Fred J. McCall wrote:

:I repeat: your position would require that the technologies for
:Mars vehicles be completely disjoint from those used in the rest
f the technosphere.

You can repeat it all you like, but you haven't shown it to be true.
That takes real data and real examples.

And the evidence that you have presented for your original
position is...?

'Spin-on' technologies occur *all the time*. That's why we
have rockets in the first place -- all sorts of mundane technologies
that were developed for other reasons, but enabled the production
of spacecraft. Why should this suddenly stop? You are proposing
a sea change in how technology progresses, with no supporting
evidence whatsoever.

Paul