A major motivation for the US to build the nuclear bomb was the fear that Germany itself would build one first. In retrospect, it is known that Germany was really nowhere close to achieving nuclearization. My question is: when did the US first learn of Germany's failures and what was their reaction?

by hrcardiox

Of course, the British became aware to the extent of the Germany's failures thanks to the Farm Hall manuscripts, but I was wondering what the US reaction was.

restricteddata

Farm Hall is of course the extreme end of knowing they didn't have much of a program, but the Alsos project had concluded the German effort was stillborn as early as November 1944. At some point, this gets into a question of what it means to "know" something — over the course of 1944, the US became gradually more and more confident that the German atomic threat was nil, but it wasn't until November 1944 that they really felt comfortable saying it was really nothing, and until Farm Hall that they felt they really understood all of its failings. I have written about this here.

As for the reaction: it varies based on who you are asking about. The most interesting reaction maybe was from Samuel Goudsmit, the scientific head of the Alsos project, who wrote a book about it in the postwar. Goudsmit essentially concluded that the problem with the German program was that science under authoritarianism was inherently flawed, and that they were doomed to fail. This is a pretty odd conclusion (the Soviet Union certainly was able to succeed), but it shows the lengths of possible interpretation.