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Project Hail Mary
(Review, Recap & Full Summary)

By Andy Weir

Disclosure: This book was provided by the publisher for review.

Book review, full book summary and synopsis for Project Hail Mary by Andy Weir, a sci-fi thriller about scientific research, evolution, interstellar exploration and a lone astronaut on a mission to save the world.


In Project Hail Mary, Ryland Grace wakes up on a spaceship with no memory, where he soon learns that he is the sole survivor on a desperate mission to save the earth.

With only the two dead bodies of his crewmates as company and his memories slowly retuning, he must piece together what has happened and complete his interstellar mission to save humanity.

(The Full Plot Summary is also available, below)

Full Plot Summary

Chapter-by-Chapter Summary
See the Chapter-by-Chapter Summary of Project Hail Mary
Quick Plot Summary

The one-paragraph version: Ryland Grace is the sole survivor of a suicide mission to stop an alien organism that feeds on stars ("Astrophage"), which is causing the apocalypic scenario of the sun dimming. His mission is to find out how to stop the Astrophage and send the data back via unmanned probes. He comes across an alien ("Rocky") from a planet ("Erid") that is faced with same problem with their star. The two learn communicate. Together, they find a solution, and Rocky has extra fuel so Ryland can go home. (As Ryland's memories return, he learns that he was sent here involuntarily and given a serum to wipe his memory.) But on the way home, they both run into trouble. Ryland sends Earth what it needs to stop the Astrophages, and he also decides to gives up his chance to go home in order to save Rocky and his alien species.

The book opens with Ryland Grace waking up next to two dead bodies. He doesn't know where he is or why he's there. As Ryland investigates his surroundings and his memories slowly return, Ryland realizes he's in a spaceship named Hail Mary with his dead crewmates, sent to investigate something called the Petrova problem.

Scientist Irina Petrova had first observed an astronomical anomaly that later turned out to be a single-celled extraterrestrial life form. These dots appear to feed on the Sun, and their trail forms an arc between the Sun and Venus (which scientists refer to as a "Petrova Line"). This has potentially apocalyptic implications since it means the Sun is effectively dying. It's predicted that it will lead to a 10-15% decrease in the Sun's output. Hail Mary's mission is to figure out how to stop this.

Ryland eventually recalls his research into these particles ("Astrophages"). Ryland is a junior high science teacher who formerly worked in speculative extraterrestrial biology. Due to his prior academic research, he is brought on to the research team, run by Dr. Eva Stratt, who is given nearly unlimited authority worldwide.

It is discovered that Astrophage can store enormous amounts of energy as mass. They can then expel that energy as light, the force of which they use as momentum to move around. They get their energy from stars such as the Sun. Then, because they need carbon, they go searching for carbon dioxide (which Venus is largely comprised of), where they breed and then return to the Sun with their offspring. The data suggests that Astrophage have infected many stars and will affect any star within an 8 light-year radius.

In present day, Ryland finds that his spaceship is headed for Tau Ceti, a star located in a cluster of other Astrophage-infected stars, but unlike the others, it has not dimmed. Presumably, he there to find out why Tau Ceti has resisted infection. There, Ryland comes across an alien spaceship. The alien astronaut ("Rocky") is from a planet ("Erid") that is dealing with the same problem regarding their star, 40 Eridani. He is investigating Tau Ceti for the same reason.

Eridians "see" using passive sonar instead of light, and their language consists of chords. Their atmosphere is also very hot and filled with ammonia, which is lethal in high amounts to humans.

Meanwhile, as Ryland's memories slowly return, he recalls how Astrophage proved to be a great fuel source because of its energy storage potential. However, given the extensive distance of the trip, there isn't time to breed enough Astrophage for fuel for a trip back so it's a suicide mission.

Stratt decides it's necessary to put the crew in extended medical comas for the four-year journey (to prevent depression or them killing each other) given that they will be confined in a small space, though only certain people have the resistances to survive the medical comas. (It's also still risky, which is why the other two crew members do not survive.) Still, Stratt manages to put together a primary and backup crew with the appropriate gene markers.

In present day, Ryland and Rocky learn each other's languages, and they agree to team up to figure out how to stop the Astrophage. Rocky is very talented at constructing and fixing things, which he does using an extremely strong material called xenonite. He also has the extra Astrophage fuel to allow Ryland to possibly return home. Meanwhile, Ryland teaches Rocky about things like radiation and time dilation, which the Eridians had not discovered yet.

They identify that Tau Ceti does have Astrophage and a Petrova Line that leads to a nearby planet, which they name Adrian. They get a sample of Astrophage from Adrian, and it indicates that the Astrophage has a predator which is why its population is being kept under control (and why Tau Ceti is not dimming). However, in order to sample it, they have to engage in a risky maneuver with the ship, the ends with Ryland and Rocky severely injured.

