W88

Missile warheadUnited StatesThermonuclear (staged)

No freely licensed photo of this device yet.

Yield · TNT equivalent475 kt

Key specs

Country: United States
Design: Thermonuclear (staged)
Type: Missile warhead
Length: 1.5 m
Diameter: 460 mm
In service: 1989 – present
Number built: 400

Overview

A 475 kt thermonuclear warhead for the Trident II D5 submarine-launched missile, which can carry up to eight. Designed at Los Alamos, it is regarded as the most advanced US warhead.

It entered service in 1989, but production at the Rocky Flats plant stopped after the FBI raid on the plant that November, so only about 400 were built. The W88 Alt 370 upgrade, with a new arming, fuzing and firing system, went into production in 2021. The length and diameter given here are approximate.

Effect radii: estimates

Calculated for 475 kt

Fireball, maximum radius: ≈ 720 m
Initial radiation, 500 rem (5 Sv): ≈ 2.7 km
Blast 5 psi: most buildings collapse: ≈ 5.5 km
Thermal: third-degree burns: ≈ 8.4 km
Blast 1 psi: windows shatter: ≈ 17 km

Estimated ground ranges for an air burst at the optimum height over flat, open ground, computed from the yield with standard scaling laws. These are not measurements: real effects depend on the height of burst, terrain, buildings and weather.

Formulas from: Glasstone & Dolan, The Effects of Nuclear Weapons (1977), chapter II; Carey Sublette, Nuclear Weapons FAQ, section 5

Sources

Complete List of All U.S. Nuclear Weapons, Nuclear Weapon Archive (Carey Sublette)
W88, Wikipedia