# Andy Weir on Reddit (u/sephalon)

Part of Creators on Reddit, researched with Autumn (https://www.autumn.ai) from public sources. Updated 2026-11-07. Interactive version: https://www.autumn.ai/resources/creators-on-reddit/andy-weir

Andy Weir: Author, The Martian and Project Hail Mary.

- Reddit account: [u/sephalon](https://www.reddit.com/user/sephalon/) (Personal account)
- How we know it's theirs: [Their 2015 r/books AMA, posted from this account](https://www.reddit.com/r/books/comments/3m34oc/i_am_andy_weir_author_of_the_martian_ama/)
- Where they post, in the records we retrieved: r/books (446), r/IAmA (187), r/themartian (95), r/sciencefiction (49), r/ProjectHailMary (26), r/vexillology (15)
- Known activity in the posts we found: 2010 to 2026
- Wikipedia: https://en.wikipedia.org/wiki/Andy_Weir

## Moments

### u/sephalon in r/IAmA, May 25, 2021 · Cut idea

Replying to a redditor:

> Of all of the ideas for writing you've ever had, is there one you can say, undoubtedly, is the single worst idea that you decided to backpedal on? If so, can you share it?

> I had an idea for a guy who appears to be really lucky, but in the end it turns out his cat is really lucky and good stuff happens to the guy because the cat likes him.
>
> I decided not to develop that idea.

Full thread: https://www.reddit.com/r/IAmA/comments/nkva3o/comment/gzf1x8o/ · 1,483 points as of Nov 7, 2026

### u/sephalon in r/themartian, Jun 14, 2015 · Cut idea

Replying to a redditor:

> Hi Andy, thank you for a fantastic book. I don't believe it was ever confirmed in the book that the Ares 3 crew arrived back to Earth safely. Although I assume they do, was there ever any doubt or was it intentionally left to the readers assumption? How did the events of Ares 3…

> The only thing I had set in stone was that he would survive. Pretty much everything else was just made up as I went along. Including the Rich Purnell Maneuver. Originally my plan was for him to just survive until Ares 4 landed, and he'd just be there at their landing site.

(Excerpt.)
Full thread: https://www.reddit.com/r/themartian/comments/39rzyx/comment/cs5zkhp/ · 36 points as of Nov 7, 2026

### u/sephalon in r/books, Dec 4, 2017 · Lore answer

Replying to a redditor:

> Is there an In-N-Out Burger in Artemis?

> Hmm. Well there could be, but it would be expensive. They could ship in flour and salt to make the bread for the buns. But they'd have to import the meat. So it would come frozen. (Definitely no Wendy's in Artemis, then).
>
> A Double-Double has a quarter pound (pre-cook mass) of meat. That's 113g of meat. Plus another 50g or so of other imported material for the bun, sauce, etc. Plus the cost of the business itself. So that's about 160 slugs. There are 6 slugs to the (2015) dollar. So that means it's about $26.60 in shipping costs. That, plus the $3.50 it costs in the real world means getting an in-n-out burger in Artemis would cost you about $30 in today's money.

Full thread: https://www.reddit.com/r/books/comments/7hjh84/comment/dqrh46j/ · 646 points as of Nov 7, 2026

### u/sephalon in r/IAmA, May 25, 2021 · Own mistake

Replying to a redditor:

> I'm about 80% done with Hail Mary so no spoilers but how did you >!Come up with the physical description of Rocky?!< Also, I've asked this question on Twitter a few times but I guess you didn't see it - Time period of a pendulum is 2\*pi\*sqrt(l/g) right? At 346 oscillations in…

> Yes I got the pendulum wrong. I will of course go into exile as a result.

(Excerpt.)
Full thread: https://www.reddit.com/r/IAmA/comments/nkva3o/comment/gzf5t14/ · 105 points as of Nov 7, 2026