
23 U.S. Navy, Chief of Naval Operations, CNO NavPlan, January 2021, p. 10. See also Richard R. Burgess, “CNO:
Divest Aegis Ashore Sites to Ground Forces,” Seapower, January 11, 2021.
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“It’s been an ongoing discussion in the building here. Right now we’ve got the Aegis
Ashore sites in Europe, and there’s discussions about potentially more sites in other places.
The general discussion has been, this is not a core Navy mission. Sailors really belong at
sea serving in ships. And we’ve got a good number of highly qualified folks serving in
those sites, they’re going a great job,” he said.
“But I think what the CNO teed up is, is this a core Navy mission? I don’t think it is. And
so there’s been some discussion with the Army. The Army, of course, has some missile
defense capability and of course great soldiers that serve in those roles. But they don’t have
any experience with that [Aegis Combat System], the systems that have been installed or
are in progress in Romania and Poland. So that’s been a running discussion.”
Schlise said the discussion is taking place at the Office of the Secretary of Defense level.
Without any final decisions, though, the Navy could not shed Aegis Ashore spending in its
most recent budgeting work, the Fiscal Year 2022 request that will come out after the Biden
administration comes in and can review it.
“For the purposes of this past budget cycle, it was just kind of tabled. So we’ll have to see
where that discussion goes. As always, here in the building, it’s about money. So if that
transition were to be considered and approved for moving forward, to transition it to
another service, ‘who’s going to pay’ will of course be part of the discussion,” Schlise
said.24
Japan Planned and Later Canceled Two Sites
Japan had planned to procure and operate two Aegis Ashore systems that reportedly were to be
located at Ground Self-Defense Force (GSDF) facilities in Akita Prefecture in eastern Japan and
Yamaguchi Prefecture in western Japan, and would be operated mainly by the GSDF (i.e., Japan’s
army).25 The two systems reportedly were to be equipped with a new Lockheed-made radar called
the Long Range Discrimination Radar (LRDR) rather than the Raytheon-made SPY-6 AMDR that
is being installed on U.S. Navy Flight III DDG-51s, and reportedly were to go into operation by
2023.26 On June 15, 2020, however, Japan announced that it had suspended implementation of its
Aegis Ashore initiative due to cost growth and technical concerns.27 On June 25, 2020, Japan
confirmed that it had canceled the plan for deploying the two Aegis Ashore sites.28 A December 6,
2020, press report stated

24 Megan Eckstein, “Navy Wants to Shed Aegis Ashore Mission, But Army Still Hasn’t Agreed to Take It,” USNI
News, January 12, 2021.
25 Yomiuri Shimbun, “Akita, Yamaguchi to Get Aegis Ashore/GSDF Involvement Expected to Strengthen Missile
Defense,” The Japan News, November 11, 2017. See also Kyodo, “Japan Mulling News Missile Interceptor
Deployment to Guard Against North Korea,” South China Morning Post, November 11, 2017.
26 Anthony Capaccio, “Japan in Talks With U.S. on Buying Aegis Missile Defense,” Bloomberg, November 7, 2017.
27 See, for example, Rich Abott, “Japan Suspends Aegis Ashore Due To Technical And Cost Concerns,” Defense Daily,
June 15, 2020; Sam LaGrone, “Japan Backing Away From Aegis Ashore,” USNI News, June 15, 2020; Mari
Yamaguchi, “Japan to Scrap Costly Land-Based US Missile Defense System,” Associated Press, June 15, 2020; Mike
Yeo, “Japan Suspends Aegis Ashore Deployment, Pointing to Cost and Technical Issues,” Defense News, June 15,
2020; Brad Glosserman, “Canceling Aegis Ashore Raises Problems—and Hopes,” Japan Times, June 17, 2020.
Prior to the June 15, 2020, announcement, Japan had announced in early May that it would evaluate alternatives to the
Akita Prefecture site due to strong local opposition to that site. (Masaya Kato, “Japan’s Missile Shield Deployment
Scuppered by Local Resistance,” Nikkei Asian Review, May 7, 2020.)
28 Mari Yamaguchi (Associated Press), “Japan Confirms It’s Scrapping US Missile Defense System,” Defense News,
June 25, 2020; Megan Eckstein, “Japan Officially Ends Aegis Ashore Plans After National Security Council
Deliberations,” USNI News, June 26, 2020.
See also Grant Newsham “Abe’s Aegis Ashore Cancellation Doesn’t Add Up,” Asia Times, June 30, 2020; Lucy Craft,
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Japan will put new powerful Aegis radars on warships to upgrade its defences against
possible ballistic missiles fired by North Korea after it cancelled plans to deploy them at
two ground-based stations, the Asahi newspaper reported.
Prime Minister Yoshihide Suga’s government is likely to approve the recommendation by
the country’s National Security Council before the end of the year, although any decision
on type of vessel or cost will be left until next year, the paper said, citing unidentified
sources….
Deploying the new Aegis radars could cost twice as much and take up to three years longer
to complete than the ground-based versions, which were expected cost of around $2 billion
to build, a source with knowledge of the proposal told Reuters earlier….
Fitted with Lockheed Martin Corp SPY-7 radars that will have at least three times the range
of older Aegis systems deployed on Japanese navy destroyers, the upgrade will allow Japan
to use new interceptor missiles to target warheads in space fired by North Korea or other
potential foes, including China and Russia.29
An August 19, 2021, press report stated
A sea-based Aegis missile defense system could be the next program to be abandoned by
Tokyo.
The Japanese Defense Ministry does not plan to seek funds for it in the upcoming fiscal
2022 budget. Citing government sources, the Asahi Shimbun newspaper said such a budget
request will “likely be impossible over the next few years.”30
Aegis BMD Development Philosophy and Flight Tests
The Aegis BMD development effort, including Aegis BMD flight tests, has been described as
following a development philosophy long held within the Aegis program office of “build a little,
test a little, learn a lot,” meaning that development is done in manageable steps, with each step
being tested and validated before moving on to the next step.31

“Why Japan Scrapped a $4 Billion Missile Defense Purchase from the U.S.,” CBS News, July 2, 2020; Tim Kelly,
“Explainer: Strike Capability, Other Military Options on Table after Japan’s Aegis U-Turn,” Reuters, July 2, 2020;
Jeffrey W. Hornung, “Japan Is Canceling a U.S. Missile Defense System,” Foreign Policy, July 2, 2020; Bruce
Klingner, “Japan Undercuts Its Defense Against North Korean Missiles,” Heritage Foundation, July 22, 2020; Tim
Kelly and Yoshifumi Takemoto, “Exclusive: As Japan Weighs Missile-Defence Options, Raytheon Lobbies for
Lockheed’s $300 Million Radar Deal,” Reuters, July 30, 2020; Rieko Miki, “The Price of Peace: Why Japan Scrapped
a $4.2bn US Missile System,” Nikkei Asian Review, August 5, 2020; Loren Thompson, “Japan’s Rethink Of Aegis
Ashore Could Tie Up Navy, Increase Costs And Cause Big Delays,” Forbes, August 11, 2020.
On June 18, 2020, it was reported that the United States and Japan were in talks to address the technical issues Japan
cited and explore potential paths forward for bolstering Japan’s ballistic missile defense capability. See Lara Seligman,
“U.S. and Japan in Talks about ‘Alternatives’ to Aegis Ashore Missile Defense System,” Politico Pro, June 18, 2020;
Idrees Ali, “U.S. in Talks with Japan after Aegis Ashore Missile Defense System Suspension: Official,” Reuters, June
18, 2020; Jason Sherman, “MDA Hopes to ‘Resolve’ Japan’s Aegis Ashore Concerns, Reinstate Project,” Inside
Defense, June 18, 2020; “U.S. Talking with Japan on Concerns over Halted Missile Defense Plan,” Kyodo News, June
19, 2020. See also Asahi Shimbun, “Japan Eyes Offshore Options to Replace Aegis Defense System,” Asahi Shimbun,
September 10, 2020.
29 Reuters staff, “Japan to Put New Aegis Radars on Warships after Cancelling Ground Stations: Asahi,” Reuters,
December 6, 2020. See also Agence France-Presse, “Japan Weighs Ships For Aegis Missile Defence System,”
Barron’s, December 9, 2020; Kyodo, “Cabinet Set to Approve Destroyers as Alternative to Aegis Ashore,” Japan
Times, November 28, 2020.
30 Chen Chuanren, “Japan’s Sea-Based Aegis System Faces Ax,” Aviation Week Network, August 19, 2021.
31 See, for example, “Aegis BMD: “Build a Little, Test a Little, Learn a Lot,” USNI blog, March 15, 2010, accessed
May 18, 2022, at http://blog.usni.org/2010/03/15/aegis-bmd-build-a-little-test-a-little-learn-a-lot, and “Aegis Ballistic
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An April 2021 GAO report on deliveries and testing of U.S. missile defense systems in FY2020
stated the following about testing of the Aegis BMD system:
In fiscal year 2020, the Aegis BMD program did not conduct any of the six planned flight
tests, deleting one and delaying the remaining five. Most notably, a major operational flight
test—FTO-03—was deleted, leaving the SM-3 Block IIA interceptor to enter initial
production with a single operational flight test. Some flight tests were initially delayed due
to range availability and higher priority flights tests (such as FEX-01) and delays were then
exacerbated by pandemic-driven travel restrictions. A congressionally mandated flight
test—FTM-44—pitting an SM-3 Block IIA interceptor against a simple ICBM, was
delayed, but executed in November 2020.
The Aegis BMD program participated in three of five planned ground tests in fiscal year
2020. The two ground tests were delayed due to the pandemic and the unavailability of the
Poland Aegis Ashore site, respectively.
All seven cybersecurity tests scheduled for fiscal year 2020 were consolidated into a single
test, which was subsequently delayed.32
For a summary of reported Aegis BMD flight tests since 2002, see Table A-1 in Appendix.
Allied Participation and Interest in Aegis BMD Program
Japan
Eight BMD-Capable Aegis Destroyers
Japan operates eight BMD-capable Aegis destroyers—the eighth was commissioned into service
in March 2021.33 Japanese BMD-capable Aegis ships have participated in some of the flight tests
of the Aegis BMD system using the SM-3 interceptor (see Table A-1 in Appendix).
Cooperative Development of SM-3 Block IIA Missile
As mentioned earlier, Japan cooperated with the United States on development the SM-3 Block
IIA missile. Japan developed certain technologies for the missile, and paid for the development of
those technologies, reducing the missile’s development costs for the United States. A July 6,
2018, press report states that “the U.S. and Japan are looking to jointly develop next-generation
radar technology that would use Japanese semiconductors to more than double the detection
range of the Aegis missile defense system.”34

