The answer to the long term radiation problem has already been given - mass. It's that simple. During transit it is harder because launch mass=$, but the increased risk appears managable. The fact that existing solutions merely reduce but not eliminate risk and limit launch periods probably accounts for why some researchers want a better solution, not that it is an unbearable problem.

I don't doubt Tumlinson's long term goals are in the best interest of humanity, it is his methods and short term tactics I disagree with. As Martian colonization is a long term goal SFF shares it is perfectly understandable that they support some MS efforts.

Many NASA people do attend MS conventions. You need to check the schedules for this and previous conferences. For example, howed you miss all the news on NASA/MS research at Devon Island? It's being presented at this convention. Perhaps with a little more study you'll be able to see a difference between a superstitious cargo cult and/or UFOology and technical research.

Glad to see you finally agree that space technology has multiple uses, but I haven't noticed many Mars enthusiasts disagreeing with that. It goes back to what I said above about choosing to spend money on something of value or on paying for a large structure in space of little use. "Usefullness" is of course open to interpretation. If we didn't already know humans can stand 6 to 12 months of 0 g, if ISS was testing a transhab module or using new launch technology, I'm sure it would be far more popular amongst both Mars enthusiasts and space enthusiasts in general. It's pretty bad when THE major space program generates so little enthusiasm amongst space fans.

Regards,
Mark