Malcolm Street wrote:
Paul F. Dietz wrote:

Correct me if I am wrong, but I can't see anybody supporting the
development of nuclear rocket engines, given the political problems
associated with simple RTGs.

Why should this follow? RTGs are much more radioactive at launch
than are reactors.

Indeed, a point that's often overlooked.

RTGs start at peak radioactivity and then decay.

Almost true.
But, the decay chain may make more radioactivity come out of the device
as time goes on, and the output switches to hard to shield stuff.