General Carl Spaatz, the commander of the 509th Composite Group, a squadron of B-29 bombers modified to drop the bomb, received orders to bomb Hiroshima any time after August 3. His orders now included the city of Nagasaki as one of the possible alternate targets should Hiroshima prove unfeasible. The weather over Hiroshima kept the planes grounded until August 6. At 2:45 A.M., Lieutenant Colonel Paul W. Tibbets took off from Tinian Island in the Enola Gay,a plane he named after his mother. He was carrying the Little Boy bomb. To prevent Tinian from being blown up if the plane crashed on takeoff, William Parsons was to finish arming the bomb on the way to Hiroshima. Two observer planes accompanied the Enola Gay to record the explosion. At 7:30 Parsons completed arming the bomb and Tibbets brought the plane up to 31,000 feet. The...