Missile Defense, Aegis Ballistic Missile Defense Overview for the George C. Marshall Institute, RADM Alan B.
Hicks, USN, Aegis BMD Program Director, August 3, 2009, slide 16 of 20, entitled “Some of our Philosophies In a
Nutshell (1 of 2),” accessed May 18, 2022, at https://web.archive.org/web/20100706133017/https:/www.marshall.org/
pdf/materials/743.pdf.
32 Government Accountability Office, Missile Defense[:] Fiscal Year 2020 Delivery and Testing Progressed, but
Annual Goals Unmet, GAO 21-314, April 2021, p. 24.
33 See, for example, Xavier Vavasseur, “Japan Commissions New Maya-Class AEGIS Destroyer JS Haguro はぐろ
DDG-180,” Naval News, March 19, 2021; Yomiuri Shimbun, “Japan Commissions 8th Aegis Destroyer Haguro,” Japan
News, March 20, 2021.
34 Nikkei staff writers, “US Taps Japan Radar Tech to Double Missile Defense Range,” Nikkei Asian Review, July 6,
2018.
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Two Aegis Ashore Sites (Canceled)
As mentioned earlier, Japan had planned to procure and operate two Aegis Ashore systems, but
announced in June 2020 that it had canceled the plan.
South Korea
An October 12, 2018, press report states that “the South Korean military has decided to buy ship-
based SM-3 interceptors to thwart potential ballistic missile attacks from North Korea, a top
commander of the Joint Chiefs of Staff revealed Oct. 12.”35
Other Countries
Other countries that MDA views as potential naval BMD operators (using either the Aegis BMD
system or some other system of their own design) include the United Kingdom, the Netherlands,
Spain, Germany, Denmark, and Australia. Spain, South Korea, and Australia 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.
FY2023-FY2027 MDA Procurement and R&D Funding
The Aegis BMD program is funded mostly through MDA’s budget. The Navy’s budget provides
additional funding for Aegis BMD-related efforts. Table 1 shows requested (FY2023) and
projected (FY2024-FY2027) MDA procurement and research and development funding for Aegis
BMD efforts under MDA’s FY2023 budget submission.
Table 1. FY2023-FY2027 MDA Procurement and
R&D Funding for Aegis BMD Efforts
(In millions of dollars, rounded to nearest tenth; totals may not add due to rounding)
FY23
FY24
FY25
FY26
FY27

(req.)
(proj.)
(proj.)
(proj.)
(proj.)
Procurement

Aegis BMD (line 32)
402.2
378.7
362.8
496.9
506.8
(SM-3 Block IB missile quantity)
(47)
(27)
(24)
(43)
(43)
Aegis BMD Advance Procurement (line 33)
0
0
0
0
0
SM-3 Block IIA (line 35)
338.0
458.2
479.2
460.5
457.9
(SM-3 Block IIA missile quantity)
(10)
(12)
(12)
(12)
(12)
Aegis Ashore Phase III (line 39)
30.1
2.4
1.0
0
0
Aegis BMD hardware and software (line 41)
78.2
115.8
116.0
61.7
32.7
SUBTOTAL Procurement
848.5
955.1
959.0
1,019.1
997.4
Research and development

Aegis BMD (PE 0603892C) (line 83)
600.1
658.8
574.0
570.0
580.5
Aegis BMD Test (PE 0604878C) (line 113)
182.8
173.5
159.1
203.9
187.5
Land-based SM-3 (PE 0604880C) (line 115)
27.7
26.9
26.0
26.8
27.4
SUBTOTAL RDT&E
810.6
859.2
759.1
800.7
795.4
TOTAL
1,659.1
1,814.3
1,718.1
1,819.8
1,792.8

35 Jeff Jeong, “South Korea to Buy Ship-Based Interceptors to Counter Ballistic Missile Threats,” Defense News,
October 12, 2018.
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Source: Table prepared by CRS based on FY2023 MDA budget submission.
Research and development funding in the table for the land-based SM-3 is funding for Aegis
Ashore sites. MDA’s budget also includes additional funding not shown in the table for
operations and maintenance (O&M) and military construction (MilCon) for the Aegis BMD
program.
Issues for Congress
Annual Funding Request
One issue for Congress is whether to approve, reject, or modify MDA’s annual procurement and
research and development funding requests for the program. In considering this issue, Congress
may consider various factors, including whether the work that MDA is proposing to fund for the
fiscal year in question is properly scoped and scheduled, and accurately priced.
Estimating and Reporting Costs
Another issue for Congress concerns the adequacy of MDA’s cost estimating and its reporting of
costs. A February 2022 GAO report on MDA’s cost estimating and reporting of costs for missile
defense programs, including the Aegis BMD program, states:
The Department of Defense’s (DOD) Missile Defense Agency (MDA) is continuing efforts
to deliver systems to the warfighter that will protect against enemy missiles. However,
shortfalls persist with MDA’s program and flight test cost estimates and reporting.
Program cost estimates. MDA continues to omit the military services’ operations and
sustainment costs from the program life-cycle cost estimates.... By omitting these costs,
MDA limits decision-makers’ insight into the full financial commitments needed for
affordability and funding determinations....
Flight test cost estimates. Accuracy issues linger with MDA’s flight test cost estimates that
could skew the agency’s annual $1.3 billion [flight test] funding request, such as not being
regularly updated with actual costs. However, MDA is taking steps to improve these cost
estimates by using a new cost model, among other things....
Program cost reporting. MDA continues to adjust program baselines without clear
traceability over time. MDA also forgoes recurrent comparisons to the original baseline.
Such adjustments and omissions impede decision-makers’ awareness of each program’s
cost performance and total system cost....
Flight test cost reporting. Congress required MDA to report on flight test costs, but we
found the information lacking due to the agency’s reporting methodology. MDA only
accounted for about $1.3 billion of at least $3.5 billion in funding the agency requested for
flight testing between March 2017 and September 2020. Moreover, the reporting
requirement ended in December 2021. Without further reporting on complete flight test
costs, Congress does not have information needed to facilitate holding the agency
accountable for its spending.36

36 Government Accountability Office, Missile Defense[:] Addressing Cost Estimating and Reporting Shortfalls Could
Improve Insight into Full Costs of Programs and Flight Tests, GAO-22-104344, February 2022, highlights page (PDF
page 2 of 58).
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Potential for Intercepting ICBMs
Another issue for Congress is what role the Aegis BMD program should play in defending the
U.S. homeland against attack from ICBMs. With the advent of the SM-3 Block IIA interceptor,
DOD is evaluating the potential for the Aegis BMD system to intercept certain ICBMs. Section
1680 of the FY2018 National Defense Authorization Act (H.R. 2810/P.L. 115-91 of December 12,
2017) directed DOD to “conduct a test to evaluate and demonstrate, if technologically feasible,
the capability to defeat a simple intercontinental ballistic missile threat using the standard missile
3 block IIA missile interceptor.” DOD’s January 2019 missile defense review report stated the
following:
The SM-3 Blk IIA interceptor is intended as part of the regional missile defense
architecture, but also has the potential to provide an important “underlay” to existing GBIs
[ground-based interceptors] for added protection against ICBM threats to the homeland.
This interceptor has the potential to offer an additional defensive capability to ease the
burden on the GBI system and provide continuing protection for the U.S. homeland against
evolving rogue states’ long-range missile capabilities.
Congress has directed DoD to examine the feasibility of the SM-3 Blk IIA against an
ICBM-class target. MDA will test this SM-3 Blk IIA capability in 2020. Due to the
mobility of sea-based assets, this new underlay capability will be surged in a crisis or
conflict to further thicken defensive capabilities for the U.S. homeland. Land-based sites
in the United States with this SM-3 Blk IIA missile could also be pursued.37
On November 16, 2020, MDA announced that the congressionally directed ICBM-intercept flight
test, called FTM-44, had been conducted on that date and had resulted in a successful intercept of
the ICBM-representative target. MDA stated that “FTM-44, originally scheduled for May 2020,
was delayed due to restrictions in personnel and equipment movement intended to reduce the
spread of COVID-19. FTM-44 satisfies a Congressional mandate to evaluate the feasibility of the
SM-3 Block IIA missile’s capability to defeat an ICBM threat before the end of 2020.”38 A
November 17, 2020, press report about the flight test stated that “the unarmed ICBM was a
replica of a target flown against the Ground-based Midcourse Defense system during a March
2019 flight test that featured a salvo launch of a pair of interceptors.”39 An April 2021 GAO
report on deliveries and testing of U.S. missile defense systems in FY2020 stated the following:
MDA’s effort to include the SM-3 Block IIA interceptor in a new “layered” homeland
defense against intercontinental ballistic missile (ICBM) threats targeting the U.S. could
introduce considerable cost, schedule, and performance uncertainty to a program that has
just entered initial production. The GMD weapon system currently provides defense
against ICBMs, but this new effort would add the SM-3 Block IIA and THAAD weapon
system as layers underneath that provided by GMD. For further details on the GMD and
THAAD weapon systems see their respective appendixes.
ICBM intercepts are more challenging than the IRBM intercepts for which the SM-3 IIA
was originally designed. MDA’s most recent attempt to create a system for intercepting
ICBMs, known as the Redesigned Kill Vehicle (RKV), re-used some parts from the SM-3
Block IIA. DOD cancelled the RKV before it could complete development after significant
cost and schedule overruns and questions about the ability of the design to overcome
specific performance risks. Parts re-used from the SM-3 Block IIA were implicated in some

37 Department of Defense, Missile Defense Review 2019, released January 17, 2019, p. 55. David Axe, “The U.S.
Navy’s New Missile Defense Is a Bad Idea,” National Interest, January 17, 2019.
38 Missile Defense Agency News release 20NEWS-0003, “U.S. Successfully Conducts SM-3 Block IIA Intercept Test
Against an Intercontinental Ballistic Missile Target,” November 16, 2020.
39 Jason Sherman, “SM-3 Block IIA Intercepts ICBM Target, Validating Potential for Homeland Defense
‘Underlayer,’” Inside Defense, November 17, 2020.
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of the RKV’s performance shortfalls. Even so, planning for an anti-ICBM capability for
the SM-3 Block IIA continued during and even after the RKV’s termination.
Achieving such a capability will require surmounting several challenges. According to
MDA, during the November 2020 flight test named FTM-44, the SM-3 Block IIA struck a
simple ICBM target. This was not an operational test, however, and it was executed under
highly favorable conditions. More development work is needed for the SM-3 Block IIA to
support a layered homeland defense capability. MDA documents show that the agency now
plans to develop and procure an upgraded version of the SM-3 Block IIA for the specific
purpose of fulfilling the homeland defense mission.40
A May 13, 2021, press report stated
The Missile Defense Agency proved that a Navy destroyer with a Standard Missile-3 Block
IIA can stop a simple intercontinental ballistic missile threat, but more work remains to
prove whether this combination could contribute to homeland defense, the MDA director
said Wednesday [May 12].
Vice Adm. Jon Hill described the Flight Test Aegis Weapon System (FTM) 44, which took
place in the Pacific in November after pandemic-related delays earlier in the year: A simple
ICBM target was launched from the Army’s Ronald Reagan Ballistic Missile Defense Test
Site on the Kwajalein Atoll in the Marshall Islands. Satellites detected the launch, and a
slew of satellites and sensors, including on the Pacific Missile Range Facility in Hawaii,
tracked the target. Arleigh Burke-class destroyer USS John Finn (DDG-113), positioned
hundreds of miles east of Hawaii, launched an SM-3 Block IIA missile from its deck based
on its best fire control solution at the time, and the missile itself maneuvered to successfully
hit the target as it received more information in flight.
The goal of the test, Hill said while speaking at the annual McAleese FY 2022 Defense
Programs Conference, was “to prove that we have the ability to leverage the robustness in
the [Aegis] program, so that was really the first test just to see if it’s feasible. And we
learned a lot.”
Hill said the crew of John Finn, with limited data due to limited sensor coverage across the
vast Pacific, maneuvered the ship to get the highest probability of kill.
“It maneuvered, shot the missile; lots of uncertainty because of lack of sensor coverage for
such a long-range flight where we were doing the exercise. So what we actually saw was a
really high divert [from the missile]. So kind of two walkaways from that first test, which
is why I think it was really important, was that it was the longest propagated error or
uncertainty that we’ve ever seen in any test. And then we had the highest divert—that
meant the [SM-3 IIA] missile was maneuvering to actually take it out, and it still took it
out, which is really great,” Hill continued.
“In terms of feasibility, did we accomplish the mission? Absolutely. Every test objective
achieved in November.”
Hill was asked about an April Government Accountability Office report that cited concerns
about the Aegis Combat System/SM-3 IIA pairing for the homeland defense mission—as
opposed to the regional defense mission it was built for, to protect a high-value asset such
as an aircraft carrier from an intermediate-range missile—and whether the simple ICBM
target used in the November test was representative of the real world.
“So what’s next? What’s next is to go against a more complex intercontinental ballistic
missile threat, and maybe even change the scenario. This scenario was a defense of Hawaii
scenario against a rogue nation—you guess which one out there in the Pacific—and in the

40 Government Accountability Office, Missile Defense[:] Fiscal Year 2020 Delivery and Testing Progressed, but
Annual Goals Unmet, GAO 21-314, April 2021, p. 24. See also Jen Judson, “Watchdog Expresses Concern over Using
US Navy Interceptor for Homeland Missile Defense,” Defense News, April 29, 2021.
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future we’re going to go to a more complex [threat], and that’s within the next couple
years,” he said.
“So we’re still analyzing data from November, and then we’re going to make upgrades and
changes to the combat system, and we’ll make changes to the missile in terms of threat set
to take on a higher end class threat.”
MDA and the military services would have to further integrate systems together to make
this a credible layer in the homeland defense network, Hill said. During the November test,
the MDA commanded and controlled the event from the Missile Defense Interoperability
and Operations Center in Colorado Springs, Colo., using the Command and Control Battle
Management and Communication System (C2BMC) to receive satellite and sensor data
and feed it to John Finn, which fired its missile on remote without having access to the
sensor data itself. While that worked in a controlled environment, for a permanent
homeland defense mission the ship would need to be better integrated into U.S. Northern
Command’s network to fully share information and targeting data.
Hill said that Aegis has been integrated to operate with the Terminal High Altitude Area
Defense system, and THAAD has been integrated with the Patriot missile defense system,
but MDA hasn’t integrated all the regional defense systems with homeland defense
systems.
Beyond the actual integration and engineering work, Hill added that there was a policy
question to answer, too.
“Do we want ships in that role of being off the West Coast … defending against ICBMs as
a layer to the Ground-Based Mid-Course Defense? That’s an incredible conversation,
we’re having that now, and it’s hard to predict where it will go.”
Asked on Thursday during the Naval Postgraduate School’s acquisition research
symposium if the Navy has the capacity and appetite to use destroyers for homeland
defense, Hill said much of it comes down to what ships are available for the mission.
“I think if you asked Gen. [Glen] VanHerck from NORTHCOM about his confidence in
defending the nation today, the answer would be confident. But as the threat evolves, right,
you start to see a little change in that view. And so it’s been viewed for a while that the
Navy can play a role in that area, but it becomes an asset problem,” Hill said. “There are
only so many ships we have up there. And they’re multi-mission ships, and they have a lot
of roles around the globe to execute.”41
A June 22, 2021, press report stated
The Pentagon’s No. 2 official has ordered 11 missile interceptors transferred from research
and development for possible deployment on Navy ships in the Pacific or European regions
after a test in November indicated they could stop an intercontinental ballistic missile.
In the test, the USS John Finn intercepted a mock ICBM intended to simulate one that
could be launched at Hawaii by North Korea. The destroyer, operating near Hawaii, fired
off one of the Standard Missile-3 model Block IIA interceptors built by Raytheon
Technologies Corp. at the target launched from Kwajalein Atoll in the Marshall Islands.
Deputy Defense Secretary Kathleen Hicks informed Congress May 27 of her rationale for
transferring the interceptors, although she didn’t disclose it publicly.
“The missiles have conducted successful intercept tests and their deployment is in the
important interest of our national security,” Hicks spokesman Jamal Brown said in an email

41 Megan Eckstein, “MDA: Test of DDG, Standard Missile-3 IIA a Good Start, But More Work Needed on Homeland
Defense Mission,” USNI News, May 13, 2021. See also Jason Sherman, “MDA Planning Second SM-3 Block IIA
Flight Test Against ICBM Target; New Development and Upgraded Interceptor Needed,” Inside Defense, May 12,
2021; Rich Abott, “MDA Planning Second Test of SM-3 IIA Against ICBM Target,” Defense Daily, May 17, 2021.
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this month. The transfer to the Navy marks the first major missile defense initiative of the
Biden administration.
Although the Navy’s Aegis combat system, which launched the missile, and the interceptor
“were not designed to defeat an ICBM-class target, this test demonstrated some potential
limited capability,” Vice Admiral Jon Hill, director of the Missile Defense Agency, said in
testimony to Congress last week.42
Required vs. Available Numbers of BMD-Capable Aegis Ships
Another potential issue for Congress concerns required versus available numbers of BMD-
capable Aegis ships. Some observers have expressed concern about the potential operational
implications of a shortfall in the available number of BMD-capable relative to the required
number. Regarding the required number of BMD-capable Aegis ships, an August 15, 2018, Navy
information paper states the following:
The [Navy’s] 2016 Force Structure Assessment [FSA]43 sets the requirement [for BMD-
capable ships] at 54 BMD-capable ships, as part of the 104 large surface combatant
requirement, to meet Navy unique requirements to support defense of the sea base and
limited expeditionary land base sites….
The minimum requirement for 54 BMD ships is based on the Navy unique requirement as
follows. It accepts risk in the sourcing of combatant commander (CCDR) requests for
defense of land.
- 30 to meet CVN escort demand for rotational deployment of the carrier strike groups
- 11 INCONUS for independent BMD deployment demand
- 9 in forward deployed naval forces (FDNF) Japan to meet operational timelines in
USINDOPACOM
- 4 in FDNF Europe for rotational deployment in EUCOM.44
Burden of BMD Mission on U.S. Navy Aegis Ships
A related potential issue for Congress is the burden that BMD operations may be placing on the
Navy’s fleet of Aegis ships, particularly since performing BMD patrols requires those ships to
operate in geographic locations that may be unsuitable for performing other U.S. Navy missions,
and whether there are alternative ways to perform BMD missions now performed by U.S. Navy
Aegis ships, such as establishing more Aegis Ashore sites. A June 16, 2018, press report states the
following:
The U.S. Navy’s top officer wants to end standing ballistic missile defense patrols and
transfer the mission to shore-based assets.
Chief of Naval Operations Adm. John Richardson said in no uncertain terms on June 12
that he wants the Navy off the tether of ballistic missile defense patrols, a mission that has

42 Anthony Capaccio, “U.S. Navy Ships Close to Getting Interceptors That Could Stop an ICBM,” Bloomberg, June 22,
2021.
43 The FSA is the Navy’s analysis, performed every few years, that establishes the Navy’s ship force structure
requirements. For further discussion, see CRS Report RL32665, Navy Force Structure and Shipbuilding Plans:
Background and Issues for Congress, by Ronald O'Rourke.
44 Navy information paper dated August 15, 2018, entitled “Ballistic Missile Defense (BMD) Capable Ships
requirement,” provided by Navy Office of Legislative Affairs to CBO and CRS on August 15, 2018. The information
paper was requested by CBO.
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put a growing strain on the Navy’s hard-worn surface combatants, and the duty shifted
towards more shore-based infrastructure.
“Right now, as we speak, I have six multi-mission, very sophisticated, dynamic cruisers
and destroyers―six of them are on ballistic missile defense duty at sea,” Richardson said
during his address at the U.S. Naval War College’s Current Strategy Forum. “And if you
know a little bit about this business you know that geometry is a tyrant.
“You have to be in a tiny little box to have a chance at intercepting that incoming missile.
So, we have six ships that could go anywhere in the world, at flank speed, in a tiny little
box, defending land.”
Richardson continued, saying the Navy could be used in emergencies but that in the long
term the problem demands a different solution.
“It’s a pretty good capability and if there is an emergent need to provide ballistic missile
defense, we’re there,” he said. “But 10 years down the road, it’s time to build something
on land to defend the land. Whether that’s AEGIS ashore or whatever, I want to get out of
the long-term missile defense business and move to dynamic missile defense.”
The unusually direct comments from the CNO come amid growing frustration among the
surface warfare community that the mission, which requires ships to stay in a steaming box
doing figure-eights for weeks on end, is eating up assets and operational availability that
could be better used confronting growing high-end threats from China and Russia.
The BMD mission was also a factor in degraded readiness in the surface fleet. Amid the
nuclear threat from North Korea, the BMD mission began eating more and more of the
readiness generated in the Japan-based U.S. 7th Fleet, which created a pressurized situation
that caused leaders in the Pacific to cut corners and sacrifice training time for their crews,
an environment described in the Navy’s comprehensive review into the two collisions that
claimed the lives of 17 sailors in the disastrous summer of 2017.
Richardson said that as potential enemies double down on anti-access technologies
designed to keep the U.S. Navy at bay, the Navy needed to focus on missile defense for its
own assets.
“We’re going to need missile defense at sea as we kind of fight our way now into the battle
spaces we need to get into,” he said. “And so restoring dynamic maneuver has something
to do with missile defense.45
A June 23, 2018, press report states the following:
The threats from a resurgent Russia and rising China―which is cranking out ships like it’s
preparing for war―have put enormous pressure on the now-aging [U.S. Navy Aegis
destroyer] fleet. Standing requirements for BMD patrols have put increasing strain on the
U.S. Navy’s surface ships.
The Navy now stands at a crossroads. BMD, while a burden, has also been a cash cow that
has pushed the capabilities of the fleet exponentially forward over the past decade. The
game-changing SPY-6 air and missile defense radar destined for DDG Flight III, for
example, is a direct response to the need for more advanced BMD shooters. But a smaller
fleet, needed for everything from anti-submarine patrols to freedom-of-navigation missions
in the South China Sea, routinely has a large chunk tethered to BMD missions.
“Right now, as we speak, I have six multimission, very sophisticated, dynamic cruisers and
destroyers―six of them are on ballistic missile defense duty at sea,” Chief of Naval
Operations Adm. John Richardson said during an address at the recent U.S. Naval War
College’s Current Strategy Forum. “You have to be in a tiny little box to have a chance at

