jacob navia wrote:
:
:An atomic bomb is two pieces of refined U235 that are pressed together
:to form a single piece 10 cm wide with the help of explosives.
:
:It required a lot of development but nothing new had to be discovered.
:

Technologies to 'refine U235' did not exist. Sufficiently fast
switches to trigger the explosives did not exist. Neutron tampers did
not exist. The required explosive (probably) did not exist.

And that's just to begin with.

much about how space technologies don't exist and that makes it
different from the Manhattan Project elided


--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson