He knew that he wanted the aliens in the book to be as distinct from humans as possible – unable to survive in our environment, just as we would be unable to live in theirs. “I started designing their biology by looking at the planet,” he says. “All we know in real life is their approximate mass, and their orbits around their stars.”įrom there, he was able to extrapolate. “Not a lot is known about them,” he says. That acted as a constraint on the types of planets his aliens could live on, and Weir scoured the galaxy to pluck two actual observed planets to base the ones in his book on. But rather than plucking a horrifying beast from the depths of his imagination, or going down the cash-strapped Star Trek wardrobe designers’ route of sticking some plastic bits on a human, Weir uses the same scientific approach that characterised The Martian to come up with a plausible alien life form for his new book. (Mild spoilers follow).ĭuring his journey, Grace encounters an alien life-form on a similar mission to him: a spider-like creature with a thick exoskeleton that breathes ammonia and finds oxygen poisonous. In the book, which is released today, a wise-cracking American man called Ryland Grace wakes up in a spaceship with no memory of who he is or how he got there, and who has to rely on just his wits and a series of science experiments to save not only himself, but the human race. It’s clearly a winning formula – MGM has already picked up the movie rights, Ryan Gosling is attached to star. That idea became the seed of Project Hail Mary, Weir’s new book, which sees a return to what he calls the “isolated scientist story”.

Author of the martian new book