John Coster-Mullen

John Coster-Mullen (21 December 1946 – 24 April 2021) was an American industrial photographer, truck driver and nuclear archaeologist who played an important role in creating a public record of the design of the first atomic bombs. He is known for his critically acclaimed self-published book Atom Bombs: The Top Secret, Inside Story of Little Boy and Fat Man.

Biography John Coster-Mullen was born on 21 December 1946. He became interested in nuclear weapons when he was in the seventh grade and the first pictures of the Little Boy and Fat Man bombs were released. "It was", he later said, "the most forbidden of topics, because it was the biggest secret in the whole world, the one you could never know."

Coster-Mullen entered the University of Wisconsin, but he struggled with mathematics. He dropped out in his junior year and instead became an industrial photographer.

Coster-Mullen's diagram of Little BoyIn 1993, with the 50th anniversary of the atomic bombing of Hiroshima and Nagasaki approaching, Coster-Mullen decided that he could earn some money creating models of the Little Boy and Fat Man bombs and selling them online or through hobby shops. Some companies were already making them, but Coster-Mullen noticed that their models contained small errors, and he believed that he could do a better job. He began collecting all the material he could about their design.

Thereafter, Coster-Mullen regularly attended reunions of the 509th Composite Group. Atom Bombs: The Top Secret, Inside Story of Little Boy and Fat Man (2003), as he gradually pieced together an unusually detailed account of how the weapons were built, assembled, and deployed. In 2004, he built, with his son Jason, a replica of Little Boy for the Historic Wendover Airfield Museum, the former training site of the 509th Composite Group in Utah.

His most sensational discovery was that the Little Boy bomb was actually a "girl": He continued revising his book until his death.