In article , John Penta wrote:

2. Saying we can do it with current tech: No, we can't. Face it, we
can't.

It all depends how you define "current technology". Currently produced
hardware? No way. Currently understood technologies? Pretty much, some
envelope-fiddling needed on tethering & rotationg (if you want that) and
Mars-surface work (suits, airlocks, that ilk) - but I don't see it
needing much in the way of a breakthrough, or a generation ahead. Okay,
building the rocket might be an interesting challenge, but I don't think
it can't be done...

IMO, as always.

--
-Andrew Gray