To MIRV or Not to MIRV |
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The Pentagon confirmed in 2003 and 2004 that it
is considering retaining multiple warheads on its 500 Minuteman III ICBMs rather
than downloading each missile to single-warhead configuration as planned under
START II Treaty only a couple of years ago. The initiative follows the signing
of the Moscow Treaty with Russia in 2002 which nullified the START II agreement.
According to
a report in Air Force Magazine in October 2003,
Maj. Gen. Robert L. Smolen, USAF’s director of nuclear and counterproliferation
operations at the Pentagon, stated that up to 800 warheads would be carried on
the force. Follow-up conversations with military officials revealed that the Air
Force dismissed the Air Force Magazine report saying that Maj. Gen. Smolen had been
misquoted and that decision had not yet been made. Instead the Air Force provided the following transcript for the
record:
Brig Gen Robert L. Smolen, Air Force Director of Nuclear &
Counterproliferation, and Adam Hebert, Air Force Magazine, July 14, 2003:
HEBERT: The Minuteman fleet itself is in a split configuration at the
moment where the Warren missiles have one warhead and the other two wings
have three warheads.
SMOLEN: If I could comment on the warhead piece, we cannot confirm or deny
the amounts of warheads on the missiles. We could say a Minuteman missile
can carry up to a certain amount, but when you say “up to,” that means it
could be one or it could be more. So the blend of missiles warheads will
largely be determined by the targeting requirements that were given by
Strategic Command. The targets … where the targets are will have a factor
on which missiles at what location might have one or more warhead. So I
don’t think it’s … certainly it has one, but it could have three, it could
have two, it could have one.
HEBERT: The way I understand the situation at Warren, though, is that
because of START obligations those are now up to one warhead missiles.
SMOLEN: According to the way we’re looking at that, we’re looking at
eventually of 500 missiles that could be uploaded to as many as 800
warheads. So somewhere in that mix of 500 is 800. And it could be one on
some, two on another, three on another.
Source:
Obtained by Hans M. Kristensen from USAF, October 1, 2003.
The Minuteman III was initially designed to
carry two or three 170 kilotons Mk-12/W62 reentry vehicles (RV). In the late
1970s, 300 of the original 550 missiles were modified to accommodate the more
powerful Mk-12A/W78 RV with a yield of 335 kilotons. The START II Treaty signed
in 1993 banned multiple warheads on ICBMs, so in preparation for the treaty
entering into force in 2003 (later delayed till 2007), the Air Force between
1992 and 2001 added the capability to the Minuteman III to also be able to carry
a single RV (see figure 1).
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In 2001, the Air Force announced that it
had downloaded 150 Minuteman III missiles at Warren Air Force Base (AFB) to
single-warhead configuration. The move was necessary to bring U.S.
accountable warheads in compliance with the START I Treaty which entered
into effect at the same time. As
recent as in June 2001, the Air Force budget still described "downloading of the
Minuteman force to single RV configuration," but the language
disappeared from the Air Force budget submitted by the Bush
administration. |
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Fig 1: Minuteman III RV configurations |
The force of 500 Minuteman IIIs is deployed at
three bases: Malmstrom AFB in Montana, Warren AFB in Wyoming, and Minot AFB in
North Dakota. The warhead loading on individual warheads may vary depending on
assigned mission, but Air Force documents describe that the two types of
warheads are deployed at the following bases: the Mk-12/W62 at Malmstrom AFB and
Warren AFB, and the Mk-12A/W78 at Malmstrom AFB (Squadron 20) and Minot AFB (see
Figure 2).
Fig 2: Minuteman Weapon System Configuration (as
of April 2001)
Beginning in 2006, Mk-21/W87 RVs from the
Peacekeeper missile currently being phased out, will be transferred onto part of
the Minuteman IIIs under the Safety Enhanced Reentry Vehicle (SERV) program to
replace the remaining 300 Mk-12/W62 on 200+ Minuteman IIIs at Warren AFB and
Malmstrom AFB. The W62 is scheduled to be scrapped in 2009. The SERV program will provide
those Minuteman IIIs with a
capability to carry one or two Mk-21/W87s each, but apparently not three. The remaining approximately 300
missiles will continue to carry up to three Mk-12A/W78 RVs each. The W78
currently on the Minuteman III has a
higher yield than the W87 (335 vs. 300 kilotons, respectively) on the
Peacekeeper, which is why some W78s will be retained on the force.
Unlike the W87, however, the older W78 is not
equipped with important safety features such as Insensitive Explosives and
Command Disable. The latter is an
inertial nonviolent
code-activated disabling device which destroys critical warhead components,
rendering the warhead useless in case of unauthorized tampering.
In addition to adding such safety features into at
least a portion of the future Minuteman III force, the decision to transfer W87
onto the missile is based on several features that will improve the targeting
capabilities of the weapon:
- more fuzing options which will allow for
greater targeting flexibility;
- the most accurate reentry vehicle
available which provide a greater probability of damage.
The final warhead breakdown under the Air
Force's new plan is a closely guarded secret, but with an overall loading of 800
warheads and the current configuration, an estimate can be made of approximately
300 Mk-21/W87s on 200 missiles at Warren AFB and Malmstrom AFB, and 500
Mk-12A/W78s on 300 missiles at Minot AFB and Malmstrom AFB. A decision to keep
the extra 300 warheads in storage would likely mean fewer W78s deployed on the
alert force.
The decision to retain multiple warheads on the
ICBM force and the consideration to keep up to 800 warheads on the missiles
suggest that U.S. nuclear planning is still strongly tied to the composition of
Russian nuclear forces. It is unlikely that 300 new targets have suddenly
appeared somewhere in the world, so the move in all likelihood is a reaction to
Russia's decision following the Moscow Agreement to retain SS-18 and SS-19
missiles with multiple warheads, and a need on the part of U.S. nuclear planners
to continue to target those silos even with the retirement of the Peacekeeper.
In other words, in stark contrast with the
description by Bush administration officials of the Nuclear Posture Review
representing a new partnership with Russia and an end to the balance of terror,
U.S. nuclear planning appears to remain firmly centered on decapitating Russian
nuclear forces.
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