
Ground-Based Midcourse Defense (GMD), previously
National Missile Defense (NMD), is an
anti-ballistic missile
An anti-ballistic missile (ABM) is a surface-to-air missile designed to Missile defense, destroy in-flight ballistic missiles. They achieve this explosively (chemical or nuclear), or via hit-to-kill Kinetic projectile, kinetic vehicles, which ma ...
system implemented by the United States of America for defense against
ballistic missile
A ballistic missile is a type of missile that uses projectile motion to deliver warheads on a target. These weapons are powered only during relatively brief periods—most of the flight is unpowered. Short-range ballistic missiles (SRBM) typic ...
s, during the
midcourse phase of
ballistic trajectory flight. It is a major component of the American
missile defense strategy to counter ballistic missiles, including
intercontinental ballistic missile
An intercontinental ballistic missile (ICBM) is a ballistic missile with a range (aeronautics), range greater than , primarily designed for nuclear weapons delivery (delivering one or more Thermonuclear weapon, thermonuclear warheads). Conven ...
s (ICBMs) carrying
nuclear,
chemical
A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combin ...
,
biological
Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, origin, evolution, and distribution of ...
or conventional
warhead
A warhead is the section of a device that contains the explosive agent or toxic (biological, chemical, or nuclear) material that is delivered by a missile, rocket (weapon), rocket, torpedo, or bomb.
Classification
Types of warheads include:
*E ...
s.
As of 2018, the system is composed of two interceptor staging bases in the states of Alaska and California, with 40 staged in the former, 4 staged in the latter, for a total of 44 interceptors, as well as the component early warning and targeting sensors based on land, sea, and in orbit.
As of 2019, a Missile Defense Review has requested 20 additional interceptors to be based in Fort Greely, Alaska, though their delivery has not materialized.
GMD is administered by the U.S.
Missile Defense Agency (MDA), while operational control is provided by the
U.S. Army, with support functions provided by the
U.S. Air Force and
U.S. Space Force.
Background
GMD after its renaming in 2002 remains a limited defense system, intended to protect the continental United States from limited launches of ballistic missiles. Examples given in the past have included countries such as North Korea.
GMD has undergone some controversy over its operational lifetime, such as with a study in 2000 by the
Union of Concerned Scientists and the Security Studies Program at the
Massachusetts Institute of Technology
The Massachusetts Institute of Technology (MIT) is a Private university, private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of moder ...
concluding that "
y country capable of deploying a long-range missile would also be able to deploy countermeasures that would defeat the planned NMD system." Countermeasures studied in detail were bomblets containing biological or chemical agents, aluminized balloons to serve as decoys and to disguise warheads, and cooling warheads to reduce the kill vehicle's ability to detect them. Currently, the Union of Concerned Scientists maintains that GMD is "unproven, unaccountable, and unhelpful for reducing the nuclear threat."
More recently, questions have been asked about the Pentagon characterizing the January 28 test in 2016 as a success, when LA Times reported that the EKV suffered a fault in its reaction control system thrusters, which resulted in "a distance 20 times greater than what was expected" according to an anonymous Pentagon scientist.
Under the Missile Defense Agency, GMD has conducted multiple test exercises, with mixed results. Early testing revealed deficiencies in the Ground Based Interceptor missile, as well as the Exoatmospheric Kill Vehicle. However, with time, success rates increased, marred by the occasional technical failure such as in 2010's FTG-06 (Flight Test Ground-Based Interceptor) where the Sea-based X Band Radar failed to perform as expected,
and the subsequent FTG-06a where despite all elements performing correctly, intercept failed to occur.
Description

GMD is tied into existing United States missile warning infrastructure, as well as purpose built radar sites. It also encompasses 44 ground-based missile interceptors housed at two military bases.
