Whilst this post is not precisely related to my efforts of becoming an astronaut, it does relate to future exploration.
We all know, thanks to Mars Phoenix and the Mars Reconnaissance Orbiter (MRO), that there is water ice on Mars. We now know, thanks again to the MRO, that there is a lot of water on Mars... and not just at the poles. An article on Scientific American announces vast subsurface formations of ice at mid-latitudes on Mars, a very important find since human colonization of Mars will likely begin nearer to the equator than the current location of Phoenix.
Why is in situ ice important? There are myriad answers to this question. Most obviously, it provides a source of water for future exploration efforts. Hauling stuff to Mars is expensive, so it's best to use what's already there. In addition, ice can be electrolyzed into hydrogen and oxygen. The oxygen can be injected into an outpost's atmosphere, and the combination of O2 and H2 can be used as fuel to either roam about the surface or head back to Earth (or... and this is really thinking out of the box... as a fuel station on the way out to the asteroid belt and outer planets).