As Ryland's memories continue to resurface, he recalls how nine days before the launch, both the primary and backup scientist on the crew died in an explosion from some testing gone wrong. Instead, Ryland was asked to step in, since there wasn't time to train anyone else. Ryland had refused, but Stratt insisted. She sedates for the launch and administers a serum to induce temporary amnesia so he wouldn't remember that he was forced involuntarily to participate.

In present day, Ryland and Rocky isolate the predator ("Taumoeba"), but discover that nitrogen can kill it which means it can't survive on Venus and Threeword (the planets where Astrophages are breeding near the Sun and 40 Eridani, respectively).

Instead, they have to breed a strain of enhanced Taumoeba that is resistant to nitrogen. In the process, some Taumoeba get loose and rapidly consume Hail Mary's Astrophage fuel, but they manage to contain the situation and swap the fuel. Once the nitrogen-resistant Taumoeba is ready, Ryland and Rocky bid each other farewell as they go home to save their respective species.

However, on the way back, Ryland discovers that the enhanced Taumoeba has also acquired the trait of being able to hide in the xenonite material that their tanks were built with. While Ryland simply swaps out the tanks, Rocky's entire ship is built with xenonite. Ryland sends his unmanned probes off to Earth with the Taumoeba necessary to stop the Astrophages, and then he turns back to save Rocky (and the rest of the Eridian species) even though it means he won't be able to go home.

Years later, Ryland is living on Erid in a bubble since otherwise he would die. Rocky reports that their scientists have discovered that Earth's Sun is now at full luminance, indicating that Earth was saved in time and that it's habitable. Ryland cries in happiness. As the book ends, he contemplates whether to attempt a trip home, which would be a long and lonely journey.

For more detail, see the full Chapter-by-Chapter Summary.

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Book Review

Project Hail Mary is the newest novel from Andy Weir, soon released in a few days on Star Wars Day (May 4). Sci-fi fans should feel free to get excited now. I was so thrilled to get an early copy of it and absolutely tore through this story about scientific research, evolution and interstellar exploration.

I loved, loved the movie The Martian and have been wanting to read something of Weir’s for a while now. However, I ended up skipping Weir’s follow-up novel, Artemis, since it had mixed reviews and the plot seemed kind of wonky to me, with stuff like space heists and gangsters and whatnot.

In Project Hail Mary, Weir gets his footing back on more comfortable territory: a dude in space doing science-y stuff.

Project Hail Mary involves quite a bit of scientific experimentation since the narrative involves a backstory about an astronomical anomaly. Weir does a fantastic job of explaining this all in a way that includes a full explanation of the science behind it while still making it very accessible and narratively interesting. This book is so impressive in that respect.

Chances are, if you read this book, you’re going to learn quite a few fun science facts! Here’s a good litmus test for whether or not you are a good reader for this book: If you read that sentence and thought, oh cool, science facts! You are a good reader for this book, and I bet you’ll love it. If you read the first sentence in this paragraph and thought, ugh, bleh, science. You are a bad reader for this book, and you will probably DNF it.

I don’t want to spoil any of the plot, but Project Hail Mary involves more speculative aspects of the story than The Martian did, so it involves similar territory but then extends outwards from there. There’s some portions of the book deals in evolution and the ways that species evolve. These were some of my favorite parts of the book, and I thought the coverage of it was compelling and astute.

It’s a very ambitious book in terms of what it’s trying to cover, and the science and technology aspect of it are so carefully and deliberately thought out. Weir’s use of actual science as a foundation for his science fiction is a particular strength of his, and it’s an understatement to say that it’s on full display in Project Hail Mary.

In terms of some general descriptors of the writing, the book progresses forward at a moderately rapid clip. The writing is what you’d expect from someone who’s more of a science guy than a writer in a literary sense, but it’s serviceable. It helps a lot that the narration and dialogue is often genuinely funny, which helps to smooth out most of the edges.

There’s one point towards the end where I thought the plot went a little off the rails. I think Weir is better with science-survivalist stuff than with plot points that involve human nature and whatnot. But I think it’s a small enough part of the book that it won’t ruin anyone’s enjoyment of the book if they feel similarly as I do. (See the Spoiler-ish Thoughts section below for more.)

Women in STEM

There’s (very) brief mention of the lack of women in STEM and the need to allow less qualified women in their selection criteria. (“Stratt stayed firm and insisted on only the best candidates, but some concessions had to be made. ‘Women,’ I said.”) Then, Weir has a character say that the way to change things is to “encourage your female students to get into STEM”.

Hm. Okay. Let’s be clear, that’s not enough. Yes, people should encourage women and girls to get into STEM. But saying that’s the reason there aren’t more women in STEM is inaccurate.

Ultimately, having more women in STEM requires addressing the structural issues that keep women out, such as not having proper mentors and not having work or school environments that are free from sexism and harassment, etc.

Having creepy men who want you to flirt with them (or more) is not the same thing as mentorship. If there’s someone who is in a position of authority over a woman and “mentoring” them but also hoping they will maybe flirt and sleep with him, then that person is a predator and not a mentor. Beyond that, other women feeling that they can’t be involved in projects and the like if they’re not willing to flirt and whatnot is another type of harassment.

