>Surely a lot of the dangerous testing could be replaced with simulation

During the cold war, starting in the 1960s, weren't there dozens of fission reactor satellites launched into orbit? I don't mean spontaneous decay devices like RTGs, I mean fission reactors. Primarily, but not exclusively Soviet.

I bring this up because every discussion I see of the risks of nuclear power in space seems to presume an alternate historical record where political opposition prevented it from becoming a reality. Where uncontrolled deorbiting of reactors or disintegration in orbit were hypothetical and unacceptable failures.

I don't know, were we always at war with Eurasia or was it Eastasia? Which history is the disinformation?