45 David B. Larter, “The US Navy Is Fed Up with Ballistic Missile Defense Patrols,” Defense News, June 16, 2018. See
also Paul McLeary, “Will Budget Crunch Pentagon Laser & Space Investments?” Breaking Defense, November 13,
2018.
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intercepting that incoming missile. So we have six ships that could go anywhere in the
world, at flank speed, in a tiny little box, defending land.”
And for every six ships the Navy has deployed in a standing mission, it means 18 ships are
in various stages of the deployment cycle preparing to relieve them.
The Pentagon, led by Defense Secretary Jim Mattis, wants the Navy to be more flexible
and less predictable―“dynamic” is the buzzword of moment in Navy circles. What
Richardson is proposing is moving standing requirements for BMD patrols away from
ships underway and all the associated costs that incurs, and toward fixed, shore-based sites,
and also surging the Navy’s at-sea BMD capabilities when there is an active threat....
In a follow-up response to questions posed on the CNO’s comments, Navy spokesman
Cmdr. William Speaks said the Navy’s position is that BMD is an integral part of the
service’s mission, but where long-term threats exist, the Navy should “consider a more
persistent, land-based solution as an option.”
“This idea is not about the nation’s or the Navy’s commitment to BMD for the U.S. and
our allies and partners―the Navy’s commitment to ballistic missile defense is rock-solid,”
Speaks said. “In fact, the Navy will grow the number of BMD-capable ships from 38 to 60
by 2023, in response to the growing demand for this capability.
“The idea is about how to best meet that commitment. In alignment with our national
strategic documents, we have shifted our focus in an era of great power competition―this
calls us to think innovatively about how best to meet the demands of this mission and
optimize the power of the joint force.”...
While the idea of saving money by having fixed BMD sites and freeing up multimission
ships is sensible, it may have unintended consequences, said Bryan McGrath, a retired
destroyer skipper and owner of the defense consultancy The FerryBridge Group.
“The BMD mission is part of what creates the force structure requirement for large surface
combatants,” McGrath said on Twitter after Defense News reported the CNO’s comments.
“Absent it, the number of CG’s and DDG’s would necessarily decline. This may in fact be
desirable, depending on the emerging fleet architecture and the roles and missions debate
underway. Perhaps we need more smaller, multi-mission ships than larger, more expensive
ones.
“But it cannot be forgotten that while the mission is somewhat wasteful of a capable, multi-
mission ship, the fact that we have built the ships that (among other things) do this mission
is an incredibly good thing. If there is a penalty to be paid in peacetime sub-optimization
in order to have wartime capacity—should this not be considered a positive thing?”
McGrath went on to say that the suite of combat systems that have been built into Aegis
have been in response to the BMD threat. And indeed, the crown jewels of the surface
fleet―Aegis Baseline 9 software, which allows a ship to do both air defense and BMD
simultaneously; the Aegis common-source library; the forthcoming SPY-6; cooperative
engagement―have come about either in part or entirely driven by the BMD mission....
A Navy official who spoke on condition of anonymity, to discuss the Navy’s shifting
language on BMD, acknowledged the tone had shifted since the 2000s when the Navy
latched onto the mission. But the official added that the situation more than a decade later
has dramatically shifted.
“The strategic environment has changed significantly since the early 2000s―particularly
in the western Pacific. We have never before faced multiple peer rivals in a world as
interconnected and interdependent as we do today,” the official said. “Nor have we ever
seen technologies that could alter the character of war as dramatically as those we see
emerging around us. China and Russia have observed our way of war and are on the move
to reshape the environment to their favor.”
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In response to the threat and Defense Secretary Jim Mattis’ desire to use the force more
dynamically, the Navy is looking at its options, the official said. “This includes taking a
look at how we employ BMD ships through the lens of great power competition to compete,
deter and win against those who threaten us.”46
A January 29, 2019, press report states the following:
The Navy is looking to get out of the missile defense business, the service’s top admiral
said today, and the Pentagon’s new missile defense review might give the service the off-
ramp it has been looking for to stop sailing in circles waiting for ground-based missile
launches.
This wasn’t the first time Adm. John Richardson bristled in public over his ships sailing in
“small boxes” at sea tasked with protecting land, when they could be out performing other
missions challenging Chinese and Russian adventurism in the South China Sea and the
North Atlantic….
“We’ve got exquisite capability, but we’ve had ships protecting some pretty static assets
on land for a decade,” Richardson said at the Brookings Institute. “If that [stationary] asset
is going to be a long-term protected asset, then let’s build something on land and protect
that and liberate these ships from this mission.”
Japan is already moving down the path of building up a more robust ground-based sensor
and shooter layer, while also getting its own ships out to sea armed with the Aegis radar
and missile defense system, both of which would free up American hulls from what
Richardson on Monday called “the small [geographic] boxes where they have to stay for
ballistic missile defense.”47
Allied Burden Sharing: U.S. vs. Allied Contributions to Regional
BMD Capabilities
Another related potential issue for Congress concerns allied burden sharing—how allied
contributions to regional BMD capabilities and operations compare to U.S. naval contributions to
overseas regional BMD capabilities and operations, particularly in light of constraints on U.S.
defense spending, worldwide operational demands for U.S. Navy Aegis ships, and calls by some
U.S. observers for increased allied defense efforts. The issue can arise in connection with both
U.S. allies in Europe and U.S. allies in Asia. Regarding U.S. allies in Asia, a December 12, 2018,
press report states the following:
In June, US Navy Chief of Naval Operations (CNO) Admiral John Richardson said during
a speech at the US Naval War College that the US Navy should terminate its current
practice of dedicating several US Navy warships solely for Ballistic Missile Defense
(BMD).
Richardson wanted US warships to halt BMD patrols off Japan and Europe as they are
limiting, restrictive missions that could be better accomplished by existing land-based
BMD systems such as Patriot anti-missile batteries, the US Terminal High Altitude Area
Defense (THAAD) anti-missile system and the Aegis Ashore anti-missile system.
In the months since dropping his bombshell, Richardson—and much of the debate—has
gone quiet.

46 David B. Larter, “As Threats Mount, US Navy Grapples with Costly Ballistic Missile Defense Mission,” Defense
News, June 23, 2018.
47 Paul McLeary, “The Navy Has Had Enough of Missile Defense And Sees Its Chance,” Breaking Defense, January
28, 2019.
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“My guess is the CNO got snapped back by the Pentagon for exceeding where the debate
actually stood,” one expert on US naval affairs told Asia Times.
But others agree with him. Air Force Lt Gen Samuel A Greaves, the director of the US
Missile Defense Agency (MDA), acknowledges Richardson’s attempts to highlight how
these BMD patrols were placing unwelcome “strain on the (US Navy’s) crews and
equipment.”
But there are complications. While it may free US Navy warships for sea-control, rather
than land defense, there is a concern that next- generation hypersonic cruise missiles could
defeat land-based BMD systems, such as Aegis Ashore, while the US Navy’s Aegis-
equipped warships offer the advantages of high-speed mobility and stealth, resulting in
greater survivability overall.
As Japan prepares to acquire its first Aegis Ashore BMD system – and perhaps other
systems such as the THAAD system which has been deployed previously in Romania and
South Korea – the possibility that the US Navy will end its important BMD role represents
abrupt change….
Japan’s decision to deploy Aegis Ashore can fill in any gap created by a possible US Navy
cessation of BMD patrols. “The land-based option is more reliable, less logistically
draining, and despite being horrendously expensive, could be effective in the sense that it
provides a degree of reassurance to the Japanese people and US government, and
introduces an element of doubt of missile efficacy into [North Korean] calculations,” said
[Garren Mulloy, Associate Professor of International Relations at Daito Bunka University
in Saitama, Japan], adding, however, that these systems could not cover Okinawa.
“Fixed sites in Japan could be vulnerable, and the Aegis vessels provide a flexible forward-
defense, before anything enters Japanese airspace, but with obviously limited reactions
times,” Mulloy said. “Aegis Ashore gives more reaction time – but over Japanese
airspace.”…
The silence about this sudden possible shift in the US defense posture in the western Pacific
is understandable: it is a sensitive topic in Washington and Tokyo. However, the Trump
administration has urged its allies to pay more for their own defense needs and to support
US troops deployed overseas.
Meanwhile, Tokyo needs to proceed cautiously given the likelihood that neighbors might
view a move on BMD as evidence that Tokyo is adopting an increasingly aggressive
defense posture in the region.
But for them, it is a no-win situation. If the US does ditch the BMD patrol mission, China
and North Korea might view the shift as equally menacing given that it greatly enhances
the US Navy’s maritime warfare capabilities.48
Role of Aegis BMD in New Guam Missile Defense Architecture
Another issue for Congress is the role of the Aegis BMD program in a new missile defense
system architecture for Guam. After studying various possible BMD system architectures for
Guam, DOD is proposing a system that would combine elements of the Aegis BMD system with
elements of Army BMD systems. MDA’s proposed FY2023 budget requests funding to begin
implementing its this BMD architecture for Guam. A March 30, 2022, press report states:
The Missile Defense Agency’s initial plan for the architecture to protect Guam turns to
proven systems to help the agency meet a 2026 fielding deadline, according Vice Adm.
Jon Hill, the agency’s director.

