Ballistic missile payload containing multiple warheads which are independently targetable
A
multiple independently targetable reentry vehicle
(
MIRV
) is an
exoatmospheric
ballistic missile
payload containing several
warheads
, each capable of being aimed to hit a different target. The concept is almost invariably associated with
intercontinental ballistic missiles
carrying
thermonuclear warheads
, even if not strictly being limited to them. An intermediate case is the
multiple reentry vehicle
(MRV) missile which carries several warheads which are dispersed but not individually aimed. All
nuclear-weapon states
except
Pakistan
[a]
and
North Korea
are currently confirmed to have deployed MIRV missile systems.
Israel
is suspected to possess or be in the process of developing MIRVs.
[4]
The first true MIRV design was the
Minuteman III
, first successfully tested in 1968 and introduced into actual use in 1970.
[5]
[6]
[7]
The Minuteman III held three smaller
W62
warheads, with yields of about 170 kilotons of TNT (710 TJ) each in place of the single 1.2 megatons of TNT (5.0 PJ)
W56
used on the Minuteman II.
[8]
From 1970 to 1975, the United States would remove approximately 550 earlier versions of the Minuteman ICBM in the
Strategic Air Command
's (SAC) arsenal and replace them with the new Minuteman IIIs outfitted with a MIRV payload, increasing their overall effectiveness.
[6]
As of 2017 the Minuteman III missile was converted to a single reentry vehicle system.
[9]
[10]
The smaller power of the warheads used (W62, W78 and W87) was offset by increasing the accuracy of the system, allowing it to attack the same hard targets as the larger, less accurate, W56.
[8]
[11]
The MMIII was introduced specifically to address the Soviet construction of an
anti-ballistic missile
(ABM) system around Moscow; MIRV allowed the US to overwhelm any conceivable ABM system without increasing the size of their own missile fleet. The Soviets responded by adding MIRV to their
R-36
design, first with three warheads in 1975, and eventually up to ten in later versions. While the United States phased out the use of MIRVs in ICBMs in 2014 to comply with
New START
,
[12]
Russia continues to develop new ICBM designs using the technology.
[13]
The introduction of MIRV led to a major change in the strategic balance. Previously, with one warhead per missile, it was conceivable that one could build a defense that used missiles to attack individual warheads. Any increase in missile fleet by the enemy could be countered by a similar increase in interceptors. With MIRV, a single new enemy missile meant that multiple interceptors would have to be built, meaning that it was much less expensive to increase the attack than the defense. This
cost-exchange ratio
was so heavily biased towards the attacker that the concept of
mutual assured destruction
became the leading concept in strategic planning and ABM systems were severely limited in the 1972
Anti-Ballistic Missile Treaty
in order to avoid a massive
arms race
.
Purpose
[
edit
]
The military purpose of a MIRV is fourfold:
- Enhance
first-strike
proficiency for strategic forces.
[14]
- Providing greater target damage for a given
thermonuclear weapon
payload. Several small and lower yield warheads cause much more target damage area than a single warhead alone. This, in turn, reduces the number of missiles and launch facilities required for a given destruction level – much the same as the purpose of a
cluster munition
.
[15]
- With single-warhead missiles, one missile must be launched for each target. By contrast, with a MIRV warhead, the post-boost (or bus) stage can dispense the warheads against multiple targets across a broad area.
- Reduces the effectiveness of an
anti-ballistic missile
system that relies on intercepting individual warheads.
[16]
While a MIRV attacking missile can have multiple warheads (3-12 on United States and Russian missiles, or 14 in a maximum payload shorter-range configuration of the
Trident II
now barred by START), interceptors may have only one warhead per missile. Thus, in both a military and an economic sense, MIRVs render ABM systems less effective, as the costs of maintaining a workable defense against MIRVs would greatly increase, requiring multiple defensive missiles for each offensive one. Decoy
re-entry
vehicles can be used alongside actual warheads to minimize the chances of the actual warheads being intercepted before they reach their targets. A system that destroys the missile earlier in its trajectory (before MIRV separation) is not affected by this but is more difficult, and thus more expensive to implement.
MIRV land-based
ICBMs
were considered destabilizing because they tended to put a premium on
striking first
.
