A nit-picky, somewhat negative review of Andy Weir’s “Project Hail Mary”.

Note: do not read this review until you have completed reading the book! The book is a decent, fast-paced, entertaining SF story. Many people praise it; and it is already on track to be a Major Motion Picture. However, the book is structured around a slow reveal of many discoveries, both scientific and emotional. To enjoy the book, you need to experience these discoveries in their proper order. This review contains MANY SPOILERS. Really. LOTS OF SPOILERS!

Ergo, stop reading now, and read the book. While you’re at it, make your own list of nit-picks and complaints. Then we can compare notes.


So, person who has finished Project Hail Mary, welcome! When I read it, I was irritated by a whole lot of things about the book: Things that I thought were wrong; but more, things I thought were huge missed opportunities for an even better story. I took notes; and I’ve collected them here.


Let’s get rid of the editing flaws first. These would appear to be down to Julian Pavia, “my editor for this book” Weir says in the acknowledgements. Not big errors, but just wrong enough to break my flow in the early pages.

Kindle Location (KL) 129: “There are two more hammock-like beds mounted to the walls, each with their own patient.” Each is singular, this should be “each with its own patient.”

KL 129, “they’ve sunken into their bedding like I had.” Should be “sunk into”. Also “like I had” is awkward; if “as I had” sounds too fancy, “the way I had” would still be better.

KL 902, ‘area labeled “Cable Faring”’, and KL 922, “the Cable Faring area.” Both wrong; it should be “Cable Fairing” A fairing is a “structure whose primary function is to produce a smooth outline (https://www.merriam-webster.com/dictionary/fairing), not a place where cables travel or eat (“faring”).

KL 1319, “my body shined like a beacon”. Should be “shone”; “shined” is the past tense. (https://www.merriam-webster.com/dictionary/shined)

KL 3532, “He pumped his fist.” This is a continuity break; Weir has forgotten that Redell is “handcuffed to the table” (KL 3437). Should be, he tried to pump his fist and was brought up short by the shackles.

Oh, “picky picky picky” you say — yes, but this is the kind of stuff a professional editor should know. And as I say, these things broke my concentration.

Hot Stuff

Starting around KL 2153, Ryland Grace receives a cylinder from the alien ship. It’s “hot as heck!… not stovetop hot. But hot.” (later he says “over 100ºC”) and it smells strongly of ammonia. He gives these two facts zero consideration, as he tosses it in the airlock too cool. Then around KL 2422 be examines the cylinder, works out how to open it, finds inside a small 3D model of the local stars.

To convey his own origin, he uses a soldering iron to attach an arc of wire from Tau Ceti to Sol in the map. This alone struck me as nuts. I’ve used solder often. The stuff melts at 190C (average, some even lower). What in the world lets Grace think his solder won’t melt? It was obvious to this reader, and I think most readers, that “room temperature” aboard the alien ship must be higher than 100C. It’s the only way to account for the hot cylinder; there’s nothing about what they can see of Grace’s ship to suggest heating the cylinder before sending it over.

If that isn’t stupid enough, he then adds a model of a Petrova line to Sol in the map using — wait for it — “hard paraffin”. What?! That would have melted at the temperature of the cylinderwhen he got it, let alone the higher temperature back in the alien ship.

There are ways he could have added the arc without paraffin, perhaps a loop of wire. This bothered me for a whole chapter.

(Note that much later, KL 2491, he begins to work out how hot the cylinder must have been, “way higher than the boiling point of water”. But that comes after he has sent it back with his paraffin arc.

Hull abaloo

KL 2481, the Eridian ship wants to attach a tunnel to the Hail Mary. Somehow Grace concludes “They’ll need a sample of my hull.” Why? He has a spectroscope that told him immediately what the cylinder was made of (Xenon), why wouldn’t the aliens have something similar? In any case his solution is insane.

He grabs a tool belt and heads out for an EVA, where he uses a cold chisel in a place where “If I breach the hull here, it shouldn’t matter.” And he chisels out a 6-inch circle of his hull! This is just nuts. You don’t breach your hull for anything! Surely he could have found a sample of aluminum inside the ship, a cupboard door or something. This stunt bothered me for another whole chapter.

At this point I made a lengthy note about how he should find a way to print the periodic table in heat-resistant ink, circle the square for aluminum with an arrow to a drawing of the ship. Send that over.

Well, it turns out that wouldn’t have worked, because the aliens don’t see by light. Later the alien finds a way to symbolically express atomic weights as beads on a string. But Grace, a science teacher, should have at least considered the periodic table as a means of communicating.

Blind witness

Let’s go to KL 2727. The alien is just the other side of a barrier and they are about to meet, and Grace says this, which is the stupidest statement in the book, and will bother me the rest of the book:

“I should go back to the lab and find a camera, but come on. No one would have that presence of mind at a time like this.”

He has had HOURS while the alien aligned the ships and built his tube. But he never even considers recording any of this. He didn’t record opening the cylinder (the first alien artifact in history), he didn’t record the making of the tube, and he isn’t going to record this, the first meeting between the two species.

After the meeting (KL 2746) “I return to the Hail Mary… I pant and wheeze with excitement. I can’t believe what just happened.”

Right. And none of it was recorded. Nor is anything else, during the weeks he and the alien share the ship and establish a common language and work together to solve their big problem. There is no further mention of cameras or recording.

My comment somewhere around here was, Ryland Grace, if you ever get home, people will revile you and curse your name forever. And I think they would. Just for selfishly keeping these historic events, life-changing for two races, to himself.

Perhaps Weir felt this was appropriate as a way of showing what a self-centered, selfish jerk Grace is? Which he certainly is; but it seems impossible to me that anyone growing up in the age of YouTube and TikTok could fail to think “Video it!” for the most momentous event in human history.


