Brown, who enlisted in the New Jersey National Guard in December 1939, said he spent most of the war stateside before being transferred to Wendover Army Air Field, Utah, in May 1945.
Brown said he is not sure what agency employed the civilians who were first told about the upcoming mission. Intelligence officers had questioned his parents the previous year, Brown said, and agents told him he was embarking on a dangerous mission to end the war.
"We were told if anything happened, if anything went wrong, not even our own families would know what happened to us," Brown said.
According to Brown, members of the 509th Composite Group were trained to assemble inert models of the bombs with the code names "Little Boy" and "Fat Man." They worked in much the same way as NASCAR crew members - each man had a job, but no one knew all of the tasks needed to complete the project, Brown said.
Members of the group left from Seattle for Tinian Island in the Mariana Islands in the Pacific on June 15, 1945, Brown said.
The mission was cloaked in secrecy, said Brown, who turned 28 the day he left the United States.
"In fact, we didn't know where our destination was until we were 24 hours at sea, and then we opened our orders up," he said.
Brown said the 509th Composite Group was segregated from other troops on the island, and surrounded by security. Some troops were critical of the unit, which was made up of greenhorns such as Brown, and they wondered whether the unit ever would receive orders.
Then, about 2 a.m. on Aug. 6, a B-29 bomber called the Enola Gay took off from Tinian Island.
Hours later, Brown recalled, troops learned Hiroshima, Japan, had been bombed.
"After Hiroshima, we waited for word from Japan, and none came," Brown said.
Brown said because the bombing was a success, troops celebrated as if they were in "a football crowd." Three days later, the B-29 bomber Bockscar dropped the "Fat Man" bomb on Nagasaki, Japan.
Brown, who returned home in October 1945 to his wife, 14-month-old son and a baby boy he had never met, said members of the 509th Composite Group had inklings of the devastation "Little Boy" and "Fat Man" would unleash.
He said he still believes an invasion of Japan would have been even more costly.
"I hope that mankind has found or keeps searching for ways to settle our international differences peaceably because I think to a man, that was the mission of every single person in the 509th," Brown said.
- Karen Hanna
For Robert Dean of Hagerstown, the Japanese surrender was treated as a mere interruption during a movie he was watching while laid over on the atoll of Kwajalein in the Marshall Islands, waiting for a plane to take him to Guam.
"It was 'hooray, hooray, it's over' but here we are out in God knows where," said Dean, 87.
After the initial celebration, those watching the movie calmed down and asked that the film be run, he said.
At the time the Japanese surrendered, Dean was on his way back to the states on 45 days of recuperation leave for treatment of stomach ulcers he developed while overseas. He had been fighting in the Pacific for two years.
Dean said he served in the 43rd Infantry Division, a unit that was preparing for the "big one" - the invasion of the Japanese mainland.
"We were being trained and prepared for it stronger than (for) any other invasions we had gone into," he said. "It wasn't going to be like Iwo Jima."
After the bombing of Hiroshima and Nagasaki and the subsequent surrender, Dean and his unit were sent home.
Dean said fighting in the jungles of the Pacific islands was a different experience from what he knew about European combat.
"In New Guinea, you're fighting in the jungle and you can be 20 feet away from your enemy and not even know it," he said. "The European war and the Pacific war were two different kinds of wars."
- Adam Behsudi
The day he heard the war ended, Ted Brindle had only one thing on his mind - getting home to his wife.
"I was going like the dickens to get home," said Brindle, who was on the island of Tinian - the same island the Enola Gay flew out of on its way to drop the bomb on Hiroshima - when he learned the Japanese had surrendered.