48 Peter J. Brown, “Japan, US Silent over Ending Ballistic Missile Patrols,” Asia Times, December 12, 2018.
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The defense of Guam from potential ballistic, cruise and hypersonic missile attacks has
become a priority for the MDA, which is seeking $539 million in fiscal 2023 to continue
to design and develop multiple-land based radar systems, procure weapon system
components and initiate military construction planning and design activity.
“Current forces are capable of defending Guam against today’s North Korean ballistic
missile threats,” Dee Dee Martinez, the MDA’s comptroller said in a March 28 Pentagon
budget briefing. “However, the regional threat to Guam, including from China, continues
to rapidly evolve.”...
The architecture will not be a fixed missile defense site like Aegis Ashore in Romania and
Poland, Hill said. “Think of it as a distributed system.” He added that the agency is
interested in using mobile launchers.
The architecture will include Navy SM-3 and SM-6 missiles, the Patriot air-and-missile
defense system and the Army’s Terminal High Altitude Area Defense System (THAAD).
A THAAD battery has been operating on Guam since 2013.
Those elements will be connected through the Army’s Integrated Battle Command System,
a command-and control-system that connects sensors and shooters on the battlefield. The
agency will also use the Aegis weapon system’s fire control capability, Hill said.
“Patriot [has] a fabulous capability for cruise missile defense, and that’s our first focus
area,” Hill said. “And we have the ability within Aegis to enable that, but, right now, we
are doing ballistic missiles, hypersonic, on the Aegis part of that overall integrated
architecture and then the cruise missile piece will be with the Army systems.”
While MDA is focused on using existing technology to make up the architecture, it will
consider new technology, including the Mid-Range Capability missile the Army will field
in FY23, as it becomes available, according to Hill....
“That topology of the island … it is a tough place,” Hill said. “An Aegis Ashore site is
limited in what it can do because of the the rise and the fall of the hills, you got radar, it’s
not a flat earth, and it’s certainly not flat on Guam, so we’ve done some really incredible
work and analysis over the last couple years ... by dispersing the systems and making sure
everything’s networked.”49
Conversion of Hawaii Aegis Test Site
Another potential issue for Congress is whether to convert the Aegis test facility in Hawaii into an
operational land-based Aegis BMD site. DOD’s January 2019 missile defense review report
states, in a section on improving or adapting existing BMD systems, that
Another repurposing option is to operationalize, either temporarily or permanently, the
Aegis Ashore Missile Defense Test Center in Kauai, Hawaii, to strengthen the defense of
Hawaii against North Korean missile capabilities. DoD will study this possibility to further
evaluate it as a viable near-term option to enhance the defense of Hawaii. The United States
will augment the defense of Hawaii in order to stay ahead of any possible North Korean
missile threat. MDA and the Navy will evaluate the viability of this option and develop an
Emergency Activation Plan that would enable the Secretary of Defense to operationalize
the Aegis Ashore test site in Kauai within 30 days of the Secretary’s decision to do so, the
steps that would need to be taken, associated costs, and personnel requirements. This plan

49 Jen Judson, “MDA’s Plan to Protect Guam Relies on Field-Proven Systems,” Defense News, March 30, 2022. See
also Rich Abott, “MDA Decides On Guam Defense Architecture,” Defense Daily, March 29, 2022; Jason Sherman,
“DOD Picks SPY-7 for Land-Based Aegis, Giving Lockheed First U.S. Customer for New Radar,” Inside Defense,
May 6, 2022.
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will be delivered to USDA&S, USDR&E, and USDP within six months of the release of
the MDR.50
A January 25, 2019, press report states the following:
The Defense Department will examine the funding breakdown between the Navy and the
Missile Defense Agency should the government make Hawaii’s Aegis Ashore Missile
Defense Test Center into an operational resource, according to the agency’s director.
“Today, it involves both Navy resources for the operational crews—that man that site—as
well as funds that come to MDA for research, development and test production and
sustainment,” Lt. Gen. Sam Greaves said of the test center when asked how the funding
would shake out between the Navy and MDA should the Pentagon move forward with the
recommendation.51
Potential Contribution from Lasers
Another potential issue for Congress concerns the potential for ship-based lasers to contribute in
coming years to Navy terminal-phase BMD operations and the impact this might eventually have
on required numbers of ship-based BMD interceptor missiles. Another CRS report discusses the
potential value of ship-based lasers for performing various missions, including, potentially,
terminal-phase BMD operations.52
Technical Risk and Test and Evaluation Issues
Another potential oversight issue for Congress is technical risk and test and evaluation issues in
the Aegis BMD program.
July 2020 GAO Report
A July 2020 GAO report on the testing of U.S. BMD systems, including the Aegis BMD system,
stated the following:
Aegis BMD demonstrated various capabilities in fiscal year 2019 tests and achieved
independent accreditation for all its models used in operational ground tests. The Missile
Defense Agency (MDA) conducted five Aegis Ballistic Missile Defense (BMD) intercept
flight tests in fiscal year 2019, successfully intercepting two ballistic missile targets and
three cruise missiles. Additionally, MDA also conducted Aegis BMD non-intercept flight
tests with live or simulated interceptors and targets, as well as five model-based ground
tests that provided data on Aegis BMD interoperability and weapon system functionality
in various regional and Homeland Defense scenarios….
Aegis BMD testing also had some limitations. For instance, while most testing limitations
are classified, DOT&E noted in its fiscal year 2019 assessment of Aegis BMD that MDA
ground tests have routinely shown the need for improved inter-element coordination and
interoperability to enhance engagement efficiency. Moreover, for the second year in a row,
DOT&E noted that flight testing and models and simulations did not address all expected
threat types, ground ranges, and raid sizes for Aegis BMD. For instance, while Aegis BMD
M&S tools were accredited for many scenarios, there were limitations for raid engagements
due to the lack of validation data from live fire raid engagements and lack of post-intercept
debris modeling. As we reported in June 2019, MDA planned to assess Aegis BMD 5.1

50 Department of Defense, Missile Defense Review 2019, released January 17, 2019, pp. 55-56.
51 Mallory Shelbourne, “DOD to Determine Funding Breakdown for Aegis Ashore Repurposing,” Inside the Navy,
January 25, 2019.
52 See CRS Report R44175, Navy Shipboard Lasers: Background and Issues for Congress, by Ronald O'Rourke.
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raid performance for the first time in December 2018, but the test was de-scoped to a single
intercept due, in part, to a test range safety asset malfunction. While MDA planned to
conduct a raid the fourth quarter of fiscal year 2020, according to technical comments we
received from MDA at the end of our audit, that plan has been canceled. In the meantime,
the warfighter will have reduced information about how Aegis BMD 5.1 performs in these
real-world-like scenarios.
MDA stayed on track to deliver the next generation of Aegis BMD capabilities. For
instance, MDA plans to deliver BMD 6.0 in the 2023 time frame to provide capabilities
against larger raids, better discrimination, and improved communication with its
interceptors. Additionally, BMD 6.0 takes advantage of the Navy’s effort to replace the
Aegis AN/SPY-1 radar with a more capable AN/SPY-6 (V)1 and to overhaul the entire
Aegis combat system. As we reported in June 2019, MDA and the Navy re-planned AWS
Baseline 10.0, after a funding reduction of $31.45 million against BMD 6.05. While the
reduction resulted in delays to completion of some technical content, its delivery time
frame did not change. In fiscal year 2019, the program remained on schedule, completing
a planned review and participated in a Navy-funded developmental test of AN/SPY-6(V)1
and FTX-34, demonstrating ballistic missile tracking capabilities. MDA efforts to deliver
integrated AWS Baseline 5.4 were also on track in fiscal year 2019 after the program
readjusted its schedule in fiscal year 2018….
According to MDA, the Aegis BMD SM-3 Block IB program considers the schedule for
awarding a multi-year procurement contract, and enduring subcontractor quality issues, to
be the two main risks facing the program. MDA officials stated that they expected to award
the multi-year procurement contract in the first quarter, fiscal year 2020. MDA had also
stated that a delay in the award could cause production delays both to the United States and
to foreign military sales. MDA’s current plans call for the multi-year procurement award
in the second quarter, fiscal year 2020.
In addition, as we reported in 2019, MDA officials have noted that the Aegis BMD SM-3
Block IB’s prime contractor has had difficulty ensuring that all subcontracted components
meet defined specifications. Similar issues occurred in fiscal year 2019, each of which
required resolution on a case-by-case basis. For example, MDA officials reported that an
important actuator was found to have contaminated lubricant, requiring the source of the
contamination to be tracked to a specific facility within the supply chain and the
procurement of new hardware. In addition, a divert valve was experiencing an increased
reject rate, slowing down deliveries of the Third Stage Rocket Motor. The program and the
contractor developed and implemented three corrective actions to address this issue and
accelerate deliveries. Even so, problems such as these can result in months-long delays,
and MDA reported that the introduction of improved quality controls drove up costs in
fiscal year 2019….
Following the failure of FTM-29 in January 2018, MDA re-organized the SM-3 Block IIA
schedule to allow it to identify the cause of the failure, implement changes, and then test
these changes to validate their efficacy. As we reported in May 2019, as a result of the test
failure, MDA and the government of Japan convened a failure review board to investigate
the causes of the test failure. The board’s conclusions identified the source of the failure.
To test the fixes identified through the FTM-29 failure review board, MDA added a new
flight test to its schedule, FTM-45. Despite criticism from Department of Defense
stakeholders that FTM-45 would not be taxing enough to make up for the failure of FTM-
29, MDA successfully conducted the test, and thus validated the corrective actions, in
October 2018.
Two months later, in December 2018, MDA conducted FTI-03, the first successful SM-3
Block IIA intercept of an Intermediate-Range Ballistic Missile (IRBM), and the first
successful SM-3 Block IIA intercept to use remote sensor data to guide the engagement,
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known as Engage on Remote. However, as mentioned previously, the test’s initial plan was
an intercept of two targets, but it was scaled down due to range safety issues.
MDA achieved its objective in FTI-03 by intercepting the target, but a more detailed review
of the system’s performance revealed at least one issue. During the interceptor’s flight, the
attitude control system in the third stage rocket motor experienced a fault whereby a valve
failed to respond to electronic instructions. A failure review board isolated the fault to a
specific component failing to provide adequate electric current. Seeking to avoid
unnecessary work, the prime contractor temporarily suspended its operations in order to
identify the root cause and then develop and implement corrective actions. This suspension
has affected delivery schedules for both third stage rocket motors and completed
interceptors.
MDA originally planned for an initial production decision in December 2018, but two
issues delayed this decision. First, owing to the fact that the canceled Redesigned Kill
Vehicle re-used parts from the SM-3 Block IIA program, the Undersecretary of Defense
for Research and Engineering requested a study to determine if the SM-3 Block IIA could
be affected by the issues which resulted in the RKV’s cancellation. Second, DOD officials
recommended against any initial production decision until the issue observed in FTI-03
was resolved.
MDA documents indicated that its officials believed an initial production decision was
possible before the end of fiscal year 2019. The SM-3 Block IIA received a positive initial
production decision in October 2019.53
January 2021 DOT&E Report54
A January 2021 report from DOD’s Director, Operational Test and Evaluation (DOT&E)—
DOT&E’s annual report for FY2020—stated the following in its section on the Aegis BMD
program:
Assessment
• Aegis BMD continues to demonstrate a capability to intercept non-separating, simple-
separating, and complex-separating ballistic missiles in the midcourse phase of flight with
SM-3 missiles. Aegis BMD has also demonstrated a capability to intercept select ballistic
missiles in the terminal phase of flight with SM-6 missiles. However, flight testing and
M&S [modeling and simulation] have not addressed all expected threat types, ground
ranges, and raid sizes. The MDA has used M&S to explore Aegis BMD raid engagement
performance, but DOT&E has less confidence in these results because COMOPTEVFOR
[the Navy Commander, Operational Test and Evaluation Force] has been unable to accredit
the models due to the lack of validation data from live fire raid engagements and lack of
post-intercept debris modeling.
• During Pacific Dragon—2020 [a Navy fleet exercise in August 2020], the MDA
demonstrated Aegis BMD interoperability with Republic of Korea naval assets while
conducting simulated ballistic missile engagements. The AAMDTC [Aegis Ashore Missile
Defense Test Complex] demonstrated Aegis interoperability with Australian naval assets
while tracking ballistic missile targets.
• DOT&E will provide an assessment of the FTM-44 [flight] test results and of the SBT
[sea-based terminal] Increment 2 capability (based on the results of FTM-31 E1 and FTM-
33) [flight tests] in separate reports.

