Hiroshima Atomic Bomb Technical Diagram Annotated by Enola Gay Weapons Officer Morris Jeppson

Morris Jeppson

Manuscript & Autographs

Jeppson, Morris, annotated “Little Boy” atomic bomb diagram, signed in reference to the Hiroshima mission of August 6, 1945, documents firsthand technical interpretation of the first nuclear weapon used in war. The sheet holds historical value for the study of the Manhattan Project, atomic weapons deployment, and the operational knowledge carried by members of the Enola Gay crew. Jeppson’s role as Weapons Test Officer gives the document particular importance, since the annotations do not merely identify the bomb after the fact but explain its mechanism from the perspective of a participant directly involved in its wartime use.
Jeppson, Morris. Annotated diagram of “Little Boy.” 1 page. Black and white printed diagram with extensive handwritten notations and signature. The diagram shows the internal arrangement of the bomb’s major components, with Jeppson adding arrows and manuscript labels identifying the “target U235,” the “projectile 235,” the “electric detonator,” the “gun barrel,” and “one of 4 radar antennas.” He further explains the bomb’s operation in functional terms, noting where the uranium projectile would strike and that it “Becomes critical mass with projectile.” Signed at the bottom, “Morris Jeppson / Weapon Test Officer / Enola Gay Mission / HIROSHIMA 6 Aug. 1945.” The notations transform the printed diagram into a participant-marked technical document linking design, terminology, and mission-specific memory.
The document is tied directly to the bombing of Hiroshima, the event that introduced nuclear warfare and altered the political and military history of the twentieth century. Its interpretive value lies in the combination of technical content and eyewitness association: the sheet preserves not only a schematic of the bomb itself but also the language used by a mission participant to explain how the weapon functioned. That combination makes it useful for examining how atomic technology was understood by military personnel at the point where scientific development and combat deployment converged. Minor handling wear; otherwise well-preserved with clear manuscript annotations and signature. Overall very good condition.

Item #12579

Price: $450.00