The "Enola Gay", piloted by Col. Tibbets carries the "Little Boy" uranium bomb. "The Great Artiste", piloted by Maj. Charles Sweeney, is assigned to drop the three instruments used to measure the blast effects of the bomb. "#91" (unnamed at the time - later "Necessary Evil"), flown by Capt. George Marquardt, carries the scientific observers. "Top Secret", flown by Capt. Chuck Knight, acts as a standby aircraft and flew to Iwo Jima in the event of mechanical problems with the Enola Gay. "Straight Flush" will act as a weather plane and fly ahead to primary target of Hiroshima. "Jabbitt III" will act as a weather plane and fly ahead to the secondary target of Kokura. "Full House" will act as a weather plane and fly ahead to the alternate target of Nagasaki.