According to Wikipedia, “A Hail Mary pass is a very long forward pass in American football, typically made in desperation, with an exceptionally small chance of achieving a completion. Due to the difficulty of a completion with this pass, it makes reference to the Catholic “Hail Mary” prayer for divine help.”
When Andy Weir’s Project Hail Mary begins, Ryland Grace is the sole living astronaut onboard a spaceship named Hail Mary heading to a distant star as a one-shot suicide mission to save the Earth. However, at the start of the novel he doesn’t know this. He wakes up connected to a machine, doesn’t know who he is, where he is, or what he is supposed to be doing. So he devises a set of experiments to figure out things, such as determining how much gravity there is and measuring centrifugal force to rule out that he is in a giant centrifuge. As his memories start returning, in chronological order conveniently, he and the reader slowly learn the events that have led to the current situation. The more Grace remembers, the more desperate he is to accomplish the mission even though he knows he can never go home again.
If you have read The Martian (or seen the movie) Project Hail Mary delivers more of the same for the first couple hundred pages. Problems present themselves, Ryland has to use science to solve these problems, and then he moves on to the next problem. Luckily there isn’t a lot of math involved for the reader, it is mainly concepts so if you are scientifically illiterate when it comes to physics and chemistry don’t fret. Through Grace, Weir does a great job in explaining difficult concepts, especially useful when he gets to relativistic physics and its application to space traversal. If you liked The Martian, or the lesser but still entertaining Artemis, I strongly recommend Project Hail Mary. I didn’t know much about it before reading it and I’m glad I didn’t. Also, I’m happy to report the 20th century pop culture references that really drug down Artemis are largely absent, other than a couple of scenes, and are mostly well integrated.
It is after the first act where things get a lot more interesting and I have to enter spoiler territory to continue.
If you were interested in the book already stop reading and go get it. There are a few leaps of faith needed and a couple of plot holes, but it does all come together and is funny, exciting, and surprisingly charming by the end. I was up late with it a few nights in a row because I couldn’t bear to put it down. I think 5 stars may be pushing it, but I can’t give it a 4.5 so in this case I am rounding up.

The big twist in Project Hail Mary is there are aliens and it is also what gives the novel so much heart and wit. The microorganism that is draining the sun, called astrophage, is also a source of incredible power. Enough to power a spaceship almost as fast as the speed of light. When the Hail Mary gets to its destination Grace quickly figures out he is not alone, another ship is out there on a similar mission. What follows is the classic situation where two opposites have to work together, but they are not rivals. They are both aliens to each other and trying to save their homeworlds. Each brings a unique skill and only by working together can they hope to survive, let alone save their planets. The passages where they are learning from each other to learn the basics of communication is grounded in realism as Grace takes a methodical, mathematical approach by zeroing in on scientific concepts that would be shared regardless of your planet. As they learn to communicate with each other a friendship grows between them as they endure one setback after another, yet are united in a common cause. This friendship powers the novel through to the end and dovetails beautifully with the flashback revelations to deliver a thrilling, heartwarming finale.