I can't find the science content in either and when I challenge people to show to me, I get the response that I'm looking too closely and need to enjoy both book and movies as works of fiction.
Thus, I now take it we are all agreed that the content and concepts of both works squarely fall into the fiction category - which is great with me.
You are so missing the point. It doesn't matter how objectively plausible something is, in fiction everything portrayed is
still false. None of it happened, and none of it's going to. Even the similarly themed historical fiction
Apollo 13 is just a loose interpretation (fictionalization) of real events
arranged into a story.
The point of Art is to
communicate something, not instruct you on how something is supposed to work. Exaggerations of artistic license exist to help
communicate an idea. In the case of
The Martian, they could have easily done a more typical "believe in yourself and you can do anything" type theme, etc. The theme of the The Martian is so unusual in it's acceptance of science as something that's not only powerful, but as human as music (and just as beautiful!), that it almost stands alone.
Small bit of film analysis linked below. Here, a guy breaks down and analyzes the famous "trio" scene from the end of
The Good, The Bad and The Ugly. He shows you the power of film to communicate something very powerful with three guys
just standing there for three minutes. If you look close, you will see substantial anachronisms. A pedantic sort of person might be "taken out of the story" because even though they are
just standing there, what's shown is
physically impossible in the setting of the story, and thus utterly miss the point of the scene. It's the difference between hearing and listening.