In the newly released The Martian, a stranded astronaut must figure out how to survive on the Red Planet after being accidentally left behind when the rest of his crew escapes a violent dust storm. Explorer Mark Watney spends many months trying to make water, grow food and send an SOS signal back to Earth. Most of the tools he uses in the film, which opened Oct. 2, are based on existing or in-development technology. The one major exception is the radiation-blocking material that allows Watney to spend much of his days outside his habitat, on the surface of a planet that lacks Earth’s atmosphere and is thus bathed in significantly higher levels of damaging radiation.

“In the book they have this really thin, light, flexible material that blocks all radiation,” says Andy Weir, author of the book The Martian on which the film was based. “There’s nothing even remotely like that in the real world. That was the magic I gave him so the story would progress. Otherwise Mark would have different kinds of cancer.”

Scientists differ on how dangerous the radiation levels on Mars would actually be for future explorers. The first on-the-ground radiation measurements came from NASA’s Curiosity rover in 2013, which suggested that astronauts who spent a year traveling to and from Mars and 500 days on the surface would receive a radiation dose of about one Sievert, equivalent to a roughly five percent increased lifetime risk of cancer compared to a lifetime of exposure back on Earth. NASA currently limits astronauts to no more than a three percent increased risk of developing cancer compared to the general population—after they reach this amount of cumulative radiation, they’re grounded. The space agency, however, is forging ahead with plans to send crews to Mars by the 2030s; among the technologies high on its list to develop for a Martian mission is better radiation shielding.

Scientific American spoke to Weir about the plausibility of a real-life mission to Mars, the prospect of space hotels and why he would never want to travel to the Red Planet himself. An edited version of the conversation is below.

How much of the technology Watney uses in the book and movie actually exists?

Pretty much all of it exists. The radiation shielding was the one magical technology I granted them. But otherwise all the technology is either current or scaled-up versions of what exists today.

Do you think humans will ever reach Mars?

Absolutely. The only question is when. But despite how I portray the missions in the book, I think the first manned mission will probably be a [multinational] effort like the International Space Station.

I suspect we lack the political will to send a manned mission to Mars right now. The money is not there, and NASA isn’t as well-funded as they used to be, but I don’t have any doubt that we will eventually get there. I’d like it happen during my lifetime but if it doesn’t, oh well. I’m just a little drop in the bucket when it comes to human history.

In The Martian, China’s space agency plays an important part in attempts to save Mark Watney. Do you think the Chinese might be the first to send people to Mars?

No. They are certainly capable, but I also question whether they have the political will to spend that much money. I do strongly suspect that by the time we go to Mars we’ll be cooperating with China.

Commercial space companies don’t feature much in the story. Do you think they’ll be a major force in getting to Mars?

Absolutely—commercial spaceflight is crucial. Companies like SpaceX say they want to drive the price down, and are vigilantly working to reduce the cost to get things into Earth orbit. That motivation is what will ultimately allow us to expand into our solar system.

Imagine if you could go up into space and spend a week at a space hotel for about $50,000. It would be once-in-a-lifetime trip, but a lot of middle-class Americans would do that. Suddenly, there’d be this huge market for it and that would cause even more competition in the industry and drive prices further down. We’re just at the cusp of a space boom, I think.

If this future comes to pass, would you want to go to Mars?

Oh hell no. I write about brave people. I’m not one of them. I have a fear of flying!