"like a bullet through butter" (p. 4) (Simile)
Watney uses this simile to describe the feeling of the antenna puncturing his suit (and his body) during the novel's initial sandstorm. The simile is a vivid one, showing just how quickly and painfully the antenna harmed him.
Vogel's "monkeys" (p. 245) (Metaphor)
Vogel uses the metaphor "monkey" to refer, lovingly, to his children. This metaphor shows the care he demonstrates toward his wife and children, even when separated from them by the vast distances of space.
"Phobos is the god of Fear" (p. 98) (Metaphor)
Watney uses Phobos, one of the moons of Mars, to locate himself while driving in the rover. He worries about the metaphoric meaning of this moon's namesake, however, since fear (metaphorically) has been his guide on Mars for weeks, helping him to develop new solutions to pressing problems.
"Two wineglasses in the sink" (p. 225) (Simile)
Watney uses this simile to describe the small pieces of evidence that can lead, often, to catastrophic consequences. At various moments throughout the novel, Watney has seen very small details (like the second dust storm on the way to Schiaparelli) that wind up leading to big events—which require new and clever solutions.
"Melting-the-pigeons strong" (p. 58) (Simile)
NASA uses this simile to describe just how powerful a messaging system would need to be, on Earth, to reach Mars, based on Watney's current tech availability. The simile is a vivid one, for of course, no denizen of Earth would want to witness a signal technology this souped-up and potentially dangerous.
