Kim Stanley Robinson is an author that's really grown on me over time--maybe I've gotten wiser or he's gotten better, but I think it's very much both. Aurora was nominated for a Locus award for 2015, and I think it probably deserved a nomination for the Hugo and/or Nebula as well.
Aurora is the name of a near-earth size moon orbiting one of Tau Ceti's planets. Earth was sending out generation starships in the 2500's, and the story is set on the ship bound to Tau Ceti. There are a few promising candidates for settlement there. Our protagonist is Freya, child of the "chief engineer" (it's an unofficial title) of the starship, Devi. They are of the generation that will reach Aurora and try to settle it.
As always with Robinson, the book is brimming with excellent science speculation. We learn about "islanding" and "codevolution". The inhabitants of the starship shrink with each generation, and live shorter lives. The bacteria on their relatively small ship evolve faster than the macro life, of course, which is making each generation less healthy. Possibly less smart--Freya is wise in many ways but cannot handle numbers even close to the way Devi can. They have endured social stress and internal dissent. But they can get around all this if they can establish a healthy colony when they get to Tau Ceti.
I'm going to have to reveal important bits to make my points, so I am going to do something I rarely do--SPOILER ALERT.
The colony on Aurora does not take. The settlers are sickened by an extremely tiny almost-prion, and many die--all but one who went to the surface. Faced with a set of very bad choices, they end up splitting, some staying on Aurora and others equipping to go back.
Robinson uses this failure to illustrate how finely tuned we are to our home. As we pursue space exploration it becomes more and more apparent how difficult it will be to reproduce those conditions anywhere else. Robinson puts this forward as an explanation for the SETI problem--the fact that we have not found or heard from any other intelligent life. Other self-aware life may be out there, but we are too far apart and too different from each other to communicate. There's no real way to get around relativity.
This book isn't quite up to the standards of David Brin's Existence, but it's a pretty good try and makes a similar argument about what the sheer distances of space do to any thoughts of interaction with aliens. There is one odd sort of error in it. Toward the end of the book we get the idea that this book is set in the same universe as 2312, last year's major award nominee. He refers to a "city on Mercury, on rails and perpetually moving around the planet"--but in this story that city was built while the travelers were away (they return in the early 2800s). That continuity issue isn't like Robinson.
I give it four stars for entertainment and educational value. This is my kind of SF.