#andy weir

I used the calculator below and simplified thing by assuming they are always accelerating (the numbers do not get simpler, and only alter a little bit if we assume they were trying to reach a cruising speed. Do know Grace's age at recruitment only gets younger)

The article below explains a method where they weren't accelerating the whole time, so you can check that out for yourself!

Because it was 1.5g (book quote) over 11.9ly (real world), we know it was 13.13y to get from Earth to Tau Ceti, with 3.89y experienced, but we have a 1.75g to 1.5g range for the 10.2ly (real world) return to Erid: respectively 11.25y - 11.42y on earth, with 3.34y - 3.71y experienced. That's a total time slip ranging between 17.15y and 16.95y respectively. Less acceleration, longer trip, less time slip

It takes a minimum of 1.57g of acceleration to get the minimum time slip (book states that 16y after reaching Erid he is technically 71yo, but estimates he is actually 53yo: 71y -53.9971y = 17.0029y of time slip at absolute minimum). Hail Mary is designed for 1.5g, and the difference between the two is small. I'll just say Grace got his estimated age wrong, since he's not confident about it.

I see in the calculator 10.2ly at 1.75g takes the same fuel as 11.9ly at 1.5g (the trip Rocky gave Grace fuel for) in the same size ship, so 1.75 is our max upper limit since that's the max the fuel allows. If they spend a while in cruise they can accelerate faster and have more time slip, but I honestly have no idea how much acceleration the ship can handle. I just don't have enough information to go higher. They'd have to have been going like 4-5g for years to have the total 18y of time slip as the book claims, which is out of the question

His time in Tau Ceti is a minimum 78d or 0.21y (book count: 64d + >2w) based on this reddit comment:

He then had 32d traveling away from Rocky and 3d to handle the Taumoebas and decide to go back (book quote), then 56d (movie read from white board) return for Rocky. Minimum 0.46y in between the two big trips, but probably longer. I doubled the days in Tau Ceti for a total 247d or 0.68y upper limit between trips. The 55yo (relative to birth on Earth) at reaching Erid is a set point (book quote: 71yo -16y)

I assumed the time to launch the Hail Mary was 3-5y based on this reddit thread:

Steve Hatch says the Beetles accelerate at 500g until 0.93c (book quote)

The book has information on the rate of Astrophage usage, the presentation in the movie shows the exact amount of astrophage they want to make, the book describes exactly the amount of astrophage the Eridian's made. The movie claims giving the astrophage means Rocky gets on 5 years slower, which people seem to agree is bogus

After the recent hype over Project Hail Mary (which totally deserves it, go read the book if you haven't, or watch the movie if that's more up your speed, it's amazing!) I also decided to rewatch The Martian.

I watched it when it first came out, but it never pinged my radar as something super cool, you know? Maybe it's because I am not a huge Matt Damon fan (sorry!), maybe it's because I wasn't in the mood, maybe it was something else, who knows. But some friends and I decided to watch it again, and it was better than I remembered, so I figured I might give the book a chance too.

If you go into this book expecting to get the same level of energy as Project Hail Mary - don't. While somewhat similar on the surface (both characters somewhat awkward scientists, stuck in space, all by themselves, trying to solve a problem to survive), the tone of this book is very different. The Martian is about people coming together even when planets apart, not about aliens or fun adventures in space. Even if there is a lot of science in both stories.

To give a bit of a disclaimer here, I am not a very sciency person. I like space stuff as much as anyone, and having complicated systems (usually magic ones) is not new to me, but the science in The Martian felt a bit...boring. I don't know enough about it to tell if it's accurate, but in general, that side of the book was a bit of a let-down, since it was a lot of talk about various chemical reactions and physics and that sort of things that flew above my head and took me out of my book enjoying zone a bit. I get that using the science to survive is the main plot of the story, so I will fully embrace that it was just not for me. Good news is, if you are into that sort of thing, there was A Lot of science.

The other theme of the book is people and relationship between them, as well as what humanity can do to achieve its goals. If you ever listened to any, the book really reminded me of the NASA podcasts (shoutout to Houston We Have A Podcast - if you are interested in space, give it a try! It's very cool while not being super hard to follow) and the way a lot of NASA staff and astronauts talk about the work they do. Sure, it's a job, but you can see the passion behind what they do. And Andy Weir managed to very accurately reflect this passion in this story - the way people come together, the hours they put in to make sure everything is going to work, the nerve wracking wait to see if what you poured into your soul will work, the cooperation between countries. This is what takes the Martian from being sciency ramblings about surviving on Mars and making it a story worth reading.