And the assumption that women in STEM are unqualified to be there is one of the many reasons why other women are reluctant to enter or stay in STEM fields. And the fact that if you are interested in STEM you have to randomly come across stuff like this is another reason why women exit STEM.

To be fair, this is just a mention made in passing, a few sentences out of the entire book, and I moved passed it. Still, I am disappointed by this nonetheless. I don’t understand why Weir felt the need to include a sexist character without having another character provide a counterargument.

As such, my general stance on stuff like this is to use it as a teaching opportunity on my blog (right here!), so thanks for reading!

Read it or Skip it?

This is a solid, sometimes quite funny and very meticulously thought-out book. In essence, it’s a great read … if you enjoy hard science.

You don’t really need to understand any of the science in advance, Weir does an honestly impressive job at explaining things in relatively accessible terms. However, you need to at least be someone who would enjoy the prospect of learning some science stuff.

The thing about women in STEM did irritate me, but let’s face it if you are a woman interested in science or technology, you deal with stuff like this all the time. It’s a part of the reason why women do not feel welcome in STEM. That said, it’s also a very, very minor part of the book.

So, I will set that aside and say that overall, I thought Project Hail Mary was pretty great. If you like science at all, read it! You will love it, trust me. If not, I’m sure it’ll become a super flashy movie at some point, so you can watch it then. Yay, space!

Is this something you’re planning on reading? Feel free to share your thought below! See Project Hail Mary on Amazon.

Spoiler-ish Thoughts

Spoilers Ahead, Beware! You’ve Been Warned

So first things first, did anyone else think the Table of Contents was a total spoiler? I saw the chapter heading when I started reading and wasn’t sure what it meant. But as soon as we meet Rocky in the book, I knew that Ryland ends up on a different planet by the end.

Secondly, I thought the part where it turns out that Eva drugged Ryland and forced him on this trip didn’t make a ton of sense. Eva’s someone who likes to use “off the shelf” products because she don’t want to rely on untested, uncertain things. It’s one thing for her to force someone to work for her on the ground where she can keep an eye on them, it’s a whole other thing to force this person on a suicide mission into space.

Eva’s also convinced that the crew being confined to a small space for four years will cause severe depression enough to ruin the mission; she’s concerned enough that she devises a whole extended coma plan.

… But then, she decides to sends a amnesiac, drugged using something with unpredictable results, who will either be in a state of having forgotten half of what he knows or being angry, unwilling, bitter and possibly ruining the morale of the other crew when he does remember?

And then she says some stuff about him always having been the tertiary science person, which is why she kept him around? Huh? If she wanted a tertiary crew, she would’ve just…trained a tertiary crew. She has all the resources in the word and her backup plan is an angry, unwilling amnesiac? If she’s known all along he was a backup plan, she would’ve just told him. That way, she could’ve found out his thoughts about it at the onset. What’s the benefit of not telling him?

It seems like a weird plot twist to me. I guess it makes the point that Ryland very much does not want to die (which is important since otherwise his choice at the end becomes a very simple one), but it seems like there were better ways to do this. I just think that the science in this book is so thoroughly reasoned out that this part being so … not like that … sticks out.

Discussion Questions

  1. Was Project Hail Mary what you expected going into it? What surprised you about it?
  2. What did you think about the character of Ryland Grace? Were you rooting for him? What did you like or dislike about him?
  3. What did you think about the science behind Project Hail Mary? Were you able to understand it, and did you enjoy reading about it? How do you think it contributed to your enjoyment of the story?
  4. What did you think about the process of planning the Hail Mary mission? Did you think
  5. What did you think about the character of Eva? Did you find her sympathetic as a character? What did you like or dislike about her?
  6. At one point, Eva calls Ryland a coward. Do you think her assessment of him was accurate or fair?
  7. What did you think about Ryland’s determination to get home? Do you think it was cowardly? Selfish? Understandable?
  8. What did you think about the different social customs of the Eridians? Did these make sense to you?
  9. If you had to choose someone to be stuck in space with, would you choose Ryland or Rocky?
  10. What did you think of Weir’s descriptions of the Eridians? Did these seem convincing to you as a species that could possibly be real?
  11. Weir goes into detail regarding the comparisons between Eridians and humans. They are located close to each other, at least relative to the vastness of space, and their planets are similar but with some distinct differences. What do you think of Weir’s reasoning of why the Eridians and humans are similar or different and the ways that they’ve evolved (Rocky and Ryland are similar intellectually, but Rocky’s bodily composition is very different, etc.)?
  12. Do you think Ryland ever makes it to Earth?
  13. Were you left with any other unanswered questions after reading Project Hail Mary? If so, what?

Book Excerpt

Read the first pages of Project Hail Mary

Movie / TV Show Adaptation

See Everything We Know About the 'Project Hail Mary' Adaptation

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