Actually, Marcia, I get it right the first time
You Zubrinite Mar fanatics can not get it through your heads: its not that I am opposed to manned Mars flight, it's simply that dealing with the impact hazard has a much higher importance, and will require CAPS.
I also think that Zubrin's Mars architecture:
1) WON'T WORK
2) IS A DEAD END
Yet again it's another case of your bias influencing your perceptions, and repeating rubbish yet once again again, as though your devotion to the true cause somehow entitles you to use whatever tactics and methods you like.
Again and again and again...