The Manhattan Project: Making the Atomic Bomb

Part VI: The Manhattan District in Peacetime

Operation Crossroads

In July 1946, during Operation Crossroads, the Manhattan Project tested its third and fourth plutonium bombs (Trinity and Nagasaki were the first two) with a large, invited audience of journalists, scientists, military officers, congressmen, and foreign observers at Bikini Atoll in the Pacific. Shot Able, dropped from a B-29 on July 1, sank three ships and performed as well as its two predecessors from a technical standpoint, though it failed to fulfill its pretest publicity buildup. Shot Baker was detonated from ninety feet underwater on the morning of July 15. Baker produced a spectacular display as it wreaked havoc on a seventy-four-vessel fleet of empty ships and spewed thousands of tons of water into the air. Both Able and Baker yielded explosions equivalent to 21,000 tons of TNT, though Baker introduced the most subtle hazard of the atomic age--radiation fallout.62 Able and Baker were the final weapon tests conducted by the Manhattan Project and the last American tests until the Atomic Energy Commission's Sandstone series began in spring 1948.