Zimmerman's latest UPI article is as usual thoughfull, and well researched.
Apparently the solar system is awash with water, mostly in the form of ice. Mars, Europa, Ganymede, Callisto and even Moon look not so inhospitable the way Zimmerman describes it.
I'm glad though he seems to have enough common sense to raise above the Mars hyperbola. No matter how much water we find on Mars it won't change the fact that it's still thousands of times farther away than the moon. And right now folks, it's the distance that counts.
We need to get costs down if real space colonization will happen. Using in-situ resources on the moon would be the best bet to create an outpost off this rock on the cheap. If these estimates are right, with 6.6 trillion tons of water on the Moon, there is the potential for millions of people to be able to live on our nearest sattelite off of Lunar water for thousands of years.
A 3 day trip to the moon is one thing in terms of fuel. A year long trip to Mars is another.
Cost is everything in this game. The first pioneers to come to this continent weren't going to pay $16,000 a pound just to get here. They did pay out the wazoo for their tickets, but it was nothing compared to the current costs to get into space.
Until that changes were all stuck here on terra firma.