Future nuclear weapon policies James M. Acton

[email protected]

(Some) elements of nuclear posture • • • • • • • • Force size and structure Deployed and reserve systems; readiness status • Military Organization Troops; training; procedures; operations • Enabling systems Command and control; early warning; ISR; targeting • Infrastructure Warhead production/maintenance facilities; industrial base; test facilities • Declaratory policy Statements; training and exercises; domestic discourse War plans Treaty obligations

Questions raised by reductions • • • • • • • Can U.S. fulfill “deterrence” requirements?

• Will weapons reach target?

Reliability; pre- and post-launch survivability • Will weapons destroy target?

Yield, accuracy and target location error Can requirements be revised?

How will allies/adversaries view U.S. resolve and capability?

What will the effects on “strategic stability” be?

…

Current U.S. force structure ICBM SLBM Heavy Bombers “Tactical” fighters

Platform

(Silo based) Ohio-class SSBN B-2 B-52H F-15E; F-16C/D

Missile

Minuteman III Trident-D5 (Gravity bombs) ALCM (Gravity bombs)

Warhead

W78; W87 W76-0/1; W88 B61-7/11; B83-1 W80-1 (+ gravity bombs) B61-3/4/10

Future of the triad • • Political context crucial; in practice force structure will be • • determined by politics of the moment as much as nuclear • strategy ICBM replacement will probably be delayed further (beyond 2020); early abandonment very unlikely (jobs!) Very strong support for SLBMs Multiple decision points related to heavy bombers and tactical fighters coming up Air leg most vulnerable

• • • • • Arguments for heavy bombers and tactical fighters • Unique ability to hold buried targets at risk But, how much do these targets really matter?

• Stealth as alternative to speed for defense penetration But, how likely is effective BMD?

• Recallable But, how many war plan options include only aircraft?

• Forward deployment as tool for assurance But, are there alternatives?

Signaling as tool for crisis management

A growing role for conventional weapons in strategic war plans?

DoD is directed to conduct deliberate planning for non-nuclear strike options to assess what objectives and effects could be achieved through integrated non-nuclear strike options, and to propose possible means to make these objectives and effects achievable. Although they are not a substitute for nuclear weapons, planning for non-nuclear strike options is a central part of reducing the role of nuclear weapons.

Report on Nuclear Employment Strategy of the United States (2013) • Probably not about large-scale replacement.

• • • Types of target in a “counterforce” attack against North Korea • Fixed, soft targets ICBM sitting on a launch pad • • Fixed, buried targets Warhead storage facilities; leadership; command and control Probably tens, potentially hundreds of metres deep • Mobile, soft targets Road-mobile missiles

Massive ordnance penetrator • • • Total mass: 13,600 kg HE mass: 2,400 kg Can reportedly penetrate to 20 m in reinforced concrete (much less than nuclear weapons)

Physics of conventional penetrators Young Penetration Equation (SI Units) 𝐷 = 0.000018 𝑆 𝑁 𝑚 𝐴 0.7

𝑉 − 30.5

D: Depth S: Penetrability of target N: Nose performance coefficient m: Mass A: Cross sectional area V: Speed • From Nelson (2002)

CPGS technological approaches

Comparison of penetrator effectiveness 𝐷 = 0.000018 𝑆 𝑁 𝑚 𝐴 0.7

𝑉 − 30.5

• • V (m/s) m/A (kg/m)

MOP

500 [?] 27,000

CPGS

1,000-1,200 14,000-21,000 Ratio of penetration depths: 1.3-2.1

CPGS penetrator would only contain about 10% of the HE that MOP does.

Mobile missile hunting • • • • • Need to locate and track missiles If using standoff weapons need to provide inflight target updates (or risk waiting until they’re stationary) • North Korea has hundreds of mobile ballistic missiles Only a small fraction might contain a nuclear warhead, but very hard to tell which is which 1991 Gulf War: 1,460 sorties; 0 confirmed kills 2006 Israel-Hizbollah war: 80-90% of Hizbollah’s medium- and long range rocket launchers destroyed. But, took time and relied on attacking launchers after missiles has fired.

Nuclear v. conventional options • • • Lethal radius from flechette weapon: <100 m, possibly • much less (my calculation) TEL can traverse this distance in 10 s Lethal radius from 100 kT nuclear weapon: 2,900 m • (McKinzie et al. 2001) TEL can traverse this distance in 260 s Hunting mobile missiles with conventional weapons much harder than nuclear weapons