A fascinating book that, like "The Martian", contains a few specific 'hand wavy' parts, but for the rest, strictly follows the rules of physics as we know it, and features a protagonist (or two) that can science (and engineer) the heck out of things to solve problems.

The book starts with Ryland Grace waking up on a spaceship with no memory of how he got there, along with fellow dead crew members. As he explores the ship and his memory of recent events starts to return, we learn that Earth is in trouble. A lifeform that is literally breeding on the energy of the sun has been discovered. As it multiplies (exponential growth), the sun gets dimmer, with catastrophic consequences for the Earth. Ryland learns that other nearby stars are also dimming, except for one: Tau Ceti. And he's on a mission to that star to discover why it's not affected before it is too late for Earth to survive.

At that star, he will make a voyage of discovery as he uses his wits and scientific knowledge to make deductions and test them by making experiments. He will encounter problems and solve them with intellect and skill, only to move on to the next one. But by the end of the story, just when you thought all the problems have been solved, one final one is presented that will require him to make a decision that may well end his life, for the sake of friendship.

This is a story of solving problems with science and engineering, yet not forgetting that you sometimes have to put them aside to do what seems to be the right thing.