E.K. Johnston recalls precisely the moment she became a young adult author.

Johnston had written a middle-grade novel and had plans to start one for adults when she picked up a copy of Malinda Lo’s Ash, a 2009 fantasy novel that reimagines the Cinderella folktale with a lesbian teenager as the protagonist.

“I read it a little bit late,” Johnston recalls. “I read it in 2010, and I remember thinking, Oh, you can do whatever you want to in YA. That’s when I started writing YA books.”

She made her publishing debut in 2014 with The Story of Owen: Dragon Slayer of Trondheim; a sequel, Prairie Fire, followed in 2015. Johnston has gone on to release more than a dozen young adult books, including A Thousand Nights; Exit, Pursued by a Bear; That Inevitable Victorian Thing; and Aetherbound, and five Star Warsbooks, most recently Crimson Climb.

Johnston returns to outer space in her latest, Titan of the Stars (Tundra Books, May 27), the first volume in a planned duology. The novel follows passengers aboard the Titan, a spherical spaceship traveling from Earth to Mars with an eerie cargo—the recently discovered bodies of aliens, preserved in permafrost, are on display for the humans to gawk at.

The book switches perspectives between two teenagers on the expedition, both survivors of a deadly earthquake in Canada. There’s Celeste, a junior engineer from a hardscrabble background, and Dominic, the adopted son of a wealthy, politically influential couple who has just broken up with his insufferable boyfriend, Adam. When the voyage goes terribly awry, Celeste and Dominic are forced to team up and fight for their lives. In a starred review, a critic for Kirkus praised the novel as “riveting and thoroughly enjoyable.”

Johnston talked about Titan of the Stars via Zoom from her home in southwestern Ontario, Canada. Our conversation has been edited for length and clarity.

What was the origin of this novel?

It’s actually an intellectual property with David Purse and [his story studio] Inked Entertainment. I was hired to do a book packaging thing, and the pitch was Alien meets Titanic. They had a whole proposal, and I read through it, and I was like, “Here are the 14 things I want to change.” And every single one of them, David was like, “Oh yeah, you can do this.” When we got to the last one, he was like, “That’s a sequel.” So it was originally book packaging, but it was definitely Take this and run with it, which was really cool.

Did either of the main characters come to you first?

That was actually one of the things I changed. In the original pitch, [Dominic was the engineer], and when I was talking to David the first time, I was like, “I’m going to flip the main characters. There’s no compromising for me on this one,” and he was like, “That’s perfect.” As soon as I flipped it, I started getting into the worldbuilding. I already had the characters’ names. Usually when I’m making up my own characters, the naming process helps me develop a lot of who they are, but I skipped that with these two. Instead, I gave them strong origin stories.

How did you go about capturing Celeste and Dominic’s distinct voices?

Celeste was the easy one: I knew what she was going to sound like. She’s very sarcastic and a little bit more worldly; Dominic is also very worldly, but his knowledge hasn’t come from his own suffering. He has a lot more optimism than Celeste does. They’re both very driven, just in very different ways. I wanted Dominic to have a very particular [Canadian] prairie accent, which you can hear. It’s kind of like the Minnesota accent, but more sharp. It’s based out of Saskatchewan. If you watch an episode of Corner Gas [an early aughts Canadian sitcom], it’s like that. The Alberta accent is a little bit more posh, and that’s the version that Dominic has. He’s a little bit more considered when he speaks. He’s less likely to hurt people’s feelings, whereas Celeste is just a straight line to the target and it doesn’t matter what’s in the way.

How did you decide to write the book in the first-person present tense?

I started in third-person past tense, and I got to 30,000 words and it was not going great. I spent three months just in agony. One day I made a batch of my favorite cookies and then I went to my computer and I deleted the whole thing. I ate the whole batch of cookies and started over again in first-person present, and it was instantly better. It’s the only time I’ve ever done that.

This isn’t the first time you’ve written a book that takes place on a spaceship. What’s the process for coming up with each individual vessel?

I love taking things and turning them into spaceships. I always want them to have interesting shapes. When it came to Titan, I was like, What’s the most wildly impractical thing that people would do that’s super not useful for everybody who has to work there, but it looks great and it feels cool and it works in zero gravity? That’s where the idea of Titan being a sphere came from.

The other two spaceships that I’ve designed recently are in my Star Wars books. I use a lot of people’s houses. In Aetherbound, the space station was the Toronto transit map, reused for a space station. In the other science fiction book I have coming out this summer [Sky on Fire], one of the spaceships is basically the Ring Road around Iceland, and then the other one is based on the Olympic rings.

Some of the characters in the book, like Dominic’s parents and Adam, are just unbearable people. Is it at all fun to write them?

Adam just says the worst possible thing imaginable every single time. He’s just awful. You can almost tell what he’s going to say before he says it because it’s going to be garbage. And for Dominic’s parents, it was a little bit therapeutic because Dominic’s mother is based on a real-life Alberta politician, so I got to work through some stress with that. It’s not the first time I’ve done that. That happens in a bunch of my books, actually, where there’s someone that I’m mad at, and I make them a villain who gets yelled at a lot in the book. That’s not when I’m doing the campyStar Wars villains; those are a different class altogether, and they’re super fun. But when you do a more human villain, you get to lean into all of the things that annoy you currently. And then you get to have them get torn apart by aliens, because they deserve it.

Have you started writing the second book yet?

I have. It’s been fun. It’s a little bit different; it’s a slightly different style of horror. This was spaceship horror and sort of monster horror, whereas the next one is going to be horror in a different way. But I’ve been having fun spooling it out and figuring out what these people are going to do next.

Michael Schaub is a contributing writer.