Moonwater!

You know what could make space exciting again?  Like, in the short term? If the moon, that thing right over our heads, that we can actually reach, was more than just a big, dead rock.  The fantasies of moon men are long dead, but it seems there's enough up there that we shouldn't dismiss the moon as a destination of fantasy, just yet. It turns out, there's way more water on the moon than scientists previously thought -- enough that it could constitute a fantastic resource for rocket fuel.  (The form it comes in isn't so great for drinking, though.)

the Christian Science Monitor writes:

"Reservoir" does not mean a source of readily tapped liquid, the researchers caution. The evidence shows up as hydroxyl – a single oxygen and hydrogen atom representing two-thirds of a standard water molecule. Hydroxyl and water molecules are captured in tiny deposits of glass in rock and soil grains. The glass forms from heat generated when micrometeoroids slam into the surface and fuse soil grains into tiny clumps.

There are a crazy number of ways water can form on the surface of an airless rock like the moon.  Like, enough ways that I'm far less surprised now that life exists anywhere in the universe than I would otherwise have been.

Some of the water could have come as ice from comets colliding with the moon. A second source: in effect, the sun, whose endless stream of "solar wind" protons strike the moon's sunlit hemisphere. Bind a pair of those protons to an oxygen atom, readily available in the minerals that make up the lunar soil, and you get a water molecule. Finally, water and hydroxyl molecules also are bound up in volcanic rock and soil that originated as water-bearing magma in the moon's interior.

If all it takes to have water on your large space-object is (a.) having some oxygen, (b.) being pretty close to a star, and (c.) being at the right band of temperature that the water stays water, I think we might have a pretty good chance, as a species, to find somewhere to migrate when we finally wreck this planet completely.