<P> The population of Hiroshima had reached a peak of over 381,000 earlier in the war but prior to the atomic bombing, the population had steadily decreased because of a systematic evacuation ordered by the Japanese government . At the time of the attack, the population was approximately 340,000--350,000 . Residents wondered why Hiroshima had been spared destruction by firebombing . Some speculated that the city was to be saved for U.S. occupation headquarters, others thought perhaps their relatives in Hawaii and California had petitioned the U.S. government to avoid bombing Hiroshima . More realistic city officials had ordered buildings torn down to create long, straight firebreaks, beginning in 1944 . Firebreaks continued to be expanded and extended up to the morning of August 6, 1945 . </P> <P> Hiroshima was the primary target of the first nuclear bombing mission on August 6, with Kokura and Nagasaki as alternative targets . Having been fully briefed under the terms of Operations Order No. 35, the 393d Bombardment Squadron B - 29 Enola Gay, piloted by Tibbets, took off from North Field, Tinian, about six hours' flight time from Japan . The Enola Gay (named after Tibbets' mother) was accompanied by two other B - 29s . The Great Artiste, commanded by Major Charles Sweeney, carried instrumentation, and a then - nameless aircraft later called Necessary Evil, commanded by Captain George Marquardt, served as the photography aircraft . </P> <Table> Special Mission 13, Primary target Hiroshima, August 6, 1945 <Tr> <Td> Aircraft </Td> <Td> Pilot </Td> <Td> Call Sign </Td> <Td> Mission role </Td> </Tr> <Tr> <Td> Straight Flush </Td> <Td> Major Claude R. Eatherly </Td> <Td> Dimples 85 </Td> <Td> Weather reconnaissance (Hiroshima) </Td> </Tr> <Tr> <Td> Jabit III </Td> <Td> Major John A. Wilson </Td> <Td> Dimples 71 </Td> <Td> Weather reconnaissance (Kokura) </Td> </Tr> <Tr> <Td> Full House </Td> <Td> Major Ralph R. Taylor </Td> <Td> Dimples 83 </Td> <Td> Weather reconnaissance (Nagasaki) </Td> </Tr> <Tr> <Td> Enola Gay </Td> <Td> Colonel Paul W. Tibbets </Td> <Td> Dimples 82 </Td> <Td> Weapon delivery </Td> </Tr> <Tr> <Td> The Great Artiste </Td> <Td> Major Charles W. Sweeney </Td> <Td> Dimples 89 </Td> <Td> Blast measurement instrumentation </Td> </Tr> <Tr> <Td> Necessary Evil </Td> <Td> Captain . George W. Marquardt </Td> <Td> Dimples 91 </Td> <Td> Strike observation and photography </Td> </Tr> <Tr> <Td> Top Secret </Td> <Td> Captain Charles F. McKnight </Td> <Td> Dimples 72 </Td> <Td> Strike spare--did not complete mission </Td> </Tr> </Table> <Tr> <Td> Aircraft </Td> <Td> Pilot </Td> <Td> Call Sign </Td> <Td> Mission role </Td> </Tr>

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