53 Government Accountability Office, Missile Defense[:] Assessment of Testing Approach Needed as Delays and
Changes Persist, GAO-20-432, July 2020, pp. 44, 45-46, 48-49, 51-52.
54 DOT&E’s annual report for FY2021, which is dated January 2022, includes a section that discusses missile defense
systems in general but does not include a section specifically discussing the Aegis BMD system.
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• MDA ground tests have routinely shown that inter-element coordination and
interoperability need improvement to improve engagement efficiency; however, flight
testing with multi-element engagement coordination has been limited. Aegis BMD has
exercised rudimentary engagement coordination with Terminal High-Altitude Area
Defense [THAAD] [BMD] firing units, but not with [the] Patriot [BMD system]. The MDA
plans to exercise engagement coordination between those three theater elements during
Flight Test Operational (FTO)-05, but that flight test has been repeatedly delayed and is
currently planned for FY28.
• DOT&E and USD(R&E) [Under Secretary of Defense for Research and Engineering]
have prompted the MDA to establish a ground testing approach to support assessments of
missile reliability. DOT&E cannot assess SM-3 missile reliability with confidence until the
MDA is able to provide additional ground test data that simulate the in-flight environment.
• The MDA delivered results from a subset of the high-fidelity M&S operational test runs
for record for the SM-3 IIA missile. The MDA found a problem in one of the models used
to conduct the M&S runs. The MDA has identified a fix action and the test runs will be re-
run and delivered in FY21. The data from these re-executed runs will support the DOT&E
assessment of the operational effectiveness of the SM-3 Block IIA missile in FY21.
• COVID-19 impacts have delayed delivery of high-fidelity M&S operational test runs for
record to support an assessment of SBT Increment 2 operational effectiveness. Verification
and validation data from flight testing will not be available until FY21 to support model
accreditation. M&S operational test runs for record will not be available until FY22.
• The developmental AN/SPY-6(V)1 radar continues to track ballistic missiles during
MDA flight tests. The radar detected and tracked the HGV [hypersonic glide vehicle] target
in FEX-01.
Recommendations
The MDA should:
1. Prioritize resources for FTO-05 to ensure this critical flight test occurs as soon as
possible.
2. Conduct Aegis BMD midcourse and terminal phase flight testing with live fire intercepts
of raids of two or more ballistic missile targets to aid in the validation of M&S tools.
3. Improve Aegis BMD high-fidelity M&S tools to incorporate post-intercept debris
modeling to better assess engagement performance in raid scenarios.
4. Provide data from high-fidelity ground tests to DOT&E to inform SM-3 Block IB Threat
Upgrade and Block IIA missile reliability estimates.
5. Work with DOT&E and USD(R&E) to establish a ground testing approach to support
assessments of missile reliability.55
Regarding the SM-6 missile, the January 2021 DOT&E report also stated the following:
Assessment
• As reported in the FY18 DOT&E SM-6 BLK I FOT&E [Follow-on Operational Test and
Evaluation] Report, the SM-6 remains effective and suitable with the exception of the
classified deficiency identified in the FY13 IOT&E [Initial Operational Test and
Evaluation] Report and two additional problems discovered during FY17 SM-6 BLK
[block] I testing to verify corrected deficiencies. The SM-6 BLK IA FOT&E analysis is
consistent with prior reporting.
• While post-flight test data appears promising, DOT&E will assess the results of the
developmental/engineering flight test to examine corrective actions to a classified

55 Department of Defense, Director, Operational Test & Evaluation, FY 2020 Annual Report, January 2021, p. 218.
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performance deficiency discovered during FY17 SM-6 BLK verification of correction of
deficiency tests. This assessment will occur in FY21.
Recommendations
The Navy should:
1. Fully assess the corrective actions implemented to address the additional problems
encountered during FY17 SM-6 BLK I verification of corrected deficiency tests by
conducting a verification of deficiency operational flight test.
2. Plan and conduct lethality assessments for the SM-6 FCD [Future Capabilities
Demonstration] capabilities.56
Legislative Activity for FY2023
Summary of Action on FY2023 MDA Funding Request
Table 2 summarizes congressional action on the FY2023 request for MDA procurement and
research and development funding for the Aegis BMD program.
Table 2. Summary of Congressional Action on FY2023 MDA Funding Request
(In millions of dollars, rounded to nearest tenth; totals may not add due to rounding)
Authorization
Appropriation

Request HASC
SASC
Enacted
HAC
SAC
Enacted
Procurement
Aegis BMD (line 32)
402.2

(SM-3 Block IB missile quantity)
(47)

Aegis BMD Advance Procurement (line 33)
0

SM-3 Block IIA (line 35)
338.0

(SM-3 Block IIA missile quantity)
(10)

Aegis Ashore Phase III (line 39)
30.1

Aegis BMD hardware and software (line 41)
78.2

Subtotal Procurement
848.5

Research, development, test, and evaluation (RDT&E)
Aegis BMD (PE 0603892C) (line 83)
600.1

Aegis BMD test (PE 0604878C) (line 113)
182.8

Land-based SM-3 (PE 0604880C) (line 115)
27.7

Subtotal RDT&E
810.6

TOTAL
1,659.1

Source: Table prepared by CRS based on DOD’s original FY2023 budget submission, committee and
conference reports, and explanatory statements on FY2023 National Defense Authorization Act and FY2023
DOD Appropriations Act.
Notes: HASC is House Armed Services Committee; SASC is Senate Armed Services Committee; HAC is
House Appropriations Committee; SAC is Senate Appropriations Committee.