It turns out that Rocky the alien “speaks with musical chords. While it’s very difficult to make a computer turn human speech into text, it’s very easy to make a computer identify musical notes and find them in a table.” (KL3220)

To drive this home, for the rest of this chapter Weir shows Rocky’s speech as musical notes. And not just “notes” meaning “single-frequency sounds” but specifically notes of the Western well-tempered scale, as shown by this passage (KL 4342):

“I don’t need the frequency analyzer anymore. That was an A-below-middle-C major fifth, followed by an E-flat octave, and then a G-minor seventh.”

At another point (KL 3387) Rocky is emotional and speaks at a lower pitch, which turns out to be exactly one octave lower. Weir has Grace say, “The octave is a universal thing,… means doubling the frequency of every note.” Well, yes and no.

Thus it is pretty clear that Andy Weir claims Rocky (and presumably all his species) speak in tones that Grace’s computer could identify using standard software. Which pretty clearly shows that Andy Weir knows nothing about musicology.

This is, simply, the most unlikely idea in the whole book bar none! There are so many specifics to the Western scale that the idea that a completely different species evolving in a completely different environment, would have settled on it for their universal language, is just… beyond impossible.

First, they appear to have settled on dividing an octave into 12 notes. That’s completely arbitrary. Yes, the octave, a doubling of frequency, is natural and universal, but to choose to have exactly 12 notes related by a ratio of the 12th root of 2 — why? They could have created scales with other numbers of notes in an octave, and if their ears are good, they could get more information into their speech by doing so.

Second, why on earth would they have settled on 440hz as the base of the system? They must have done so; otherwise the computer wouldn’t recognize a G-minor 7th or any other chord, without auto-tuning up or down.

It’s somewhat incredible that alien speech would be based on notes and chords. After all, there is no natural human language that ever did so. (Yes, there are tonal languages, where a bend of tone up or down adds meaning, but the bend is relative, not between specific notes.) What is truly incredible is that they would have chosen to base it on exactly OUR octave structure and scale.

Rocky’s language snapped my belief suspension hard. But there’s another musical issue.

It ain’t got that swing

Having established that Rocky’s people speak in human music structures, it never once occurs to Weir (or at least to Ryland Grace) to do what was screamingly obvious to this reader: play him some human music! What would Rocky make of a Sousa march, a Bach sonata, or any kind of music. It should at worst come across to him like scat singing, melodic nonsense syllables.

It is established in the “copyright trial” scene that Project Hail Mary has loaded the ship with all human documents, although there is no mention of audio files. But at least there should be music recordings in the personal effects of Grace’s crew mates. It’s just sad that Weir, having set up this very unlikely scenario, did not use it to full effect. I kept wanting that scene to happen and it never did.

And, let’s not be cultural imperialists here; so turn it around: Besides trying human music on Rocky, consider that, if Rocky’s people have any culture at all, surely they must have made an art form based on their speech. What does an Eridian poem, or a great oration, sound like to a human ear? Another wonderful dramatic moment that Weir fails to grasp. (Maybe the movie will do better?)


KL 4300: “During the decades that Rocky’s been here, he observed the system very well. He gave me all the information he’d accumulated. He cataloged six planets, noted their size, mass, positions, orbital characteristics, and general atmospheric makeup. He didn’t have to travel around to do it. He just did astronomical observations from the Blip-A.”

Wait, what? Earlier it has been firmly established that Rocky does not perceive light at all! His people evolved in a completely lightless environment, miles deep in a thick ammonia atmosphere. But here he is using highly sophisticated telescopes and spectroscopes. Which raises the question, What kind of astronomical instruments can a blind race have?

Obviously they can’t use sound for this; so what are their instruments? Do they have telescopes? And if so, what kind of transducer converts the focused image to sound for them to sense?

Later (KL 4562) it turns out that Rocky has a “camera” that captures a light image and renders it in texture that he can perceive. This explains how, if they could invent a telescope, they could “look” through it. But the problem lies earlier: how the hell did they ever conceive of, let alone perfect, optics at all? Since there were literally no optical sights for them to see, how would they invent the prism, let alone the lens or the mirror?

I can see no explanation that would account for a blind species living in permanent darkness, inventing the lens. Living in Stygian darkness, they literally have no motive to invent any kind of optics. There is nothing to look at.

Again, this incongruity bothered me and made it hard to focus on the book.

Animal magnetism

KL6028, “They haven’t invented the transistor yet…” Well what did they have? Certainly not the vacuum tube! If there is one device that will not, cannot, be invented at the bottom of 29 atmospheres of ammonia, it is the vacuum tube.

One can imagine how the Eridians might discover magnetism and even electricity. But they are stuck for switching elements. Electricity is if little use if you can’t open and close circuits and vary resistance. They might manage relays. But no way can they do vacuum tubes. In fact it is more likely they would invent the transistor first, given their skill in solid material handling and synthesis. But you need some kind of electronics to get a vessel up to the top of that atmosphere. You need stepper motors and servos, you need switches, you need batteries and generators (note that at one point Rocky repairs a generator from the Hail Mary).

In the dark

That leaves open the biggest question of all: how did they ever discover there was anything outside their world? They had to get to the top of the atmosphere somehow, and even then, what could they learn? The air gets thin, the temperature drops, there is a source of heat that comes and goes. That’s it. How would they know that there was a universe of radiant and reflective objects to look at? They’re blind!

At the very end, Weir tries to paper this over by describing a social or communal mind (KL 7518) in which multiple Eridian minds can merge to be smarter. I’m not buying it, and the lack of a good explanation of how Rocky’s people could have ever been motivated to invent optics, discover the universe, and invent space travel, remains a major flaw in the book for me.

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