THE ATOM: From the Air

Almost two weeks behind schedule because of unfavorable winds, the U.S. this week fired its eighth hydrogen device—its first superbomb to be dropped from a plane. Estimated size of the big shot: 10 megatons, the equivalent of 10 million tons of TNT.

During predawn darkness in the mid-Pacific atomic proving grounds, the B-52 intercontinental jet bomber Barbara Grace roared upwards from Eniwetok Air Base, the big bomb in its belly. A fleet manned by 13,500 men stood 39 miles off target—Namu Atoll at the northwest edge of Bikini Atoll—while the big B-52 climbed...