One thing I enjoy about writing science fiction is discovering how many of my conjectures turn out to be true or false. In The Orthogonal Galaxy, my astronaut camp on Mars has reservoirs of water below the crater where the camp is located. A recent article concludes that scientists are increasingly convinced of water on Mars... and lots of it.
If we do find existing subterranean water on Mars, it will go far in supporting those who may colonize Mars in the future. That will be imperative in the absence of the subatomic replicator that my astronauts were able to use on Mars to sustain their lives... well, at least until they had to evacuate the planet. 😉