Boeing Defense, Space & Security
Boeing Defense, Space & Security (BDS) is a division of Boeing, the Boeing Company based in Arlington, Virginia, near Washington, D.C. The division builds military Military aircraft, airplanes, Military helicopter, rotorcraft, and Missile, missil ...
is the prime contractor of the program, tasked to oversee and integrate systems from other major defense sub-contractors, such as
Computer Sciences Corporation and
Raytheon
Raytheon is a business unit of RTX Corporation and is a major U.S. defense contractor and industrial corporation with manufacturing concentrations in weapons and military and commercial electronics. Founded in 1922, it merged in 2020 with Unite ...
.
The key sub-systems of the GMD system are:
*
Exoatmospheric Kill Vehicle (EKV) – Raytheon
*
Ground-Based Interceptor
The Ground-Based Interceptor (GBI) is the anti-ballistic missile component of the United States' Ground-Based Midcourse Defense (GMD) system.
Description
This interceptor is made up of a boost vehicle, constructed by Orbital Sciences Corporatio ...
(GBI) – boost vehicle built by
Orbital Sciences; for every interceptor missile there is a
missile silo and a silo interface vault (SIV), which is an underground electronics room adjacent to the silo.
*
Battle management command, control and communications (BMC3) –
Northrop Grumman
Northrop Grumman Corporation is an American multinational Aerospace manufacturer, aerospace and Arms industry, defense company. With 97,000 employees and an annual revenue in excess of $40 billion, it is one of the world's largest Arms industry ...
* Ground-based radars (GBR) – Raytheon
*
AN/FPS-132 Upgraded Early Warning Radar (UEWR) – Raytheon
* Forward-based
X band
The X band is the designation for a band of frequencies in the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of the X band is set at approximately 7.0–11.2&nbs ...
radars (FBXB), such as the
sea-based X-band platform and the
AN/TPY-2 — Raytheon
Interceptor sites are at
Fort Greely
Fort Greely is a United States Army launch site for anti-ballistic missiles located about southeast of Fairbanks, Alaska, Fairbanks, Alaska. It is also the home of the Cold Regions Test Center (CRTC), as Fort Greely is one of the coldest areas ...
,
Alaska
Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...
and
Vandenberg Space Force Base
Vandenberg Space Force Base , previously Vandenberg Air Force Base, is a United States Space Force Base in Santa Barbara County, California. Established in 1941, Vandenberg Space Force Base is a space launch base, launching spacecraft from the ...
, California. A third site was planned for a proposed
US missile defense complex in Poland, but was canceled in September 2009.
In late 2013, there were plans for a proposed Eastern United States site to house a battery of these missiles.
Four sites were shortlisted in January 2014 for an East Coast site -
SERE Remote Training Site in Maine (
Rangeley),
Fort Drum in
New York,
Camp James A. Garfield in
Ohio
Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...
, and
Fort Custer Training Center
Fort Custer Training Center, often known simply as Fort Custer, is a federally owned and state-operated Michigan Army National Guard training facility, but is also used by other branches of the armed forces and armed forces from Illinois, Indian ...
in
Michigan
Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...
.
Camp Ethan Allen Training Site in
Vermont
Vermont () is a U.S. state, state in the New England region of the Northeastern United States. It borders Massachusetts to the south, New Hampshire to the east, New York (state), New York to the west, and the Provinces and territories of Ca ...
was dropped from consideration in late 2013.
In January 2014 the Pentagon announced they were starting a two-year environmental impact study under the 2013 defense authorization bill, which required two missile-defense sites to be identified on the East Coast.
The CBO has estimated that a site would cost US$3.5bn.
In June 2019,
Fort Drum in
New York was chosen as the location for the potential East Coast missile defense site.
In December 2008, the U.S. Missile Defense Agency awarded Boeing a $397.9 million contract to continue development of the program.
In March 2013, the Obama administration announced plans to add 14 interceptors to the current 26 at Fort Greely in response to North Korean threats. The deployment of a second TPY-2 radar to Japan was announced at the same time. While President Obama said that the additional deployment was a hedge against unexpected capabilities, Chinese Ministry of Foreign Affairs spokesman Hong Lei complained that the additional defenses would affect the global strategic balance and strategic trust.
On 30 April 2014, the Government Accountability Office issued a report stating that the system may not be operational any time soon because "its development was flawed". It said the GBI missile was at that point "capable of intercepting a simple threat in a limited way".
