W47

The LITTLEJOHN was a free flight artillery rocket designed to deliver either nuclear or conventional warheads. In May 1953 the Assistant Chief of Ordnance outlined plans for studies of a family of atomic rocket weapons based on the HONEST JOHN and having overlapping tactical range capabilities. In August 1955 the Army General Staff directed the Chief of Ordnance to stop work on the 17.35-inch round and develop the LITTLEJOHN rocket for delivery of a smaller atomic warhead about 11.5-inches in diameter. The LITTLEJOHN reached the field in November 1961 and remained in the Army inventory until August 1969.

By shaping the plutonium pit into an ovoid [like a small watermelon, smaller than a football], Livermore weapons designers were able to dramatically reduce the size and number of explosives needed to detonate the bomb. The W47 was the first warhead in this new generation of weapons. Although it was only half as large as the bomb that leveled Hiroshima, but it had 80 times the yield.

The Livermore-designed W38, W45, and W47 share a common primary, the "Robin."