Zubrin?

I'd say all four are right. I think it basically boils down to this: Zubrin has probably been in love with Mars since he was a teenager (possibly before), and he wasn't about to re-tool his entire view of the future just because some Princeton professor came along and pointed out several significant disadvantages of living on planets. Unfortunately, when you refuse tomodify your world views due to a new idea, the only recourse left is to attack that idea. Zubrin has done this in two books. In the first, he asserted that the fatal flaw in the concept of permanent orbital habitats is the engineering difficulties (left unexplained) of creating mirrors in space several miles across. This in the same book that later projects orbital mirrors for speeding up Mars terraforming efforts which are thousands of miles across. In his second book, he declares O'Neill's plan defunct because what's proposed as the export for orbital settlements, SPS, is (by his calculation) economically unviable. He then proceeds to project settlements on Mars in the absence of any multibillion dollar export products marketable to Earth people, ignoring the obvious conclusion that if settlements on Mars could be built strictly for their own sake, settlements in orbit could be as well.

Regards,

Mike Combs

Why is Zubrin so fanatic? I've identified four possibilities.

1) He is simply a man with a specific dream.
2) His true belief about the destiny of mankind simply differs from mine.
3) He wishes to see a man on Mars or the existance of alien life before his
death.
4) He wishes to go to Mars.

These are just possibilities, If I were being objective I'd go with number
2. Any insights?