Miles O’Brien was on PBS Newshour today, talking about the significance of the liquid water on Mars discovery.
He correctly pointed out that a drilling operation to a depth of 1.5 km would require humans and heavy machinery. And I’d add, a LOT of power too.
Anyone who follows the space industry knows of the fierce debate between “Selenians” and “Martians” (should we go back to the Moon first or on to Mars?). There are compelling arguments on both sides, but no decisive evidence yet. This discovery might change that, if more aquifers like this one are found closer to the Martian surface in the mid-latitudes, where humans are more likely to go.
The Moon is only three days away, but is even less habitable than Mars. There are water deposits in the polar areas, but they are so dilute as to require extensive surface mining operations. Add in the extreme temperatures and abrasive dust, and humans would be hard-pressed to live there, even with Earth only a short distance away.
I think liquid aquifers are more likely to be found on (under) Mars than on the Moon. We know that Mars had liquid water activity on its surface billions of years ago. The Moon has no sign of it that we’ve found so far.
Mars has a much more benign thermal cycle, owing to its 24-hour day length. Its dust grains are less abrasive. If liquid water is easily accessible there, this would make all the difference for a viable human base there.
The Moon vs. Mars debate would then come down to resources versus distance. Personally, I think humans should go first and more frequently to the places where they can be more easily maintained. And if we find water ice inside Phobos or Deimos, the case for Mars becomes much stronger.