Signs of flowing water have been found on Mars. http://www.nytimes.com/2011/08/05/science/space/05mars.html?_r=1
That of course makes Mars even more tantalizing than it is already.
Now Mars has been added to a growing list of bodies in our solar system that are believed to have water, and in some cases entire oceans. Let me be so bold as to pronounce, where you have water, you will eventually need divers.
I once attended a joint NASA – Diving Conference at Disney World in Orlando. It was largely devoted to discussions of the science and engineering that would be required to send men and women to Mars and to sustain them in a colony. I was presenting a diving related talk at the invitation of one of the editors of the Life Support & Biosphere Science journal, a short-lived scientific journal that reported on the science conducted in Biospheres and other life-support systems.
After hearing a number of fascinating NASA accounts, I talked about a rather arcane subject: A Priori models in the testing of diving life support equipment. That work was published in 1996. At the end of the talk, a NASA engineer asked, somewhat smugly I felt, how diving had anything to do with space.
Well, that wasn’t at all the purpose of the meeting, or the reason why I was talking. The organizers believed, correctly, that sojurns in space and underwater share elements in common; namely, people and breathing equipment. We could, and should, learn from each other.
Now, regarding the question: I can ad lib with the best of them. Knowing that Jupiter’s moon Europa was believed to be hiding a large ocean beneath its icy surface, I responded that someday astronauts will be carrying a dreadfully expensive piece of hardware to an alien moon or planet with water, and that priceless tool will get dropped — into the water. It happens all the time on Earth.
Now what? You can’t go on-line, order a replacement, and expect an overnight FedEx shipment. That is when a space diver would be worth his Earth-weight in rhodium.
Since that time, we’ve learned that Saturn’s moon Enceladus jets water from its south pole. As reported in the journal Icarus, that suggests that, like Europa, there may be a liquid ocean beneath the moon’s icy crust.
My suspicion is that long before we’ll need cowboys in space, 
we’ll need divers in space.
So divers, keep your diving helmets oxygen clean. You may get the call any day now.