[17]
The world's first MIRV?US
Minuteman III
missile of 1970?threatened to rapidly increase the US's deployable nuclear arsenal and thus the possibility that it would have enough bombs to destroy virtually all of the
Soviet Union's nuclear weapons
and negate any significant retaliation. Later on the US feared the Soviet's MIRVs because Soviet missiles had a greater
throw-weight
and could thus put more warheads on each missile than the US could. For example, the US MIRVs might have increased their warhead per missile count by a factor of 6 while the Soviets increased theirs by a factor of 10. Furthermore, the US had a much smaller proportion of its nuclear arsenal in ICBMs than the Soviets. Bombers could not be outfitted with MIRVs so their capacity would not be multiplied. Thus the US did not seem to have as much potential for MIRV usage as the Soviets. However, the US had a larger number of
submarine-launched ballistic missiles
, which could be outfitted with MIRVs, and helped offset the ICBM disadvantage. It is because of their first-strike capability that land-based MIRVs were banned under the
START II
agreement. START II was ratified by the
Russian Duma
on 14 April 2000, but Russia withdrew from the treaty in 2002 after the US withdrew from the
ABM treaty
.
Mode of operation
[
edit
]
In a MIRV, the main rocket motor (or
booster
) pushes a "bus" (see illustration) into a free-flight
suborbital
ballistic flight path. After the boost phase, the bus maneuvers using small on-board rocket motors and a computerized
inertial guidance system
. It takes up a ballistic trajectory that will deliver a re-entry vehicle containing a warhead to a target and then releases a warhead on that trajectory. It then maneuvers to a different trajectory, releasing another warhead, and repeats the process for all warheads.
The precise technical details are closely guarded
military secrets
, to hinder any development of enemy counter-measures. The bus's on-board
propellant
limits the distances between targets of individual warheads to perhaps a few hundred kilometers.
[18]
Some warheads may use small
hypersonic
airfoils
during the descent to gain additional cross-range distance. Additionally, some buses (e.g. the
British
Chevaline
system) can release
decoys
to confuse interception devices and
radars
, such as
aluminized
balloons or electronic noisemakers.
Accuracy is crucial because doubling the accuracy decreases the needed warhead energy by a factor of four for radiation damage and by a factor of eight for blast damage. Navigation system accuracy and the available geophysical information limits the warhead target accuracy. Some writers believe
[
weasel words
]
that government-supported geophysical mapping initiatives and ocean satellite altitude systems such as
Seasat
may have a covert purpose to map mass concentrations and determine local
gravity anomalies
, in order to improve accuracies of ballistic missiles.
[
citation needed
]
Accuracy is expressed as
circular error probable
(CEP). This is the radius of the circle that the warhead has a 50 percent chance of falling into when aimed at the center. CEP is about 90?100 m for the
Trident II
and
Peacekeeper
missiles.
[19]
A multiple re-entry vehicle (MRV) system for a
ballistic missile
deploys multiple warheads above a single aimpoint which then drift apart, producing a cluster bomb-like effect. These warheads are not individually targetable. The advantage of an MRV over a single warhead is the increased effectiveness due to the greater coverage; this increases the overall damage produced within the center of the pattern, making it far greater than the damage possible from any single warhead in the MRV cluster; this makes for an efficient area-attack weapon and makes interception by
anti-ballistic missiles
more challenging due to the number of warheads being deployed at once.
[6]
Improved warhead designs allow smaller warheads for a given yield, while better electronics and guidance systems allow greater accuracy. As a result, MIRV technology has proven more attractive than MRV for advanced nations. Multiple-warhead missiles require both a miniaturized
physics package
and a lower mass re-entry vehicle, both of which are highly advanced technologies. As a result, single-warhead missiles are more attractive for nations with less advanced or less productive nuclear technology. The United States first deployed MRV warheads on the
Polaris A-3
SLBM
in 1964 on the
USS Daniel Webster
. The
Polaris A-3
missile carried three warheads each having an approximate yield of 200 kilotonnes of TNT (840 TJ). This system was also used by the Royal Navy who also retained MRV with the
Chevaline
upgrade, though the number of warheads in Chevaline was reduced to two due to the ABM counter-measures carried.
