kuniga.me > Books > Project Hail Mary
Project Hail Mary
This is a book by Andy Weir. I enjoyed his other book, The Martian, and since I got tickets to watch the movie based on the book in theaters, I decided to read it beforehand.
Plot
In the earlier timeline: The astronomer Irina Petrova spots an infrared line from Venus to the Sun and notices that the Sun is dimming exponentially faster, with only 30 years to figure out a solution before a climate catastrophe happens. This line is called the Petrova line. Scientists manage to collect samples from this line and believe this could be alien life. The European Space Agency head, Eva Stratt, reaches out to Grace because he published a controversial paper that claimed life can arise without water, for which he got shunned, which led him to abandon academia.
He's asked to investigate the samples, figures out how to make them reproduce, and calls them *astrophages*. These organisms can store huge amounts of energy they're "stealing" from the Sun. They notice that other suns in the galaxy are also being affected by the same issue, except for the star Tau Ceti, which does have the line but isn't dimming. They plan to send three astronauts to Tau Ceti, which is 12 light-years away, and they plan to use astrophages as fuel since they can store so much energy per mass.
Due to relativity, the voyage would only take 4 years for the astronauts, and it's decided they will be in an induced coma for the greater part of this time. They realize most people cannot survive for this long, but they identify a genetic marker that increases the likelihood. Very few people have that gene, but one of them is of course Dr. Grace. However, since this is a one-way trip, it's effectively suicidal so he doesn't want to go. A side effect of the induced coma is memory loss. This sets up the context for the second timeline.
Grace wakes up from the coma but doesn't remember anything. His other two crewmates didn't survive the coma and are deceased. He slowly regains his memory and realizes he's in the Tau Ceti star system. He spots a spaceship next to his and eventually makes contact with alien life, a 5-armed spider-like creature with a hard carapace. He nicknames the alien *Rocky*. Rocky is from the star system 40 Eridani, from a planet he calls Erid, and he had 23 other crewmates (Eridians) who perished due to radiation.
Together they are able to collect extra samples from the astrophage in Tau Ceti. And they discover that there is other alien life in this particular system, a predator of astrophage which he calls *Taumoeba* which is keeping astrophage growth in check. They figure out how to breed Taumoeba and plan to send back samples to Earth and Erid. Rocky's ship is also powered by astrophage, however Eridians did not know about relativity and overprovisioned on fuel, so Rocky has spare to let Grace afford returning to Earth.
They part ways, but during the voyage back, Grace realizes that Taumoeba can cut through xenonite, the material Rocky's ship is made of, and that it will "eat" all the astrophage fuel. He realizes that if he doesn't go back to help Rocky, the Eridian civilization will disappear. He sends probes with Taumoeba back to Earth and turns around to rescue Rocky. He decides to stay on Erid and becomes a teacher there.
Themes
The Extended Phenotype
It seems like Rocky builds his carapace from harvested metal. It doesn’t seem like his body synthesizes it, so it reminds me of the idea of the extended phenotype popularized by Richard Dawkins, in which animals make use of external elements to be part of their bodies, such as the caddisfly larvae.
Cultural Shock
Eating is a very private habit for Eridians, much like pooping. On the other hand, it’s commonplace to watch each other sleep. This “clash of cultures” reminds me of the difference in customs between Spacers and humans on Earth from the Naked Sun.
Blindness
Rocky is blind, and he uses echolocation to see. I kept wondering if it is really possible to evolve into an advanced society without sight. For example, I think writing (external memory) is a prerequisite to advance, and I was initially thinking that would not be possible without sight, but I think carving is a valid option.
I guess I just lack imagination, so I am curious about the details of the history of such a civilization.
AI
Maybe this is just availability / recency bias, but I keep thinking that Rocky is like an AI agent like Claude Code. He’s blind, has photographic memory, can calculate very fast, is friendly and cooperative, and can do certain things much better than humans, while they complement each other.
The pairing of human and artificial-life also reminds me of Elijah Baley and the robot Daneel Olivaw in Asimov books (e.g. The Caves of Steel).
Conclusion
I like how Andy Weir grounds his story in actual science. Like in The Martian, he often cites numbers and back-of-the-envelope calculations. I tend to prefer science fiction that leans more towards science than fiction, and even though in Project Hail Mary there’s imagined alien life, I think Weir does a good job of explaining things and giving the worldbuilding believable constraints, at least for a layman like me.
The protagonist also felt oddly similar to Mark Watney from The Martian, a loner trying to figure things out largely on his own. More generally, the characters sometimes came across as a bit flat and predictable. Rocky in particular occasionally felt more like a pet or mascot rather than a true equal. Still, the bond between Grace and Rocky, the plot twists, and the scientific realism made the story deeply immersive for me. 5/5.
Book Connections
In one of Asimov’s short stories, Escape! (From I, Robot) the characters also go through a very long journey which involves renering the occupands unconscious.