What do you think is best and why: a human mission to Mars costing up to $1-trillion, many $1-billion robotic missions, or neither?

I'll go for robotic exploration. Economy wise, we could greatly benefit from space exploration to "civil" industry technology transfer. Think about the robotic vehicles that are roaming Mars now - how efficient they are in harvesting (scarce) solar energy over there, and how efficiently they utilize every bit of energy they manage to get onboard.

Now, compare that with what we have here, on this planet, in terms of solar powered vehicles - we can barely manage to get few solar cars race through hot Australian desert! Why is that? For purely political reasons, bad thinking.

There is nothing about space exploration, on one side, and the rest of human economic, technological activity, on the other, that prevents these areas from overlapping and supporting each other. How many more jobs would space exploration produce if the technologies were "disseminated" more quickly, and more readily, throughout the industries, wherever they can be utilized? We could have self-sufficient solar & wind powered households, from Nebraska to Alaska, before the new generation of our spacecraft reaches Mars!

Which brings me to the second point, the main objection to human mission - time. The biggest obstacle is psychology, the enormous psychological and emotional pressure, when you have small number of individuals confined within very limited space over very long periods of time. Just to give you an idea, a return trip to Mars, plus the stay there, would take between two and two and a half URL1 may not sound long, but people who plan such missions are well aware of this problem.

I think that a $1-trillion human expedition is best, because it what we'll eventually do, even if we send lots of robots first. However, I don't believe that now is the time for us to be spending so much money on something that will have very little impact on the economy, but maybe in the near future (10-20 years).

Neither. If $1 trillion is going to be spent, it should be spent fixing the global economy. I don't know how but I'm sure it would help more than anything going to mars.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.