In 1988,author Richard Rhodes received a Pulitzer Prize for "The Making of the AtomicBomb" in which he described the previously top-secret inner workings of thebombs that were dropped on Hiroshima and Nagasaki in 1945.

Hedivulged â€” through his own personal research — what had been America's biggest secrets about thebombs, which were called LittleBoy and Fat Man. Infact, Julius and Ethel Rosenberg were put to death on charges they had leaked atomicbomb secrets to Soviet agents.

But by hisown admission, Rhodes has been topped by truck driver John Coster-Mullenof Waukesha, WI, who has built a highly accurate replicaof the atomic bomb through an amazing piece of engineering research. Hisreplica of a bomb casing is on display atthe Wendover AirfieldMuseum in Utah. The precise inner workings of the bombare disclosed in a self-printed bookthat Coster-Mullen sells on Amazon.com for $49.95.

TerrySunday of El Paso, TX, says of Coster-Mullen's book, "Quite simply, there is NObetter source of information on the technical details of the world's first twonuclear weapons ... Coster-Mullen describes the design, configuration, materialsand assembly procedures of "Little Boy" and "Fat Man" to anunprecedented level of detail."

Some areshocked that Coster-Mullen would undertake such a task. Lawrence S. Wittner, a history professor, says,"The reality is that Coster-Mullen informs us about minutiae-the technicalfeatures of the original atomic bomb-rather than about far larger and moremeaningful issues, such as why the Bomb was used, what it did to the people ofJapan, and how its development and use triggered the nuclear arms race since1945."

Wittnerfails to understand that engineers take great interest in understanding howcomplicated machinery works, even if it is 64 years old and had been used forextremely destructive purposes. What's also interesting about Coster-Mullen isthat he is not an engineer. In fact, he doesn't even have a college degree.

Coster-Mullen says he was originally inspired by a high school teacher who hadworked on the Manhattan Project. He had hoped to study physics in college but wasderailed into a 30-year career as a commercial photographer. After that hebegan driving trucks and, he says, "About 15 years ago I reintroduced myself to the (Manhattan) project,thinking I would build small replicas of the bombs." He and his son traveled tomuseums displaying bomb casings, taking measurements and photographs.

"Once theweapon casings were revealed to the public, anybody familiar with physics overthe past few decades would be familiar with what the basic design features would be,"says Coster-Mullen. "In the case of the Fat Man, it was an implosion design andfor Little Boy it was what was called a gun-assembly weapon."

Coster-Mullencontacted officials at Los Alamos before Sept.11, 2001, when they were much freer with the release of declassified documents.Then he interviewed original participants in the Manhattan Project. "I also hadaccess to a lot of photographs," he says. "I started applying proportionalmeasuring to these photographs, and I was able to derive specific dimensionalinformation."

The beautyof Coster-Mullen's work is in the details. For example, he obtained a piece ofa tungsten-carbide tamper used in test bombs from a Los Alamos engineer who had saved the piece as a memento. The tamperhad a key role in the Little Man bomb and its exact dimensions were notpublicly known.

The tamperwas used as a neutron deflector, boosting the critical masses in the uraniumcore. Its density was also crucial inholding the core together to further boost the power of the explosion.

Accordingto an articlepublished in the New Yorker, the tamper fragment was half an inch wide, an inchlong and two inches deep. Coster-Mullen got access to sophisticated industrialmeasuring equipment and determined the original diameter of thetungsten-carbide cylinder was 13.1513 inches. According to another source, the tamper cylinderweighed about 680 lbs.

"In somecases, one person would have saved one thing, and then I'd find out three yearslater that someone else had a piece of the very same object," saysCoster-Mullen. "And then when interviewing people, they would fill in theblanks."

Bombsdeveloped after Little Boy and Fat Man became far more sophisticated.

"The guyswho worked on the first atomic bombs, particularly Little Boy, saw themselvesas blacksmiths," says Coster-Mullen. "They constructed Little Boy literallywith soldering guns, monkey wrenches and sledgehammers."

Cross-section drawing of Y-1852 Little Boy

This cross section shows the major mechanical components, including a tungsten-carbide tamper, used in the Little Boy atomic bomb. Cross-section drawing of the Y-1561 implosion sphere
This cross section shows the placement of the major components used in the implosion sphere of the atomic bomb called Fat Man.

Listen to a podcast withJohn Coster-Mullen:
John Coster-Mullen on the Engineering behind the First Atomic Bombs