56 Department of Defense, Director, Operational Test & Evaluation, FY2020 Annual Report, January 2021, p. 168.
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Appendix. Reported Aegis BMD Flight Tests
Table A-1 presents a summary of reported Aegis BMD flight tests since January 2002. In addition
to the flight tests shown in the table, on February 20, 2008, a BMD-capable Aegis cruiser
operating northwest of Hawaii used a modified version of the Aegis BMD system with the SM-3
missile to shoot down an inoperable U.S. surveillance satellite that was in a deteriorating orbit.
Table A-1. Reported Aegis BMD Flight Tests From January 2002 to the Present
Name of flight
Cumulative Cumulative
Date
Country
test of exercise
Ballistic Missile Target
Successful?
successes
attempts
Exo-atmospheric (using SM-3 missile)
1/25/02
US
FM-2
Unitary short-range (TTV)
Yes
1
1
6/13/02
US
FM-3
Unitary short-range (TTV)
Yes
2
2
11/21/02
US
FM-4
Unitary short-range (TTV)
Yes
3
3
6/18/03
US
FM-5
Unitary short-range (TTV)
No
3
4
12/11/03
US
FM-6
Unitary short-range (TTV)
Yes
4
5
2/24/05
US
FTM 04-1 (FM-7) Unitary short-range (TTV)
Yes
5
6
11/17/05
US
FTM 04-2 (FM-8) Separating short-range (MRT)
Yes
6
7
6/22/06
US
FTM 10
Separating short-range (TTV)
Yes
7
8
12/7/06
US
FTM 11
Unitary short-range (TTV)
No
7
9
4/26/07
US
FTM 11
Unitary short-range (ARAV-A)
Yes
8
10
Event 4
6/22/07
US
FTM 12
Separating short-range (MRT)
Yes
9
11
8/31/07
US
FTM-11a
Classified
Yes
10
12
11/6/07
US
FTM 13
Unitary short-range (ARAV-A)
Yes
11
13

Unitary short-range (ARAV-A)
Yes
12
14
12/17/07
Japan
JFTM-1
Separating short-range (MRT)
Yes
13
15
11/1/08
US
Pacific Blitz
Unitary short-range (ARAV-A)
Yes
14
16

Unitary short-range (ARAV-A)
No
14
17
11/19/08
Japan
JFTM-2
Separating short-range (MRT)
No
14
18
7/30/09
US
FTM-17
Unitary short-range (ARAV-A)
Yes
15
19
10/27/09
Japan
JFTM-3
Separating short-range (MRT)
Yes
16
20
10/28/10
Japan
JFTM-4
Separating short-range (MRT)
Yes
17
21
4/14/11
US
FTM-15
Separating intermediate range
Yes
18
22
(LV-2)
9/1/11
US
FTM-16 E2
Separating short-range (ARAV-B)
No
18
23
5/9/12
US
FTM-16 E2a
Unitary short-range (ARAV-A)
Yes
19
24
6/26/12
US
FTM-18
Separating short-range (MRT)
Yes
20
25
10/25/12
US
FTI-01
Separating short-range (ARAV-B)
No
20
26
2/12/13
US
FTM-20
Separating medium-range
Yes
21
27
(MRBM-T3)
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Name of flight
Cumulative Cumulative
Date
Country
test of exercise
Ballistic Missile Target
Successful?
successes
attempts
5/15/13
US
FTM-19
Separating short-range (ARAV-
Yes
22
28
C)
9/10/13
US
FTO-01
Separating medium-range
Yes
23
29
(eMRBM-T1)
9/18/13
US
FTM-21
Separating short-range (ARAV-
Yes
24
30
C++)
10/3/13
US
FTM-22
Separating medium-range
Yes
25
31
(ARAV-TTO-E)
11/6/14
US
FTM-25
Separating short-range (ARAV-B)
Yes
26
32
6/25/15
US
FTO-02 E1
Separating medium-range (IRBM
n/aa
26
32
T1)
10/4/15
US
FTO-02 E2
Separating medium-range
n/ab
26
32
(eMRBM)
10/20/15
US
ASD-15 E2
Separating short-range (Terrier
Yes
27
33
Orion)
11/1/15
US
FTO-02 E2a
Separating medium-range
No
27
34
(eMRBM)
12/10/15
US (Aegis
FTO02 E1a
Separating medium-range (IRBM
Yes
28
35
Ashore)
T1)
2/3/17
US-Japan
SFTM-01
Separating medium-range (MRT)
Yes
29
36
6/21/17
US-Japan
SFTM-02
Medium-range
No
29
37
10/15/17
US
FS17
Medium-range target
Yes
30
38
1/31/18
US (Aegis
FTM-29
Intermediate-range target
No
30
39
Ashore)
9/11/18
Japan
JFTM-05
Simple separating target
Yes
31
40
10/26/18
US
FTM-45
Medium range
Yes
32
41
12/10/18
US (Aegis
FTI-03
Intermediate-range target
Yes
33
42
Ashore)
11/16/20
US
FTM-44
ICBM target
Yes
34
43
5/26/21 and
US-
ASD/FS21c
Non-separating MRBM target
Yesc
35c
44c
30/2021
Netherlands
Endo-atmospheric (using SM-2 missile Block IV missile and [for MMW E1 and subsequent] SM-6 Dual 1 missile)
5/24/06
US
Pacific Phoenix
Unitary short-range target
Yes
1
1
(Lance)
6/5/08
US
FTM-14
Unitary short-range target (FMA)
Yes
2
2
3/26/09
US
Stellar Daggers
Unitary short-range target
Yes
3
3
(Lance)
7/28/15
US
MMW E1
Unitary short-range target
Yes
4
4
(Lance)
7/29/15
US
MMW E2
Unitary short-range target
Yes
5
5
(Lance)
12/14/16
US
FTM-27
Unitary short-range target
Yes
6
6
(Lance)
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Navy Aegis Ballistic Missile Defense (BMD) Program

Name of flight
Cumulative Cumulative
Date
Country
test of exercise
Ballistic Missile Target
Successful?
successes
attempts
8/29/17
US
FTM-27 E2
Medium-range target (MRBM)
Yes
7
7
5/29/21
US
FTM-31
Medium-range target (MRBM)
No
7
8
7/24/21
US
FTM-33
Two SRBM targets
Yes and
8 and
9 and 10
unconfirmedd unconfirmedd
Sources: Table presented in MDA fact sheet, “Aegis Ballistic Missile Defense Testing,” February 2017, accessed
on May 18, 2022, at https://web.archive.org/web/20170929180757/https:/www.mda.mil/global/documents/pdf/
aegis_tests.pdf, and (for flight tests subsequent to February 2017) MDA news releases.
Notes: TTV is target test vehicle; ARAV is Aegis Readiness Assessment Vehicle. In addition to the flight tests
shown above, there was a successful use of an SM-3 on February 20, 2008, to intercept an inoperative U.S.
satellite—an operation called Burnt Frost.
a. MDA’s table shows this as a test that did not result in the launch of an SM-3. MDA as of August 3, 2015,
had not issued a news release discussing this event. MDA’s count of 31 successful intercepts in 37 launches
through July 29, 2015, does not appear to include this test, suggesting that this was considered a “no test”
event—a test in which there was a failure that was not related to the Aegis BMD system or the SM-3
interceptor. News reports state that the test was aborted due to a failure of the target missile. (Andrea
Shalal, “U.S. Skips Aegis Ashore Missile Test After Target Malfunction,” Reuters, June 26, 2015.) MDA’s table
similarly shows the test of December 7, 2006, as a test that did not result in the launch of an SM-3. MDA
issued a news release on this test, which stated that an SM-3 was not launched “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 ship from launching the first
of the two [SM-3] 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.” MDA
counts the test of December 7, 2006, as an unsuccessful intercept in its count of 31 successful intercepts in
37 launches through July 29, 2015.
b. MDA’s table shows this as a test that did not result in the launch of an SM-3. MDA as of November 10,
2015, had not issued a news release discussing this event. MDA’s count of 32 successful intercepts in 39
launches through November 1, 2015, does not appear to include this test, suggesting that this was
considered a “no test” event—a test in which there was a failure that was not related to the Aegis BMD
system or the SM-3 interceptor.
c. ASD/FS21 was an at-sea demonstration that occurred during a multilateral naval exercise called Formidable
Shield 2021. In the demonstration, a Dutch frigate used its radar to provide early warning track data to a
U.S. Navy destroyer that used the data to calculate a firing solution and launch its interceptor. Some press
reports state that ASD/FS21 involved two successful ballistic missile intercepts, rather than the one shown
in the table.
d. MDA stated that “based on initial observations, one target was successful y intercepted. At this time, we
cannot confirm the second target was destroyed.” (“MDA Test Intercepts Target,” MDA News Release 21-
NEWS-0012, July 24, 2021.)

Author Information

Ronald O'Rourke

Specialist in Naval Affairs

Congressional Research Service

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Navy Aegis Ballistic Missile Defense (BMD) Program

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Congressional Research Service
RL33745 · VERSION 236 · UPDATED
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