It was a self-contained unit, with personnel strength of about 1770.
The 509th deployed to Tinian in the Marianas in May 1945. The crews trained with practice bombs called 'pumpkins' because of their size and shape, which was the same as 'Fat Man' atomic bomb. The unit that dropped the atomic bombs was activated at Wendover Army Air Field, Utah, Dec. The 509th Composite Group/509th Bomb Wing