W47

Missile warheadUnited StatesThermonuclear (staged)

No freely licensed photo of this device yet.

Yield · TNT equivalent0.6–1.2 Mt

Key specs

Country: United States
Design: Thermonuclear (staged)
Type: Missile warhead
Weight: 330 kg
Length: 1.18 m
Diameter: 460 mm
In service: 1960–1974
Number built: 1,060

Overview

The warhead of the Polaris A-1 and A-2 submarine-launched missiles, 600 kt to 1.2 Mt in a package of about 330 kg. In the Frigate Bird shot of 1962 a submarine fired a Polaris with a live W47, the only full test of a US strategic missile.

Effect radii: estimates

Calculated for 1.2 Mt

Fireball, maximum radius: ≈ 1 km
Initial radiation, 500 rem (5 Sv): ≈ 3.2 km
Blast 5 psi: most buildings collapse: ≈ 7.5 km
Thermal: third-degree burns: ≈ 12 km
Blast 1 psi: windows shatter: ≈ 23 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

Tests and use

Date	Event	Site	Yield
May 6, 1962	Dominic Frigate Bird	Pacific Ocean, near Christmas Island	600 kt

Sources

Complete List of All U.S. Nuclear Weapons, Nuclear Weapon Archive (Carey Sublette)
W47, Wikipedia