[6]
The Soviet Union deployed 3 MRVs on the
R-27U
SLBM and 3 MRVs on the
R-36P
ICBM. Refer to
atmospheric re-entry
for more details.
MIRV-capable missiles
[
edit
]
- China
- DF-3A
(retired, 3 warheads)
- DF-4A
(retired, 3 warheads)
- DF-5B
(active, 3-8 warheads)
- DF-5C
(active, 10 warheads)
- DF-31A
(active, 3-5 warheads)
- DF-31B
(active, 3-5 warheads)
- DF-41
(active, up to 10 warheads)
- JL-2
(active, 1-3 warheads)
- JL-3
(under development)
- France
- M4
(retired, 6 warheads)
- M45
(retired, 6 warheads)
- M51
(active, 6-10 warheads)
- India
- Israel
- Jericho 3
(active, suspected capability, not announced, 2-3 technically possible)
[27]
- Pakistan
- USSR
/
Russian Federation
- R-36 mod 4
(retired, 10-14 warheads)
- R-36 mod 5
(active, 10 warheads)
- R-29R
(active, 3 warheads)
- R-29RK
(retired, 7 warheads)
- MR-UR-100 Sotka
(retired, 4 warheads)
- UR-100N
mod 3 (retired, 6 warheads)
- RSD-10 Pioneer
(retired, 3 warheads)
- R-39 Rif
(retired, 10 warheads)
- R-29RM Shtil
(retired, 4 warheads)
- RT-23 Molodets
(retired, 10 warheads)
- R-29RMU Sineva
(active, 4 or 10 warheads)
- RS-24 Yars
(active, 3-4 warheads)
- R-29RMU2 Layner
(active, 4 or 12 warheads)
- RSM-56 Bulava
(active 6-10 warheads)
- RS-28 Sarmat
(active, 10-15 warheads)
- RS-26 Rubezh
(development stopped, 4 warheads)
- BZhRK Barguzin
(development stopped, 4-16 warheads)
- United Kingdom
- United States
See also
[
edit
]
Notes
[
edit
]
- ^
"Pakistan is confirmed to possess MIRV technology, but there is no confirmation yet that it has deployed MIRV missiles."
[2]
[3]
References
[
edit
]
- Notes
- ^
Parsch, Andreas.
"UGM-133"
. Directory of U.S. Military Rockets and Missiles.
Archived
from the original on 2011-03-15
. Retrieved
2014-06-13
.
- ^
"Statement for the Record: Worldwide Threat Assessment"
. March 6, 2018. Archived from
the original
on 2018-03-13
. Retrieved
March 31,
2024
.
- ^
a
b
Usman Haider; Abdul Moiz Khan (18 November 2023).
"Why Did Pakistan Test Its MIRV-Capable Ababeel Missile?"
.
The Diplomat
. Retrieved
11 March
2024
.
- ^
"Agni-5 missile: What is MIRV technology?"
.
The Times of India
. 11 March 2024
. Retrieved
2024-03-11
.
- ^
"Military says Minuteman missiles ready"
.
Lewiston Morning Tribune
. (Idaho). Associated Press. July 20, 1970. p. 1.
Archived
from the original on August 28, 2020
. Retrieved
May 31,
2020
.
- ^
a
b
c
d
Polmar, Norman
; Norris, Robert S. (1 July 2009).
The U.S. Nuclear Arsenal: A History of Weapons and Delivery Systems since 1945
(1st ed.).
Naval Institute Press
.
ISBN
978-1557506818
.
LCCN
2008054725
.
OCLC
602923650
.
OL
22843826M
.
- ^
"The Minuteman III ICBM"
.
Archived
from the original on 2019-01-18
. Retrieved
2017-09-17
.
- ^
a
b
"Nuclear Chronology"
(PDF)
.
www.acq.osd.mil
. July 2021.
Archived
(PDF)
from the original on August 12, 2022
. Retrieved
January 18,
2024
.
- ^
"The End of MIRVs for U.S. ICBMs"
.
The Equation
. 2014-06-27
. Retrieved
2024-01-19
.
- ^
"NMHB 2020 [Revised]"
.
www.acq.osd.mil
. Retrieved
2024-01-19
.
- ^
"W87-1 Modification Program"
(PDF)
.
energy.gov
. March 1, 2019.
