The Martian was a fun, self-contained space drama that became a mega bestseller and, eventually, a Hollywood movie starring Matt Damon. Project Hail Mary, from the same author, takes the same context - a lone scientist, shipwrecked in space - and ups the stakes. It's science fiction with an emphasis on science unlike almost anything else I've read. If you've seen Matt Damon planting potatoes on Martian soil and using his own feces as fertilizer, you'll know what that means.
I mostly steer clear of spoilers on this blog, but it's hard to describe any part of the plot of Project Hail Mary without immediately revealing a few of its many twists. So I'll make an exception this time. Ryland Grace wakes up from a medically induced coma with no memory of what has happened. It's a trope and, luckily, Weir quickly moves on. Grace realizes he's on a spaceship and, as his memory returns, replays in his mind how humanity slowly understood that our sun was dying. And he's the only person who can do something about it.
The first half of the book flies by. The sun is slowly being eaten by an invasive alien organism, the Astrophage, which means that Earth will freeze solid in a matter of decades. Grace, who's research earns him an unlikely front row seat in the global effort to stop the Astrophage, is one of the first people to put their hands on the culprit. He wakes up just as his spaceship reaches Tau Ceti, a nearby start system and the likely source of the Astrophage, only to realize that the rest of his crew has passed away during the journey. As he prepares to investigate Tau Ceti, he makes contact with someone from another planet who's there for the same reason he is. Several equally unlikely twists follow.
Weir focuses on the minutiae of research and engineering that might go into all of this. Project Hail Mary is almost an attempt to guess how the scientific community might react to extraterrestrial challenges and it painstakingly describes things like lab experiments, biochemistry, cell cultures and centrifuges. Grace is a teacher by vocation and at times it felt like Project Hail Mary was a sneaky attempt to get teenagers excited about a STEM education. Weir's style works wonders during that exciting first half. It almost feels like a police procedural or a murder mystery, except that the sun is the victim. Unfortunately, being so meticulous has its downsides. Some latter parts fall into a cycle of tedium: a new problem emerges, Grace overcomes obstacles to piece together a solution, that solution creates a new, even bigger problem. At times, paragraphs sound like flight checklists and a leaner format would definitely have been more digestible.
In the end, Weir is able to rescue the story (and the protagonist), but only barely. There's not much to see beyond the midway point, unless you're really excited about the exact way to breed nitrogen resistant amoeba. I'm not joking. Try swapping Project Hail Mary for the movie Arrival once you hit that point in the book. There are several overlapping themes and, unlike Project Hail Mary, Arrival has genuinely compelling characters and a plot that excites from beginning to end. Or better yet, wait until the Hail Mary movie comes out - they cast Ryan Gosling as a nerdy science teacher! - to enjoy a few genuinely exciting surprises without the need to constantly manipulate your centrifuge or adjust the angle of attack of your spacecraft.