The target audience for The Martian is pretty broad. It is aimed at novel readers, suspense lovers, and science fiction enthusiasts. The design for this book appeals to this audience by being as informative and as minimal as possible. The title tells the reader that they are picking up a sci-fi novel, but the image on the front is a type of contrast to this point, depicting a more realistic space suit. The viewer is told through imagery that the martian in the novel is not an alien, it is a human, and this will be a much more grounded story than your typical sci-fi epic.
The layout of the cover gives all of the necessary information as clearly as possible. The use of heavy-weight blocky white text on a red and black background creates contrast and makes the cover simple and easy to read. The clarification at the bottom that this is a novel is an added touch that sinks in the message that this is a work of fiction and the depiction of the astronaut clarifies that this is a story of survival in a martian environment (and not about actual martians).
The tone of the image is suspenseful and clinical. All information is presented the the viewer as bare as possible, but with a hint of something foreboding. The viewer knows little about the book when going into it, except that it is about a person struggling to survive on Mars. The story can go anywhere and the cover leaves it to the reader to investigate.