On 12 August 2015, Lt. General David L. Mann (commanding general
USASMDC/
ARSTRAT) characterized GMD as the nation's only ground-based defense against limited
ICBM
An intercontinental ballistic missile (ICBM) is a ballistic missile with a range (aeronautics), range greater than , primarily designed for nuclear weapons delivery (delivering one or more Thermonuclear weapon, thermonuclear warheads). Conven ...
attacks.
Issues with the EKV prompted the MDA to work with Raytheon, Boeing, and Lockheed Martin on a new Redesigned Kill Vehicle (RKV), scheduled to debut in 2025. In 2019, the government issued a stop work order for the RKV after recent test results indicated that the current RKV plan is not viable. The government "initiated an analysis of alternative courses of action";
on 21 August the MDA cancelled the $5.8 billion contract for the RKV.
[ This initiates new work on bids for the successor to the Exo-Atmospheric Kill Vehicle (EKV) to 2025.][Loren Thompson (8 Oct 2019) Inside The U.S. Missile Defense Agency's Secret Next Generation Interceptor]
* 50 threat scenarios have been defined (Classified)
* The GBIs will be Hit-to-kill
* Each GBI will have multiple warheads (multiple kill vehicles)
* The GBIs will fit in existing silos
* The GBIs are expected by 2026
* The interim GBI solution until then is to be determined The current GMD programs continue per plan, with up to 64 GBIs (meaning an additional 20) in the missile fields for 2019.
Program costs
Expenditures on the Ground-Based Midcourse Defense program were estimated to be US$30.7 billion by 2007. In 2013, it was estimated that the program would cost $40.926 billion from inception through fiscal year 2017; in 2013–17 spending was to total $4.46 billion, an average of $892 million per year.
Flight tests
:BV: Booster Verification Test
:CMCM: Critical Measurements and Countermeasures
:CTV: Control Test Vehicle
:FTG: Flight Test Ground-Based Interceptor
:FTX: Flight Test Other
:IFT: Integrated Flight Test
Intercept tests
After the FTG-12 test on 11 December 2023, 12 of the 21 (57%) hit-to-kill intercept tests have succeeded. No flight intercept tests from 2010 to 2013 were successful. In response the Pentagon asked for a budget increase and another test for the fielded program. The successful intercept FTG-15 was accomplished by an operational team of the 100th Missile Defense Brigade using their standard operating procedures (round-the-clock 24/7). Although they knew in advance that there would be a test launch, they did not know exactly when it would occur or its exact nature.
Non-intercept tests
Canceled tests
Throughout the program's history, multiple test flights have been canceled, including BV-4, IFT-11, −12, −13, −13A, −15, FTC-03, and, most recently, FTG-04.
Estimated effectiveness
The system has a "single shot probability of kill" of its interceptors calculated at 56%, with the claimed total probability of intercepting a single target, if four interceptors are launched, at 97%. Each interceptor costs approximately $75 million.
The claim of "97% kill probability" has been dismissed by some experts as a flawed application of basic statistical methods. Said James M. Acton, co-director of the Nuclear Policy Program at the Carnegie Endowment for International Peace, "It assumes that the failure modes of the interceptors are independent of one another. But, in practice, if one interceptor fails because of a design flaw, say, it's much more likely that others will do so too for the same reason."
See also
* (THAAD), mobile land-based missile defense system
* , mobile land-based air and missile defense system
* , sea-based missile defense system
*
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* Comparison of anti-ballistic missile systems
This is a table of the most widespread or notable anti-ballistic missile (ABM) systems, intended in whole or part, to counter ballistic missiles. Since many systems have developed in stages or have many iterations or upgrades, only the most notabl ...
References
External links
Ground-based Midcourse Defense (GMD) System page on Boeing site
Missile Threat – GMD on CSIS.org
{{United States Missile Defense
Missile Defense Agency
Anti-ballistic missiles of the United States
Boeing
Raytheon Company products
Lockheed Martin
Missile defense