So, verdict - solid. Not as good as The Martian. Way better than Artemis. A decent enough story, let down by a long slow bit in the middle.
The slow bit was several chapters of Grace breeding taumoeba and cleaning fuel lines. I feel like that went on for way too long, and was even less interesting to read about than it probably was to actually do.
Also, why does Rocky say things like "Thank" instead of "Thank you" or "Thanks"? What Grace is hearing is the output he entered into his spreadsheet and voice synthesizer. So why did he tell the spreadsheet that that musical note was to be said "Thank" and not "Thanks"?
I'd say we've crossed the threshold of everybody reading it should have finished by now or stayed out until they did.
Let there be Spoilage
I think Grace got used to hearing the notes for the words they meant, as noted he stopped relying on the spreadsheet and at the very end was speaking with an organ to students. So because he knew the tone for "you" that wasn't what Rocky was saying so it's not how he transcribed it.
Mostly what I noticed was a very simplistic challenge/resolution pattern. Aside from the original problem (planet in danger), problems roll up and are solved right away. No onion layering of complexity. Additionally, up until the far middle, nothing goes wrong. A stark contrast to Watney, where he can't take a leak without a crisis. This made everything feel too easy both in present time and past for most of the story. Which also made the "surprise" problem less of a surprise, oddly enough.
We knew something bad would happen so Grace would have to go. Probably the best surprise was the final bit that got him there. Which didn't really change anything in the story.
Overall, it was a fun read. But didn't really have any tension, given the stakes. And as noted much earlier in this thread, not realistic as to how the world would react, based on what we saw with Covid.