At first it felt like a shove in the chest. Then they were pushed back in their chairs, and for a second the pressure was deeply familiar: one g, the gravity they would never live in again. The Ares had been orbiting Earth at 28,000 kilometers per hour. For several minutes they accelerated, the rockets' push so powerful that their vision blurred as corneas flattened, and it took an effort to inhale. At 40,000 kilometers per hour the burn ended. They were free of the Earth's pull, in orbit to nothing but the sun.

The colonists sat in the delta V chairs blinking, their skin flushed, their hearts pounding. Maya Katarina Toitovna, the official leader of the Russian contingent, glanced around. People appeared stunned. When obsessives are given their object of desire, what do they feel? It was hard to say, really. In a sense their lives were ending; yet something else, some other life, had finally, finally begun.

Basic Set up:

A bunch of people are on a spaceship, leaving earth forever, on their way to colonize Mars.

Road trip—we're going to Mars! Well. Not us. But the colonists in Robinson's Red Mars are. These guys and gals are going to Mars forever. It's kind of sad, but it's also a big adventure.

The space voyage is right at the center of this famous sci-fi novel. And in the passage above, we get a wonderful description of what it might actually feel like to go on a space journey. The passage also highlights the importance of the "journey" as a theme or a motif in sci-fi in general. After all, what is science (or fiction, for that matter) but a journey into the unknown?

This passage provides us with lots of details that make us understand what it might actually feel like to be on a spaceship blasting off to Mars.

The colonists' corneas "flatten" as the spaceship takes off. Within minutes they're "free of the Earth's pull." Their new life is "finally, finally" beginning. This description serves to give us readers a sense of the magnitude of this voyage. These courageous people aren't just popping over to Mars for a visit. They're going to stay there for the rest of their lives. Would you have the courage to do that? We'd probably say "Um, no thanks" and stay put right here on earth, if we're going to be super-honest.