Review of Andy Weir’s third book, “an epic story of redemption, discovery and cool speculative sci-fi”, according to USA Today. Several people recommended it in a larger ratonalist group, so I bought and read it sometime last month.

I can only recommend it to everyone interested in ‘hard’ science fiction, but you should take a bit of time for this – I read the 476 pages within three days after buying it, spending every free minute (and even some dedicated to sleep) reading it.


I don’t intend to spoil it to you too much, so here’s the books descriptions:

Ryland Grace is the sole survivor on a desperate, last-chance mission–and if he fails, humanity and the earth itself will perish.

Except that right now, he doesn’t know that. He can’t even remember his own name, let alone the nature of his assignment or how to complete it.

All he knows is that he’s been asleep for a very, very long time. And he’s just been awakened to find himself millions of miles from home, with nothing but two corpses for company.

His crewmates dead, his memories fuzzily returning, Ryland realizes that an impossible task now confronts him. Hurtling through space on this tiny ship, it’s up to him to puzzle out an impossible scientific mystery–and conquer an extinction-level threat to our species.

And with the clock ticking down and the nearest human being light-years away, he’s got to do it all alone.

Or does he?

An irresistible interstellar adventure as only Andy Weir could deliver, Project Hail Mary is a tale of discovery, speculation, and survival to rival The Martian–while taking us to places it never dreamed of going.


I had an absolute blast reading it. I thought it was starting slow, but the story is picking up pace fast. The book is interesting throughout – I always wanted to know what would happen next. Exceptionally well-written too, though that’s maybe what is expected of a book of this caliber.


I really liked the amnesia-style storytelling structure of the book. Things were happening, and we were slowly getting more and more of the necessary context. It was mostly concise and very detailed in its world-building while being both interesting and building suspense throughout.

This may sound real bad in a bit, but I did like the book quite a lot. The world was consistent – mostly.

Warning: SPOILERS ahead. Skip ahead to conclusion if you want to avoid them.

Well, You have been warned. Good luck drawing conclusions, they are pretty out of context and all over the place.

Maybe-Wrong Science Facts

As this was recommended to me by a group of rationalists, they also criticized its science part especially. And, well … thinking back, there were a few confusing parts.

  • Someone else mentioned that the book got the ATP energy density wrong by multiple orders of magnitude. I don’t know, but wanted to pass it along - I wonder about its temperature resistance, actually. I don’t think ATP will still be just fine at multiple hundred degrees celsius. Also, what about the oxygen? Anyways …
  • I think I paid attention to it, but it was never explicitly mentioned if all of astrophage mass can be turned into radiation energy or not, or what happens to ‘empty’ astrophage.
  • I found it unusual that nitrogen levels increased at most marginally each time, instead of stagnation with infrequent breakthroughs. At least, that’s the setup in most bacteria penecilin experiments, so that’s where my intuition comes from. Can someone confirm/deny this gut feeling?
  • Someone else mentioned the noticable absence of checklists, which are quite commonly used in both aviation and space travel. Many of his ‘stupid mistakes’ could have easily been avoided.
  • I remember the beetle-farms to be made at least partially from xenonite, so how did they survive the journey?
  • Outside-sections of his ship were repaired with xenonite and he got very close to the other taumobia-80-infected ship. I would have expected at least these tanks (and later his full ship) to be contaminated again.

I’d gladly be proven wrong on any of these, feel free to write me a comment or mail!

Neglecting Their Main Job

Something I found at the very least weird was how they were barely starting to communicate around halfway through the book. And they were bound to continue like this for a while longer, by the pace they were going. I was wondering: “what’s stopping you from attempting to do some proper research, you established rudimentary communication after all”. But, well, they didn’t – and it turned out not to be necessary, but still.

Yeah I know. “Don’t berate someone when he’s successful” – it’s still a bad policy. I would have had a real urgency to get this solved first, even if I just made a new friend – he’s in a similar situation as well.

Overly Precise Physics Experiments

It really irritated me that he did ten gravity experiments first before confirming that yes, he is indeed subjected to about 1.5 gravities. I would have measured it once for a rough measure and thrice for maybe slightly more precise results – and he was only looking for a ballpark figure anyways!

Surprisingly Human

All things considered, Eridians appeared to be strangely human. Even when going by just Rocky, his psychology and behaviour seemed strangely human. I was expecting a culture-clash somewhat akin to what happened in Three Worlds Collide (which you should give a read). In the real world, even humans seem more alien than Rocky sometimes.


As you might have noticed, I really like this book, even though I have some … nitpicks. Maybe that is exactly why I like it so much? Anyways, go get it yourself and read it. Or ask me to borrow it – though I might have lent it to someone else already.

Favourite Quotes

I didn’t take notes when reading it, so no quotes today. But, you can find some very good quotes on goodreads.

Other Recommendations

If you’re interested in more ‘hard’ SciFi or want to compare my other tastes with how this book fits in, this section is for you.

I can absolutely recommend the following SciFi Books:

  • The Daemon series from Daniel Suarez
  • Everything from Greg Egan (I read Luminous, Diaspora, and parts of Axiomatic)
  • Everything from Ted Chiang (I only read Story of your Life and others)
  • The Foundation-series from Isaac Asimov, and other books from him in the same universe
  • Die Optimierer from Theresa Hannig, which I think is available in German only
  • It’s been some time, but I’ve also read a few books of the Mark Brandis: Weltraumpartisanen-series. Appear to be available in German only

I had high expectations for Zero from Marc Elsberg (the author of Blackout, which I really liked), but it turned out to be a disappointment. I’ve also been told that Enders Game is way better than the movie, and it’s a shame I didn’t get to reading it yet (Today I Learned: it’s a whole series, not just a single book, huh).

You can find a lot more books I have read and reviewed here.