BESERJakeBeserMuseumLt. Jacob Beser, was the only military officer to fly on both atomic bomb missions over Japan.

Lt. Beser interrupted his engineering studies at Johns Hopkins University to join the Army a day after the Japanese attack on Pearl Harbor. He was eventually assigned to a special Army Air Force unit training at the secret atomic test center at Los Alamos, N.M., for the missions that would bring an end to World War II.

As the radar operator, he was also responsible for insuring that radio broadcasts did not accidentally trigger the fusing devices, as the bomber Enola Gay flew over Hiroshima on Aug. 6, 1945, and dropped the first atomic bomb ever used in warfare. He filled the same role when a sister plane, Bock's Car, attacked Nagasaki with an atomic bomb three days later.

Mr. Beser, who retired in 1985 as an engineer for the Westinghouse Electric Corporation, always defended the Government's decision to drop the bombs, citing the heavy American casualties that had been expected if ground troops were to invade Japan.

He frequently spoke about his role and wrote a book, "Hiroshima and Nagasaki Revisited" (Marshall, 1988), which dealt with the two missions and his visit to the cities on the 40th anniversary of the attacks.