Archived
(PDF)
from the original on March 26, 2023
. Retrieved
January 18,
2024
.
- ^
"Last Malmstrom ICBM reconfigured under treaty"
.
Great Falls Tribune
.
Archived
from the original on 2020-08-28
. Retrieved
2018-09-08
.
- ^
"Putin has touted an 'invincible' nuclear weapon that really exists ? here's how it works and why it deeply worries experts"
.
Business Insider
.
Archived
from the original on 2018-09-08
. Retrieved
2018-09-08
.
- ^
Buchonnet, Daniel (1 February 1976).
"MIRV: A BRIEF HISTORY OF MINUTEMAN and MULTIPLE REENTRY VEHICLES"
.
gwu.edu
.
Lawrence Livermore Laboratory
.
United States Department of Defense
.
Archived
from the original on 15 September 2019
. Retrieved
24 November
2019
.
The idea of multiple warheads dates back to the mid-1960s, but the key year in the history of the MIRV concept was 1962 when several of technological developments made it possible for scientists and engineers to conceive of multiple, separately targeted warheads that could hit a growing list of Soviet nuclear threat targets. One important innovation was that the weapons laboratories had designed small thermonuclear weapons, a necessary condition for deploying multiple reentry vehicles on the relatively small Minuteman.
- ^
The best overall printed sources on nuclear weapons design are:
Hansen, Chuck
.
U.S. Nuclear Weapons: The Secret History.
San Antonio, TX: Aerofax, 1988; and the more-updated Hansen, Chuck, "
Swords of Armageddon: U.S. Nuclear Weapons Development since 1945
Archived
2016-12-30 at the
Wayback Machine
" (CD-ROM & download available). PDF. 2,600 pages, Sunnyvale, California, Chukelea Publications, 1995, 2007.
ISBN
978-0-9791915-0-3
(2nd Ed.)
- ^
Robert C. Aldridge (1983).
First Strike!: The Pentagon's Strategy for Nuclear War
. South End Press. pp. 65?.
ISBN
978-0-89608-154-3
.
Archived
from the original on 16 July 2014
. Retrieved
26 February
2013
.
- ^
Heginbotham, Eric (15 March 2017).
"China's Evolving Nuclear Deterrent: Major Drivers and Issues for the United States"
.
Archived
from the original on 2017-12-01
. Retrieved
2017-12-01
.
- ^
"Question Re Mirv Warheads ? Military Forum | Airliners.net"
.
Archived
from the original on 2007-10-16
. Retrieved
2008-07-02
.
- ^
Cimbala, Stephen J. (2010).
Military Persuasion: Deterrence and Provocation in Crisis and War
. Penn State Press. p. 86.
ISBN
978-0-271-04126-1
.
Archived
from the original on 26 April 2016
. Retrieved
3 May
2013
.
- ^
"India conducts first test flight of domestically developed missile that can carry multiple warheads"
.
apnews.com
. 11 March 2024.
- ^
"India's MIRV-tipped Agni-5 Missile Test : All your questions answered"
.
Business Standard
.
- ^
"One missile, many weapons: What makes the latest Agni-5 special"
.
The Indian Express
. 2024-03-12
. Retrieved
2024-03-14
.
- ^
"Why India Testing Agni-5 is a Milestone Moment"
.
News18
. 2024-03-12
. Retrieved
2024-03-14
.
- ^
Rout, Hemant Kumar (2021-09-13).
"India to conduct first user trial of Agni-V missile"
.
The New Indian Express
. Retrieved
2024-03-12
.
- ^
"Mission Divyastra successful: A look at evolution of Agni missiles"
.
India Today
. Retrieved
2024-03-12
.
- ^
Gady, Franz-Stefan.
"India Launches Second Ballistic Missile Sub"
.
thediplomat.com
. Retrieved
2024-03-12
.
- ^
"Jericho 3"
.
Missile Threat
. Center for Strategic and International Studies.
Archived
from the original on 21 January 2013
. Retrieved
4 April
2020
.
- ^
"Pakistan missile test confirms its MIRV ambitions"
.
IISS
. Retrieved
2024-04-04
.
External links
[
edit
]
Wikimedia Commons has media related to
MIRV
.