Jim, thanks for the comment, and I hope this reply suffices.
First, given all the potential threats to our existence combined with the fact that all our proverbial "eggs are in one basket," and if we really want to up the odds of survival of an Earth derived species, then we need to branch out as soon as possible. Humans have been working on problems here as long as we have been social creatures and will hopefully continue to do so; but you can see where that has got us thus far.
As for the technology involved, i.e., propulsion and energy systems, we have ample ability now to begin this branching out. Remember, Columbus did not wait for the development of the steam engine to discover the "New World" and just because its dangerous or difficult we should not wait to begin our settling of Mars.
I look forward to reading your paper also.
Cheers,
Don