This article has massive science spoilers to the novel (and presumably the film) The Martian. Pssh. As if science could spoil anything.
On Monday, NASA scientists announced that they are almost certain that there is water on Mars. I couch that statement much more than the headlines normally do, because nothing is science is certain. That’s what make it so powerful, such a tonic against the superstition that is unwilling to stand against the harsh and unsentimental forces of the universe. The basic gist of the finding is that there are some odd dark spots on photos of the Martian surface. They come and go. And we have extraordinarily cool satellite chemical analysis that suggests that the dark spots correspond to water soluble salts moving across the surface, which heavily implies that under certain conditions, water runs across the surface.
Immediately after the announcement, which was apparently surreptitiously leaked to Ridley Scott months ago because NASA is just as excited about The Martian as the rest of us, tongue-in-cheek articles started popping up questioning whether the film and novel were basically invalidated by the discovery.
They are not. I will tell you why.
First, there is the simplest reason. The landing site of the Ares III in The Martian is several thousand kilometers from the nearest “dark streaks” identified as possibly being caused by running water on the surface of Mars. So that immediately makes Mark’s use of this newly discovered water implausible, given the immense lengths he has to go to in order to get to the Pathfinder and the Ares IV launcher in the first place.
Second, there’s the more involved argument that suggests that the knowledge of this water would mean that the Ares III wouldn’t have landed where it did in the first place, that obviously it would have landed next to the water. Couple of problems here as well. We have known for a long time that Mars has frozen water, that’s what those ice caps are at the poles. And even with that knowledge, the Ares III wasn’t landed at the poles because it actually had a scientific mission to carry out where it was landed. The rationale for its location is not particularly explored in the book, but given that it followed the Ares I and Ares II landings, it’s reasonable to assume that if the dark flows are still important to explore twenty years from now, that those first two landings would have done so.
Further, even if the Ares III happened to land right on top of an area with this sort of presence of water, it wouldn’t really solve any of Mark’s problems at all. Recall Mark’s issue with water isn’t that he doesn’t have enough to drink (the mission brought its own water and he used the water reclamation system throughout) but that he didn’t have nearly enough water to grow crops. The newly discovered water is so salty that it is liquid down far below freezing. This isn’t tap water, it’s the slush at the end of your driveway in February after you dump a bag of chemical salt on it. It is not directly usable.
So Mark would be faced with having to either generate water through the technique he devised in the book: essentially (I know I’m skipping a step or two of chemistry here) of burning off hydrogen so that water is generated as a byproduct. Or he’d need to build a desalination plant. The first one is a lot easier, if more explosive.
And even worse, if Mark had happened to be based on top of a formation like this, he would have been stuck from page one, because the soil itself would be toxically salty. In the book, the soil was (presumably) relatively PH-neutral, since he was able to add manure and water to gradually turn it into living soil. But if it was saturated with the massive levels of salt we’ve detected in these patches, then he would have just been salt out of luck.
Finally, let’s remember that in the book, water was just one piece of the puzzle that Mark was assembling. Solving that problem by placing him on a different part of the planet would not invalidate the story, it would just make it a slightly different story as different challenges would replace that single piece.
In other words, this discovery wouldn’t change the fact that he’d have to science the shit out of the situation.